decompressor clearance ?

[HRC_rider]

I checked the valves on my '05 R last night for the first time and the decompressor clearance was way out of spec but the valves weren't. The left side intake and exhaust valves were right on at 0.006" and 0.011", the right was .005" and 0.010". The decompressor clearance was greater than .024", the largest guage I had. The decompressor was working but why would it have been so far out of adjustment? The lock nut on the screw was tight. I set it to 0.016" but haven't been out for a ride yet and I'm wondering if I did something wrong?

[fast-trx450r]

was it pretty hard to kick over before you adjusted it? i would think so unless you are conan the barbarians younger brother. jk :D
tightening it up to .016 with make it easier to kick but it might not start too well. you need good compression for quick starts. the bible(honda service manual) says 100 psi cranking compression when adjusted properly. i have a hc2 cam and mine is set at .024 to get the 100 psi. stock was .018. bigger cams should need more decomp clearance to make up for the extra overlap bleeding off comp.

[compedge]

I forget what my clearence is. But it is set to 85 psi and it starts first or second kick every time. with a hot cam 2

[cals400ex]

with the stock cam the decompressor clearance is supposed to be the right exhaust valve clearance + 0.006". so if the right exhaust valve clearance is set too 0.011" the decompressor clearance should be .011 + .006 = 0.017. with the HRC cam the decompressor clearance should be the right exhaust valve clearance + .010".

[shamisc]

Originally posted by cals400ex
with the HRC cam the decompressor clearance should be the right exhaust valve clearance + .010".

Not doubting your comment, but where did you find out that info? I've got mine set at .017 with the 02 CRF cam, should I change it?

[Tripyn]

Cals, the info you got over on the .org from 450RRR is correct but that is for an 06' not the 05'

06' is +0.10 for any Honda cam including the HRC

05' is +.006 This is stock-HRC specs is +.010

On the 06' the only time you need to increase from stock is when you have an aftermarket cam-like a hotcam.

[HRC_rider]

Are the intake and exhaust clearances the same for the HRC cam and the stock cam? I'm running the HRC cam so it sounds like 0.016" is too tight for the decompressor and it should be at .020". I rode it all weekend and it was harder to start but ran fine.

[pug288]

Has anyone had the decompresion spring break. Mine did and it is rattling something bad. I hope that is all that is the matter eith it.

[Tripyn]

HRC_Rider, from what I have read on the 05' the total decomp should be this:

Stock= exhaust clearance .011 + .006 =.017 +/- .001
HRC = exhaust clearance .011 + .010 =.021 +/- .001

The intake I am not sure, I would assume they stay stock:
at .006 +/- .001

The cranking compression on an 05' is much higher then an 06', -some people set their decomp by this. Maybe someone with the 05' HRC manual will chime in here with the info right out of the HRC manual. If not check over on the .org-plenty of 04/05 owners over there with the HRC kit installed.

[cals400ex]

Originally posted by shamisc
Not doubting your comment, but where did you find out that info? I've got mine set at .017 with the 02 CRF cam, should I change it?


this info came from my manual that came with my whole HRC kit for the 04-05 450r's. i honestly don't know what your clearance should be with that CRF cam. i have not used that cam nor have i read anything about it. sorry.

[HRC_rider]

Unfortunately I don't have the HRC installation manual since the dealer installed the kit when I bought the quad. I've got all the stock parts in the box but no paperwork:( so I was using the specs for the decompressor in the service manual although I thought there might be some differences with the HRC cam. Thanks for the info cals400ex! I'll be opening it up a bit to 0.020". What about the intake and exhaust valve clearances? Are they the same, 0.006 and .011?

[cals400ex]

the only difference is the decompressor clearance in terms of adjustment specs. ;)