hydrolocked engine grrrrrrrrrrrrrrr

[farquare]

well, i had the valve covers off today and the clearences on the front and rear cylinders are within spec.

When turning the bike over on the crank with no plugs in there is definite sticky bit which i'm guessing is not normal. I'll get a shot of a comp tester and see what i can see.

Does this give anyone any more clues.

Hi still sounds like a bent conrod to me

Gaz

[muzikill]

turn the engine over by hand at the stator and keep an eye on the camshafts if everything looks fine then you need to dig deeper into the engine

[farquare]

Yes, all looks fine spinning the engine over with the valve covers off.
Would it be possible to have valve damage but for the clearances to be okay, or would this always manifest in clearances being higher than expected?
Comp tester should help narrow down where the prob lies.
I've been told that the rings could be damaged by oil in the clyinder, so once I see where the issue is some oil in the cylinder should rule that out too.
If you were to pay someone to repair valves or change a rod do you have any ideas what kind of charge i'd be looking at?
On the other topic, does anyone know if you can fit later clocks onto a curvy and what wiring needs done?

Sent from my U20i using Tapatalk

[yorkie_chris]

Repair valves is big PITA, easier to buy replacement head.
Couple of hours labour at least, not cheap. Same with rod, plus it depends what else is damaged.

To use late clocks on curvy you just need to wire it all up a bit different and use a couple of cheat circuits, you need to use MOSFET trigger on rev counter or it jumps about and couple of resistors for fuel light. Depending what year of clocks you using.

[farquare]

done a quick compression test tonight and i was scratching my head at the results.
Front clyinder compression was more than the front but both were really low.

Just looked at the manual after putting everything away for the night and realised i didn't do it with the throttle fully open which would explain the weird readings...........

i'm a plum.

I'm struggling to figure out what difference the throttle position makes to a cylinder compression test. I'm not saying it's wrong, just that I don't understand why.

[yorkie_chris]

The throttle creates a partial vacuum in the cylinder. If you squash less air into the same space there is less pressure.

Originally Posted by yorkie_chris

The throttle creates a partial vacuum in the cylinder. If you squash less air into the same space there is less pressure.

OK, so it's not the throttle as such thats creating the vaccum, it's the downstroke on the cylinder sucking on the manifold and creating the vaccum because the throttle is closed and no air can get in, so when the piston comes back up on the compression stroke, there is less air in the cylinder.

Having the throttle open relieves this vaccum on the downstroke.

I wasn't thinking about the air getting into the cylinder, I was only thinking about what happens on the compression stroke when the valves are closed and the air is already there, at which point throttle makes no difference.

[farquare]

okay, done the compression test correctly tonight, and results are as follows:

rear - 11.5 bar 165psi
front - 12.4 bar - 175psi

so compression test seems okay, valve clearences are okay, swapped the plugs and it still only runs on the rear.

i will try swapping the coils round just to rule them out but this is looking like a fuelling issue.

i have been advised to drain the float bowls, can show me a link to some pics on how to do this, i've had a quick look and cant see anything on the forum and the manual isn't very clear picture wise......

any thoughts?