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GP200 poor starting/running

Posted: Sat Mar 08, 2014 7:33 pm
by vRSG60
I have a SIL GP200 refurbed by Rayspeed with 260 miles on the clock.
It's been fine up until today. Now It takes forever to kick start hot or cold. Worse when hot.
When it is running it splutters at quarter throttle like it "missing" and can take a while to rev. I stripped the carb to give it a clean but it's still the same.
Jetex 22mm SOI-100 carb with jets pilot 48, main 128, choke 50. Slide don't know didn't take it out.
The main 128 one unscrewed from another (Atomiser) but that didn't have a marking on it.
Rayspeed Fresco exhaust.
When I do get it going it seems better to hold the throttle wide open when kick starting it.

Air screw tried at half a turn out and three quarters out, no difference. Plug wet when I took it out and before it starts fuel in the rubber bellows.

Any ideas other than Jetex are s**t.

Re: GP200 poor starting/running

Posted: Sat Mar 08, 2014 8:09 pm
by mick1
Not too familiar with Jetex carb's but the main looks big, id have thought 112 would be nearer the mark. the fuel in the bellows is usually sorted by a small hole in the bottom to allow fuel to drain (fuel in bellows is normally a cause of poor starting when warm).

Re: GP200 poor starting/running

Posted: Sat Mar 08, 2014 8:20 pm
by bristolmod
main jet around 118/123- use Dellorto branded jets/ atomisers etc as well

Chris

Re: GP200 poor starting/running

Posted: Sat Mar 08, 2014 8:43 pm
by vRSG60
Thanks both, Yes I thought a 123 main and a 45 pilot were closer to the mark,
I tried to put a 1mm hole in the bellows but it just closes up.

Re: GP200 poor starting/running

Posted: Sat Mar 08, 2014 8:53 pm
by Weston-scooterist
I wouldent alter the jetting, i had the same size on my 200, 122 is factory standard, i had 128 with an ancilloti. I reckon it could be the pickup on the stator, i had similar symptom when hot, assuming air filter is new

Re: GP200 poor starting/running

Posted: Sat Mar 08, 2014 8:55 pm
by dave wheeler
sounds like its flooding, check your float needle is sealing correctly

Re: GP200 poor starting/running

Posted: Sat Mar 08, 2014 9:14 pm
by cgt75b
Put a new Dellorto carb on it and forget about starting problems, I have had the same issues. Looking at your set up I think the pilot is too big. And ignore what it says on the carb about 3/4 max turned out. Start at 1 1/2 turns out. Also check that the pin for the float is pushed all the way home in the carb body .

Good luck hope this helps .

Ps start the scoot without turning the fuel on there should be enough in the bowl for it to start. Once it's running then turn the fuel on. Likewise when refueling turn fuel off just before stopping this method used to work for me.

All the best happy scootering :D

Re: GP200 poor starting/running

Posted: Sun Mar 09, 2014 11:58 am
by vRSG60
Thanks all. What are Mikuni carbs like? I've ordered a 123 (couldn't find a 123) main jet and a 45 pilot.
I'll look into getting a different carb too.

Re: GP200 poor starting/running

Posted: Sun Mar 09, 2014 8:39 pm
by boris
You say 260mls since you had it refurbed.
Take it back to AF.

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Re: GP200 poor starting/running

Posted: Mon Mar 10, 2014 10:26 am
by shocky
boris wrote:You say 260mls since you had it refurbed.
Take it back to AF.

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What ^ said