2 stroke pressure test question? with pictures help

[curtis slawson]

hey im doing a pressure test on my bike,

do to loss of bottom end oil plug smell's like a 4 stroke :naughty:

Im havein trouble with the powervavle shift linkage im lossin all the pressure threw that hole. I was wondering how should i plug that hole :wondering

cause if i put my finger over the hole it hold pressure. welll here's the picture

also the powervalve linkage cover was leaking air there too what damage could that cause to the motor
thanks

[cr480r]

i would try using a ball of clay

[curtis slawson]

ya i will try some clay tonight . and also i was looking at my crank seal bushing has 2 groves on it guess it's from the were from the seal? here some more pictures

and would this cause bottom oil loss from crank seal

http://i51.tinypic.com/33xiwt3.jpg
http://i52.tinypic.com/330baxf.jpg
http://i51.tinypic.com/33vofug.jpg

[curtis slawson]

anybody? humm

[4cylinders]

hey, the crankcase doesn't hold oil. the seals are for pressure/ vacuum. the trans has the oil for lube. trans oil loss is either a leak to outside, or hole in crankcase sucking it through the cylinder.

[Dirtcrasher]

The crankcase DOES hold oil (I guess it's all in what you call the crankcase), the combustion chamber does not, it's lubed by the premix and the reason for this test.

The crank seals can suk in crankcase/clutch. That spacer you've shown came from behind the primary gear and out of the seal cavity I imagine? If you can feel that groove with your fingernail, then I'd replace the seal and collar/spacer. Some of those spacers you can flip around as long as they don't ride on the seal surface again.

The other problem is worn main bearings that let air in the left side or oil in the right side.

Be sure to look for any up and down main bearing play by grabbing the crank ends and checking the play.

I had an RM250 waterpump seal cut a nice deep groove in the shaft. Had to have it Tig welded and turned down smooth again........

[j4duncanr]

you need to go to duncanracing.com technical documents 2 stroke pressure test.read down to where it talks about suzuki 500r with powervalve it willl tell u what u need to do.i did this yrs ago on that bike and got perfect results.

[cbx1170]

Read and think about the Duncan Racing pressure test real hard. Idea is to find out if either crank seal leaks. ignition side to atmosphere, trans side IN TO trans. if you pressure test like they say to BOTH SIDES of trans side crank seal you are now reduced to ONLY testing Ignition side seal ....... and head and base gaskets and intake and exhaust plugs!!!!!!!! THINK HERE. ISOLATE WHAT YOU NEED TO TEST.

Their test needs to isolate power valve leaking and STOP it from going into transmission area to be a valid test of the trans side crank seal.

SAME with vacuum testing!!! Think about what you are testing. 6 PSI Pressure and 6 PSI vacuum with <1 PSI per minute loss either way.

[curtis slawson]

The crankcase DOES hold oil (I guess it's all in what you call the crankcase), the combustion chamber does not, it's lubed by the premix and the reason for this test.

The crank seals can suk in crankcase/clutch. That spacer you've shown came from behind the primary gear and out of the seal cavity I imagine? If you can feel that groove with your fingernail, then I'd replace the seal and collar/spacer. Some of those spacers you can flip around as long as they don't ride on the seal surface again.

The other problem is worn main bearings that let air in the left side or oil in the right side.

Be sure to look for any up and down main bearing play by grabbing the crank ends and checking the play.

I had an RM250 waterpump seal cut a nice deep groove in the shaft. Had to have it Tig welded and turned down smooth again........

ya that spacer came outta the seal cavity i can put my finger nail into that grove pretty deep on both groves

and also the crank has no play in bearings

[cr480r]

is that seal collar directional? or could you flip it so the new seal rides on a fresh surface? if you can feel the wear it needs to go... and definately replace the seals while you have it apart... even if they test fine now doesnt mean they will in the future..

[curtis slawson]

there some pretty deep groves on the spacer i think that's the resson for bottom end oil lost . The space look's like it can be put it both way's but the part is only 10$ for a new one might as well put new one in. and also found a air leak around the power vavle linkage cover that was letting in air into the motor an i never knew about befor would this cause the crank seal to go too?

[cr480r]

The space look's like it can be put it both way's but the part is only 10$ for a new one might as well put new one in.
yeah definately a good move.


found a air leak around the power vavle linkage cover that was letting in air into the motor an i never knew about befor would this cause the crank seal to go too?

a leak in the powervalve cover is no big deal, unless it leaks oil... it only needed to be sealed for testing purposes.. You may as well fix it, but it should have no affect on air leaking in or out of the crankcase during operation.

[curtis slawson]

here the problem iv notices on part of the power vavle cover it rounded off a little bit so it dosen't sit supper flat on to the cyilnder where the cover gose.

ya the valve case leaks had allways done this . but never has it loss bottom end oil befor do to the leak on the cover. but i am gunna make the case flat so it sit proper on the cylinder

[j4duncanr]

what do you mean by bottom end oil loss where are you losing oil at???