JH600 stalling

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Originally Posted by Bart Sanders

Anyway, if it fixes the stalling problem, for the better! And then again, what is not present cannot malfunction.....

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I have thought about this matter ever since we had the meeting last week.
I asked the service guys the reasoning behind the disconnecting, and why it should solve the problem.

Without going into details, it was a long story of bad, wearing-out camshaft chains which get longer, and mis-communication between signals.
From a technical point of view, and, after thinking it over for almost a week, I think this is absolute BS.

If the chain should really get longer (which I doubt 100.000%), your valve timing goes off as well, and that is much worse.
A 1-cylinder does indeed not need a camshaft sensor, but, although I am really really wrong, dis-connecting it will not make any difference.
Why do bikes run better after it? Well, I guess that dis-connecting and connecting parts to get there might give your badly set-up bike a little boost.

Eric

Oh yeh, Milton's bike has the sensor connected. Will not dis-connect that one till I am desperate.

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If the chain should really get longer (which I doubt 100.000%), your valve timing goes off as well, and that is much worse.

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Hi!

Camshaft chains do get longer over a long period of running. That's why there is an automatic chain tensioner which keeps the slack out of the non-pulled half of the chain. As long as the chain does not become too long - i.e. the tensioner can not compensate anymore slack - the chain and camshaft timing are perfect. Please note, the camshaft is controlled by the PULLING part of the chain. And indeed, in our beloved Jialing JH600 the camshaft rotates counter clockwise, as does the crank-shaft, viewed from the left side of the engine. And the non-pulled side with the slack is (of course!) at the correct side, i.e. the right side viewed from left side of engine.

But, back to the sensor. I seriously doubt if you need it, when the engine has a crankshaft position sensor anyway!. Remember that the crank-shaft and the cam-shaft always run in a fixed ratio of two revs for the crank, make one rev for the camshaft, so 2:1 gear ratio.

In other words, if you know the crankposition and the cam chain/ cam gears are correctly installed, the position of the camshaft is also always known to the ECU!

The only (small) error which creeps in over time is the camshaft timing which indeed changes a little bit when the chain gets longer and longer. But, this elongation is (very) small and most likely introduces such a small error in camshaft timing that one can accept this.

I suspect (!!!) that Jialing/AVL tried to make it perfect and measure exactly this small timing error over lifetime of the chain and keep the ECU timing moments (injection, ignition) as good as possible at the optimal moment.

I further suspect (!!!) that this positive endaveour results in too much problems in real-time, like..... stalling!

As stated, our JH600 works without this sensor and guess what, it does NOT stall. At all.

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Originally Posted by Bart Sanders

Hi!

Camshaft chains do get longer over a long period of running. That's why there is an automatic chain tensioner which keeps the slack out of the non-pulled half of the chain. As long as the chain does not become too long - i.e. the tensioner can not compensate anymore slack - the chain and camshaft timing are perfect. Please note, the camshaft is controlled by the PULLING part of the chain. And indeed, in our beloved Jialing JH600 the camshaft rotates counter clockwise, as does the crank-shaft, viewed from the left side of the engine. And the non-pulled side with the slack is (of course!) at the correct side, i.e. the right side viewed from left side of engine.

But, back to the sensor. I seriously doubt if you need it, when the engine has a crankshaft position sensor anyway!. Remember that the crank-shaft and the cam-shaft always run in a fixed ratio of two revs for the crank, make one rev for the camshaft, so 2:1 gear ratio.

In other words, if you know the crankposition and the cam chain/ cam gears are correctly installed, the position of the camshaft is also always known to the ECU!

The only (small) error which creeps in over time is the camshaft timing which indeed changes a little bit when the chain gets longer and longer. But, this elongation is (very) small and most likely introduces such a small error in camshaft timing that one can accept this.

I suspect (!!!) that Jialing/AVL tried to make it perfect and measure exactly this small timing error over lifetime of the chain and keep the ECU timing moments (injection, ignition) as good as possible at the optimal moment.

I further suspect (!!!) that this positive endaveour results in too much problems in real-time, like..... stalling!

As stated, our JH600 works without this sensor and guess what, it does NOT stall. At all.

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Some info on the timing chain elongation here.
As far as I understood the issue - I've been following this thread from the very beginning - some stalling came only after a several thousand k's. Timing chain elongation could be a reason and it may be a worth to try a chain replacement on one of the bikes. Just my 2 Fen.

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Originally Posted by Bart Sanders

Camshaft chains do get longer over a long period of running. That's why there is an automatic chain tensioner which keeps the slack out of the non-pulled half of the chain. As long as the chain does not become too long - i.e. the tensioner can not compensate anymore slack - the chain and camshaft timing are perfect. Please note, the camshaft is controlled by the PULLING part of the chain. And indeed, in our beloved Jialing JH600 the camshaft rotates counter clockwise, as does the crank-shaft, viewed from the left side of the engine. And the non-pulled side with the slack is (of course!) at the correct side, i.e. the right side viewed from left side of engine.

