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new to me GSXR


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so been out on it a few times, and runs well except when setting off stalls really easily, it has a big stumble at low revs, once past that it revs fine,  but i am sure its rich, plugs indicate this as they are dark, not sooty but not far off, doesn't like the transition when just cracking the throttle, idle seems fine, carbs well in balance, main jets are 144, and it looks like a dynojet kit has been fitted needles are set on second groove from top, i have set the mixture screws 2 1/2 turns out, carbs appear to be clean internally, i have yet to have the pilots out to check size and blockages

makes it a pain in the arse when setting off you have to over rev it to stop from stalling, once past this  it pulls fine,

anyone got any pointers please???

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not sure what i am looking for with the drilled slides, i will check the emulsion tubes/ needles and post pics of the slides, one thing for sure is it starts easily from cold with no choke, also when riding when the engine is stone cold  setting off is almost normal, much easier than when warm, virtually no stumble.

i cant get my noggin round this one, i would have thought that rich running would get worse the more open the throttle is, but it seems opposite it gets better, and the stumble is only present very low down the rev range worse with light throttle opening

it really does make it a pig to ride, you cannot set off normally or it will stall, over revving is essential 

its running a pretty much open exhaust and k+n pod filters, i am a bit stuck with this one i don't know what to do except change the mains  so any help is appreciated

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As gixer1460 "check the needles / emulsion tubes for wear"

Also check pilot jets are not blocked or muck in the tubes to the pilot screws.

Very basic, upto 3rpm pilot juts/screws 3-6rpm needles above main jets with a slight overlap between each. Like I say very basic did have a diagram that came with a Dyna jet kit some where and someone posted a pic of one once, it a help/ guide for carb tuning.

The slides at the bottom part have (can't remember if it's one or two holes) one will be drilled out and sometimes a plastic plug/jet put in.

 

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will check as you said i will give the carbs a good going over and post some pics i think the slides have been drilled though, i am suspicious of the pilot jets/circuit as i know the bike has been stood for a number of years, there is no debris/ gumming in the bowls though, 3-6 rpm is where the stumble is worse with light throttle openings

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so... stripped the carbs and, checked the needles, appear to be stainless no visible wear, checked the emulsion tubes and they are worn oval stripped everything else and cleaned out with brake cleaner and blew out everything else, snapped one of the floats, found that most of the o rings/gaskets perished.

Ordered new set of floats and emulsion tubes o rings and gaskets, started putting them back together and found that the needles wont fit the new emulsion tubes, so i fitted a good set of std needles, refitted the carbs, fired up more or less straight away, road tested and........ the stumble is gone:banana:, easy to set off without stalling  but it now wont accept any throttle except just cracked open, give it 1/4 on and it dies like i have hit the kill switch:(, back off the throttle and its back to life,WTF.

anyone got any pointers, i think it has got to be the mains but it ran fine before with the present mains, albeit a pig to set off but would accept throttle

 

 

float.thumb.JPG.0e616c3a7ba1984ca29c74e36ee41e1c.JPG

oops

 

slide.thumb.JPG.c5f08f963079cbdb728cb0781761ec54.JPG

slide with a plastic insert which i think is not std

 

needle.thumb.JPG.a21a13b41dafc4aae57b32f9a5000e7d.JPG

needle which is dynoshit i am guessing

does anyone know what would be a good starting point for the main jet so i can junk the dynojet stuff please? as i am guessing the dynojet emulsion tubes, if thats what they are, are not available, there are no markings on the original tubes.

i have a stage 3 dj kit for a 1200 blandit, for bst 36's but on cross reference the gsxr dj kit lists  3 sizes of mains 124,128,132, but the dj for the blandit is 150,155, i dont get that, i would have thought they would be broadly similar, the dj needles for the blandit look nothing like the ones fitted to the bike

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I think PDQ are still official DynoJet Dealers / Importers and should be able to supply replacements 'free of charge' due to the DJ lifetime warranty. The slides are deffo DJ modded! Trying to get std needles and emulsions to work without an airbox is an act of futility taking hours and hours to get anywhere near correct but never perfect. Blandit jetting is nowhere close to GSXR even though of the same heritage!

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no luck with dj, spoke to them today and they said the needles were lifetime warranty but not the emulsion tubes.... they did have stock of these though at just over a tenner each so i ordered 4, but it did sound as though they would swap the needles if they were worn, they didnt mention proof of purchase or anything.

not a bad outcome, at least  they are still available

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