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Discussion Starter · #1 ·
Hi,



I have a 1996 GSXR750 that is fitted with a Dynojet kit and a K&N filter. The bike was fitted with this when I bought it and the kit was fitted by Crescent Suzuki. Since I have had the bike it has tended to run very rich and the plug insulators are sooty black. All the plugs are the same colour so it led me to believe it is a fault common to all carburetors, I have cleaned and re-oiled the K&N but it is still the same. I am assuming that the bike must have been right at one time or the previous owner would have complained about it. When the engine is just warming up it is reasonably OK but the hotter it gets the worst it gets, until it will not run right or pull below about 5000rpm. I have the carburetors off at the moment and have checked the choke mechanism which seems to be in good condition and working OK. If once it has warmed up after a run and left for a while, but not enough to fully cool down it starts badly and will not except throttle until a considerable period has elapsed. I understand that it sounds like it is flooding, but all four plugs are the same black colour and I think it is very unlikely that all four float levels are wrong. I have fitted new plugs, and it ran sweet as a nut for about 20 miles! Any suggestions would be greatly appreciated. The only thing I can think of is that the needles have worn the needle tubes and that it is running rich that way.
 

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Originally posted by Mr.Gixer:
Hi,



I have a 1996 GSXR750 that is fitted with a Dynojet kit and a K&N filter. The bike was fitted with this when I bought it and the kit was fitted by Crescent Suzuki. Since I have had the bike it has tended to run very rich and the plug insulators are sooty black. All the plugs are the same colour so it led me to believe it is a fault common to all carburetors, I have cleaned and re-oiled the K&N but it is still the same. I am assuming that the bike must have been right at one time or the previous owner would have complained about it. When the engine is just warming up it is reasonably OK but the hotter it gets the worst it gets, until it will not run right or pull below about 5000rpm. I have the carburetors off at the moment and have checked the choke mechanism which seems to be in good condition and working OK. If once it has warmed up after a run and left for a while, but not enough to fully cool down it starts badly and will not except throttle until a considerable period has elapsed. I understand that it sounds like it is flooding, but all four plugs are the same black colour and I think it is very unlikely that all four float levels are wrong. I have fitted new plugs, and it ran sweet as a nut for about 20 miles! Any suggestions would be greatly appreciated. The only thing I can think of is that the needles have worn the needle tubes and that it is running rich that way.
<font size="2" face="Verdana, Arial">Has it std can cos might be jeted for race can
ifso get a dyno run.
hope this helps john
 

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Just see the post rep tab so this will be ok now
also check diaphragms for holes and the float
valve are sealing right ifit had a race can on
when you got it post more info
john
 

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Any idea what the jet size is in it? Maybe the guy had a different pipe (like said above) and has a big pilot jet in it??? Or maybe the adjusted the float level incorrectly??

John
 

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Discussion Starter · #6 ·
Thanks for the replies, here is an update!
I cleaned the outside of the carburators until spotless using a parafin air gun full of petrol, I then removed the float bowls and checked the float height using a vernier, spot on!
I then removed the diaframs and slides and checked the needles etc, perfect!
I then cleaned and put back the choke plungers which also looked perfect.
I put everything back together and took it for a blast----------- faultless, so far!!!
It is on a standard can at the moment, as it just had it's MOT, but this seemed to make little difference to this problem over the ART carbon race can it usually has.
It's fixed, but I'm not sure what did it, maybe it was the choke plungers? I'm told by a ex-Suzuki mechanic that these were very tempremental on this model and must seat absolutley perfectly (to the thou) or they run like a bitch!
Anyway I'm very bike happy now and just had to tell someone!

 
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