JH600 Valve Problem

A week ago I was riding in Suzhou and started to hear a rattling noise upon arrival. I've had chain issues with the JH600 before (emailed some of you on the rubber guard issue), as well as general chain slack which has needed tightening. While out in Suzhou, it was tightened up once again but the tapping sound could still be heard on the way back to Shanghai.

Few days later I rode out to local mechanic in Shanghai to have him check the chain. We opened the front sprocket cover and could see the chain "jumping" a bit. Upon further inspection of the chain, it was obvious that as it rotated around the sprockets it went from being taught to loose to taught. Seems there was damage to the chain which created irregularities throughout. A call was made to the local Shanghai Jialing representative to discuss all the issues, and we agreed to swap the chain for a new KISS O-link.

The change was magical. There was more consistent pull through the gears and it moved from 1st thru 5th without effort. [FYI: Mechanic suggested I find a better chain lube which can penetrate the inner-core of the links and keep it properly conditioned.]

Pleased with my new ride I was off to install my new Taobao handguards, but the noise was coming back again, this time more noticeable. Louder now, I could tell it was coming from the front of the bike, and the sound was more clear. A pinging (Shit, my engine! :gaah:)

After handguard installation, I rode back home with one of the guys from the Jiaoji Lu Motomarket, and it was now loud enough that he could hear it from on his bike sitting next to me at the red light. He suggested it was the timing chain.

Next day I was back at the mechanic, and he checked the timing chain adjuster, but this didn't solve anything. Another call was made to the local Jialing representative, and he suggested to take it to Pudong to see "The Dr." He's The Dr. because he can confidently strip down a bike and reassemble before I can finish looking up translations of the first few parts that come off!

Rode out to Pudong to meet him with euphonius and watched him go into action. After opening up the bike to check, he determined that it wasn't the adjuster or the timing chain itself....but the 减压阀 (jianyafa) - the valve.

http://farm7.static.flickr.com/6001/...01fd52bf_z.jpg

Before the replacement could be sent from Chongqing, I was asked to bring the bike back to The Dr. so he can actually open the cylinder head to inspect the valve. This was done with amazing speed (The Dr. cursed Chinese engine design thru the whole process - he normally works on Japanese bikes which have much better design which makes working on them much easier). Well yes, it was as he determined - bad valve (see red circle below indicating area of issue which was loose and creating the rattle).

Enough backstory, on to the photos:

http://farm7.static.flickr.com/6008/...c63367a2_z.jpg

http://farm7.static.flickr.com/6139/...c8ebd586_z.jpg

http://farm7.static.flickr.com/6001/...52dd90f3_z.jpg

http://farm7.static.flickr.com/6004/...03248b47_z.jpg

http://farm7.static.flickr.com/6124/...a90919d9_z.jpg

http://farm7.static.flickr.com/6145/...8e999367_z.jpg

http://farm7.static.flickr.com/6140/...4d8398ec_z.jpg

http://farm7.static.flickr.com/6147/...9ac87c69_z.jpg

http://farm7.static.flickr.com/6023/...3d174cb0_z.jpg

Very interesting.

Do you know which actual part was loose and was therefore tightened/adjusted/replaced? The red circle seems to be highlighting something by the cam/rocker. Hard to tell, but is that a rocker arm to the right of the circle? (the vertical metal piece that appears to disappear near the base of the lower right valve).

I am guessing that the ticking followed the RPM changes? i.e., more ticking as RPMs increased, less ticking as RPMs decreased? Was there the same volume of ticking in any RPM, and was it consistent? (i.e., no missing ticking)

Not sure about the chain thing. If you are watching a chain go over the front sprocket when the bike is on the centre stand, at idle, in gear (with the rear wheel lifted), it might appear that the chain is tightening/slackening ... and you might see some "apparent chain slap" in the main run of the chain (the "slack" area between the two sprockets). This is caused by a load/no-load situation where the chain tightens to spin the rear wheel, but then the wheel speeds up and actually spins faster than what the chain is causing, so the chain momentarily slackens. Then the rear wheel slows a bit and the chain tightens to turn it, again. And so on. When a "slapping" chain (btw, it isn't really slapping) goes over a smaller sprocket, it appears to be occasionally lifting off the teeth.

