Rich and rough engine woes -- 2001 (03 US) Gen 1

[Donal]

Sounds to me like you have taken this just about as far as you can without replacing the chain/sprockets.

Have you tried rotating the engine a number of times?

Do the 'marks' all come back to exactly the same place each time?

How many miles has this engine completed?

I think I would be inclined to button it all back up and try it out . It will be interesting to see if your original problems have gone/reduced.

I guess the only question is which way is better, slightly advanced or slightly retarded?

 

[Fred W]

It can't be the chain stretch. That would never create that much error. The dimension we are talking about stretching (wearing actually) is just the length of chain between the exhaust cam sprocket and the crank sprocket.

Are you 100% certain that you are setting the cams in their correct positions? In all of the pictures above, none of them shows the cams correctly oriented.

It is very difficult to see the arrows on the faces of the two sprockets, and the distance between the dots in the shafts and the arrows on the caps makes that indication somewhat ambiguous. If you can take a picture of the cams in what you believe is the correct position that may be helpful.

After you get the two cams into their right positions, just placing the detensioned chain across the top of the sprockets it should be perfectly taught between the two sprockets. Once you have that relationship you can ty-wrap them in place while you work on the lower sprocket.

edit - Since it appears that you are off by 1/2 of a tooth on he crankshaft, the real problem is that you are off by one full tooth on the cams. Remember that the crankshaft turns two revolutions for ever single revolution of the cams.

 

[sath182]

Sounds to me like you have taken this just about as far as you can without replacing the chain/sprockets.
Have you tried rotating the engine a number of times?

Do the 'marks' all come back to exactly the same place each time?

How many miles has this engine completed?

I think I would be inclined to button it all back up and try it out . It will be interesting to see if your original problems have gone/reduced.

I guess the only question is which way is better, slightly advanced or slightly retarded?

I've had to rotate multiple cycles to bring it back on time when i've gone too far, they come back the same, crank slightly advanced.

If the engine is original, and i have no reason to believe it's not, then it's at over 65k. I'm also inclined to put it together, but there is one last thing i want to do. I'm gonna PM RadioHowie and see if his scrap engine still has the top off. I'd like to see if he'll measure a known number of links for me, then I can compair that measure to my chain and see if it really is worn too much. Since it's Monday, I'm gonna try calling some british shops and see if they can help. The Americans I talked too were too rude to be much help. I suppose it wouldn't be acceptable to get just the chain, huh?

It can't be the chain stretch. That would never create that much error. The dimension we are talking about stretching (wearing actually) is just the length of chain between the exhaust cam sprocket and the crank sprocket.
Are you 100% certain that you are setting the cams in their correct positions? In all of the pictures above, none of them shows the cams correctly oriented.

It is very difficult to see the arrows on the faces of the two sprockets, and the distance between the dots in the shafts and the arrows on the caps makes that indication somewhat ambiguous. If you can take a picture of the cams in what you believe is the correct position that may be helpful.

After you get the two cams into their right positions, just placing the detensioned chain across the top of the sprockets it should be perfectly taught between the two sprockets. Once you have that relationship you can ty-wrap them in place while you work on the lower sprocket.

edit - Since it appears that you are off by 1/2 of a tooth on he crankshaft, the real problem is that you are off by one full tooth on the cams. Remember that the crankshaft turns two revolutions for ever single revolution of the cams.

I'll get you some pictures of the cams flush and in time. If I could get a video off my phone, I'd do that too, but I don't know how. The chain sit's taught between the crank and echaust sprockets, and then taught between the intake and exhaust sprockets as well. The error only shows up when tension is applied between the intake and crank and the system is rotated fully around. I've tried retarding the crank one tooth, then retarding the cams one tooth each thinking along the 2-1 train of thought as well, but no joy on that one. when I rotate the engine it's always been one full cycle, two full turns of the crank.

 

[Fred W]

What I was saying was to try just moving the cam sprockets back or forward (together) by one tooth while maintaining the crank in the same position on the chain with a ty-wrap. The cam sprockets have twice as many teeth as the crank's so would result in 1/2 a tooth rotation on the crank.

I would not button this up until you get it right. Keep at it, you'll get it eventually.

 

[Donal]

"Since it's Monday, I'm gonna try calling some british shops and see if they can help. The Americans I talked too were too rude to be much help. I suppose it wouldn't be acceptable to get just the chain, huh?"

If you want good advice, I would strongly recommend that you pay the ~£17.00 membership fee and contact Ernie at the FJClub in Gloucester. He only works on FJRs while his sidekick Doc works on FJs. These guys are very experienced and totally honest. In addition to phone support they carry out routine servicing at VERY competitive pricing, and supply spares etc.

