JH600 Valve Problem

[Bart Sanders]

Dear all,

The "valve problem" turns out to be an automatic decompressor problem, right?

We may have it as well. Here's the text I have mailed to my support guy at Jialing.

My question to you is if you can deduct from what I write, if it is the autom. decompressor or even a combination with some problem in the motormanagement (nozzle, sensor etc.). Here we go:

We are in the process of making many testkilometers with our two Jialings.

Up to this afternoon, all was very fine. And then the JH600 solo broke down.

What has happened:

This morning we started for a 5 days holiday in the Eifel, the city of Prüm. Me driving the JH600B and my wife the JH600. On the way to Prüm, in the city of Malmédy in Belgium, we stopped at a gasstation to fill up both bikes.

When we wanted to start again and follow our road, my wife could barely start her JH600 solo. And when it started and run in idle mode, she could not increase the revs, turning the gas handle resulted in dying of the engine and it stopped each time.

Now I pushed the bikes aside and turned my full attention the her JH600 solo.

Both bikes are now at ca. 800 km and both bikes got an oil change at 500 km according to the grinding in instructions in the Users and Maintenance Manual. The oil out of both engines was still quite clean and on the magnetic oil plugs only very little metal particles had accumulated. From this I read that the engines are grinding in fine.

These are the facts we have observed at the gasstation:
1. Up to the stop at the gasstation the JH600 ran fine. I asked my wife if she had observed some misbehaviour, anything. She reported nothing special was noted by here when driving all day.
2. When she turned off the engine, she did not hear anyting unusual.
3. When she started the engine again, I was in front of her and I could here the startmotor, the click of the engine starting mechanism and I heard some tickling noises which were never there when the engine started before.
4. However, when it started, it idles at ca. 1800 revs/min.
4. Very carefully opening the gas did increase the revs/min. but at ca. 2.500 revs/min. the engine suddenly dies and stops. Consistently.
5. When turning off the engine, one has to hear a quite loud click just before the engine is silent, there are now two (!) states:
5A. There is the loud click
5B. There is NO click at all.
6. When state 5A is present, the engine can be started again. However, the strange tickling noise is present just after the engine started and then this strange noise vanishes.
7. When state 5B is present, the engine starting motor can not start the engine. It does not turn the crankshaft over, one hears that the startmotor tries, but the power is insufficient and the lights dim a lot.
8. The battery is 100% OK and fully charged.
9. For both states 5A and 5B the engine can not be reved up anymore past 2.500 - 3.000 revs. It always dies in this range.
10. Driving is impossible and we had to leave the JH600 behind at the gasstation and pick it up in the coming days.

Anybody any idea were to start looking or better to tow it away back home?

Best regards,

Bart

[Lao Jia Hou]

The "valve problem" turns out to be an automatic decompressor problem, right?

Yes, that is my understanding.

These are the facts we have observed at the gasstation:
1. Up to the stop at the gasstation the JH600 ran fine. I asked my wife if she had observed some misbehaviour, anything. She reported nothing special was noted by here when driving all day.
2. When she turned off the engine, she did not hear anyting unusual.
3. When she started the engine again, I was in front of her and I could here the startmotor, the click of the engine starting mechanism and I heard some tickling noises which were never there when the engine started before.
4. However, when it started, it idles at ca. 1800 revs/min.
4. Very carefully opening the gas did increase the revs/min. but at ca. 2.500 revs/min. the engine suddenly dies and stops. Consistently.
5. When turning off the engine, one has to hear a quite loud click just before the engine is silent, there are now two (!) states:
5A. There is the loud click
5B. There is NO click at all.
6. When state 5A is present, the engine can be started again. However, the strange tickling noise is present just after the engine started and then this strange noise vanishes.
7. When state 5B is present, the engine starting motor can not start the engine. It does not turn the crankshaft over, one hears that the startmotor tries, but the power is insufficient and the lights dim a lot.
8. The battery is 100% OK and fully charged.
9. For both states 5A and 5B the engine can not be reved up anymore past 2.500 - 3.000 revs. It always dies in this range.
10. Driving is impossible and we had to leave the JH600 behind at the gasstation and pick it up in the coming days.[/SIZE]

Prior to my "B" getting a new decompressor assembly (reference the stalling issue thread), when I turned the bike off, there would be a noticeable "clunk" from the engine. There was also excess engine noise (not really a ticking, per se, but more like a "loose" valve train). I think Motokai had a highly noticeable ticking. My "clunk" and "noise" seems to have disappeared after the decompressor/cam replacement.

It is very interesting that it appears the JH600's starter does not have enough "ooomph" to turn over the single cylinder unless the decompressor is activated, if that is what is happening in your case (i.e., decompressor is NOT activated, therefore not allowing the starter to turn the engine over). Presumably, that is the theory behind the decompressor - release some of the compression to permit the low-power starter to turn over the engine.