BTW, a common situation happens when people "adjust" a chain when it is on the centre stand, using the owner manual's specs. The specs (usual free travel of about an inch) are intended for when the bike is resting on the ground with its riding weight (i.e., rider & gear). Obviously, you need two people (one to sit on the bike, one to measure the chain's play), but after you have set it with two people, throw the bike back on its centre stand and measure the chain play in its unloaded state. Depending on the geometry of a bike, a loaded bike causes a chain to be "loosen" because the distance between the sprockets decreases as the suspension compresses.

In my experience, one actually has to feel, by hand, each link to see if they move freely. If you can visually see a frozen link move over a sprocket, I'd have thought you'd hear it first. And I think there is considerable debate about using anything that penetrates an O-ring.

BUT .... if you noticed a big difference with the new chain ... hmmmm. Interesting. Did you inspect the old chain? Were some links indeed frozen?

Anyways, thanks for the info re our lovely JH600s. Fortunately, we haven't been freaked out by anything near the BMW 650GS fork problems that seem to have recurred. Check this out for a scary story ...

BMW front fork failure.

Quote:

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Originally Posted by Lao Jia Hou

Do you know which actual part was loose and was therefore tightened/adjusted/replaced? The red circle seems to be highlighting something by the cam/rocker. Hard to tell, but is that a rocker arm to the right of the circle? (the vertical metal piece that appears to disappear near the base of the lower right valve).

I am guessing that the ticking followed the RPM changes? i.e., more ticking as RPMs increased, less ticking as RPMs decreased? Was there the same volume of ticking in any RPM, and was it consistent? (i.e., no missing ticking)

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Thanks for the input LJH.
I don't know the details of the actual part affected, just that it is with the 减压阀 (valve) and specifically the area I highlighted in red. At a certain point it gets lost in translation, so if anyone here has additional info, I'd be very interested to learn more. Something with the cam/rocker?? What usually causes this part to fail?

The ticking wasn't specifically related to the RPMs as even after getting on the throttle I would sometimes hear the sound increase after letting off (when the RPMs were in fact lower). In general we couldn't detect anything consistent between the sound and the RPMs.

Quote:

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Originally Posted by Lao Jia Hou

In my experience, one actually has to feel, by hand, each link to see if they move freely. If you can visually see a frozen link move over a sprocket, I'd have thought you'd hear it first. And I think there is considerable debate about using anything that penetrates an O-ring.

BUT .... if you noticed a big difference with the new chain ... hmmmm. Interesting. Did you inspect the old chain? Were some links indeed frozen?

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Yes. I failed to mention that when turning the chain by hand around the sprockets, there was a squeak in the rear sprocket at one specific point. After replacing the chain, the old one was inspected and a frozen link discovered.

Hi MK

Upon looking at your pics again, it looks like the rocker arms were removed as an assembly when the top end was removed. Your valves will be under the four springs' caps, showing in the last pic, far away from the red circle. The red circle seems to highlight something on your overhead cam shaft, that is exposed/accessed by that little open tab. I am not sure what that little open space is for, or what is underneath that was the source of your problem. It might be driving something else off the cam's rotation?

I'm not familiar with the internals of the JH600 engine, having never taken mine apart (heaven forbid!), but it looks like the cam has only one node for both the intake & exhaust valves. I looked at that parts manual we all have, but it doesn't give a clear picture, nor a proper explanation. And, of course, it is all in Chinese.

My two-wheeled JH600 purrs without any glitch, but my sidecar JH600B has an occasionally noisy engine, emitting some strange noises. I've wondered about incorrectly adjusted valves on that bike, but then I thought that the JH600 engine didn't require valve adjustment maintenance? Hence, I am very curious as to what the source of your problem was, and how it was remedied. My "B" might be needing the same, or at least it is very helpful to know what you uncovered.

Cheers

This is definitely an issue of translation, compounded by our relative naivete (Motokai's and mine) about the inner workings of our engines.

I had a long conversation with Dr Cui, trying to understand the function of this 减压阀 (jianyafa), which dictionaries indeed translate as "valve". Cui confused the hell out of me by insisting that the JH600 "has only one valve" -- when I knew perfectly well that it has four valves. I was using the terms 排气 (paiqi exhaust) and 进气 (jinqi intake) but couldn't remember the full term for the respective valves -- 排气门 paiqimen and 进气门 jinqimen. So Dr Cui stood his ground and insisted that there was "only one valve".

So if the thing in the red circle is indeed something referred to in Chinese as a 减压阀 (jianyafa) aka "valve", what function would that valve have and what might it be called by a competent English-speaking motorcycle mechanic?

