oil on the good foot

[bikerphil]

When reinstalling the timing plate it could go on 2 ways 180 off or right

Yes it can, but if you look at it closely you will see it is offset so it properly fits only one way. Yes, it could be forced on 180 deg. off.

If you remove the valve cover and check the valve clearances with a feeler gauge, you will find the bent valve(s) fairly easily. The clearances will be huge compared to the unbent valve's normal clearances.

[speedlimit85]

I think the chain failed. The compression test is hard to do with the bike running so bad. I tried to be wide open throttle. The test showed the left 2 cylinders at half and the right 2 are good, I think.

I wiil look again to see if I forced it 180 off.

[bikerphil]

To do the compression test...

Remove all 4 spark plugs
Attach gauge to cylinder #1
Hold the throttle wide open and crank 10 seconds until the highest reading is acheived
Write down the number and move on to the next cylinder

Don't do the test with the engine running if that's what you did.

If/when you check the valve clearances, with the engine cold, they are...

.004"-.006" intake
.008"-.010" exhaust

They would be much, much larger if there is a bent valve.

Never seen a chain fail, the bike wouldn't run at all if it did. They need to be changed every 60K with the stock tensioner. With ACCT, they can go much further. I have one running with +125K on it.

[speedlimit85]

You are right. The timing plate is on right.

I redid compression and now get 0 on all 4

I may be making it worse by running it

[speedlimit85]

ok will do now

[speedlimit85]

Looks like it bounced to 90 on all 4 so compression is good.

[bikerphil]

Well, they are all even, but they should be around 140.

Something is amiss.

You did hold the throttle wide open when cranking right? Is the battery weak?

[bikerphil]

My guess would be the chain skipped a couple teeth and the compression is low as a result. Only way to verify would be to remove the valve cover and see if the dots on the cams line up with the arrows, with the crank at TDC.

[speedlimit85]

Yes the battery is good and I held the throttle open with the plugs out.

I think one of the times the timing plate went on wrong and I adjusted the chain.

Sounds fixable.

[bikerphil]

Anything is fixable, hopefully it's just off a few teeth. Let us know when you have the valve cover off.

[speedlimit85]

Can you tell me the easiest ACCT to get for my bike? This may be the time to do it.

[bikerphil]

Yamaha Vmax, 85 and up to 2000. I usually try to get one closer to 85.

[speedlimit85]

https://suncoastcyclesports.com/yama...ain-tensioner/

Part is off a 1986 Yamaha VMAX

Yamaha VMAX V Max Rear Timing Chain Tensioner

This one?

[bikerphil]

Yes, that's it. You will need to use 1 size shorter bolts with this Vmax unit, the XS tensioner bolts are too long.

[speedlimit85]

cover off...what to look for?