Power loss after valve clearance adjustment/CT installation???

[bloodline]

Agree with above. Maybe off by 1 tooth.

no doubt. VERY easy to do by mistake.

 

[avc8130]

Not exactly true. Take the bolts out of the electrical "tray" and it moves away just enough to see the marks on both cams and aids tremendously in checking your gasket upon replacement of the valve cover.

Good tip. I'll have to remember that for the 52k service.

I think there are also stake marks on the cams that line up with the cam caps when properly timed.

ac

 

[avc8130]

no doubt. VERY easy to do by mistake.

Will the bike start 1 tooth off? I've read conflicting information on this.

ac

 

[fredz43]

Will the bike start 1 tooth off? I've read conflicting information on this.

ac

I saw one in our dealers shop that jumped a tooth when tightening the cam caps (he found later) that absolutely would not start.

 

[bloodline]

Will the bike start 1 tooth off? I've read conflicting information on this.

ac

I guess it would depend on which way it's off and which cam. One tooth off on intake and I think it would run.

 

[Koinz]

I guess it would depend on which way it's off and which cam. One tooth off on intake and I think it would run.

::026::
I would agree with this. Theres a mod that the kids are doing on the yamaha 450 quad to boost it's power slightly. They retard the exchaust cam 1 tooth, so in some cases it could actually increase performance in the higher revs.
http://www.yfzcentral.com/forum/32-yfz-powertrain/46023-yfz450-cam-mod.html

 

[OldRider]

I'll bet that 1 tooth off in any direction won't stop it from starting. Put either cylinder on TDC and 1 or 2 teeth in any direction isn't going to open a valve.

 

[avc8130]

I'll bet that 1 tooth off in any direction won't stop it from starting. Put either cylinder on TDC and 1 or 2 teeth in any direction isn't going to open a valve.

That was kinda my thought...but I had read a lot of the claims that it wouldn't run. With no cam position sensor, I don't see a reason the engine would stop trying to run electronically.

ac

 

[fredz43]

That was kinda my thought...but I had read a lot of the claims that it wouldn't run. With no cam position sensor, I don't see a reason the engine would stop trying to run electronically.

ac

In my post above, I said the one I saw at my dealer had jumped a tooth. It may have been more than one tooth, but it did jump. After trying unsuccessfully for about half a day, rechecking wiring, etc, they got on the phone with Yamaha tech line who suggested going back and checking the cam timing, which is what they found. Once corrected, it started right up.

I had been giving my bogus opinion that it was the dreaded cold restart flooding problem since it had been started from cold, ridden into the work area and shut down before they started checking valves. 4 hours later it wouldn't start. I gave them my "expert" advise on WOT, then pulled the EFI fuse, but nothing helped. Turns out it wasn't that at all and now they know to be very careful when tightening down the cam caps.

 

[avc8130]

In my post above, I said the one I saw at my dealer had jumped a tooth. It may have been more than one tooth, but it did jump. After trying unsuccessfully for about half a day, rechecking wiring, etc, they got on the phone with Yamaha tech line who suggested going back and checking the cam timing, which is what they found. Once corrected, it started right up.

I had been giving my bogus opinion that it was the dreaded cold restart flooding problem since it had been started from cold, ridden into the work area and shut down before they started checking valves. 4 hours later it wouldn't start. I gave them my "expert" advise on WOT, then pulled the EFI fuse, but nothing helped. Turns out it wasn't that at all and now they know to be very careful when tightening down the cam caps.

I guess I was putting to much weight on "A tooth" to mean ONE tooth.

I'm sure if the timing was far enough off, but no so far to smack valves into pistons, the engine might not start.

ac

 

[avc8130]

This fell off the first page. BUMP!

Any update?

ac

 

[twinrider]

I phoned the mechanic up yesterday. He said he just finished the job and that I was right, the timing had been off by one tooth. So it sounds like the issue has been resolved.

Thanks to the posters who suggested to check the timing, very valuable input. ::008::

I'll post up any additional info/details I get after I pick up the bike.

 

[fredz43]

Great news, twinrider.

BTW, as a followup to my earlier posts about mine not starting following a valve adjustment, I checked with the tech and it turned out that when he rechecked the timing, it had jumped 2 teeth. It would crank, but not start. Fortunately, it had not jumped enough to harm any valves or anything. My exhaust valves were ok, but he had to remove the intake cam for reshimming, as 2 of them were too loose and it had jumped those 2 teeth when he tightened the caps down.

 

[RED CAT]

Not all mechanics are created equal. I prefer to do my own for that reason. Not to mention $100. an hour to screw up your bike and plenty of down time at no extra charge.

 

[longride]

"Not all mechanics are created equal."

Actually most mechanics are fairly equal. The bums they hire at many car and motorcycle shops don't qualify. I wouldn't trust them to check my tire pressure.