New Kibble Whites and HARD To kick over??

jimt_yz400

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Dec 25, 2000
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Hello Dirtrider friends! :)

I haven't posted for a very long time but I thought I would toss a problem out to you all.
I have replaced valves many times in the many CRF450's that I've owned but I thought that I would give the Kibble Whites a go this last time around. The guides were in great shape and I had the seats cut for the new valves. I assembled the head myself. Everything went together fine and I adjusted the valve clearance, we had to use larger shims for all valves (for example 210 to 235 on one of the exhaust valves, I didn't think this was a big deal).
It's very hard to kick over; it runs like a raped ape though!
I checked the compression release clearance and if I read the manual, while at TDC, valve clearance + .014 = compression release clearance: ie: .012+.014 = .026 so the compression release should be .026 in.
That is what the clearance is, .026.
I checked the alignment of the cam and it is right where it should be ( I have had the cam in one tooth retarted and it was difficult to kick over, but had lots of low end! ).

With these valves is the kick over to start the same as it would be with the stock valves?
Is the stiffer valve springs causing this?
Am I not measuring the compression release correctly?

Thx in advance!
Cheers!
 

Ol'89r

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Jan 27, 2000
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You may have too much clearance in your auto compression release. Reset it to .014". Don't add the exhaust clearance to it.

The stainless valves or new springs will not make it harder to kick over.
 

jimt_yz400

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Dec 25, 2000
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ok, I'll check that. Do you need to keep the feeler gauge in between the ex valve and the lifter ( so it doesn't move) when measuring the gap between the compression release lever and the lifter? Otherwise the lifter will compress to hit the shim on the ex valve.
I'm just trying to get the correct procedure to measure the gap.
 

Ol'89r

LIFETIME SPONSOR
Jan 27, 2000
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jimt_yz400 said:
Do you need to keep the feeler gauge in between the ex valve and the lifter ( so it doesn't move) when measuring the gap between the compression release lever and the lifter? .


No. Only use the .014" feeler gauge in between the compression release lever and lifter. If you are adding the valve clearance to the compression release lever clearance, you will have too much clearance and the compression release will not open the exhaust valve enough.

That is most likely the problem.
 
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