leak test help

[nick20555]

I am currently leak testing my blaster and I know I have a leak because it will loose about a pound every 15 seconds.

I got a spray bottle with soapy water and sprayed every square inch of my motor and the leak tester to make sure. I put my finger on the crankcase vent tube to make sure it isn't leaking thru that and still nothing.

I don't know what I'm doing wrong. Any ideas or thoughts as to where to look or what I'm doing wrong. I checked the reed cage connection and everything.

 

[nick20555]

Does the piston have to be at a certain point in its stroke?

 

[Fast6hand]

Make sure the spark plug is tight. Also, put a thin layer of grease around the exhaust plug, and the intake plug. The part that goes into the boot. Or you could be leaking out the crankshaft seals. Test it without flywheel and clutch basket on so you can spray those seals. Good luck!

 

[dirtysquared]

Spray your leak down tester as well. Check all threaded and barbed connections. Check your exhaust plug as well. Its possible they could be leaking off air.

Spray the Bottoms of your cases looking for cracks. I had a set like that one time, and it took me awhile to catch it.

Another way to check the crank case vent is to put the tube in a cup of water and look for air bubbles.

 

[nick20555]

I didn't check the spark plug connection so I'll do that. The exhaust, I put some inner tube rubber smashed between the port and flange so that's tight. I will put some grease on the intake side but I sprayed that so I don't think that's it.

I figured if it's the clutch side crank seal then it would leak out the vent tube and if it was the flywheel side seal then it would leak on the stator cover connection.

 

[Fast6hand]

You might not see it leaking out the stator cover. There's so much area on the seal, it may not be enough pressure to catch it. You would really need to check it at the seal.

 

[nick20555]

Ok. If it comes to that then I'll take it off and check seal. But the vent hose should be enough to see if the clutch side is leaking wouldn't it?

 

[Fast6hand]

Yes I would think so.

 

[nick20555]

It's not the stator side seal. Just checked. I think I'm just going to put some yamabond on the intake just to be safe. Where do i put it? Before and after reeds? Should both before and after reeds have a gasket as well?

 

[Fast6hand]

It's not the stator side seal. Just checked. I think I'm just going to put some yamabond on the intake just to be safe. Where do i put it? Before and after reeds? Should both before and after reeds have a gasket as well?

I put it on both sides of the gasket. Put a real thin layer, and don't over torque the bolts.

 

[nick20555]

I have a gasket between reeds and intake and another gasket between cylinder and reeds. Is that correct?

 

[Fast6hand]

It should be one gasket between cylinder and reed cage. The manifold seals itself to the cage, but I put some yamabond there to for safe keeping. Remember a little bit goes a long way.

 

[nick20555]

I tried that and it leaked as fast as I could pump it in so I went back to the gasket. I'm still losing about a pound every 30 seconds but every now and then it will hold around 5 or 5.5 pound and very rarely hold 6. Other times it will go down to 3. I have no idea. I have checked every part on it. Made sure everything is torqued properly and can't find it anywhere

 

[pudvah]

I was having almost the same issue except mine wouldn't ever hold pressure so I couldn't find the leak. Ended up having a cracked case thankfully KOR had some. Have you broken a chain recently ?

 

[nick20555]

The whole reason I decided to leak test it was because I couldn't get the air screw setting to cooperate. I had it idle and I'd turn it one way or the other a half turn and wait for the rpm to respond and it would just stay constant even it I did a full turn. I eventually just set the idle to barely stay alive and then at about 1 1/2 turns it would die and then at about 4 1/2 turns it would die but between those ranges it would keep the same idle. So I decided leak test.

 

[nick20555]

I was having almost the same issue except mine wouldn't ever hold pressure so I couldn't find the leak. Ended up having a cracked case thankfully KOR had some. Have you broken a chain recently ?

KOR is the one that built and reassembled my motor so that's why I didn't really even think I would need to leak test it cuz I figured he probably leak tests the motor before it's sent out if he takes the time to do accurate compression tests for you.

 

[pudvah]

I'm sure he does leak test every engine he sends out. Gotta be missing something. Did you do three heat cycles and then retorque the head and base bolts? No WOT the 1st tank of gas ?

 

[Blaaster]

Put the end of the vent tube in a jar with water in it bubbles may appear.

 

[Larry's Shee]

KOR is the one that built and reassembled my motor so that's why I didn't really even think I would need to leak test it cuz I figured he probably leak tests the motor before it's sent out if he takes the time to do accurate compression tests for you.

Call the builder.

 

[nick20555]

Thanks for the help guys. Its just frustrating putting literally hours in just trying to find a leak that isn't always consistent. Like I said before, every now and then it will hold at 5.5 give or take a pound but most of the time its leaking still.

If I can get some more time this evening I'll run over to our shop and put the vent in some water and I'll retorque the head and cylinder. I did my heat cycles and I'm about 3/4 of the way thru my break in tank without any WOT yet. I was wanting to try and get my air screw/pilot and my needle right while I was breaking in and then after break in, start on the main but I need to find this leak first.