I have no direct link with the club but do use their services from time to time as well as buying most of my servicing lubes & spares at competitive prices. YMMV

 

[Fred W]

Oh yeah, although they recommend replacing the sprockets at the same time as the chain, it isn't an absolute requirement. For one thing you can't replace the sprocket on the end of the crank, the whole crankshaft would have to be replaced. And that being the smaller sprocket will have the greatest wear. If I thought the problem was a worn chain I'd just replace the chain. But I seriously doubt that is the problem.

 

[sath182]

Donal, I'm seriously considering doing just that. I'm sure he would at least know where to go from here. Especially with working on only FJRs. He'd be in tune with the problems and nuances as well as the community.

 

[sath182]

Fred, have some pics to show the cams flush and in time with each other.

I also rotated the engine enough times to check that all the valves were going through their full range of motion. All good in the valve realm, but still not the timing realm.

 

[Fred W]

OK, thanks for the pictures. There is only one little discrepancy and that is: on the exhaust cam sprocket, the mark in the correct position should be an arrow, not a dash. But based on the location of the "I" in the picture I believe that your cams are in the correct position and the crankshaft is advanced too far. Maybe they changed the marks on the sprockets somewhere along the line?

So, try this:

Rotate the engine around (2 turns on the crank) and get the mark on the crankshaft perfectly aligned.

Ty-wrap the chain near the bottom sprocket so it won't move.

Release the CCT and work the two cam sprockets one tooth in the CW direction on the chain.

Retension, rotate and recheck.

I think this will get you home.

 

[sath182]

I'll admit, it's not the best picture of the exhaust cam. But the top of the arrow is there. It just shows as a different color in that lighting. I will try to do what you suggest, but how do you suggest I get the chain disengaged from the exhaust cam? So far I haven't been able to get the cams to advance on the chain because of the runner down that side.

On that note, wouldn't it be the same as retarding the crank on tooth, then pulling the chain slack one tooth from intake to exhaust?

I bought a membership to the club last night so I'll contact Ernie later and see what he has to say.

 

[Donal]

Well done for sticking with it, hope it all works out as Fred suggested................... I'm sure it must be very frustrating but like all difficult problems will be well worth it in the end. Just think after all this you will be the resident expert on cam timing......

 

[Fred W]

I'll admit, it's not the best picture of the exhaust cam. But the top of the arrow is there. It just shows as a different color in that lighting. I will try to do what you suggest, but how do you suggest I get the chain disengaged from the exhaust cam? So far I haven't been able to get the cams to advance on the chain because of the runner down that side.

First step is to ty-wrap or wire the chain to itself just above the crankshaft sprocket so it will not move on you when de-tensioned.

Once you release the tension at the CCT there will then be slack chain on the left (rear) side.

Next turn the crank CCW about 1/2 a tooth distance (the amount your crank marks were off before). The crank will move but the cams won't. This will move some of the slack to the right (front) side.

Now you should be able to work the slack chain around backwards on the exhaust and then the intake sprockets. In effect you will be advancing those sprockets on the chain.

Retension, cut off ty-wrap and recheck the alignment marks.

On that note, wouldn't it be the same as retarding the crank on tooth, then pulling the chain slack one tooth from intake to exhaust?

Yes, that would be an alternate way to achieve the same thing. You would retard the crank by one tooth (the equivalent of a 2 tooth advancement of the cams), then retard the cams by one tooth to make it a one tooth advancement.

I think you said once before that you did one tooth on the crank and 2 teeth on the cam which would be a net zero change.

edit - I just found in the prior post where you said that you had tried one tooth bottom and one tooth top and that didn't get you there. It should have given you exactly what you need, so all I can suggest is to try it again and be very careful to only make a one tooth change on the cams.

 

[sath182]

I just tried every combination of teeth I could. When each sprocket was out of time it was very noticeable, and the difference was much greater than where it is at now. I'll take pictures of it tomorrow. I didn't have the fore thought to take them tonight. So I set them to what I feel is the closest to being in time and washed up. Either way, I just ordered a chain and will see if that fixes the issue. In 2 weeks time I may be able to close up the engine and enjoy the end of May with 2 bikes!

I did go, real quick, to take pictures of the sprocket teeth though. Is there any reason to believe they are too worn? They don't look anymore worn than RadioHowie's examples here. Also, echoing what Fred mentioned, the guys at the FJR Center said there shouldn't be any reason to change them. But, they also said the same about the chain....

