SuzukiHayabusa.org
TECHNICAL => GEN II BUSA => Topic started by: Turbo Train on October 27, 2015, 07:46:13 PM
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On a cold start it idles fine around 1100 but when temp starts rising so does the idle? Idle will go up to 1600-1700. No codes. This happened after running at the track. 2011 with a bone stock motor on a direct 40 direct dry shot. Plugs look great, log is showing 12.0 A/F, compression is good.
Thanks.
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Raise the fuel tank, put a small towel under the idle adjustment screw and locknut (clearly visible near the left frame spar) in the event you drop the hex key you will be using, the towel will catch it, but leave yourself enuf room to adjust the idle when bike reaches full operating temp, take a single 7mm open end/closed end ratchet 12 point wrench and a 2.5 mm/.097 in. hex key to get started. Use the hex key to find the current position of the idle adjustment screw.............remember the screw adjusts from the underside so you will have to feel your way until the hex key drops into the hole in the middle of the screw. Remove the hex key and slide the ratchet end of the 7mm wrench over the hex key so that you will be unlosening the lock nut by pulling it towards you. DO NOT loosen the lock nut until you have the hex key re-inserted into the idle adjustment screw......once you break the lock nut loose, fire the bike up and adjust the hi-idle downwards a couple of hundred rpms and then turn the 7mm ratchet wrench over, and without moving the position of the idle screw, retighten the lock nut. Fire the bike up once you are done to make sure nothing changed as you re-tightened that lock nut. If hot idle drops 200 rpms or so, let the bike sit overnight and give it a cold start in the morning and see where the idle is. It can, according to the book be as low as 1000 or a tad lower on a cold start, as long as it idles smoothly. Your oil pressure will be sky high anyways cuz it is cold. Ride the bike for 15 minutes and see where the hot idle is............I would be happy with 1350-1400. :bike:
What I am doing to adjust my idle downwards is I bought (from Schnitz Racing) the Robinson Hi-Speed oil pump gear (behind the clutch basket) so I could adjust my idle down to about 1300-1400 or so and still maintain 25+ lbs of oil pressure (right now idle is at 1900) at full operating temp, with .395 lift web cams and 20 more lbs of spring seat pressure and 13.2 to 1 compression. You have a stock motor, but that gear would not hurt you to have in your bike at all. Retail is 109 bucks. More oil pressure, particularly on a hot day in traffic is preferable to less, IMO. :tu:
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You also may want to check that you don't have an intake leak.
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If he had an intake leak, would that not effect his 12.0 A/F readings across the board/lean the bike out?
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If he had an intake leak, would that not effect his 12.0 A/F readings across the board/lean the bike out?
Possably, however a very small leak may affect idle speed and qaulity but not really bother A/F when in the throttle
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12.0 is a bit rich for a bone stock bike--- even up top you would like 12.8 or 12.9 with good fuel. Cruising and idle should be high 13's, even low 14 for decent economy.
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Unless I am mistaken, my chart was showing about 13.something all away across the RPM band after Rodney got thru tuning it..
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Can't wait to install this and lower my idle and raise my oil pressure.
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12.0 is a bit rich for a bone stock bike--- even up top you would like 12.8 or 12.9 with good fuel. Cruising and idle should be high 13's, even low 14 for decent economy.
Stock ECU's now are programmed rich down low (12.1) and waaaaaaaaaay too lean up top (as high as 16+ to 1). I like my 13's all the way just fine.
Only issue is that I love to keep these cams at a minimum of about 5500-7500 when goin' thru turns in 2nd and 3rd, and on straights in the two laners, never out of 4th gear............which will easily pull 160+. Keepin' those revs up, the motor begins to take on a completely different character..........it sounds like it is growling like a panther, just waiting to strike.. All that fartin' around burns fuel. On the hi-way cruisin at 75-80 I am good for 38 all day long. Buzzin' around "in the woods" it drops to about 31. Lots of accel, decel, accel, decel and yada-yada.
Power curve is nice and linear and torque is pretty flat over a broad RPM range..............great tune by Rodney. IMO.
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On TMH's old bike, which I ended up with, there was a small leak at one of the exhaust manifold gaskets that you could just barely hear, as I recall, the idle was a bit "bouncy" and did not want to stay steady. We pulled the header pipe and found that one pipe was about 1/32nd of an inch shorter than the other three so I took the header to my guy Kevin at the local machine shop and he put the entire header on the flat belt sander until all four were stone-cold flat when compared to each other. Remounted everything and bike idled smoothly after that with no exhaust leaks at the head whatsoever.