Small block upgrade

[Tom Russell]

Currently standard LI150, with choice of 18 or 20 carb, AF Clubman exhaust (wants to keep) and electronic kit.

So what's the best (value for money) upgrade(s) one could do to give some more torque/bhp/speed, without putting the standard crank under too much stress, and (ideally) also keeping standard(ish) carb (though might go for bigger 28/30 if needed) and the AF exhaust?

Not heard good things about the (cheap) Indian Ali kits, which apparently wear quickly, so where/how would you spend your money (say max £250-300 budget) to get a good reliable, reasonably hard wearing option? Bore out (maybe port) current cylinder to 175, with good piston, fit 185 or 200 conversion kit etc. etc??

The scoot is not going to be doing lots of miles/rallies, mostly around town and odd rideout.

I'd rather have feedback from individuals with genuine firsthand experience, and could also recommend a starting point for jetting the same, so we don't have to also factor in the cost of a dyno session as well.

Cheers,

Tom


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[Stokie]

Hi Tom
I had a bog standard Italian GP150.
I opted for an AF Clubman, had a LI150 barrel bored to 175 and stage 4 tuned by Mark Broadhurst to suit a solid mount 30mm PHBH carb and he supplied the conversion piston and an appropriate head.
Gearing and everything was as it left the factory.
I was very pleased with the result, pulled well around town, acceleration was good, the big gap between 3rd & 4th seemed to disappear and it had a decent enough top speed for the A road trips that I'd make.
It was a while ago now and I honestly can't remember the cost but it wasn't expensive and pre-dated many, if not all, of the aftermarket small block kits available now.
Arguably a smaller carb may well have performed just as well and been more frugal on fuel but I had the carb already an no budget for another.
Hope this helps

[bristolmod]

Tend to take a standard TV175 cylinder out to 64mm giving 186 or thereabouts. Slightly raise the exhaust port as well.

Pistons (in standard or TV rod lengths) from Beedspeed c/w a "proper" 186 head and a 42mm Clubman gives me a fair increase all round without putting undue strain on a standard crank.

20 or 22mm carb jetted accordingly.

Cheap and cheerful

Chris

[Lamaddict]

The AF 175 kit runs okay. I like 20mm carbs, they are underrated IMO.

[bristolmod]

The AF 175 kit runs okay. I like 20mm carbs, they are underrated IMO.

+1. Keeps it nice and simple IMO

[CPH Lambretta]

My advice would be to send a 150 barrel and head to a tuner like Harry Barlow at Pro Porting. Get it bored to 175 and a stage 4 tune ,using an Asso or Escort piston. It will run really well with a 20mm carb and Clubman. The piston and tune/rebore costs about £140-150 including machining the head.
If you really want to spend more money then maybe upgrade to a 22mm carb like a sorted Jetex or Scootopia repro. Or maybe a crank/ ignition upgrade.
I had a barrel done by Harry a couple of years ago and have been really happy with it, running a 22mm jetex and various exhausts, the best alround pipe was a KBA Clubman. The jetting/ setup advice from Harry was Spot on.

[Muttley McLadd]

Do you have anyone local that could fettle your barrel to (Italian) GP150 spec? That'd be cheaper than making heaps of changes. A reasonable increase in power.

[lambro]

Do you have anyone local that could fettle your barrel to (Italian) GP150 spec? That'd be cheaper than making heaps of changes. A reasonable increase in power.

Tom is the 'go to man' that people go to.

[Muttley McLadd]

Do you have anyone local that could fettle your barrel to (Italian) GP150 spec? That'd be cheaper than making heaps of changes. A reasonable increase in power.

Tom is the 'go to man' that people go to.

Heh.. Its a very small screen, and its early on a Sunday morning

[Tom Russell]

Thanks for the feedback so far, anyone have personal experience of the cheap Indian Ali kits, that they'd like to share??


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