Mikuni Jets

The place to come to share your technical expertise, or just find out what the little springy thing is that's just pinged out of sight under the work-bench.
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YZF750R
Brolly Dolly
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Joined: Tue Apr 05, 2011 9:51 am

Mikuni Jets

Post by YZF750R »

Hi,
Just bought some K n N Pods and the blurb that comes with them recommends that you increase your jet sizes by 15%.
On my Model 1993 YZF750R the jet sizes are
Main Jet
#1, 4 cylinder - #125 which will increase to 143.75
#2, 3 cylinder - #122.5 which will increase to 140.875
Pilot Jet #45 which will increase to 51.75
Starter Jet 57.5 which will increase to 66.125
Does anyone know of anywhere in the UK I can source Mikuni Jets?
banner001
Pit-lane Reporter
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Joined: Tue Sep 25, 2012 3:50 pm
Location: Nuneaton, UK

Post by banner001 »

Current bikes:
1989 UK FZR 1000 EXUP-R Streetfighter @48,000 miles
1993 ZXR 400 L3 UK-spec Track-bike @21,000 miles
1994 ZXR 400 L4 UK-spec Commuter @48,000 miles
1999 Malaguti Phantom F12 scooter with 70cc kit+mods @14,000 miles
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nugget
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Location: North Yorkshire

Post by nugget »

You could try these too. :nod:

JETS
Bit of advice. Buy a good bed and a good pair of shoes, because if you aren't in one you'll be in the other.
YZF750R
Brolly Dolly
Brolly Dolly
Posts: 19
Joined: Tue Apr 05, 2011 9:51 am

Post by YZF750R »

Decided to go with the Factory Pro Street 30 kit
4 x #130,
4 x #135,
4 x Needles + Clips.
4 x Titanium Emulsion Tubes
Let the carb setup fun begin.
Object... Get rid of fecking useless airbox and replace with K n N Air Filters. Also smooth out flat spot in the middle part of the rev range, due to lack of exup valve.
Standard Jets are #125's, do I go for the #135's first, with the needles set at their standard position or hedge my bets with the #130's and play around with needle clip position and float height....
banner001
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Joined: Tue Sep 25, 2012 3:50 pm
Location: Nuneaton, UK

Post by banner001 »

on my race bike i have always tried to get the bike fuelling ok, so that it will run up to full rpm ok, then i tune it from top down:
main jets
needle clip position
pilot jets

i usually set float position to be slightly on the rich side of "standard" and tune from there.
Current bikes:
1989 UK FZR 1000 EXUP-R Streetfighter @48,000 miles
1993 ZXR 400 L3 UK-spec Track-bike @21,000 miles
1994 ZXR 400 L4 UK-spec Commuter @48,000 miles
1999 Malaguti Phantom F12 scooter with 70cc kit+mods @14,000 miles
YZF750R
Brolly Dolly
Brolly Dolly
Posts: 19
Joined: Tue Apr 05, 2011 9:51 am

Post by YZF750R »

Thanks for the tips.

Which club do you race with?
banner001
Pit-lane Reporter
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Posts: 739
Joined: Tue Sep 25, 2012 3:50 pm
Location: Nuneaton, UK

Post by banner001 »

its just a dedicated track bike at the moment, i dont think i can afford to go club racing, both in time and money as i already work a 70-hour 7-day week :D

i go to mallory, donnington, rockingham and silverstone when they have deals on, or when i know im free, as they are close by (within an hour), engine is putting out ~64bhp at the moment which sould make me eligible for the sub-64 class if i want to go that route, im looking for donor engines at the moment so i can build up a collection of race engines that i can swap in as rebuilds are underway, main thing is trying to get the weight down and im toying with the idea of cutting my radiator to fit ram-air along with new fairings.
Current bikes:
1989 UK FZR 1000 EXUP-R Streetfighter @48,000 miles
1993 ZXR 400 L3 UK-spec Track-bike @21,000 miles
1994 ZXR 400 L4 UK-spec Commuter @48,000 miles
1999 Malaguti Phantom F12 scooter with 70cc kit+mods @14,000 miles
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