Hi all,

I would appreciate any ideas as my Jumbo is now generally running fine but when going down a hill or slope with the throttle closed it needs the clutch pulled and a bit of revs to clear it out before going on. You can use the decomp.-valve to clear it but a few revs are better. One thing I must add is that it has a rear silencer from the TL320 which has 2 smaller exit tubes (th Jumbo should have one bigger one). The silencer is not restricted though. The carb was jetted according to the works specs. without reed valves as from the engine number it should be a late bike.

Hi Ian, what ratio are you running ? Have you repacked the first box ? Has it had a decent run at speed to really clear the exhaust out. The first pipe can also be full of carbon, I stuck a hot air paint stripper in one and it burnt for a long time.

Hi Ross,

can´t really answer the question about ratio as the bike was standing for about 1/2 a year.

First box hasn´t been touched.

It was run quite well today and didn´t smoke.

Did the tail pipe with the hot air gun last sommer.

I will get the middle box off and give it a burn out.

Can also try some better quality petrol but something tells me thats probably not going to help as it runs just fine with bags of power and picks up great as long as it isn´t rolling with the throttle closed before and as soon as you pull the clutch and give it just a few revs all is well (my bike has a lovely light clutch with no slip).

Ian

Whens the last time you cleaned the carb out ?

You tried running it a little richer on the petrol screw, of experimenting with needle position ?

It is a while ago.

Yes played around with running it a bit richer.

I´ll do some basics clean the carb, new plug, middle box etc. (points and cond. are new ones).

I was wondering if this is a problem that was common. For example the Beamish RL325 does the opposite it fires a few times with the throttle closed.

Is it not just the float needs adjustment?

@baldilocks: thanks will check that out when doing carb.

@b40rt: Ross I have had a nights sleep and think you may have hit the nail on the head with the middle box. Be testing and cleaning out first asap !

Cheers

Ian