LCGB Forums

I'm running a PHBH 30mm on my RT255cc, its never been a good starter from cold (10 kicks)
so i've finally decided to investigate
It has a No 70 choke jet this seems the standard for these carbs but you can get 75, 80, 90, 120.
The No 70 isn't blocked and the carb has been cleaned out, has anyone ever had to change a choke jet and how much did you go up.

I have tried without the choke just in case it was over jetted, the plunger does move all the way, I just want one kick starting it's not too much to ask

Sounds like you could have a hotter spark plug than required to cope with a tuned engine, if you have a standard one try that first. Just a thought.

St George wrote:Sounds like you could have a hotter spark plug than required to cope with a tuned engine, if you have a standard one try that first. Just a thought.

Plug used is NGK BPR 8ES
Ignition is the latest from BGM

Is it open mouthed or filtered? My mugello was a bi*ch to start from cold open mouthed but is now 1st or second kick from cold.Check your choke cable is operating properly and you dont have too much slack there.Also try putting your hand over the bellmouth and see if that makes a difference.

Choke jets aren't dear, £6/7 each, try a richer one. They start at 40 and go to 90 in increments of 5, then 90 to 130 in increments of 10.

I've got a 60 in my PHBH26, on Sunday I changed it for a 50 to see if I could get away with it, but I struggled to get it started. I'll put the 60 back in for now as I've no 55s.

Denis

Agree with hand/cloth over bellmouth. If it starts when you do this then you need to up-jet the choke. Another factor could be over retarded ignition, what's your timing set at and do you have an auto advance/retard ?

Train driver wrote:I'm running a PHBH 30mm on my RT255cc, its never been a good starter from cold (10 kicks)
so i've finally decided to investigate
It has a No 70 choke jet this seems the standard for these carbs but you can get 75, 80, 90, 120.
The No 70 isn't blocked and the carb has been cleaned out, has anyone ever had to change a choke jet and how much did you go up.

I have tried without the choke just in case it was over jetted, the plunger does move all the way, I just want one kick starting it's not too much to ask

Hi I'm having same problem did you ever resolve it cheers