Bing 40mm v 32mm on R100GSPD

[cobbster]

I picked up a pair of carb's 32mm this week, which may come in use for a bike I haven’t got yet!!

I'm sure I've read somewhere that these are useable on above bike. If so is there any benefit to change from 40mm?

The picture below is one I picked, which what I would call a flat top!
The numbers on them are 64/32/201 & 202.

One thing I can't work out is the must be a return spring missing for the choke? If so any help as to which part and where it fits?

Thanks in advance.

 

[Shurv]

1000cc bikes run on 40mm,800's on 32mm. You can move the chokes by hand or gletter do some nice levers instead of springs.

 

[Rob Farmer]

Not all 1000cc bikes have 40mm carbs.

 

[slowkitty]

Not all reported a gain from using the 32mm v 40mm. You will need suitably sized manifolds for the carbs.

For the return springs, some complained that the springs are too stiff. There is an alternative for lighter stainless springs that google will show.

Rob is right. The Mystic uses 32mm.

 

[Rob Farmer]

Cant believe I'm posting on a carb thread at 4:30 in the morning

The carb youve posted there Paul is from a heavy flywheel 77/78 machine. They had a choke lever that mounted on the side of the airbox and used a stiff single wire cored cable to operate the choke, No return spring at all, if you look at the choke arm the clamp at the end has a small hole through it for the cable.

To change the carbs to a conventional, later, setup you wull need new choke arms and a different carb top along with the appropriate slide. Basically not worth your while and the reason those carbs were cheap on ebay


In my opinion the 32mm carbs are much better suited to the 1000 GS bikes than the 40's they pull harder at low and middle range, tickover better and run smoother. The US bikes all had 32mm carbs and all 1000cc road bikes from 85 onwards had them except for the paralever machines.

 

[cobbster]

Thanks for the info Rob, I thought I got up early.

 

[Rob Farmer]

Thanks for the info Rob, I thought I got up early.

Somebody has to drive to London and bail the f*ckwit southerners out

 

[Rob Farmer]

I, and several of the other GSers at various times, owned the Red 100GS that appears at the top of the screen sometimes.

This one

Givitsum imported it from the States. it had 32mm carbs that had knackered O rings. Once they were replaced it went like billyo and was very smooth, bags of mid range and shot straight upto 110. Good stuff.

 

[(RIP) Arkwright]

My Mono is on 32mm Bings and runs better than the GSPD which is on 40mm and they've both been modified to make them run better (which they both do, but the Mono is better). Before anyone asks, yes, they are both 1000cc and 10.1 CR.