Mikuni RS38 Carbs on stock GPZ1100B2 with Kerker 4-1?

[jacobb]

Does anyone have any experience with Mikuni Radial Slide carbs? Would the 38mm run ok on a stock gpz1100 B2 with a Kerker 4-1 with a 2" baffle if I put some smaller jets in? Or would I be constantly fiddling to remove flatspots etc...? I was looking into buying some new and was recommended not to go any bigger than 34mm. Can they be tuned down to suit?

Some have come up for sale relatively cheap and I am very tempted...

[Gosling1]

a stock B2 would go heaps harder with 31mm smoothbores mate. 38mm RS carbies are great for big 4-valve motors that make heaps of power up to 11 or 12k redline, not the 9k redline of an old 2-valver.

Having said that - if you were drag-racing the B2, had the capacity pushed out to 1300cc with massive valves and big cams - then the 38mm RS carbs could work well.

Your biggest problem will be finding the inlet manifold rubbers to suit these massive carbs. If you do find some can you let me know where you found them ?

[z900/zx9]

Big fuel does not equate to fast,correct fuel delivery and burn= equal fast.

[jacobb]

Yeah Righto, Thanks for that Gos and z900/zx9 - makes sense, and stems my temptation...

Another question for you Gos - I am cleaning up some used 34mm CV Mikuni's from a z1000j that are in pretty good nick at the moment. I have pulled them apart and am about to get them vapour blasted and ultrasonically cleaned. When I took them apart the main jets are 120's - should i give them a go before trying anything bigger, or do you reckon I'll need larger main jets and should put some bigger ones in from the get go...?

[Gosling1]

120's will be sweet for an 1100 motor. The cam specs between the J and the B2 are pretty close, and the capacity increase from 994? to 1075 is not that big.

Will you be running a stock airbox of some type or pod filters ? You may need to fiddle a bit with needle height and possibly go up a size or 2 in the pilot jets as well. All this will also be affected by the type of exhaust you use.

For the initial set-up though - just go with all the stock J jetting in the first place. If you do find that the response is a bit fluffy down low or hesitates a bit up high - then you might need to do some fiddling...

[jacobb]

Thanks again mate - I've got pod filters that came with the carbs, So I'll clean them up and give them a go, but also have an airbox that it is out of the bike at the moment, which has had all the B2 DFI stuff taken off it - I have some holes to patch if I want to use it, so that's an option...

I'll give it a go with the 120 mains and then and adjust the needle height as necessary!