leakdown test revealed weird leak!

[Langbolt]

I did a leak down test on my ESR-330 today and it wouldn't hold 6psi for more than 10 seconds.....So I started spraying the windex all over the gaskets.

The intake, Exhaust & base all came up with no bubbles.

So off came the iginition cover to check the left crankseal.....nope she wasn't makin' bubbles.

So off comes the clutch cover .....clutch....and check the right crank seal.....then to my surprise I see bubbles.

But it's NOT the seal.

It's leaking between the crankshaft and the collar......as shown in the pic.

The collar doesn't have any grooves or look worn ???

ANYONE EVER see a leak here ?????

:(

[Honda 250r 001]

wow man thats really weird. maybe try some loctite on the splinds or something. thats really wierd i cant believe taht it would seal at all!

[C-LEIGH RACING]

Normaly I'll put a couple o rings inside that spacer to help with sealing.
It could be, if you have a leak with the two gears bolted in place, that spacer is deformed some on the inside & outside mating surfaces.
Clean those two gears good & the face of that spacer, apply a thin coat of Three Bond sealant to the gears & the underside of the cup washer & the bolt & it should seal that area.
You could just simpley mop some sealant on the crank & then slide the spacer over it.
Neil

[Langbolt]

Thanks Neil,

I've never in 18 years of rebuilding R-motors ever seen a leak there.

I see the inside of the collar has been cleaned up with some emery cloth (hatch pattern) maybe that's why.

I bought the bottom end from a friend who kept squeaking (seizure) the motor.....I wonder if this was the root of the problem.

I think I'll get a new collar and some o-rings to seal it up.

I'll keep ya posted on my results

:devil:

[86 Quad R]

i've had that happen with me a couple of times in the past........... i remedied it as neil described. :cool: it's now part of the building routine. ;) best be safe then sorry.

[machwon]

I would say you are using either a hot rods or wiseco crankshaft. The only cranks I have seen pass a pressure test in that spot is OEM. I've told both hot rods and Wiseco about how their cranks are machined there, but I doubt they have changed. I personnally use one of their 4mm cranks that doesn't pressure test, but it's never shown any air leak symptoms. The material used could be slightly different with a different expansion rate when it gets hot. I've done dozens of aftermarket cranks, none have had an issue on 250r's. It definitely doesn't give you a comfortable feeling about your engine though.