CBX Top End Mess


haden2342
New Member & Happy To Be Here
New Member & Happy To Be Here
Posts: 15
Joined: Sat Jul 23, 2022 4:30 pm
Location: Oregon
Location: Oregon

Re: CBX Top End Mess

Post by haden2342 »

I tested all the valves by pooling some gas in the head and I found that most of the exhaust valves were leaking, some badly. The exhaust valves didn't clean up all that well so I think that may have been part of it, but I had planned to lap the valves anyways. I lapped 3 valves in cylinder 6 and got the leaking to mostly go away, but I noticed that put the valve seats way over the service limit for the exhaust and near the limit on the intakes. I figured before I go any further I should take the time to measure all the valves, guides, and seats which I know I should've done first. I found that I should probably replace all the exhaust valves and maybe the intakes as well. The guides seem to be in good shape as well as the springs and buckets. Given these measurements below, does replacing all the valves and getting the seats cut sound like the right choice?
ValveMeasurements.PNG
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daves79x
ICOA Technical Director
ICOA Technical Director
Posts: 4801
Joined: Sun Oct 01, 2006 8:05 am
Location: Knox, PA
Location: Knox, PA

Re: CBX Top End Mess

Post by daves79x »

Just figure on replacing all the exhaust valves. If you bead blast the intakes valves, they should lap in OK. The Supersport Shed carries a really nifty set of valve seat stones/cutters that make this job so much easier. The stones clean up most valve seats without removing much material. Cutting the seats leads to other problems (very thin shims mainly). Don't worry about the guides unless they are cracked. More trouble than it's worth to change them.

Dave

haden2342
New Member & Happy To Be Here
New Member & Happy To Be Here
Posts: 15
Joined: Sat Jul 23, 2022 4:30 pm
Location: Oregon
Location: Oregon

Re: CBX Top End Mess

Post by haden2342 »

Sounds good, that's what I was leaning toward. Thanks Dave.

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