Timing Belt Questions (about T1 mark)

bikertucker said:

What you are describing is exactly what you find on an engine with a stretched timing CHAIN. On some of the old Hondas the points lobe ran off the end of a cam, timing was taken off crank markings. So as timing chain stretched with age your timing with ignition was off also. I am new to ST1100, and have heard 90,000 mile timing belts look new. I wonder if they look new but stretch enough to create your problem of either crank marks aligning but not cams or vice versa. If it ran well, think I would align per service manual and follow all instructions when replacing the timing belt. Have noticed the tension spring seems much stronger then on the older Goldwings which I do have a bit of experience on. I'm betting your problem will go away when new timing belt is installed. Looking forward to your completing your project. Waiting for one more part to arrive before I change out my timing belt also. Good Luck

Click to expand...

if the belt stretched you would have uniform stretch, so not only would the crank position indicator be off, the cam sprockets would also be off, which is not the case. His symptom is consistent with everything being aligned correctly, but the crankshaft position indicator, and ONLY the crankshaft position indicator is way off. Its well beyond anything that could be explained by belt stretch, the timing belt would break before it could stretch that much.

Dumb suggestion here, but I assume you are cranking the engine in the correct direction and not backwards?

Like biketucker and others say, I'd go for aligning everything like the book wants. When Honda makes these parts they are on CNC machinery and if one is off, dozens or hundreds are manufactured incorrectly. It is unlikely that the guy who put the bike's engine together would not have blown the whistle (assuming quality control did not pick up the mistake before he got the gears/sprockets) - and he was using these marks too.

Engine was cranked correctly all the time (so clockwise) and marks line up perfectly (cam alignment) both before and after the belt swap and I just checked the new vs old belt, and they are exactly the same size, so belt stretch doesn’t explain the difference. Lastly, with the crank mark off by the 30 degrees or so I indicated, piston #1 was at TDC. I checked my marks many times before removing the old belt and reinstalling the new one. The old belt looked as good as the new one, as many have said on ST-Owners in the past.

I think the last thing I’ll do before final assembly is place the carbs back, fire the motor (very briefly), make sure it runs nice and smooth, shut it down, and then reinstall the TB cover, radiator, etc. I’m very sure at this time it’ll run fine since the marks were the same pre and post belt replacement. Very strange and rather unexplainable, but it is what it is.


I think if I set everything according to the manual, I might actually mess everything up and as it is now, the engine rotates nice and smooth without any parts colliding- if I set it the proper specs in the manual, piston 1 will before TDC and I risk wrecking the engine. As I’ve said, I’ve checked this at least 10 times before taking the old belt off and the belt was not at all stretched.

Hopefully when I do this work on the 2000 ST, all will be as expected/ normal- that bike I’ve owned since new and the TB has not been changed, so it should be as ‘factory sealed’.


EDIT: Here’s something interesting and I didn’t notice it until after I used the starter with the engine in the ‘no run’ position (on the 94, you can still spin the starter in the no run position- can’t do that on the 2000). Anyway, the crank bolt when turning is normal but the plate directly behind it but in front of the sprocket spins very slightly eccentrically- to me, this means someone was in there before and probably messed up the crank mark cover/ sprocket cap. Since I have everything set properly and it’s difficult to break the crank bolt free, I’m just going to leave it as is- what I may do is fire the engine after carb reinstallation (just for a few seconds) to make sure it starts/ runs properly, then reinstall everything- sounds OK to do that I assume. I don’t foresee myself ever changing the belt on the 94 again- I probably won’t put another 90K miles on it in my lifetime or will sell it by the time a new belt is required

SMSW said:

Snip ...

Like biketucker and others say, I'd go for aligning everything like the book wants. Snip ........

Click to expand...

Be advised sometime it take some futzing to get all the marks aligned when replacing the timing belt. It may take a few tries, but everything will / can be aligned properly. Don't settle for what you are seeing now.

Update: I installed the hoses under the carbs, the rubber sheet and the carbs this AM- fired it up briefly and...
It runs perfect! Now all I have to do is install the radiator, change the oil, refill and burp the coolant, install the plastics, and I’m done. I’m eventually going to do this rehab on the 2000, but maybe wait a few weeks to do it. The cam sprocket cover is called in the manual a Guide Plate A- mine is still off position wise but as I said, the bike runs perfectly- I would need an impact driver to break the bolt of the sprocket free (and I tried putting it in gear and applying the back brake pedal while trying to loosen the bolt)- no dice with a breaker bar (I don’t have an impact driver). Someone has been in there before and when they reassembled the works, that guide plate was put in wrong, but it doesn’t affect the operation of the engine.

Again, thanks for all the assistance!

Glad to hear that you solved the mystery and successfully did the belt transplant. I frequent these forums as I find such oddities fascinating and each discovery adds to my own knowledge, thanks for posting your conclusion.

BTW: I waited a long time before buying an impact driver, I finally gave in and bought a cheap mains-powered tool. It's not very maneuverable and weighs a lot, but at certain moments it is the Right Tool For The Job. I believe it has saved enormous frustration in the few times that I've used it, most recently on the socket bolts holding the back disc on, where the hammer action gently broke the threadlock loose without any damage. I'm sure if I tried the same thing with a big breaker bar, I would have rounded out the hex sockets or broken a bolt.

Sorry to bring back an old(er) thread...I completed the hose and timing belt rehab on the 2000 ST in the past few days. This time, after tearing it all down, the timing belt replacement took about an hour (including taking off the timing belt covers)- all marks lined up perfectly and I got the belt on properly the first time. The only issue I had was a few days ago (Christmas Eve actually and I started the work on 12/23- work gets in the way...)- getting the carbs back on despite new carb boots and lubing them was a HUGE PIA! I couldn’t get them to line up (one side would go in and then the other would be popped up)- the TB cover actually came out and went back in easily (I did the little plastic trim job to accommodate the crank bolt). I’m glad it’s all done and the only thing left is to replace the bodywork. While I had everything apart, I bled the clutch even though I did it only a year ago. Both bikes are now rehabbed (and I’m never planning to do that again). By the way, my hoses and the timing belt appeared to be in great condition, so I’m sure I could have gone a lot longer without doing the work, but it is great peace of mind given the age of these bikes.