Carb recommendation - modified Z900 A4

[martinz1000r]

What carbs would you recommend for a modified Z900? Engine is 1260cc with gas flowed head, hot cams and 4-1 exhaust (currently Marshall but likely to change to RaceFit).

It currently has old GSX-R flatslides but the choke lingages have fallen apart so intend splashing cash as had good year!

Like the idea of Keihin CR but what size? I do have a set of Mikuni RS34 in garage but are they big enough for this motor?

It is road use and occasional track day use.

Recommendations and potential vendor recommendations please!

[neilbarrett]

think my choice would be the old style kehins 35 or 37s,more in keeping in with the image of the bike ,rs36s a good set as well

[Ginger Bear]

Sounds a 'beasty' martin........ Any pic's

[martinz1000r]

i like the idea of the Keihins as the styling is more in keeping with the age of the bike. Is there a science in terms of size needed? There are a set of 39s on eBay at moment brand new at £810 (expensive?). Advice from the experts out there gratefully received!

GB - it's for my Z900. Odd postings on here before but will be starting full project thread soon. I bought it just over 2 years ago as a non runner due to bent kick starter shaft. Replaced this and it runs but then the weird race alternator burnt out after 20 mins. After 4 months of waiting Electrexworld have finally delivered the new one so I am going to give it a bit of a refresh ready for spring. It needs decent paint and the brakes are seized on but apart from that it is good to go.

[PJ]

Hi Martin I remember that being on Ebay - looks like you got a good deal!!

How's the Moto Martin?


Cheers



PJ

[neilbarrett]

a brand new set of kehins for £800 ,aint a bad price i think,normally if you want top end bhp figures you use the biggest carbs you can,but on the road you want midrange power as well ,which a smalller carb will give better,ive a gsx 1260 making 169bhp with rs40s,but when ? it goes back on the road il be using a smaller carb,last bike project i bought some 41 kehins for, second hand,next time id buy new if the $ was right.

[paul doran]

nice Zed Martin
looking forward to seeing more pictures

[martinz1000r]

PJ - it was on eBay back in December 2009. Remember trekking through the snow to go and collect it somewhere near Cambridge. It's a great bike that someone spent a lot of money on in the past. I will start a project thread with lots of photos as soon as it is warm enough to venture outside.

Moto Martin is a very long term project as i want it to be something very special. I am accumulating bits as i find them and i reckon i'll start working on it in the summer

Neil - thanks for the carb advice. Mid-range is important as this is a road bike.

[Pigford]

I'd go for RS36's - 38 max as the 40's need gurt big manifold stubs, and the inlets on the head won't be much over 34mm opened out

You can use the larger carbs with a restrictor - this will give good performance.

Also Mikuni are easier to tune than Keihin - but Keihin has more range available

[buzzard]

I had a set of 34mm amals MK2's with a home made throttle linkage on my RC1200cc motor, big valve Phil Manzano head andrews 3x cams back in the mid 80's, ran low to mid 10's all day, but that is the biggest size a z1 head (34mm) will go out to. I'd ditch the z1 head and fit a gpz1100 head fit 32mm exhaust valves and 38mm inlet valves and a set of 36mm/38mm flatslides. BUZZARD

[Iain marshall]

That the bike Buzzard?

[buzzard]

fookin ell, not a grey hair on my head then, yes thats the one. Please note, no power ranger full leathers in them days. BUZZARD