Fuel starvation then high revs.

[Watfordwhite]

Thanks Grandpa,
Will give this a go. I may swap my Lambretta for a bus pass. More reliable...

[St George]

Hi Martin. Have you got a spare carb you can put on the scooter just to answer the question. Unfortunately all I have is my OKO and a new Jetex otherwise you could borrow one. Keep at it mate.
Regards Colin
PS all my electrics are finished Yipee.

[Watfordwhite]

Thanks Colin, yes I have the same carb on the 175GP so plan to swap over the weekend just to see if that's the problem.
I do hope for a ride out on Sunday on either the S2 or the GP.
Well done on yours. I might come down to Essex one day on the S2 for a ride out with you mate.

[Watfordwhite]

A great read for those of us with little / no carb knowledge

http://bristollambretta.webs.com/dellorto_manual.pdf

[Watfordwhite]

All working fine now. Stripped the carb once more this time with the diagram and below the float needle was a jet I didn't know as there. There was a massive bit of fluf in the jet. This was obviously blocking the flow and stopping the floats from closing. Blew that out. Rebuilt. Started first kick. Went for a run, and all is good with the world. Until the next time.

Thanks guys, I could not of done this without all of your help and advise. Just in time for the club run tomorrow morning.

[Warkton Tornado No.1]

Phew!

Well done & its great that you've let us all know the good news!

[St George]

That was a good thread Martin. A lot of input from the boys and a learning curve for all. Till next time LOL.

[bike grim]

Just out of interest, did you stick with the massive 158 main jet? The reason I ask is I am running a 138 in a Rapido with reed, 30mm PHBH and BGM clubman and I think that is on the big side but the ride and plug colour was telling me that it was ok. (266 atomiser and X7 needle on third clip and a breath sweet air filter) So I did a leak down test for the first time ever and there was a indeed a leak on the inlet manifold gasket. I have now stripped and rebuilt and will do another leakdown test later. I am expecting to down jet as a result of finding the air leak even though I had no real symptoms, just a gut feeling that 138 sounds too big. Or is it?

[Watfordwhite]

Yes at the moment, but it's booked into JB to have the carb set up and dynoed. Strangely JB said it may show up an air leak.
Will let you know mate.

[ULC Soulagent]

Just out of interest, did you stick with the massive 158 main jet? The reason I ask is I am running a 138 in a Rapido with reed, 30mm PHBH and BGM clubman and I think that is on the big side but the ride and plug colour was telling me that it was ok. (266 atomiser and X7 needle on third clip and a breath sweet air filter) So I did a leak down test for the first time ever and there was a indeed a leak on the inlet manifold gasket. I have now stripped and rebuilt and will do another leakdown test later. I am expecting to down jet as a result of finding the air leak even though I had no real symptoms, just a gut feeling that 138 sounds too big. Or is it?

Hi Gareth,
I'm running HB 240 now with a modified bgm clubman and 28 Vhst delly, currently on 135 main but I think it can come down a f w more points

[bike grim]

Cheers S. Dyno today. Sticking with the 138 main jet after all. Tried it with a 130 ( too lean) and 135 no real difference between that and the 138 so safety rules OK. Rather a tad rich.

[ULC Soulagent]

Cheers S. Dyno today. Sticking with the 138 main jet after all. Tried it with a 130 ( too lean) and 135 no real difference between that and the 138 so safety rules OK. Rather a tad rich.

Yes rich is better the devil ya know

[Watfordwhite]

Quick up date. Been on some good run outs with little issuse (about 40 miles) However problem returns. This time weak spark. Changed Plug, HT lead and cap worked fine.
40 mile run, put it away. Got it out next week, wouldn't start. Checked plug, weak spark. Changed plug worked fine.
Changed over the coil from my GP same thing. Could this all of been a faulty stator plate braking down?

[grandpa]

Hi Watfordwhite,
I assume engine has good earth?
Grandpa

[Fast n Furious]

As Grandpa sez. Make sure all your earth's are in order.
Use a digital multimeter set on AC volts (200v or more scale)
Pull the green wire of the cdi (the one that goes to the ignition switch)
Connect the multimeter red lead to the now open terminal on the CDI box.
Connect the black lead to earth.
Start the engine.
It should read at least 60VAC at tickover and rise to around 200VAC when revved out.
If you're not getting this value then most likely the magneto primary coil is goosed.
It's quite a common problem.

[Watfordwhite]

Thanks Grandpa,
yes it's a copper earth lead from engine to frame to CDI bracket. New condition and all solid connections.
Working away in Goole ATM so won't get to test until the weekend.
Will this never end?
When it's going it's great, but feels like it's holding back a bit. Probably down to the jetting. Still trying to get it to PM for setting up.

[Watfordwhite]

Amuse a quick up date. After trying everything else I have had the stator replaced. I did about 40 miles on Sunday and all seams good. Still need to sort out the jetting next. But at the moment all is running well fingers crossed...

[St George]

Have you got a pet name for your scooter ?

[Watfordwhite]

Named after the James Dean Porsche. Litle Bitch...

Out on the ride out last night, 30 degrees and it broke down again. Pushed it 3 1/2 miles back to the lock up. ( 1 1/2 hours )
So, all new jets and reed valuve ordered. It's the only thing left to change ( apart from getting a VE**a only kidding)

To top,off the week, just been told I'm to be made redundant tomorrow so now plenty of time to ride, but no scooter..

[Warkton Tornado No.1]

Hey Mate.

Jumping in with both my feet I doubt that I'm the only one that would suspect the recent change of stator to be the root cause of this latest issue...

How is the spark?