BUT ... why would it die again at around 2500 RPM?

I think the theory is that the auto decompressor retracts from centrifugal force when the engine rotates over a few hundred RPM. Maybe yours is not? And maybe it is re-engaging at that higher RPM?

You say that it now idles at 1800 RPM ... what was the idle before this issue arose?

Really sorry to hear about getting a new bike stranded, far from home. Well, at least you speak the language!

[Bart Sanders]

BUT ... why would it die again at around 2500 RPM?

I think the theory is that the auto decompressor retracts from centrifugal force when the engine rotates over a few hundred RPM. Maybe yours is not? And maybe it is re-engaging at that higher RPM?

You say that it now idles at 1800 RPM ... what was the idle before this issue arose?

Hi! Thanks for your reaction. Indeed, strange behaviour at the 2500-3000 rpm dead stop. You describe the function of the auto decompressor correctly. I also think that it is "kaputt" and one of the valves open. The engine runs "a bit" but as soon as serious power has to be developed, it dies. One can not drive away in 1st gear, it dies immediately.

Both our 600B and 600 solo have an idle of around 1800 rpm, out of the box. We are testing the bikes and I do not want to tamper with ex-factory settings. To our belief, the idle of 1800 rpm fits the engines well.

I very much suspect the automatic decompressor to be busted.

[Bart Sanders]

Hi there!

I think it was Motokai suggesting to change the spark plug for an NGK Iridium version. Easy to shove this advice aside as "too far fetched" so I did not and yesterday I tried his suggestion. Alas, to no avail. The engine starts - when the decompressor wants to to its job - and then runs at 1800 rpm idling. Increasing up to 2.500 or so and it consistently dies.

Now, Jialing support today proposed that filling up the gas tank - which we did in the first place at this gas station - can also be done too much. Jialing states that when the tank is over-filled, gas may leak into a filter which serves EC-II environment ruling. If that happens, Jialing states that the engine indeed has a lot of trouble running.

Does anybody know about this problem, filling up the tank too full and then no revs anymore? Their solution is simple: get 0,5 to 1 ltr. of gas out, wait a while and then start again. The engine now should run fine again.

We can not test this yet, but it still leaves the large ticking noises we hear when idling.

Anybody?

Regards!

PS: up to now the Jialing JH600B performs fine, having 1265 km on the clock. Knock on wood.....

Anybody?

[euphonius]

Dear Bart,

Sorry to hear you are having problems with the 600A. I've never heard of this overfilling problem, and I'm one who likes to really top off the tank.

Who are you dealing with at Jialing? Do you think they are competent, or just making this stuff up? Do they have a strategy for addressing the problem? We're aware that they are starting to think about marketing this bike internationally, and plans are already under way to launch in Brazil. They'd better have a good service strategy or it's going to be painful! Are you considering a dealer relationship with Jialing for the Netherlands or Europe?

Good luck getting the bike back into riding shape!

Cheers!

[Lao Jia Hou]

Hi Bart

Hmmm - a couple of times I have filled to the brim without incident, but maybe I was lucky?

That ticking certainly points to something mechanical. And the fact that the bike wouldn't turn over, and the starter seemed to be drawing all of the battery's power (lights dimming), again points to the auto-decompressor not working. And, of course, the fact that some of us have already experienced problems with the decompressor.

Happy to hear your enjoying the B - I think those bikes are an incredible amount of fun!

[998S]

Overfilling a tank should result into the fuel being leveled off through a spill-hose.
This hose connects the top of he tank (actually the collar around the fuel-cap) to street level.
I am not sure on the Jialing, but should be very surprised if they did not have such precaution.

I further consider the reply you received as BS, it is impossible that overfilling should result into an internal flooding (presuming the bike has fuel delivery by either a vacuum system or a fuel pump). Internal flooding can only occur with a traditional pet-cock, or a dramatic failure in the fuel supply components.

Good luck solving it!

E.

[Bart Sanders]

Who are you dealing with at Jialing?

First of all thanks to all for thinking with me! Indeed, the first suggestion of overflooding some component was not correct, to say it politely. In any case it was not the problem. The tank indeed has a spill-over hose which runs to down-under the engine. Nothing special here.

No, the problem is much more serious. Firstly, responding to the quoted question: I work with my chinese agent who "sits" between Jialing and myself. This works great, he has access to product support and in second instance (after the fuel overfill diagnosis) they came up with my original suspicion: the camshaft and most likely the decompression automate. So, they asked me to get the camshaft out, inspect it and if the diagnosis is correct I get a new camshaft for free.

I am now studying the chinese service manual in order to make a work plan. Fixing someting on my BMW R60/2 is a bit easier.....