Oh, and for the record, as Motokai and I rode home that day, with my own senses heightened by Motokai's predicament, I could hear through the lovely exhaust thunder a clattering of engine sounds, the sounds of metal banging on metal, of gears being put to the test. Not the same tapety-tapety that MK's JH was making, but a quiet symphony of its own. She's running beautifully.

cheers

Exchanged sms today with nostalgia, as he's arranging a moto event this weekend in Shanghai (Ferarri Festival @ F1).
After telling him I may not be able to attend due to the above matter, he provided some consolation since his JB already went thru some work related to his 减压阀(getting interesting LJH?).

Check out this link to see more of Dr. Cui's work, in particular what he's done on nostalgia's JB600: http://www.mychinamoto.com/forums/sh...ll=1#post18041

Hoping in the next day or two to get a bit better understanding of "what that little open space is for [and]....the source of [my] problem."

The little open space: 这个叫凸轮轴减压器,作用是当摩托车起动时,让排气门打开,使起动转速快速达到规定转速,当车发动以后,这 个减压器就不起作用了
The function of the camshaft regulator (凸轮轴减压器) is only to open the exhaust valve when the motocycle starts, so that the motobike can accelerate from its start speed until it reaches a steady fast speed.

Quote:

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Originally Posted by MotoKai

The little open space: 这个叫凸轮轴减压器,作用是当摩托车起动时,让排气门打开,使起动转速快速达到规定转速,当车发动以后,这 个减压器就不起作用了
The function of the camshaft regulator (凸轮轴减压器) is only to open the exhaust valve when the motocycle starts, so that the motobike can accelerate from its start speed until it reaches a steady fast speed.

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I did a quick Google search on "camshaft regulator" and discovered that it relates to sensing engine timing on EFI engines. I'm old school, and can fuddle my way around old technology, but whenever EFI or ECM stuff comes along ... it's off to the experts.

So, the camshaft regulator probably sends info to the ECM, or EFI, or both, to alter fuel delivery? I can't see how opening a valve (which is a fixed mechanical event) can be modified by the engine ... but, then again, there is something out there called "variable valve timing" (VVT) on certain cars. Who knows how that works? Maybe the cam is multi-piece and can rotate internally, adjusting the camshaft lobes' effect for valve timing?

The magic of an engine always comes down to that combustion chamber, that requires all valves being closed during the compression & firing strokes. But the timing of when intake & exhaust valves open is supposedly controlled by the camshaft spinning around, with its bumps (lobes) lifting one end of a rocker arm so that the other end of the rocker arm pushes down the valve (to open it up to allow fuel/air to come in ... or just air in an EFI engine .... or to allow exhaust gases out). Back in the old old days, there were mechanical thingies that advanced/retarded timing of ignition. I have no idea how it works now.

Re the 600B ... yeah, I saw that depressing post by nostalgia. I've toyed with the idea of swapping out the B's entire engine/tranny/controls for a regular JH600 engine. Jialing says it can't be done, but I've some contacts in the military that say they have done it. One loses the reverse gear, but that is ok.

Thanks very much for sharing your experience. I really feel helpless without an English service manual for these bikes. Bit by bit, though, we can learn from each other.

Cheers

i think what you are looking at there is the decompressor which holds open one of the valves when the engine is spinning on the starter.
it should then allow the valve to operate normally once the engine fires

and yes it will make a hell of a racket if it gets out of line

Quote:

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Originally Posted by zhu

i think what you are looking at there is the decompressor which holds open one of the valves when the engine is spinning on the starter.
it should then allow the valve to operate normally once the engine fires

and yes it will make a hell of a racket if it gets out of line

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thanks, zhu.

I'm looking at the exploded diagram of the JH600 upper head, with the camshaft and valve assemblies, and can see this part clearly. Alas, I cannot make out in the diagram how it is activated and how it links to the intake/exhaust valves. I've googled a bit for "decompressor single-cylinder four-stroke motorcycle engine" and the like, but not found anything truly instructive.

So what you and Lao Jia Huo seem to be saying is this mechanism intervenes in the normal exhaust/intake valve operations during and only during startup to achieve some desired effect, such as, err, starting up the engine? Or starting it up more efficiently/smoothly than in the absence of this mechanism?

EDIT: Hmmm, I do have contacts for a guy here in Shanghai who's with the liaison office of AVL GmbH, which provided the design and engineering for our JH600 engines. I'll try again to track him down.

