Hey guys, Im new to the forum here and just wanted to say hey and thanks for letting me in here!

I recently picked up a 2000 foreman 450 that was smoking bad when I got it. I should have listened to it a bit longer than I had before I went in and did a top end rebuild. new piston, rings, wrist pin, fresh one size over bore etc. No smoke at all now and everything works the way it should, but i noticed a noise coming from the engine. I took a stethoscope and listened to various parts of the engine while it was running and there is a clunking sound under the clutch cover...more precisely near the top left had side of clutch cover (riders perspective) which would lead me to believe something funky with the secondary clutch. I pulled the clutch cover and inspected everything in there, though I haven't removed either of the clutched yet. I can't seam to see or feel anything out of the ordinary. cutch nut is on good and tight, no broken springs that i can tell, no major play on the clutch hub itself. Just wondering if anyone had any ideas as to what may be causing the noise....something I am over looking? After using the stethoscope I'm quite certain thats is where the noise is coming from and definitely sounded louder on the secondary clutch side of the cover. i should also mention that my one way bearing is toast id say since I seam to have little to no engine braking and when I shut the bike down I can hear it spin for a couple seconds....just not sure that would be the cause of the noise. any suggestions would be greatly appreciated.

cheers

 

I've never had any problems with the secondary clutch, except the thrust race once broke up on a 350. Shed steel ***** all over the internals and one went through the balancer gear. I guess the one way clutch could be grabbing when the bike is idling but things would quieten when it was revved up as the centrifugal clutch comes in. I don't put much trust in where the sound seems to come from, as it can travel in odd ways through the cases, check the cam chain isn't stretched while you have the cover off.

 

hey thanks for the reply! I checked timing chain and its good for a bit yet, it's not a chain noise for sure. My main concern was that it was maybe a crank bearing, but i sorta don't think it is. i gave the centrifugal clutch a few good wiggles on the shaft to feel that side of the crank anyway and no up and down play at all that i could feel and I'd think id hear it a lot more predominantly through the throttle ranges. would almost think would get worse with throttle if was a crank bearing?

i am quite certain that the noise is generating from somewhere under the clutch cover. I had the stethoscope pretty much on every part of the engine and that is the only place where you really here it. I know a noise can travel through other parts of course and you can hear it all over, but as soon as it's placed in that spot the noise is real obvious. I just find it strange there isn't something popping right out to me there. just gonna have to pop the clutches off and investigate more I guess. I've got a spare set of clutches here from a 400 and checked them online they are the same part numbers for everything.

anyone had experience with a bad crank bearing? just wondering what sorta of sounds you were getting?

 

well I took the clutches off an still, nothing really popping out at me. I just don't want to have to put it all back together and not fix the issue. while i have the clutches off I checked the crank for play and everything seams solid. the only possible issue i can really see is maybe the ring gear on back of the main clutch. there is some play there. the whole ring gear can be moved back and forth a bit with a bit of pressure. I have another clutch from a 400 here and I checked the ring gear on that one...and it will move a bit, but not as easily and not as much as this one. here's to hoping that is the issue. really wish someone else would chime in on this. I'm sure someone has had a similar issue before. here is a link to a build someone did...he mentions the ring gear issue in here.

Foreman Upgrades & Repairs Part 2: Clutch Basket | Nicholas Fluhart


picked up a clutch cover gasket from the dealer today...what an absurd price for a gasket at 34$. guess who's gonna pick up some gasket material and make a template..

anyways, please any help would be great!

 

something else i should mention...i've read in the manual that if you take the centrifugal clutch off and place on the bench...if it spins one way and not the other the bearing is fine. mine will only spin the one way, but i know the one way isn't working as i have no engine braking and also the classic spinning noise when i turn the bike off. sorta feel like i may catch sometimes and then spin other times...

 

The type of one way clutch used on Honda Utility quads can be shot at and still seem to work when tried by hand. Often, if you take them apart, the steel "spring ring" has broken. be warned, they are difficult to get back together again.