New member with a stalling out problem.

[CaptainWombat]

First off let me say thank you for allowing me to join this forum. I’m a motorcycle collector, mechanic, seller, and trader. I run an eBay store out of Milwaukee WI.
Now let me introduce myself and my problem.
My name is Zak Hittman. Last fall I rescued a 1973 Hodaka Wombat. It was parked in a dry building for an estimated 30 years. I secured a deal, and brought it home. It currently has 1,400 miles and has nearly 180psi of comp.
Since being in my possession I’ve cleaned and set point gap, set ignition timing to book spec, replaced spark plug, replaced trans fluid with 50w, cleaned up some electrical issues, and installed a new battery and air filter.
Im not a restoration guy, I like to keep my bikes as original as possible.

Now my issue....
The Wombat starts, and runs. Good! Throttle response is great, shifts through all gears, and idles perfectly. When I first got it running it puked oil out of the breather however it’s possible I overflowed the trans.
When the bike is fully warmed up, it begins to sputter out and loose power to the point it dies. WILL NOT RESTART until engine is cold. Usually the next day.

I’ve been through the carb, replaced fuel lines, installed a inline fuel shut off valve....

Can’t figure it out.

Any help would be greatly appreciated.

[matt glascock]

Replacing the condenser may solve the issue with the bike crapping out when the bike gets warmed up. I wouldn't run it another minute without proving the case is air tight. Leak down test is an absolute must at this point. Incidentally, 180 psi sounds awfully high for a bone stock Wombat. Was the engine modified?

[thrownchain]

Shuts down when warm or hot it's usually electrical, most likely condenser, but could also be the coil, the condenser is cheaper to replace so do that first. When you did the compression check did you have the throttle wide open? If not you won't get the correct pressure reading. And doing a leak down test tells you the basic condition of the seals and gaskets as well as possible leaks in the cases.

[CaptainWombat]

Thank you for the tips. Took the bike out today, ran perfect for 10 minutes then started sputtering and loosing power. I looked behind me and it was basically big cloud of white smoke every time I’d get a little burst of power. I’m not a big two stroke guy, so this is all new to me.

[thrownchain]

Might be an idea to move the new condenser up next to the coil. There are a couple of conversations on how to do it. Use the search mode.

[matt glascock]

Another basic move when sorting out a bike that has sat for years (decades) is to burn out the pipe. Many descriptions of the process on this forum and elsewhere. Not necessarily an explanation for the thermal effect but I've found everything from mouse nests to rocks. The big cloud (poorly burned fuel charge) you describe is probably the bike being loaded up then firing again suggesting an ignition issue - likely the condenser. There is also the possibility that there is an issue with the ignition wiring due to the relationship between heat and resistance. Partially fractured wire or crappy soldering may be the culprit. May be time for a careful examination of the entire magneto and coil wiring and a condenser replacement.

[taber hodaka]

Well white smoke? I have seen hodaka,s loose power when they get hot because of a bad seal. Could be a bad seal on the flywheel side. It sat for over 30 years in dry storage , white smoke ? -------Clarence

[matt glascock]

Good point Clarence. My Road Toad developed a leak at the clutch-side seal allowing transmission oil into the crank case. Fouling plugs and dense white smoke were the symptoms leading to the leak down test. I'd go so far as to say the leak down test should be considered essential when putting a 2-stroke motor back into service.

[Bullfrog]

It is virtually certain that the seals have failed or in the process of doing so - clutch side seal seems suspect due to the white smoke reference. Actually, it is better that the clutch side seal failed before the magneto side seal. When the magneto side seal fails, engine seizure might well be the first noticeable symptom (not good). Note that the seal failure is not why the engine dies when it warms up. It is most likely a failing condenser which is the cause of that symptom. What's the world coming to? It seems ya'll just can't trust 50 year old rubber seals or condensers.
Ed