Motokai and I did get a glimpse recently of the phone-book sized JH600 shop manual, all in Chinese of course, and damn I'd like to lay my hands on one of those. The guy who is working on Motokai's engine does NOT have one of these shop manuals. There's probably only one in all of Shanghai.

Wonder if Jialing would sell me one, as they did with the service parts catalog?

cheers

yeah what the decompressor does is allow the engine to get a bit of momentum as it dosnt get slowed down by hitting the compression stroke for the first few revolutions.

how it works.. is the problem as they are a complicated arrangement of levers cams springs and other assorted piblets

all of which are prone to sticking or failing to work in the advertised manner

such is the joy of 600 singles

Quote:

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Originally Posted by euphonius

So what you and Lao Jia Huo seem to be saying is this mechanism intervenes in the normal exhaust/intake valve operations during and only during startup to achieve some desired effect, such as, err, starting up the engine? Or starting it up more efficiently/smoothly than in the absence of this mechanism?

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Hmmm - I'm missing something. How does an engine fire without compression? Certainly, the starter would more easily turn over the engine with less/zero compression ... so maybe opening one valve decreases compression enough to ease the starter load, but there is still enough compression to fire? Maybe without this mechanism, the bike would need a huge battery & starter motor?

Quote:

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Originally Posted by euphonius

Motokai and I did get a glimpse recently of the phone-book sized JH600 shop manual, all in Chinese of course, and damn I'd like to lay my hands on one of those. The guy who is working on Motokai's engine does NOT have one of these shop manuals. There's probably only one in all of Shanghai.

Wonder if Jialing would sell me one, as they did with the service parts catalog?

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OMG - I'm in. I will also ask Mr. ZHT in Beijing if it is possible. This would be enough motivation to learn to properly read Chinese. MUCH more important than a menu!

Quote:

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Originally Posted by zhu

yeah what the decompressor does is allow the engine to get a bit of momentum as it dosnt get slowed down by hitting the compression stroke for the first few revolutions.

how it works.. is the problem as they are a complicated arrangement of levers cams springs and other assorted piblets

all of which are prone to sticking or failing to work in the advertised manner

such is the joy of 600 singles

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ah, ok - thanks a LOT zhu. This site is always helpful.

Cheers

Speaking of the JH600 engine, I just had a look at the website of the Austrian designer AVL, and came across an amazing description of their Shanghai technical center. Turns out their roots in China go back to the company's founder Hans List, who actually lived in Shanghai between the wars a decade before he started AVL in Graz! Damn, I would LOVE to organize a Jialing owners' "field trip" to their tech center...

cheers!

Quote:

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AVL's business relationships with Chinese customers have been enhanced by the establishment of a new purpose built technical centre in Shanghai.

The founder of AVL, Professor Hans List, began making contacts in China from 1926 when lecturing and researching at Tongji University, Woosung(Shanghai). He lived in China from 1926-1932.

AVL List GmbH was set up by Prof. List in 1947 based in Graz-Austria. Business relations with potential Chinese customers were reestablished in 1974 and actual contracts started to be undertaken from 1975. In 1985 AVL opened a sales office in Beijing.

Today AVL China consists of sale offices through out China and a technical centre formally known as AVL List Technical Centre (Shanghai) Co.,Ltd. based in the Pudong area of Shanghai approx 30 minutes drive from the new international airport.

The main activity of the new Technical Centre is the design, simulation and development of both petrol and diesel engines used in all forms of transport and industrial applications. The work in the Technical Centre is performed in close collaboration with AVLs HQ in Austria. The inter-reaction of staff between the two locations and other AVL affiliates is key to AVL's success.

Using AVL Technical /equipment engine test beds and vehicle chassis dynometers are already in operation upon which customer projects are being carried out.

The new Technical Centre not only implements its own projects, but also sees itself as a bridge between the headquarters in Graz and business partners in China. This ensures both better understanding of the requirements of the Chinese market and personal customer care. The offer of the option of working at clients' test beds and factories both underlines the Centre's strong focus on customer service and helps business partners leverage for significant cost reductions.

By helping Chinese firms to build up their own research and development facilities, and supporting customers all the way through to the manufacturing stage, the China Technical Centre will be laying the groundwork for its future business activities.

