retro 4,048 Posted April 15 6 minutes ago, Igetby said: what kind of damage would it cause riding it like that? If its a guide or the seat.. No point in riding it, just tear it down and fix it. Who knows, it might have been sunk... just gonna do more damage running it. Share this post Link to post Share on other sites
Igetby 1 Posted April 15 36 minutes ago, retro said: No point in riding it, just tear it down and fix it. Who knows, it might have been sunk... just gonna do more damage running it. Right. Don’t want that.. I’ll probably have the head worked on at a machine shop when I tear it down if I can find one in the area.. i’ve replaced valves before but never the guides. Share this post Link to post Share on other sites
retro 4,048 Posted April 15 I'm not saying your guides are bad... your 450 is low miles and if you've replaced valves before you won't need a machine shop. Likely just replace the valve seals and lap the valves in and run it. Share this post Link to post Share on other sites
Igetby 1 Posted April 15 (edited) 53 minutes ago, retro said: I'm not saying your guides are bad... your 450 is low miles and if you've replaced valves before you won't need a machine shop. Likely just replace the valve seals and lap the valves in and run it. Right. I was just saying i’ve replaced valves before not on this one though. Previous owner claims to have rebuilt it last yr… i’ve done a few top ends on sports quads but never anything more than that or clutches. Plan on doing a compression test and taking rocker cover off and just slowly working my way into her and checking everything down to the case… if the rod is ok then i’ll probably have the head worked just to be safe .. incase its an issue with seat or guide only when its up to temp.. I just hope n pray everything in the bottom ends ok! Edited April 15 by Igetby Share this post Link to post Share on other sites
shadetree 5,869 Posted April 15 if its making a rattle noise when engine braking ?, this tells me one of the one-way bearings may be bad ?..they wear out over time. as for the bad valve guide ?, you can not tell if its bad just by looking at it ?..it does not show !. i ran across this yrs ago with a trx350 rancher, early model. they left the factory with defective heads is why. the valve guides would be tight on a cold engine, but once started, ran for a few min's..i could blip the throttle, and hear a rattle noise. finding another head was the only fix..no machine shop can solve this..as the head is made for a press fit for the valve guides. 1 Share this post Link to post Share on other sites
Igetby 1 Posted April 16 (edited) 22 hours ago, shadetree said: if its making a rattle noise when engine braking ?, this tells me one of the one-way bearings may be bad ?..they wear out over time. as for the bad valve guide ?, you can not tell if its bad just by looking at it ?..it does not show !. i ran across this yrs ago with a trx350 rancher, early model. they left the factory with defective heads is why. the valve guides would be tight on a cold engine, but once started, ran for a few min's..i could blip the throttle, and hear a rattle noise. finding another head was the only fix..no machine shop can solve this..as the head is made for a press fit for the valve guides. Ahh makes sense. & that sucks! That they cant be replaced.. i’ve tried looking up the one way bearing but only find the one im assuming is for the starter clutch / reduction gear..? Thats not the one-way your referring to is it? Sorry for all the questions throughout this thread.. soaking it all up like a sponge and have so many questions I have to hold back on with each post 😂 I know the manual and hands on will answer most. Edited April 16 by Igetby Share this post Link to post Share on other sites
shadetree 5,869 Posted April 16 2 hours ago, Igetby said: Ahh makes sense. & that sucks! That they cant be replaced.. i’ve tried looking up the one way bearing but only find the one im assuming is for the starter clutch / reduction gear..? Thats not the one-way your referring to is it? Sorry for all the questions throughout this thread.. soaking it all up like a sponge and have so many questions I have to hold back on with each post 😂 I know the manual and hands on will answer most. there is also a one-way bearing behind the centrifugal clutch, so you have one in front, and one in the back behind the flywheel. most times engine braking is controlled by the centrifugal clutch one-way bearing. i do not know if they still sell heads for your make/model ?, you can look it up on rmatv, or check power sports nation for a used head ?, they stand behind used parts. Share this post Link to post Share on other sites
Igetby 1 Posted Saturday at 10:00 PM Hey everyone! Just posting an update. These kids keep me so busy I hardly have time to get anything done.. I started getting into it this morning but went no further then the valve cover. At tdc on comp stroke intake clearance was .005 and ex im thinking was around .007mm. Didnt have 007 on my gauge but 6 glided through easy and couldnt have taken much for .008 to slide in. Got them both at .005 and it no longer sounds like its about to grenade. I did notice it still has the slightest chatter.. when I revved it up once I seen the exhaust heat shield vibrating enough to move.. its missing a bolt on left side. Im really hoping that’s the rest of the noise im hearing. Plan on taking it off tomorrow just to see.. will try to get a vid too. Keeping my fingers crossed it’d sure be nice to putt around through the summer without having to tear it down. 1 Share this post Link to post Share on other sites
