Carb problem

[Wack]

Obviously the plug is far too lean so I suggest firstly checking that the airbox hasn't been gutted, ie the swan neck removed as this will drastically alter the airflow and would need far bigger jets.Next is to try a 5899-1 as this has smaller air bleed holes so richens the mixture up even though the atomiser bore is slightly smaller than the 5899-2.Lastly.the motor could have an air leak.

[Rushy]

I've just done another plug chop 2nd gear uphill for 15 sec and it looks like it too weak. I think I will take my exhaust off and measure the bore

[Rushy]

I've just done another chop and it looks like it too weak I will have to take the exhaust off and measure the bore

[Rushy]

The swan neck has been removed

[Rich Oswald]

It's advisable to do plug chops on an older, used plug. They give a far better picture of the mix.

[Storkfoot]

The swan neck has been removed

If the swan neck in the airbox has been removed and the scooter had a 130 main jet, there’s a good chance that it isn’t anywhere near standard. If it was mine, I’d take the cylinder off and find out what has been done to the top end. It may have just been rebored to a 175, it may be a kit of some description, or it may have had some tuning work done. You’ll be forever guessing if you don’t take the cylinder off.

[Rushy]

I'm going to to take a deeper look at what's going on this week and I will get back. Thanks

[Rushy]

I've just taken the exhaust off and measured the bore and it 62mm. Dose it mean it's a 175

[Storkfoot]

I've just taken the exhaust off and measured the bore and it 62mm. Dose it mean it's a 175

Yes it does. It could be a rebore on the original barrel or an Indian conversion barrel. I’ve never checked the timings on one of the Indian barrels but I have heard that they can be a bit hit and miss. If the timings are alll over the place, it can be a struggle to jet the carburettor.

Please post some pictures of the outside of the barrel, showing exhaust and inlet and also some pictures inside the bore showing the ports inside.

[Rushy]

Here is the photo of the exhaust port. . I've managed to find an airbox with the swan neck still in so I am going to fit that and start from scratch and set up for a 175.

[hullygully]

I had a mick Abbey tuned cast iron 175, sh2/22 carb bored out to 25mm, ancillotti big bore, breathe sweet air filter, swan kneck removed & air box drilled out, jets & slide as gp200 & main jet of 132, timing set @ 19deg btdc.
Hope this helps Rushy

[Rushy]

Brilliant I will give it a go it will be a good base line to start from. Cheers

[Rushy]

Just done another plug chop what do you think

[Rushy]

[Rich Oswald]

Still very slightly weak, imo.

[Rushy]

That's with a 135 main 45 pilot

[Rich Oswald]

That's with a 135 main 45 pilot

At what throttle opening was the plug chop done?

[Rushy]

Just short of full throttle

[Rushy]

I've just measured a spare Jetex 22mm and it has been bored out to 25mm I wondered if this would be better

[Rich Oswald]

I've just measured a spare Jetex 22mm and it has been bored out to 25mm I wondered if this would be better

I think it would, i've had success with a bored out AF Jetex.