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Originally Posted by chinabiker

Some info on the timing chain elongation here.As far as I understood the issue - I've been following this thread from the very beginning - some stalling came only after a several thousand k's. Timing chain elongation could be a reason and it may be a worth to try a chain replacement on one of the bikes. Just my 2 Fen.

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Hi Bart & Andy, perfect description on the pulling side story, and correct.
Exact the same came up during the meeting during our discussion with the JL technicians.

Where I however disagree, is that cam-chains get longer, and that is confirmed by the link of Chinabiker.
The tensioner is basically to keep the chain tight, to prevent it from skipping a teeth if too loose.
And the adjustability in the tensioner (mostly by spring pressure) is more to compensate for manufacturing tolerances then for wear-compensation.
Of course it is a mechanical system, and subject to wear, but I still put this very low on my list of possible causes.

I do not want to rule out that disconnecting the sensor is the solution, but I still miss the technical reasoning behind it.
You furhter might consider that if so, you might have a far larger problem inside your engine; the longer cam-chain will NOT get shorter by dis-connecting the sensor.

You failed to convince me so far....:icon10:

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Originally Posted by Bart Sanders

As stated, our JH600 works without this sensor and guess what, it does NOT stall. At all.

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Nobody more than I wishes this was true - but it is not.

As noted in an earlier post, my camshaft sensor was disconnected and although it reduced the stalls, the stalls were still present ... and increased to the point of pre-disconnect. In essence, I now have a JH600 with the camshaft sensor disconnected that stalls as much as ever.

This is with a 2010 JH600, and this happened 7 months (and 4,000 kms) into ownership ... earlier this year (2011).

Something else is going on with this stalling.

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Originally Posted by Lao Jia Hou

...Something else is going on with this stalling.

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It's been said before (mainly by 998S) but it bears repeating: The ECU at the heart of the Bosch EFI used on our JH600 does far more than simply take eight or ten variables and put them through a simple algorithm to determine a correct fuel/air mix under given throttle conditions. It also is programmed to sense changes over time, which might be caused by many different variables (wear to various parts, reduced air flow caused by a dirty filter, even changes of engine-related components like tail pipe, air filter, spark plug, etc). In other words, it's got feedback systems that try to adapt to changes in engine function over time. The changes are reflected in changes to the fuel mapping, which alter the fuel/air mix under various load conditions.

It seems to me that it's this "intelligence" in the ECU that causes these seemingly inexplicable changes -- particularly the presence or absence of stalling under various conditions. How could the bike be stall-free under one set of conditions, then be stalling under the same conditions six months or several thousand kilometers later, unless it's because this feedback intelligence is overcorrecting or undercorrecting or miscorrecting for some change that the EFI's system of sensors is sensing?

There are many guides to fuel injection available online, some actually useful. I've not found anything yet that really drills into the Bosch system, but there are many references to how our friends at Bosch are super anal about the workings of their ECUs and protect this intellectual property the way a mother bear protects her cubs. (This, alas, is not a point in our favor.) Here's one fairly good overview:

Fuel Injection: A Brief Piece on How it Actually Works

I think ultimately, our best hope is to finally persuade Jialing that EFI is not something that never needs to be touched again after manufacture, but rather is a dynamic system that like other systems is subject to wear and change over time. And that the best way to serve their customers is to train and empower a network of shop technicians to provide annual and spot service for our EFI systems by providing them with the appropriate test and control modules. This way trained technicians can implement "factory adjustments" to our ECUs as conditions merit.

Attachment 5948

This is especially true for you, Bart, if you are thinking of fostering a fleet of JH600s there in Europe. In the absence of this kind of intelligent service -- which all serious manufacturers offer as part of their service -- you inevitably will come up against these problems with your own bikes or bikes that you helped others to obtain. If you indeed are building a European franchise for Jialing, you are in a great position to make these demands on them. Ditto for Traxx in Brazil and any other Jialing allies in Latin America, the Mideast, Africa and Southeast Asia.

And we'll all benefit.

cheers!

And so it looks Jialing won .... soooo silent ........
Don't tell me you all gave up .......

Dear Eric,

Did you hear a fat lady singing? Not me.

Stay tuned.

Have you contacted these people?
http://www.dynojet.co.uk/powercomman...der-prices.php

I highly doubt that what is on that bike is not similar to units on other makes.. Jialing may not be comfortable allowing its customer to adjust the setting to what is likely outside compliance.

The too lean theory makes a lot of sense, if you hack into the signals you could see the values being sent to the ECU.

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Originally Posted by MJH

Have you contacted these people?
http://www.dynojet.co.uk/powercomman...der-prices.php

I highly doubt that what is on that bike is not similar to units on other makes.. Jialing may not be comfortable allowing its customer to adjust the setting to what is likely outside compliance.

The too lean theory makes a lot of sense, if you hack into the signals you could see the values being sent to the ECU.

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Thanks, MJH. Have not talked to them yet, but that's definitely a possibility. What I don't quite understand about the PowerCommander is how it interacts with the stock fuel/air map. It appears that it applies an overlay map, and my brain just cannot grasp this concept. It can barely grasp the idea of a single map.

Will keep you posted!