Bandit Alley
MODEL SPECIFIC => SUZUKI BANDIT 600 thru 1200 - AIR/OIL COOLED TECHNICAL => Topic started by: dickbarton on October 15, 2005, 11:57:17 AM
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I said I'd let this forum know how I got on with a new B12 that was running too lean. Well it took three weeks to get some new pilot jets ordered from Japan. They were 20's to replace the production 15's.
Its made all the difference in the world. It now runs much smoother on a partial throttle, and means I dont have to accelerate everywhere if I dont want to. Problem is, it now runs so well that I do!!!
The bike is standard apart from that, but hooo boy does it ever shift, and it goes round corners like a rat up a drainpipe.[/b]
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Do you have a 2005? Do you have a slipon or stock exhaust? Did they change the main jets?
Sorry for all the questions' I have an 05 that seems to run lean :thanks:
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Yes 2005 special edition.
Everything is standard.
Suzuki apparently changed pilot jet size from 20 to 15 a while ago on new bikes, to meet emission regs. All my dealer did is change them back.
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Did they cover it under Warranty?
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Yes and they did the first service with no labour charge because of the inconvenience.
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Hi Dick,
Do you know know the suzuki (or aftermarket number) for the #20 Mikuni Pilot Jet?
Thanks,
Keith :motorsmile:
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BUmp
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Hi Dick,
Do you know know the suzuki (or aftermarket number) for the #20 Mikuni Pilot Jet?
Thanks,
Keith :motorsmile:
Mikuni p/n: VM28/486 + size
I've heard good things about Carb Parts Warehouse (http://www.carbparts.com/) - put couldn't find any specifics, like prices for various parts, so you'd have to contact them.
Also heard good things about Sudco (http://www.sudco.com/) and they list the VM28/486 #20 as p/n 004-030 ($3 each)
Also worth considering is the #27.5 recommended on Fast Larry's Bandit FAQ. (Sudco p/n 004-033, also $3/ea.)
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:thanks:
I'm using the stock muffler right now. Do you think the 27.5's would be too rich?
Thanks for your reply!
Keith
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The 27.5 is probably too much for a stock pipe.
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Hello All,
I followed Dick's advice on my 05 1200S. Runs great with the 20's. Main difference is there is no longer a lean spot off idle on acceleration. Very noticable improvement in low speed cornering.
:banana:
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I have installed 17.5 pilots in mine and a good rule to follow with pilot jets that someone posted here is.
If you can obtain a good idle with the a/f screws being no more than
3 1/2 turns out you don't need to change them. If you are anymore than 3 1/2 turns out go with the next size pilots.
From what I have seen, after 3 1/2 turns the metering of the a/f screws becomes less accurate. The 17.5's in mine work well, and would probably work great with a stock bike.
In essance going up a size in pilot jets is like opening up the a/f screws more.
Just as a comparo (and this is a rough example and by no means accurate) The larger pilots get you the same a/f mixture with less turns out on the screws.
15 Pilots 3 1/2 turns
17.5 Pilots 3 turns
20.0 Pilots 2 1/2 turns out
Larger Pilots do help you obtain a smoother idle.
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This advice is based on the assumption that the pilot jets only feed the idle circuit. This advice, while well intentioned is incorrect.
There is also a transfer slot (Part of the low speed circuit) that straddles the bore opening at the throttle plate. This bridges the gap between the Idle Cicuit (Mixture Screw) and the Main Circuit (Main Jet). As the the throttle plate is opened is draws fuel from this slot (as well as the idle cicuit) until the slide lifts and fuel is delivered from the main jet.
A review of the carburetor design will show this. :wink:
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my 05 bandit 1200, doesn't seem to be running lean or stumbling off the line?
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The Holeshot Stage 1 jet kit includes a #17.5 pilot jet. However, Dale recommends starting with the stock #15 pilot jet and with the screws out 3.75 turns as a base setting for a stock motor with stock exhaust. That is what I did, along with #107.5 main jets and 4 shims under the needles. Results are great.
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Hi again,
I bought a Scorpion pipe, fitted it and took it off again when the initial 'bite' on acceleration went AWOL. I guess this means that the mixture is too weak again. Tickover is fine, in fact it runs much better and I can take it off choke sooner. I read that main jets need to be increased, but whats this shimming under the needle business? The stock needles come with different slots (according to the Haynes Manual), so dont I just have to choose a lower slot; effectively raising the needle?
Also, why would I need to increase main jet size AND raise the needle?
Please help.
Dickbarton
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Hi Dick,
Shimming the needles changes the fuel curve as the slide rises on throttle opening. In other words, raising the needle will allow more fuel at a lower RPM. However, it will not affect maximum feul delivery. If you need more fuel you need a larger main jet/
Hope this helps. :motorsmile:
Keith
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US/Canada bikes don't have adjustable needles stock. Many other markets do, such as UK & EU. So shimming the needles is the way to raise the non-adjustable needles.
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Thanks lads, in an imperfect world its refreshing to get not one but two perfect answers. I'm impressed.
Regards
Dickbarton
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I just received my Mikuni Pocket Tuner from Dennis Kirk. It is a slide rule like device that makes it very easy to see the relationship between Main Jet, Jet Needle, Needle Jet, Throttle Valve, and Pilot Screw settings. It shows specific jet size corrections required to maintain proper mixture for changes in ambient temperature and evevation. I was surprised to see the cumulative effect of these variables and now understand why my Bandit is affected as it is by weather changes and location. ie Cooler weather makes it run leaner, higher evelation makes it run richer. It might be the best $4.95 I have invested so far.
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From my signature you can see my set up. Af srews set to 2. 1/2 turns inners and 2 1/4 outers still to rich on primaries will try to get #20's that might help also note with this config std filter and 1 1/2 " airbox hole. May look at Holeshots new backless airbox with K&N.