I'm looking at buying a 450r, but I've recently heard that the valves on the TRX450 require constant adjustment...is there any truth to this, or is this just another rumor? Why would this be an issue? Any of you guys that already own one have this issue?

No Honda bashing please, if you're a Yamaha owner and don't like Honda's, stay out of the Honda forum!

 

bump...im interested 2

 

If they needed constant adjustment it would be because of wear and i doubt honda would build an engine with excessive wear in the valve train.

 

I was about to ask a question like this too. The day i bought my 450r the mechanic was going over the quad with me. I asked him if i should adjust the valves after i get it broken in and he said no, i wont have to get my valves adjusted for quite some time, like next year. He told me it was because they are the under bucket shim type. I dont know if hes right or not, i would like some info on this subject too.

 

If they are bucket under shim, then that means a lot less worry about adjustment. But, when you do adjust be sure to have some shims. Finding them isn't easy for these quads.

I wonder if they take the same type as the Z400... I know I went to my local MC mechanic and he had a whole load of shims, but they were the big ones (quarter size), not the ones I needed (hearing aid battery size).

 

I think many guys worry way to much about valve adjustment. I have been doing engine work on quads for 20 years and unless there was something wrong with the engine allmost all the valves have been spot on regardless of age or mileage. I dont include highly modded engines in this statment .

 

Check out this picture:

TRX450 Top End

Did they remove the buckets for display purposes, or is this NOT shim under bucket design?

 

I'm not very experienced with this, but that looks to me like a spring, valve seat, shim, and rocker arm. In that order, with the rocker arm directly on the shim. Shouldn't there be a stainless bucket that covers the shim and seat, under the rocker arm?

 

To me, the 450r is a screw and lock nut valve adjustment. Ussally and shim and bucket is for a DOHC. The cams run on the bucket, one for the intake, and one for the exhaust (Z-400 for example is a shim under bucket). The 450r is a SOHC, so rocker arms are needed, and the screw and lock nut is the popular way to adjust.

 

Okay, hopefully this will reduce some confusion...or add more... [img]i/expressions/face-icon-small-wink.gif[/img]

Check out this picture:

CRF450 Top End

I bet the intakes are shim-under-bucket design, since they are directly actuated by the cam. However, I still don't see how the exhaust valves are adjusted. The only thing I see is the adjustment for the decompression lever on the bottom exhaust rocker arm... [img]i/expressions/face-icon-small-confused.gif[/img]