GT Kit 30mm Manifold, Reed Petals

[Graham]

I am running a gt kit on my small block GP. I started out with a 25 mil carb and clubman, then upgraded to a fresco, then a dev tour.
The set up now feels a little "under carbed" and i am thinking of upgrading to a 28 or 30mm carb.
For this I need to find a GT 30mm manifold, but as the kits are out of production this may be difficult.
So firstly does anybody know where i can get one?
Failing that, SIP sell a "conversion rubber" that small frame vespa pilots use to fit a 28mm carb onto a 25mm manifold as I assume a 30mm manifold will not fit on their barrels.
That sounds great (and cheap) but would you not loose the benifit of the big carb with the small manifold ?
Finally I am told that the reeds used on the GT kit do not have a long life, does anybody know where to get replacements (they may have come from a kart engine) or better quality substitutes ?
This is my first post, apologies if it comes out looking odd !

[vicvega]

I run a GT kit with a 30ml Mikuni, no worries. I had to get a manifold about a year ago but I'm sure it was from MBD, don't know if they are still doing them but might be worth giving them a bell. If not try scooter center in germany I think they used to do them and the reeds. Had no problems with the reeds as yet but will keep my eye on them.

[CPH Lambretta]

Scooter Center have the manifolds in stock

[carlos fandango]

Try Dez at gran sport birmingham he had a load of barrels behind the counter last time i was there. he should have or know were to get them from. or you could just email Richard on his website (granturismo) or pm him on here "rich_t" as he comes on here occasionally.

[Diablo]

Go on the LCGB forum and pm Richard Taylor direct is probably the easiest option.
I have a 30mm on my GT186 and the barrel is std.
In my opinion unless you tune the barrel you will gain nothing from fitting a 30mm. This is backed up by dyno runs on other GTs with smaller carbs. I recently built one with a 24mm oko carb and it made the same power as mine.
What you are feeling as being "undercarbed is probably down to exhaust timing. I recommend either raising the exhaust port a little or give it some more gearing. These kits will pull 4.8 final drive.
The reed petals are from a Kart but I don't know which one. I buy mine either from Richard direct or MB. They suffer more if you use an expansion but the solution is simple. You basically double up the reed petals that sit above the boost port and this seems to cure the problem.
Raising the exhaust port a little also helps Richard tells me but at the moment mine is std as it pulls SX200 gearing nicely.
Exhaust wise they do work well with the devtour so you are alright there.

[Graham]

Ordered one from Scooter Centre.
The barrel is tuned so a bigger carb may work well.
On the 25 mm the jetting probably needs doing (its the same as when it was set up for the fresco) and I will try that before going for a bigger carb.
Mainly its nice to have options for the future as I think this engine may end up in a cut down project for which I now have 3 parts...the manifold, a ripped snetterton and 1 massive pike nut.
Thanks everybody for the advise.

[soulsurfer]

Go on the LCGB forum and pm Richard Taylor direct is probably the easiest option.
I have a 30mm on my GT186 and the barrel is std.
In my opinion unless you tune the barrel you will gain nothing from fitting a 30mm. This is backed up by dyno runs on other GTs with smaller carbs. I recently built one with a 24mm oko carb and it made the same power as mine.
What you are feeling as being "undercarbed is probably down to exhaust timing. I recommend either raising the exhaust port a little or give it some more gearing. These kits will pull 4.8 final drive.
The reed petals are from a Kart but I don't know which one. I buy mine either from Richard direct or MB. They suffer more if you use an expansion but the solution is simple. You basically double up the reed petals that sit above the boost port and this seems to cure the problem.
Raising the exhaust port a little also helps Richard tells me but at the moment mine is std as it pulls SX200 gearing nicely.
Exhaust wise they do work well with the devtour so you are alright there.

Who would you entrust to tune a GT cylinder Al?