Carbs frezing, cold engine, fuel starvation or ignition

[oneshortplanck]

ive been losing power after 10 mins of 60mph driving, dip the clutch and the engine dies off, pop it in third and it revs up and will work again for another 10 mins and then die off again. a bit of choke also solves the problem. so too does pulling over to the side of the road and waiting for a bit.

also it only happens on a cold frosty day;

got the heaters on full and therefore less spark? - doubt it

crap in the fuel lines and tank, blocking the carb needles - all seems clean and have fuel filteron, also twin carbs so wouldnt cut out fully would it?

finaly, cold day, coldr air, colder carbs, are they frezing up? - again twin carbs, so would they both stop giving fuel/freeze at the same time?

has anyone else had this problem???? any tips??????

[xvivalve]

Wilksey uses his Sprint daily. During the winter he runs old vacuum hoses from his airbox around the front of his engine so the air intake comes from over the exhaust manifold; claims it stops this happening.

[Jon Tilson]

This is classic fuel starvation caused by carb icing. SU's by nature of the needlin a hole design arent so prone to this as other carbs because the needle moving breaks up the ice that stops the fuel flow. Its only likely to happen at all in a steady cruise, as youve found. Pulling the choke will break the ice and off you go again.

Its annoying but rare enough for Triumph to not bother solving it until the TR7 came along.
I suggest you take off the inlet hoses, which I do in winter, if you still have them or duct in soem warm air as Wiksey has...

Jonners

[rolf]

I had icing on my SU's. I used K&N filters. As I stopped at a traffic light or a jam, the engine was revving on high, static RPM's, it took a minute and when the heat of the engine removed the ice, RPM went down. Only on cold, wet days that was.

[DavePoth]

It never affected my car, but then it sucks warm air from the engine bay. Taking the air hoses off the box sounds like a good solution to me.