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The exhaust cam arrived today from Chongqing, so went over to Dr. Cui's to watch and learn. Here's a recap of the chinese parts and what I have gathered is going on. [Feel free to chime in with clarifications and any additional insights.]

减压阀 Pressure Reducing Valve
排气门 Exhuast Valve
凸轮抽 Exhaust Cam

As a reminder of what was the diagnosis from last week, see the below photo once again with the red circle indicating area of issue which was loose and creating the rattle.

http://farm7.static.flickr.com/6023/...3d174cb0_z.jpg

The part which was sent from Chongqing is a new 凸轮抽 Exhaust Cam. Which up to a limited rpm (approx 1500) will control the 排气门 Exhuast Valve to achieve the right amount of decompression during this critical stage.


http://farm7.static.flickr.com/6130/...4b800fb0_z.jpg

The red circle again indicates the original point of rattle detection. Once the new Exhaust Cam arrived, Dr. Cui went in and pulled out the old one allowing the core of the problem to be realized. The part indicated with the yellow rectangle [this is the piblet Zhu referenced above] is supposed to turn (spin) over the Exhaust Cam Shaft controlling the opening and closing of the exhaust (see red circle), but wasn't working properly. This was causing the piece in red to be "loose" and thus create a rattling sound.

After the new part install, Dr. Cui checked my pulg (a NGK spark plug which I purchased at the Shanghai Motomarket on Jiaoji Lu), and it was pretty shot. Most likely this was a fake plug, as I only used it for about 7,500kms and the center electrode was ratty. It was replaced it with a new imported Denso Iridium plug and the Doctor put her back together.

Test spin felt great. There was power back that I didn't realize was lost. And of course the rattle-tinging sound was gone.

So, was it a bad plug the problem that triggered this? No. Jialing rep smiled and said, 你就是骑了太猛。 (fierce riding). Guess I'll have to keep reminding myself it's just a one-banger! But sometimes I just keep chasing that Honda VF500F V4 feeling of days lost.

[Also worthy of mention is the comment after Dr. Cui's first ride on the JH600, 它有力气! (The bike has strength). And this is a guy who repairs and tests out crotch-rockets.]

Thanks a bunch for this info MK. It is truly helpful.

Damn, that cam (and associated "piblets") looks complicated. My farmer Honda 125 is getting more love each day - she might not be the fastest or the prettiest on the dance floor, but she's easy to understand & always reliable.

Real bummer about the fake plug.

Yeah, on the few times I've really pushed my JH600 aggressively, it protested by acting a little weird for a period of time afterwards. Sort of like a teenager pouting. But if I hugged it, and said nice things to it, it returned to normal.

Re service manual: went to Jialing service centre in Beijing last weekend. ZHT wasn't there, but a snarly mechanic was. I asked about the service manual, and he snarled "Hah! Why would I need one of those things?" Oh ... my ... god. I will wait until ZHT is back.

I'll ask our Jialing guy here in Shanghai about availability of the shop manual.

Congratulations on the happy ending of your valve/cam/阀/门/抽 woes.
I made real effort in trying to follow those discussion on various piblets of our JH600 and failed. Fortunately I still have the phone# of Dr. Cui's.
Cheers!

Quote:

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Originally Posted by Lao Jia Hou

I will wait until ZHT is back.

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Got the service manuals for both the A and B - will try to get them into an e-format in the coming days/weeks/months/years (I've never done it before).

My JH600 has been stalling like crazy recently, usually during idling or downshifting. I had a new spark plug put in and replaced the following with genuine Bosch parts:
1. cps crankshaft position sensor (曲轴位置传感器)
2. tps throttle position sensor (节气门位置传感器)

Both may affect the idling performance of the bike but did not make much difference to the problem.
Dr. Cui took a listen to the engine and suspected that it might have the same 减压阀 (valve) issue. I will need to take my bike in for an inspection on that valve. It involves some major disassembling and probably takes a few days.
Wondering if this has anything to do with my JH being black.

Quote:

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Originally Posted by milton

My JH600 has been stalling like crazy recently, usually during idling or downshifting....

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同情！Since fixing the original problem with my 减压阀, my bike stalls more than ever now. Also have a problem getting it started from time to time. It turns over and over and over taking multiple attempts before catching (sometimes as long at 30seconds).

