[fireyphoenix1989]

Think i may have ....actually hoping to hell is did lol as that would identify the problem im having exactly ! .

i just hope my friend will let me use his workshop tomorrow so i can fit the float.

(Hes my mechanic and does work for me at extremely low rates so much so that after my top end rebuild i added a crate of beer to his bill as he only charged me £40 for 7 hours labor and letting me use his equipment and work bench for 3 days while i sorted a load of other jobs out)

........just hope this fixes it lol.

[crazycraven420]

good luck man! Hope you find a bad float and end this madness lol

[fireyphoenix1989]

Done the float swap today .....seems to have cured it, well it rode home fine anyway...
But i examined the old float and it looks completely fine, ah well


Thanks to all for support and advice
The rat fighter lives again

[crazycraven420]

dude that's fuckin awesome! I love the headlight!! Congrats on fixing it too!

[fireyphoenix1989]

Cheers there is a proper build thread in the streetfighters sub forum

can crack on with my plans anyway now . next thing on the agenda is to fit the 2001 750 wheels i got

[fireyphoenix1989]

Bikes running on 3 again !!!!!!

This time its number 1 playing up .....Sick to death of this machine. No matter what i do after a few days it start playing up again

[shpielers]

Dude that sucks, that's got to be extremely frustrating.

That is an absolutely WICKED bike though! I'm not a fan of the street fighter look, but yours is bad ass! Hope you get it figured out!

[crazycraven420]

Well 1 an 4 are on the same coil so I would check that, doesnt explain cyl 3 though.

Have you moved the airbox at all? Boots on both sides of the carbs are good and sealing? A loose, cracked or not sealing boot can and will cause misfire for a too lean mix. Just my 2 cents

I know mine are a PITA lol

[fireyphoenix1989]

OK .....now im confused lol .
I did a cold compression test on my GSX750F its making
Cyl 1 158 lbs/sq in
Cyl 2 155 lbs/sq in
Cyl 3 158 lbs/sq in
Cyl 4 155 lbs/sq in
.
So the engine its self is in theory perfect (should be with the amount of work i have done on it + whats been replaced)

Now its starting with full choke perfectly
...but as soon as i go near the throttle it dies instantly.
If i close the choke off it dies instantly.

Carbs are clean as new with 100% new orings through out and brand new pilot jets (mainjets + needles are only 3 months old)

I restore carbs as a pastime (i find it very rewarding) and have done dozens of mikuni BSTs...i know it isnt a blockage or anything so im stumped

[Kreylyn]

Cyl 1 158 lbs/sq in
Cyl 2 155 lbs/sq in
Cyl 3 158 lbs/sq in
Cyl 4 155 lbs/sq in

So it's not the engine, that can be ruled out at this point.

Now its starting with full choke perfectly
...but as soon as i go near the throttle it dies instantly.
If i close the choke off it dies instantly.

So it runs and probably isn't electrical issues as changes to the fuel input are what is killing the engine...

Carbs are clean as new with 100% new orings through out and brand new pilot jets (mainjets + needles are only 3 months old)

I restore carbs as a pastime (i find it very rewarding) and have done dozens of mikuni BSTs...i know it isnt a blockage or anything so im stumped

Well, it's not the engine and it's probably not electrical... "Choke" adds fuel, throttle adds air.

If it runs with choke but not with out it, then it's fuel starved.

If the throttle kills it instantly, then it's very fuel starved and the throttle is adding air that overly leans out the mix to kill it fast.

It's definitely a carb related issue. Massive air/vacuum leaks could also cause a problem along those lines. The butterflies on the carbs will control the air flow, so if those are very out of sync then that can cause a very poor throttle response killing the engine. If the airbox/engine carb boots are not properly attached, again.. air leak causing an issue. If the slides are not freely moving or the diaphragm/caps are not properly sealing then throttle won't add fuel for the transition and kill the engine.

Ultimately on CV carbs... air flow, vacuum, and the venture effect have a huge effect on how they function due to their design. I've seen carb bodies that were clogged on the air side of things, I've seen filters put on the carbs that covered the pilot/main air jets causing issues. I've seen people try to use after market air boxes/pod filters or other air box modifications that ultimately just did not work well. Bad O-rings on the engine side boots or worse... cracked boots make a huge difference as well.

Personally I would go back to pulling the carbs and tear them down to the individual bodies again. I would then inspect every part separately, I would check every port is fully open and clear, I would double check against a parts diagram that the parts I'm using are correct and properly installed (nothing missing) and I would give the carb bodies a good full 24 hour chem dip soaking one more time just for making sure there isn't a passage I'm missing.

Then on reassembly I would triple check the parts as they go on and finally make sure the bench sync is right, and then actuate the butterflies to make sure they snap closed cleanly and when opening them back up do not bind or catch on anything.

I would then pull the air box boots off, clean them and the box, use a gasket sealer to re-seal those boots on the air box. I would pull the engine boots and make sure the O-rings are not flattened and replace with good if they are. I would also very closely inspect the boots themselves and replace any that show signs of cracking. Even if it just looks like a "surface" crack, it's probably needing replacement.

I would double check the caps on the top of the carbs are flat (a fine sand paper sheet on a flat surface and just a tad bit of rubbing makes this very clear....) and they are properly seating/sealing. I would double check the float heights. I would double check on the bench before installing the carbs that all 4 of the bowls are fully filling and properly holding the correct amount of fuel.

I would then triple check the fuel lines, petcock, (fuel filter if you have one) and all aspects of the fuel delivery are fully functioning and giving more than enough fuel delivery. A slow fuel delivery will cause these problems as well fyi... enough to put fuel in the bowls, but not enough to run the main jets. This would mean choke (which pulls from the bottom of the bowls) would make it run but no choke no go.

So... my conscious streaming thoughts on what I would do and check for... some may not be in the optimal order.

Krey

[fireyphoenix1989]

Cheers krey, lots to go through thanks

[fireyphoenix1989]

Gone through the carbs everything is spot on :
clear jets and passage ways
2.5 turns out F/A mix
14.6 mm floats

The rubbers dint appear to have been sealing to the airbox correctly . and as thats the only thing i "could" be i have re sealed them

I have epoxied them in place then put a thick layer of tiger seal (flexible adhesive sealant ) on top of it ...24 hours to dry tho

but im 100% sure the air box will have no vacuum leaks now

Rebuild tommorow.

[fireyphoenix1989]

didnt work ....
It still needs choke to run.
No vacuum leak anywhere either


Gonna go through everything again ....but i honestly dont have anyhope as i have already checked and triple checked everything

[Kreylyn]

Well, I hate to say it but I would check the CDI at this point.

Krey

[fireyphoenix1989]

how would i do that ?