22mm with 175 kit Jetting

[Tony Hart]

Genuine need for info. Currently running a 175 iron kit through the air box (drilled out) with a 42mm clubman and a SH1/20 carb. I am thinking of trying a 22mm carb but need a start point for jetting. All I can find is either for a 150 or 200cc. My current jetting on the SH1/20 is as for a TV 175 S3 with a slightly larger main to account for the clubman exhaust and now the barrel is run in the improvement in performance over my previous iron 150 barrel isn't much Hoping for a bit more with the slightly bigger carb.

Any advice (relevant) greatly appreciated as usual

Tony

[St George]

I de tuned my SIL 200 Stage 4 from a 30 mm Delly and fitted a 22mm Jetex carb with air filter. I fitted 122 main ( 118 may suit yours ) and a 50 pilot. It pulls very well indeed and they are easy to set up. Cheap as chips new on ebay. Keep me updated ?

Colin

[Tony Hart]

Cheers Colin. It is the similarity to the Dellorto SH that I like. Will order one and see how it goes.

Tony

Just seen DaveTomo's post. Looks like you are in the ballpark Colin

[St George]

Hi Tony. Just check those jets are the right size from the factory. As I said two of mine were wrong from the production line.

Colin

[Tony Hart]

Got hold of a Dellortho SH2/22 at Whickstead last month and have finally managed to fit it to my S2 with 175 kit and 42mm Clubman mentioned in original post. Purchased three different inlet manifolds and ended up cutting two and getting the bits welded together to allow the carb to fit Carb is set up as for a 200 but with a 118 main. Started second kick but spluttered and died when fuel turned on as if flooded and was then very reluctant to start. To get it going again I had to turn the fuel off, fully open the throttle and kick for ages. Cleaned jets and checked float and needle works and put a small hole in carb rubber to try and drain spit-back. Spluttered and died again same as before

Any ideas what the problem is and more importantly how to solve it

Cheers

Tony

[Cgt75b]

Hello Tony

What is your air flow like ? By this I mean, what kind of scoop are you running has the scoot got a bench seat on ? All these things make a difference.

[Tony Hart]

Hi. I have drilled out the neck of the airbox and it has saddle seats. I was thinking that I might need to go up from a 45 pilot jet to starts and then possibly try a leaner atomizer with a smaller main. Not a lot else to try with one of these carbs. The whole set up was fine with a SH 1/20 with the smaller air hose.

Tony

[Adam_Winstone]

I've had similar issues when running into float level issues, with fuel level too high so that it is massively rich when trying to start it. I've had this happen because of leaking float (with petrol in), faulty/worn float needle, and float pin hole or pin worn and not allowing the float needle to shut off fuel flowing into the bowl.

If the motor was working ok on the 20mm then you may want to change the float needle, pin and float from that carb and try again.

Adam

[Tony Hart]

Thanks Adam. I did notice that the level of fuel in the bowl was higher than it had been in the 20mm carb. Hopefully get chance today to try.

Tony