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Cam chain/ noise

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Rebuilt the bike this weekend-new valves, seats, piston, cam chain, guides etc. The bike is timed correctly (28th pin right?... at TDC) I never replaced the chain before, but that damn thing is tight going on! It is so tight that I couldn't seat the adjuster past the o ring without tightening the 8mm bolts that hold the tensioner to the head. Is this normal..to be that tight? After starting the bike and running it for about 20 minutes, it is vibrating and whining bad...bad enough where you say "This bike is ready to self destruct" All I can think of is the flywheel???? maybe? And the whining noise? Don't know-cam caps are 104 inch pounds per the manual--I think the valves may be a little tight, but would it cause noise like this?

Thanks, any experiences with this would help

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cam caps are 104 inch pounds per the manual

Damn! I wonder how many people got screwed by that misprint. I hate to tell you this, but you probably just roached your head. Cam cap bolts must be 87 in. lbs. 104 is WAY too tight and will almost always seize the cams. DON'T run it any more and take it apart and inspect the cams. Good luck! :thumbsup:

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Alright, going to pull it down tonight and check the valves again and check the cams--I'll retorque at 87 inches and give er a shot--I'll let you know what happens

Thanks

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I took it down tonight-cams look good, no heat discoloration. I checked all the valves and they are in spec. (according to the manual) The cam chain loosened a little, which was expected. I removed the tensioner and reset and reinstalled that-double checked the timing and torqued the cam cap bolts to 87 inch pounds. The flywheel nut is still in place, torqued to 36' pounds.

The bike started after a few kicks (normal), but it still is making a clanking noise which increases with the RPM. I restarted the bike several times and it fired right up. The power seems to be very good as compared to before I replaced the valves, piston etc.

The bike has about 50-60 hours on it total, racing or riding on a motocross track. I just can't figure out this thing. There aren't THAT many moving parts on this thing! It is definitely an engine noise and doesn't appear to be coming from the clutch or transmission. I'm stumped1!??*** Do I just ride it and see what happens? I hate to go to a dealer to have them look at it, but I may have to. Any suggestions?

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Whne you re-torqued the caps, did the whinning noise go away? Also you indicate it is making a "clanking" noise now.

Got your PM will send some thoughts tonight. Sorry for the delay

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The retourqing made no difference at all. I didn't have time to fool with it tonight-I haven't thoroughly inspected the clutch side gears, but everything looked okay when I pulled the cover off and the oil was clean with no metal stuck to the drain plug.

This noise is so loud you can hear it from 25 feet away and say-"damn, that's not good at all, something is seriously wrong"

If I don't figure it out by Friday, I'm going to have shop look at it---SOMETHING is amiss somewhere---I'll post the solution--it should be interesting

Thanks for your help

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Some of this you have already ruled out.

Knocking noise

Fuel quality too low

Improper spark heat value

CDI faulty

Throttle valve not opening fully

Oil level too low

Crankshaft bearings or runout

Connecting rod bearing worn, excessive run out

Piston/Ring groove clearance excessive

Piston pin malfunction

Decompression spring broken

Cam shaft chain guide worn

Cam shaft chain tensioner malfunction

Primary gear worn/broken

Finally if all the above checks out, its gotta be transmission or clutch.

One final question, what was the problem with the valves or piston that made you do a top end, or was that just maintenance. If so, and this noise was not there prior to that, it has to be in the top end area. If this is the case, I would focus on those areas in Italic above.

Let us know!

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I think I have figured this out, though I'm not sure until I have more time to tear through it. I looked at a friend's '04 and I believe the guide near the exhaust cam became unseated during the installation of the head and it is binding the chanin. This would account for the very tight cam chain and the engine running fine otherwise. I'll post again if that's it.

Thanks!

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Took it apart again! Everything was fine and the same loud knocking noise---I'll post when it gets fixed. Never had a knock like this before--

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I dropped it off on Monday to a reputable shop and explained the problem to him. He didn't want to start it for fear that it might do more damage. The mechanic tore the top end down and checked the cams, rod, head, piston, valves, cylinder etc. He said the cylinder was "a little loose" but not out of spec. He had another cylinder at the shop, so he put that on and put it back together. The same loud knocking/whining noise. He believes it is a bearing in the crank or somewhere in the bottom end, so now I have no idea until he splits the cases (something beyond my limits, I'm not afraid to admit!) - I should know in a day or two what the exact problem was. This bike only had about 40-50 hours on it and the mechanic said this is unusual for this bike. He did say the top end was very clean and well lubricated as well. So, we'll see what happens--I'll repost when I know.

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Heard back from the mechanic today and the parts are ordered. Here is what he said--the right side crank bearing is toast and the left side is worn to where it is out of spec. The crank is within spec and doesn't need replaced. How did this happen? My exact question and he asked how often I changed the oil. I told him every other weekend, usually about 1-1.5 hours of ride time each weekend with Yamalube R 15-50. So that would make 2 to 3 hours of ride time before changes. He strongly suggested changing the oil after each ride because the clutch and engine oil run together (unless you have a Honda of course) and the clutch fibers wear off and contaminate the oil. He also recommended Motul 15-50 and said that is the only oil he sells. He said whether you buy it from me or somewhere else, they can tell engines that run Motul, so it looks like I'll be switching oils as well. So, $500+ and we should be good to go with basically a new engine. It will be a nice bike for someone in a few months when gets sold for an RMZ 450. I hope someone learns from my misfortune--

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Man sorry to hear that, the tech is right about the oil issue however. Although it sounds like you were in line as far as the intervals. What a bummer, hope the 450 works out better, Gotta hang on to that thing though!

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You may find this hard to believe, I use Castrol 10w40 with Two2Cool added. I get it in 6 gallon jugs for $8.00 (less the Two2Cool) I change my oil after every race, this also includes 1 practice day as well. I have (knock on wood) never had any premature bearing or piston wear.

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