Last time it happened was on Saturday when I was in traffic on a busy highway - switching lanes at low speed (downshifting from 3rd to 2nd). There I was sitting in between lanes with trucks and buses trying to slalom around me (honking their horns). After about 20seconds of thumbing the starter it finally caught and I moved over safely. Not sure why this stalling problem is happening now, but guessing that it's related to the 减压阀 since this was just repaired.

[Edit: Agree with euphonius (see below) that I will start documenting the problem - frequency and other related data]

Damn and double damn.

My bike stalls from time to time, but why would it be that mine stalls so much less than yours.

Perhaps we should try to quantify the problem with some data on how often it happens to each of us. Then we can plan a class-action lawsuit. OK, maybe we just start raining down on Jialing like a ton of bricks.

How about other JH600 owners? Richard? David? Barry? Pfaelzer? Others?

cheers

sadly motokai the problem you had before may have caused some valve damage

if its stalling and hard to start you may have a leaking valve... you can test for this by giving it a compression test, which is a bit tricky with an auto decompressor for obvious reasons

so the only way is to give it a leakdown test

that is pressurise the cylinder at tdc and see if its leaking
if your lucky you may find a workshop with a leakdown tester , if not you can use any source of compressed air attached to a gutted out spark plug

Quote:

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Originally Posted by zhu

sadly motokai the problem you had before may have caused some valve damage

(snip)

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Dear Zhu,

Interesting hypothesis. What would be the mechanism by which the decompression valve fault would cause damage to either intake or exhaust valves? A chunk of the failed part gets flung into the valves during the piston's upstroke?

Damn.

Quote:

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Originally Posted by zhu

sadly motokai the problem you had before may have caused some valve damage

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Your response has me concerned. But here's my optimistic afterthought:

Since I have refueled twice since the repair, I'm hoping it's "Bad Gas" on the last one.
But to be honest with myself, the bike is reacting different from the normal JH600 "Bad Gas" symptoms.
She'll be going on the train this week (heading to Beijing), so after I siphon out the remaining fuel of the last fill and get some new fuel in her, I'll see how she reacts.

Double-post deleted

guys i really hope this is not the case but if the decompressor malfunctions it could hold the exhaust valve open slightly and cause it to be burned
result of this is loss of comp = stalling and hard starting

hope this hasnt happened , but as i said you can check by testing the cylinder sealing at tdc

Both my 2-wheeled "A" and my 3-wheeled "B" are stalling much more frequently these past few weeks. Very odd that it seems to be happening simultaneously with several bikes, both in Beijing and Shanghai.

How can this be? Both of my JH600s were running fine until recently. The stalling and hard starting are way more than before. What has changed?

What makes a bike run? Compressed fuel & air, ignited by a spark at the perfect moment.

Is there any way that this high summer humidity can be wreaking havoc with our mixture? Wild shot in the dark, but I'm grasping at straws. We know altitude affects mixture ... etc, etc, etc. It is damn hot & humid in Beijing these days, and I'd guess the same in Shanghai.

Look no further than the great bar scene in Hitchcock's The Birds, when crazed birds are attacking everyone in town (in little Bodega Bay, Sonoma County).

A drunk Scot at the bar:

"It's the end of the world, I tell you! The end of the world!"

Or not.

cheers

Just out to get my Du Rui racks fitted (BTW: don't try to install these racks the same way as the stock racks!), and she stalled on me at every fourth stoplight - about 7 times in total back and out. Would have been more but I jumped on the NeiHuan when returning as I needed to get back to the office and didn't want her to stall any more.

Also, after fitting the racks she wouldn't start at all....firing and firing but no start. The other Jialing owner I was with (Master Zhang), pressed the dashboard controls in a certain sequence to bring up the diagnostics check. This is probably in the owner's manual but I didn't get past page 4! I'm sure LJH you can find it in the Service Manual. The dashboard readings showed a series of error number which he then cross-referenced against a chart he kept on his HTC. It showed that the problem was indeed the battery. After a quick charge off of his mianbaoche I was on my way.

So......I throw this into the conversation. LJH mentioned "heat" as a culprit which in fact puts the fan to over-use. Could this (or something else) be drawing some needed current away from the "core" causing stalls and making starting difficult? [Sounds better than a decompressor problem.]

* P.S. During the valve repair the coolant was dumped out when they removed the radiator. After putting the bike back together, the fluid was replaced with H20 rather than coolant. Could this have an effect?
The other thing that was changed was the spark plug. Any relation?

* P.S.S. I'll get the dashboard sequence and the reference chart from Master Zhang and distribute here for our use.