Running on when hot

79 250 OR carburates great from idle, part throttle, and full throttle but when hot it runs at very high idle and if I miss a shift the engine is screaming. When I stop it takes time for the idle to settle down. I am thinking float/needle seat issue. It is sometimes hard to start due to wet plug also. Any ideas. Plug color is absolutely perfect. I have tried the air screw in and out but no luck.

Check your spark arrestor is not blocked.

engine seals leaking when hot? split in the inlet manifold? my bike used to run on after landing from a jump or dropping the front wheel down hard as the split in the lower half of the manifold would open letting in a heap of air. took a while to figure it out as it was split on the step up and very hard to see.

Sounds like a vacuum leak.

After you have checked the inlet for air leaks, go up on the pilot jet if it still persists and see if it is any better...

Andy

Check slide could be worn out too much clearance in bore of carb..

If the carb checks out ok, a leak down test is probably the next step.

The pilot was 2 sizes smaller than stock. I went up one to a 40 and man it starts, idles and revs much more freely. I have not ridden it yet but I suspect that it should be much better. I also lowered the float level allittle.

good job ! well done

a simple fix is always a great relief.....said the bishop to the barmaid...

Well it is not fixed. I raced it this weekend and still running fast. It starts and off idle is awsome. I think I need to look at the intake when the engine is hot.

Check the stator side crank seal.

Paw Paw

Do a leak down test to find out exactly where the leak is. I am just making a tester now, so I'll post some pictures when I have all the bits together. If you just start replacing stuff at random you will never know for sure. The favourite is always the stator side seal as PawPaw said above. But it could be something else.
I have seen Motion Pro sell a kit for $189 plus shipping (to the UK it is expensive). I reckon I can make mine for $20

Do not forget to check your timing as retarded timing will give you and engine that run hot