GP200 lack of oomph!

[Hughieboy]

I’ve been trying to help a mate out who’s having problems with his scooter. It’s an Indian GP200 with an Indian stage 4 kit on it we believe. Currently has a 28mm phbh Dellorto carb and a JL3 exhaust, although we have also tried an AF slope side clubman. Gearing etc is standard as far as we know. Fast flow fuel tap.

The issue is that it has no ‘oomph’ about it, it won’t go over 50mph and it loses power going up hills. Things we have done-
Carb cleaned and set up according to ballpark figures, various tweaks made depending on exhaust. Currently as follows-
X7 needle 1st clip
112 main
70 choke
55 pilot
AV264 needle jet
200 float needle(orange/red)
45 slide

Leak down test is fine.
Timing set at 19 btdc and checked with ‘buzzwangle’
New plug and cap.

It has a bgm stator and recently the low tension coil failed so we fitted one of the ReadSpeed cdi’s that bypass it.
We have also fitted a new pick up to the stator.

It starts and runs fine, it just lacks power and top end, it kind of feels like it’s restricted. Oddly, it bogs down if a larger main jet is fitted yet it only has a 112 fitted. We have looked in the exhaust port and it has a 3 ring piston, we haven’t taken the top end off yet.

Hope I haven’t forgotten anything, it’s a bit of a mystery. Can anyone suggest anything else to try?

Thanks.

[ULC Soulagent]

First I’d up the float needle jet 250+
Check compression and Squish and take it from there,
There will be a lot more talented bods with useful tips n hints along shortly

[hullygully]

+1 &
you could be chasing your tail for months, carb, stator, exhaust, fuel flo etc................................BUUUUUUUUUT until you know what's in your casing, ie what the gearbox & final drives are, they're your usual suspects for loss of power on gradients & on windy days bud

[MickYork]

Stuck or worn piston rings would be worth looking at.

[Hughieboy]

We can check the squish, I need to find out how to check the compression…. But it sounds like a top end strip down is in order….

[missing lynx]

Has it had oomph and lost it or has it never had it?

[al pushpak]

Could it be you've got a cheap pattern indian cylinder head fitted? I know these can affect performance due to the combustion chamber being too deep .

[Hughieboy]

It could well be. I’ll need to het more info from the owner about its history.
Thanks for all the suggestions guys