Running problem

[Geezerray]

I am having problems with my TV 175 fitted with a 185 casa block piston etc, and a jetex carb, with a 118 main jet and casa electronic ignition. The engine seems to hold back and does fire properly. I have rechecked the timing with a strobe. Partially removed the baffle in the air scoop, to give more air etc. It still gives the same problem , the only thing I can think of now is a fast flow petrol tap. I would be grateful for any suggestions as I am running out of ideas.

[weeks]

Technical questions get more response posted in the correct section ….. I will move to the technical area : Tuning and Kits

[HxPaul]

Do you have the correct thickness of cylinder base packer.

[CHRIS in MARGATE]

Stator plate would be my first suspect.

[MickYork]

Blocked exhaust ?

have you plugged chopped it at different throttle positions ?

What is the full set up ? gearing, exhaust carb jets, exhaust, etc ?

[Scooterlam]

Costs nothing to check the flow from your current tap before you buy a new one.
Personally I would try a known good stator.

[HxPaul]

I have 2 engines with Casa 185 kits,one of them has an SH2/22 carb with a 130 main jet and 48 pilot jet.Maybe your main jet is to weak.

[ToBoldlyGo]

I suspect your main is too small. I run a 185 kit with a 22mm Jetex and Clubman exhaust and that uses a 123 main with a 48 pilot. I find that spot on.

[Knowledge]

The usual test for an undersize main jet is to run the scooter and when it starts to hold back at wide-open-throttle, to then throttle back a bit and see if it picks up and runs more happily.

And who doesn't want a happy scooter?

[Nudger]

Stator plate would be my first suspect.

If it was OK before and has just started running badly then this^

[Knowledge]

I note you have tackled the baffle in the air box. Have you also removed the restrictor (membrane) in the air scoop?

You can experiment by running the scooter without the scoop on (just the hole beneath). I assume it is the wide-mouth air box that you have.

[Paul_from_Thornbury]

My first port of call would be the pick up on the stator, I've had loads of these fail on BGM stators, and the symptom is they run up to a certain point on the rev range, and then just cough/splutter or just don't rev.
Try a known good stator or even better fit an Anthony Tambs external trigger, these work a treat and get rid of all the pick up height nonsense.

[stephena]

Had a very similar problem when I did a 175 conversion ran well for about a thousand miles then started backing of a high revs messed about with different main jets but didn't get anywhere fitted scootronics stator must have done another thousand miles without anymore problems have put the original main jet back in. Just sent for scootronics cdi will be interesting to find out if there is any noticeable difference.

[Geezerray]

Many thanks to all those that replied and I still have the same problem, and even more curious is that I rebuilt another TV175 with a casa 185 pot and piston (for our son), and a scootopia carb instead of the jetex and still the same problem. I have changed the jet etc and cut away the baffle as suggested in sticky's manual and still the same affect. On another subject I viewed an LI 150 today which was a 1966 LI150 Eiber, can anyone tell me how the stamping is on the frame etc. I did not buy as I was unhappy with the number stamping that appeared to be amatuarish to say the least.

[dickie]

Many thanks to all those that replied and I still have the same problem, and even more curious is that I rebuilt another TV175 with a casa 185 pot and piston (for our son), and a scootopia carb instead of the jetex and still the same problem. I have changed the jet etc and cut away the baffle as suggested in sticky's manual and still the same affect. On another subject I viewed an LI 150 today which was a 1966 LI150 Eiber, can anyone tell me how the stamping is on the frame etc. I did not buy as I was unhappy with the number stamping that appeared to be amatuarish to say the least.

Indian lambretta frames are stamped by monkeys. Spanish ones are stamped by trained monkeys so look a little better.l, but not mich. Don't worry too much as long as the numbers don't look like they've been tampered with.