 

[Fred W]

yeah, whoa... The two teeth on the right in the first picture look really bad. I don't know if it's just the angle or for real, but those do NOT look real good.

edit - I don't know what happened, but the picture seems to have changed and now the teeth all look fine

That said, I'm still in agreement with your guy who discounts chain and sprocket wear as a likely problem of the mistiming. Still, if that first shot is representative of your cam sprockets I'd be looking at replacing them (the cam sprockets) and the chain. The picture of the crank sprocket looks fine, and you can't change it anyway, so just go with what you can do.

I cannot imagine why you have had such apparently extreme wear only in some sections of the cam sprockets, what with only 75k miles, but it is whatever it is.

Good thoughts coming your way for a better outcome.

 

[sath182]

I'm going to try the chain alone first. If it fixes the timing, I'll close it up, if it doesn't I'll order the sprockets and wait a few more weeks

before trying again. At this point, I'm sure I have the teeth in the right place at the start, and I'm not skipping one when I crank it around. The whole feel of the engine changes when I change a tooth from this point. It gets much easier to turn over (spark plugs are very loose in their holes to keep everything out) when it's out. When I do get it fixed, I'll take the offending part(s) down to the FJR Center for their reference.

 

[Donal]

AFAIK There are two ways of checking chain wear. One is to stretch the chain out and measure the length, then 'push' the links together and re-measure. The difference will give you an indication of wear. The other way is to 'drape' the chain over one of the camshaft sprockets (to form a semi-circle) and then see if you can pick up the links closest to the centre. If there isn't any wear you shouldn't be able to pick up anything.

Unfortunately the manual doesn't give any numbers for acceptable wear, so you're on your own.

FWIW If it were me and I suspected wear I would replace the chain AND the sprockets. Worn sprockets will not be kind to a new chain, ask any cyclist!

As you are doing all this yourself you're only paying for parts, not someone else's time. YMMV

 

[Fred W]

I think maybe you swapped pictures, but now the picture of the sprockets look fine. I would go ahead and try the chain first. If the sprockets were actually worn they would only advance or retard the timing by the amount of wear on one tooth. Chain wear is different in that it is cumulative so the amount of wear in each link between the exhaust cam and crankshaft cam adds up. I still really doubt that this is the problem on a 70k mile cam chain bathed in oil there should be negligible wear.

What about the chain guides running up on the right (front) side. Are they all looking good? Maybe one is misplaced somehow and that is causing the incorrect dimension?

But based on the two pictures you gave us previously where you moved the chain only on the bottom sprocket that showed the timing was advanced by half a tooth in one case and retarded by half a tooth in the other, I really do not understand why it doesn't get corrected when you move the chain by 1 tooth on the top two sprockets. Logic says that should have worked to vary the timing by 1/2 a crankshaft tooth. There's still something fishy there.

Before you give up on it just being a chain/sprocket position problem, try what I laid out above where you ty-wrap the chain to the crank sprocket and back the crank up (CCW) to give enough slack to move the chain backward on the top two cam sprockets by one tooth. I really think that this is the answer.

 

[sath182]

Nope, didn't change the pictures at all. Maybe they didn't load for you properly the first time. I will try to get more pictures up tonight of the sprockets timed one tooth different in either direction for comparison. I'll keep the crank at TDC when doing it, too. They become much more exagerated and I'll try to capture that.

As far as the chain goes, I wonder just how long this engine has been having problems idling. If it has been lugging at the bottom of the idle rev range because of fouled up timeing or fuel settings; perhaps that has stretched the chain? Lugging the engine that much would produce stresses the system is not designed for, and highlights the need for my over-arching goal of sorting the idle issues.

 

[Donal]

While you are waiting for the new chain, it might be worth going back to Howie's post referenced above. Have a good read through, particularly towards the bottom where he talks about getting the timing wrong on the Intake cam.

It might even be worth removing the timing rotor (as Howie did) just to make sure everything looks kosher down there.

It might just be possible to get the chain on the exhaust sprocket with the cam bolted down if you remove the exhaust side chain guide with the CCT fully retracted (just hoping)!

 

[sath182]

I have referenced Howies post, and that's pretty much what I have been doing. I will need to take the timing rotor off though, reguardless. I do wish I had a paint pen to mark the chain and sprockets for reference in my pictures.

The exhaust side chain slider is in good condition, but the only way to get it out is through the top of the engine. There is no room to get the chain off the teeth of the cam sprocket with it in place, which makes doing what Fred has suggested unfeasible. Also, since I have no capacity for removing the engine from the chassis, there is no way to get the slider out with the cams in place. Even with the engine out of the bike, I don't think this is possible either. Perhaps this has changed on newer models?

I might try timing the exhaust first, then pulling the chain to the bottom and securing it on the crank, then timing the intake. That should be possible without removing any componants. But, I wager I'll end up with the same results as soon as I release the tensioner and crank the engine through a cycle or 3.