Leaky Motor!

[Snopczynski]

Well I split a motor for a friend and let my cousin help me. I used 1104 on the case halves and fired the engine up about 3 hours after I sealed it up. Anyone know the dry time on 1104? Cause it looks like gas is leaking out on the left front of the motor when its running. Also, bike runs about 30 seconds with no coolant in it. I go to pop the radiator cap off and it hisses off like theres pressure in it. I never tore apart the top end, but this seems like a bad head gasket. With coolant in it, it built up quite a bit of pressure in about 1.5 minutes of run time. Any input fellas?

[swrbansheeboy]

i know that you know this already but a leakdown test will tell you where your fuel leak is coming from and may even show you your head gasket leak if the gasket is blown on both the inner and outer sides. in theory if the head gasket is only blow on the inner edge when you pump the motor up the air could escape to the coolant system and it should hold it since the radiator caps rated at 8 lbs ( correct me ) but thats if the test is done in the bike. as i've never done a leak down in the bike with the coolant system connected i can only speculate how you could get a false reading. either way, it sounds like you have a base gasket leak or maybe a base stud isnt sealing ( i had a motor that did this and i ended up pulling the base nut and gushing yamabond around the stud, after 2 years the motor still runs hard with no leaks) but i'd do a leakdown and see what i came up with since i cant see any reason to have fuel coming from the front of the motor unless it's overfueling and leaking from the pipe flange on the head and i know your smart enough to know if thats the issue... pull the motor and leak it down, fix the base gasket problem then leak it down again. if it passes after all of that then run it, if it's still building pressure then maybe the mating surface on the head is jacked up and needs to be trued. unless it's got o-rings and then maybe one got out of place on install. i know you know your shit but sometimes you cant see the forest for the tree's... i know i have gotten blind to a project like when i called my buddie to ask his oppinion about why my bike was running rich on one side and he said "did you turn the choke off??"....

[Snopczynski]

It's leaking out of the case halves, I never had the cylinders or head off when I split it. I was thinking of hooking up my cylinder leakdown tester though.

[theshee]

My 4 mil motor did the same thing one time with yamabond. Just split the cases again,clean the case halves with carb/ brake clean, and put em back together. I think I must have gotten something on the halves where they meet up and the yamabond just didnt adhear to it very well. Id bet your did the same. Just my 2cents.

[Snopczynski]

Sealed up the cases, thats ok now. It shifts good now, the 2-3 upshift problem under load is gone. I took the flywheel holder and put the right cylinder on tdc. Took off the radiator cap and pressurized the cylinder with my air compressor nozzzle. Bubbles in the radiator. So, just got to change the stupid stock head gasket. I like o-ring heads more.