- Posts: 5
- Thank you received: 0
I think I bent my valves
- thenorm
- Topic Author
- Offline
- User
The motor was locked up due to water in the cylinders, and the odometer says 24k (what little history I have on the bike says this is probably correct).
So I tore the motor down for a quick and dirty rebuild.
1. Inspected the bottom end, all looks quite good, nothing done.
2. Replaced the jugs, pistons, etc.
3. Tore down the head, cleaned and inspected it. Yes, a valve job is in order, but it looks good enough to run. Cleaned the valves and entire head, checked the springs, replaced the stem seals.
4. Re-assembled with needed cam chain idlers, gaskets, etc.
5. Quick check of valve clearance: 3 need adjustment, but are not too far out, and ALL have clearance between lobe and tappet (all should close completely).
-
Now the first problem...
I turned the motor by hand slowly and it seemed to ever so slightly bind up. I should have stopped right here and investigated, but I didn't. Very, very dumb! Thinking this was just the new parts, I didn't look any further. After that it turned easily and smoothly.
It cranks under the starter just fine, but there's no compression in any cylinder. I pulled the valve cover and found the cams running in perfect sync, so there won't be any compression.
I fixed the cam position, and verified valves open and close with correct timing.
Re-check compression and I get:
cyl 1: 45psi
cyl 2: 0
cyl 3: 0
cyl 4: 65 psi
It's clear something is wrong but I gather more data:
Add 1 tblsp oil in each cyl and re-check compression:
cyl 1: 75 psi
cyl 2: 0
cyl 3: 75 psi
cyl 4: 100 psi
My theory is that the 180 out cam installation and subsequent turning of the crank bent some valve(s), no seal, no compression. The oil just helps slow the leak and probably helps build up the brand new ring sealing.
What do you think? If valves are bent, what generally needs to be replaced (just valves, or more?)
thanks,
n
1980 KZ1000 shaft
1992 EX500 ratbike
1987 Virago 535
Please Log in or Create an account to join the conversation.
- PLUMMEN
- Offline
- User
- Posts: 8139
- Thank you received: 104
Still recovering,some days are better than others.
Please Log in or Create an account to join the conversation.
- thenorm
- Topic Author
- Offline
- User
- Posts: 5
- Thank you received: 0
I was actually blown away how clean the inside of this motor was... what killed it was a small amount of water in 3 cylinders. Wasps got into the reed valve caps too, but all else was impressive.
Do you think the 180 out cam would have caused valve damage?
1980 KZ1000 shaft
1992 EX500 ratbike
1987 Virago 535
Please Log in or Create an account to join the conversation.
- PLUMMEN
- Offline
- User
- Posts: 8139
- Thank you received: 104
Still recovering,some days are better than others.
Please Log in or Create an account to join the conversation.
- thenorm
- Topic Author
- Offline
- User
- Posts: 5
- Thank you received: 0
Here's the thing though. In the 180 out position I caused (at TDC, the intake was correct, and the exhaust was 180 out), the lobes on the cams are pointing in the same direction, so the intake and exhaust will open and close at the same time.
The intakes should be happy, and the exhausts should be ok too since they are opening and closing as the intakes do...
or am I missing something?
1980 KZ1000 shaft
1992 EX500 ratbike
1987 Virago 535
Please Log in or Create an account to join the conversation.
- PLUMMEN
- Offline
- User
- Posts: 8139
- Thank you received: 104
Still recovering,some days are better than others.
Please Log in or Create an account to join the conversation.
- thenorm
- Topic Author
- Offline
- User
- Posts: 5
- Thank you received: 0
Thanks for your input. I'll pull the head and pay more attention this time.
1980 KZ1000 shaft
1992 EX500 ratbike
1987 Virago 535
Please Log in or Create an account to join the conversation.
- PLUMMEN
- Offline
- User
- Posts: 8139
- Thank you received: 104
Still recovering,some days are better than others.
Please Log in or Create an account to join the conversation.
- timebomb33
- Offline
- User
- Posts: 4288
- Thank you received: 10
1973 z1 2-1974z1-a,2-1975z1-b dragbikes1015cc+1393cc, 1977kz1000,1978kz1000,1981kz1000j, 1997 zx-11, 2000 z12r,1428turbo nitrous pro-mod and a shit load of parts thats all for now leader sask.,CANADA
I THINK MY POWERBAND BROKE
Please Log in or Create an account to join the conversation.
- PLUMMEN
- Offline
- User
- Posts: 8139
- Thank you received: 104
Still recovering,some days are better than others.
Please Log in or Create an account to join the conversation.
- larrycavan
- Visitor
i sunk a dragboat with a brandnew heavily breathed on Ls-7 454 in it with 30 minutes on motor, i put a bunch of pieces through the bottem of a kaw turbo cuz i didnt think welding the crank was needed with that little back tire,i put 5 rods through the sides of a small block chevy once,i drove my 61 chevy 1t 4x4 dumptruck across a good chunk of the platte river out to the sandbars to prove to my buddies in the jeeps it was no big deal,spent next 2 days cleaning mud/sand out of my axles but it was fun!:woohoo: ....... trust me ive done much stupider things in the name of trial and error!:laugh:
All normal things that occur in the lifespan of a gear head......Down the road, those are the funny stories that get told....
Please Log in or Create an account to join the conversation.
- irishwill
- Offline
- User
- Posts: 598
- Thank you received: 6
PLUMMEN wrote:
i sunk a dragboat with a brandnew heavily breathed on Ls-7 454 in it with 30 minutes on motor, i put a bunch of pieces through the bottem of a kaw turbo cuz i didnt think welding the crank was needed with that little back tire,i put 5 rods through the sides of a small block chevy once,i drove my 61 chevy 1t 4x4 dumptruck across a good chunk of the platte river out to the sandbars to prove to my buddies in the jeeps it was no big deal,spent next 2 days cleaning mud/sand out of my axles but it was fun!:woohoo: ....... trust me ive done much stupider things in the name of trial and error!:laugh:
All normal things that occur in the lifespan of a gear head......Down the road, those are the funny stories that get told....
I love you guys...LOL
Please Log in or Create an account to join the conversation.