gsxr 750 L BST38 jetting issues (DJ stage 3 kit / won't start)

[1168turbo]

You're right! But thank god for the internet and people who help other people!!

 

none of which worked for me...

[Oilyspanner]

Nikos - I've just re-read your post. I see you've not bought a dynojet kit and were actually trying to sort out the jetting by looking at their spec sheet for a stage 3 kit.

Don't use their settings without having their whole kit. You have Mikuni carbs, so better to buy Mikuni jets and fit those. Start afresh. You'll need a size up or so on the pilots and quite a few up on the mains (sorry I haven't got a 750)if . The problem will come with the jet needle, you'll probably find that even lifting the needle right up won't make that circuit rich enough and will need a thinner needle - it's this problem that makes people buy jet kits - stage ones are easy, stage threes not so because of the jet needle.

You could see how close you can get by upping pilot and main jet sizes and lifting the needle up - perhaps someone could tell you what pilot and main jets they're using - someone !

[nikos1400]

Nikos - I've just re-read your post. I see you've not bought a dynojet kit and were actually trying to sort out the jetting by looking at their spec sheet for a stage 3 kit.

Don't use their settings without having their whole kit. You have Mikuni carbs, so better to buy Mikuni jets and fit those. Start afresh. You'll need a size up or so on the pilots and quite a few up on the mains (sorry I haven't got a 750)if . The problem will come with the jet needle, you'll probably find that even lifting the needle right up won't make that circuit rich enough and will need a thinner needle - it's this problem that makes people buy jet kits - stage ones are easy, stage threes not so because of the jet needle.

You could see how close you can get by upping pilot and main jet sizes and lifting the needle up - perhaps someone could tell you what pilot and main jets they're using - someone !

Thanks for the reply.

I DO have the stage 1+3 kit for US models (750 L).

The problem was 1) MY not understanding the Powerjet circuit and what was needed to begin with, 2) the mechanic not actually familiar with the Powerjet circuit.

Right now I have the complete stage 3 setup installed but with the DJ155 mains instead of the DJ160 stated in the kit's instructions. These were not returned to me

I've got my battery charged, and the spark plugs that were new, don't know if I flooded/short circuited them with the last try to start. New plugs on the way, but I might try to start with the refreshed battery tomorrow. Would I be able to save the plugs with a good wipe off and dry?

 

[steve.w]

have you fitted the dyno-jet needles and air corretors  in the slides ??ive fitted stage 3 in my 750 j ...no probs at all

[nikos1400]

have you fitted the dyno-jet needles and air corretors  in the slides ??ive fitted stage 3 in my 750 j ...no probs at all

I haven't plugged the slides, it gives you the option to leave them open "for hard street riding or  racing". I didn't want the extra fuss so I left them alone. DJ needles and emulsion tubes in of course.

I actually got it started tonight.

Battery charged, new spark plugs.

Float bowls set to 15,5 maybe 16mm, pilot srews 1,7 turns out. I had some "lean surging" when giving a little throttle when cold, so maybe I'll try about another 1/2 turn out (??)

Didn't have any more time, might test ride tomorrow. I left the DJ 155 mains, so we'll see.

 

I noticed something that might've caused the flooding and spark plug fouling the previous time I tried to start it. The throttle cable was binding at the carb rack, which didn't let the whole set of butterflies close completely. So basically I was trying to start the bike with maybe 1/3 throttle open... I'm not sure this happened that previous time, but it's highly possible.

[nikos1400]

For reference while I have the pics handy, on the left Mik 117,5 main, in the middle K 140, on the right DJ 155.

 

[steve.w]

doesn't it say leave one air corrector out for racing not both ??

[steve.w]

Defo says remove only one my kit for 750 j e3122.005 is running 144 mains mixture screw 2 1/2 turns out 

[nikos1400]

Defo says remove only one my kit for 750 j e3122.005 is running 144 mains mixture screw 2 1/2 turns out 

3135 stage 1 &3 says you can leave slide holes stock for "hard road or racing" for "better acceleration".

for the L 750 it also recommends 2,5 turns out, which I might end up with after all.

 

[nikos1400]

Forgot to say thanks for the help.

Plugs and battery charge it was. Also pilot screw back to DJ instructed 2,5 turns.

Now to put some klms on it.

 

Edited January 3, 2016 by nikos1400

[Captain Chaos]

Good that you got it sorted.

Nice and clean L by the way. Now install that 1100 engine.