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triumph twenty one 3ta 350cc 1958

1.7K views 4 replies 4 participants last post by  Tritn Thrashr  
#1 ·
I am having problems with my bike. I can get her started she runs fine but once she is hot and you turn her off she wont restart. I have rebulid the carb, changed the plug, distributor cap, leads, also cleaned and rest points. Anyone any other ideas what it may be. Compression test is 110 on one and 140 on the other.
 
#2 ·
Bill, possibly the fuel is evaporating in the carb so tickle the carb and try again. If the bike runs out on the road, it is not so likely to be all the parts you have changed. Welcome to the forum. Not many people here with a 3TA but a lot of knowledge.
 
#3 ·
As well as needing tickling when hot, my Triumph only starts hot with throttle completely wide open. Until I started doing this I couldn't start it hot, and dreaded refueling, or any stopping.

If it's just 'a bit' hot, it's a bit more tricky, tickle and throttle open 'a fair bit '. How much depending on how hot.
 
#4 ·
My T120r nearly always requires tickling when hot to ensure a first kick start up. It would normally start without tickling but i dont have the leg strength to try too many times.
Bill, your compression readings are quite a bit different but if it is running well, keep riding it and check again later. Might only be a small valve seat leak. That compression is quite good for a bike that normally has 7.5 to 1 pistons
 
#5 ·
At least tickling it when hot is cheap to try.

May we assume the valve clearances are set?

If you’re doing the compression tests properly (hot, full throttle, repeated hard kicking until the reading stops rising), there may be something up with the 110 psi cylinder.

Test again with a teaspoon of oil in the cylinders, to temporarily seal the rings. If that makes no difference, you may get some benefit from checking the valves, seats and guides and fixing what you find.