GSX750F ......help

[fireyphoenix1...]

right .......

someone


i need advice as im completely at my wits end

i ride a 1991 GSX 750F
it has a really really annoying recurring issue. i used it all morning .... and now it wont start
i have stripped and rebuilt it more times than i care to think about
(at least once a day for last 3 weeks)

cutting it down to this tho
it has......
Coil relay mod (a relay to supply power directly to coils as suzuki designed a shit one includeing about 10 block connectors between the battery and coil)

factory pro jet kit

full carb strip clean and rebuild with all perished rubber replaced
settings needle jets position 3 A/F at 2.25 as at 2.5 it was too rich
15 mm float height (as specified in jet kit instructions)
carbs re synced perfectly
brand new dynavolt battery (which i think is s**t imo)
valve clearances done
new spark plugs
airbox rubbers RTV sealed in to place
rebuilt petcock with new rubber and resealed tank

NO vacuum leaks anywhere
NO blockages in carbs

i would just literally write it off as a waste of space time and even metal used to build it in the first place but the insurance company have this nice thing going that makes it almost impossible for me or my mates to afford to insure anything other than SV 650s bandit 600s or GSXFs as im on low income and cant afford to replace it..... im stuck with it

having checked ...double checked and just incase i missed something triple checked ...

the bikes my ONLY form of transport

any ideas ...i mean im at my wits end
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2014 Aprillia dorsoduro 750 factory.

[Johnser]

just hot starting?

does it bump start when its not behaving?

[fireyphoenix1...]

its an absolute ball ache to bump start it mate ....fking heavy old beast, starts fine when hot usually starts fine in the morning but if its parked for a hour or so it just wont start
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2014 Aprillia dorsoduro 750 factory.

[bootsbiker]

have you done a compression test on it when it is cold...?
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https://justfuckinggoogleit.com/

[Casper]

91 will be the old model yes? They had a problem with coils. More to do with the shape of the tank and where the coils sit. Water ran down under the tank and on to the coils. You should have a sheet of rubber under the tank to help stop this. Try and take the HT leads out the coils and cut 2mm and stick them back in. If this fixes your problem then coat the coil/HT connection in some silicon.

[fireyphoenix1...]

[Johnser]

[fireyphoenix1...]

[Hetzer]

[fireyphoenix1...]

[Robby]

Don't cock around with the resistors in the plug caps, leave them in. You use resistor plugs (the R in the NGK plug numbers means resistor) so you should use resistor plug caps.

Spark breaking down when hot sounds like a possibility, so the tips above on sorting your HT leads are good. Duff plugs is also a possibility, it would be worth trying refitting the old ones, or coils not working when hot.

Certainly sounds like you have all of the fuelling side sorted, so the electrical side is the one to look at. If it started fine from cold your compression will be fine - and it would have to be really terrible to be a problem.

Personally I would just fit new HT leads and plug caps, the ones you have could be 20 years old now.

[bootsbiker]

so did you ever find out the problem....?
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https://justfuckinggoogleit.com/

[fireyphoenix1...]

yer its running good now ...

i replaced both coils fitted NGK spark cap kit and new NGK plugs
runs good .


im on to sorting all its little issues atm like the weird random oil leak its got lol
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2014 Aprillia dorsoduro 750 factory.

[temeluchus]

The coils used on these were never great, I always ditched em for dyna or accel units.
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Some shite cruiser. Now with guns and FREEDOM!

[fireyphoenix1...]

think im gonna do that when funds allow
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2014 Aprillia dorsoduro 750 factory.

[prawny1]

bandit coils fit the gsx1100f so i'm guessing the 750 will take them too
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hellkat wrote:

Some people are only alive cos its against the law to kill them.

[temeluchus]

[prawny1]

For some reason i thought the gsx750f was the air cooled tscc engine, but i guess that would be the gsx750e. my bad, still takes the same coils though.
____________________
hellkat wrote:

Some people are only alive cos its against the law to kill them.