Rattling Engine?? 1 way bearing????

Alright here goes...Blew her up, sleeve busted so I got a new one. Flushed lower end several several times. Did not split cases to do it, just clutch side. Put back together, 11:1 ---.20 over. Sounds great runs great. 3 weeks later Out of no where rattling!!! Ran it for 5 months. Sounds like a rolling trashcan--(or a Cannondale I guess) Tear her down again. Flush the heck out of it again, clean clean, no junk in there. No play in the rod, Sleeve beautiful, Piston Rings Beautiful----Put back together .80 over 416. Still rattles!!!! Someone told me of a 1 way bearing???? Where is it and could this be my infamous rattler!???? Either way, she runs like a raped ape, had no probs out of her, just sounds like a Cannondale.......I get it next to everyone elses and it sounds like a pile, them we race and its not such a pile......HELP!!!

[RIKR4X]

did it rattle before you blew it up? mine vibrates real bad ,my buddies 02 just started vibrating real bad .just curious if were talking about the same problem? only when u rev?

[Lil90man!!]

yea i have a 300 and mine just started vibrating like that too and its really annoying, it does it really bad now like enough that after riding for a while i have to stop to let my hands recoperate(SP) whats wrong here its really annoying is there something wrong here?

[Leo]

I'd be checking for a stretched timing chain and/or defective timing chain tensioner if I was you :(

Leo

I did check the tensioner and it was good to go, chain was a bit sharp but not horribly stretched. That is my next move to get a new chain and see if thats it!!! Anyone know anything about this 1 way bearing???? Where is it??????

[DEAL]

RIKR4X
Your Vibrating is from that Dg belly pan, Mine does the same thing, annoying huh?

Just a couple of questions to help narrow it down.

Is it a high or low pitch rattle?

When does it rattle?

Does it change with rpm or load?

Is it coming from any one part of the motor?

When is it the loudest?


Also there are a few one way sprag or clutch type bearings. Two that come to mind are the de-comp device and starter gear.

[deansfastway]

Maybe the rod is starting to go south? It can be hard to really check a 4stroke rod and thyll run a long time before they really blow out . I have had many of these motors apart and have never seen the starter sprag go bad. Maybe the rod is just now starting to oval out or the crank pin is going away. Does it get louder when the pil this out or gets hot? It seems to me that when a QUAD has a bellypan on it or nerf bars an engine could seem louder . Do you feel a banging in the frame? If you do thats not a good thing. GOOD LUCK

[deansfastway]

DOES IT GO AWAY when you pull inthe clutch , If it does it could have a problem in the trans itself like a chipped gear from a peice of broken piston or something .ALSO I have seen more than a few EX motors where the #rd gear mainshaft loses its hadrdfaceing and starts pucking away . 3rd gear is directly behind the crank & rod on the mainshaft of the trans and can be seen quite easily with the cyl/piston removed. It seems as though this gear goes out when the power is turned up = added stress. At my shop we send them out for CRYO TREATMENT which we beleive helps aid in longevity of that non billet gear. Whenever Ive seen these EX trannys really break it has been from the 3rd gear exploding and coming through the cases . Not a lot but maybe three times but it was all on strong motors in sandy NJ riding. GOOD LUCK , DEAN

[honda250xrider]

i dont know this could be far off but i guess it could be your rocker arms if there are rattling have u checked to make sure they are right

I have had many of these motors apart and have never seen the starter sprag go bad.

Dean I guess I am lucky as I have done 2 of the starter sprags for friends. One on a big bore and the other on a stocker. And would you believe I have a raptor in my garage that is awaiting the same part.


It can be hard to really check a 4stroke rod and thyll run a long time before they really blow out
Are there any typical indications when the rod is just starting to "blow out" ?




Whenever Ive seen these EX trannys really break it has been from the 3rd gear exploding and coming through the cases . Not a lot but maybe three times but it was all on strong motors in sandy NJ riding. GOOD LUCK , DEAN
You just described my quad, should I skip third gear. JK but have you seen any other problems with the tranny?

[deansfastway]

440EXfor me : What went wrong with the starter sprags ? Did they slip , lock up or just get noisey? I just never saw them go bad yet . You learn something everyday I guess. I have also seen Counter bearings go bad (sprocket side) They also will break the cases when the chain is really tight.. And when the shifter shafts get bent/stripped its a real chore since you have to split the cases to replace it . CHEERS , DEAN

[deansfastway]

When the crank starts getting bad you might feel a bang in the frame or footpegs and like you might swear that the engine is loose in the frame . Just starts feeling real harsh on the melon.

The bearing face or sprag rollers were worn down real bad.

They did not exhibit any kind of abnormal wear or fatigue, just worn out.


When the crank starts getting bad you might feel a bang in the frame or footpegs and like you might swear that the engine is loose in the frame . Just starts feeling real harsh on the melon.

Ok I was hoping that it wasnt an occasional squeeking noise since I cant figure where the he11 this is from, and it hides when you listen for it. its real weird sounds like a suspension noise but it isnt.

[deansfastway]

Sometimes a loose head gasket will squeak and go away as things get hot and expand , esp with those fiber gaskets . Did the starter clutch slip or just make noise? CURIOUS , DEAN

Hmmmmm so like my cometic head gasket. thanks I think that may be it.

I wouldnt be surprized it the starter sprag clutch was noisey before it started slipping. I had some knowledge of one of the 400ex's and it went bad pretty slowly. Originally just making a racket and not always engaging, and then later just completely slipping.

Some good news in that I may not have to do the raptor as the owner may have worked a deal to have it covered under warr. even though its 3 weeks past.

help me here as I am having a senior moment but isnt the 89mm xr400 head gasket .025 thick I just cant feel like I am completely sure. I had used the cometic previous and may want to save a few $$ buy ordering it from the same (WB ) place as the other stuff I am going to need.

Thanks

[stevengates45]

Yea, if none of that seems to be the problem, just try something simple & make sure your motor mounts are tight???:confused: