GSX750 ( Inazuma ) Losing power at high RPM?

[MudSweatnGear...]

Hi everybody,

Right at this moment im not very happy with my old girl, recently she has been playing up something silly and Its having all of us here scratching our heads...

So here goes: Lately she has been really reluctant to start, most of the time she will go after a few turns of the motor but if she doesnt start then im having to leave her for a while before i can go back and try again.

Then today ( and the day before ) humping down the M25 i found that if im giving her a "vigorous" amount of welly she will bog out - she wont die but its certainly not an inviting noise when she decides to cut out; Its almost like shes not getting any fuel.

If i back off the throttle it gets better, but its still nowhere near what it should be. Also just to make things really complicated ive also found that when i was passing cars on the motorway every time i got next to the car the bike would start to play up?! bogging out not letting me gain speed and then having to drop back off the throttle or chop it to get her to start pulling again.

Whilst i was at the workshop today I checked the coils ( New about 6 Months ago ) just to make sure nothing had shifted or been pulled and I also checked the battery as im having problems with electrics eg: Tacho - Dead, Neutral light - dead and other oddities. the coils checked out okay, but my battery seemed to be getting 14.5v just off of the idle? im assuming thats slightly too much at idle as it creeped up slightly as i built up the revs but it did not go past 15v.

Right now im in a quandary in regards to where I start. Ive checked basics but its now getting to a point where im starting to loose interest with her and Im honestly thinking about just lumping her around as is till she dies completely. The only annoyance about that is she is my only transport and my work is 50miles away...... sod push biking that....

Heres a list of what has been done recently:
New Coils - Nothing fancy just Wemoto OEM replacements.
New Spark Plugs - NGK Iridiums
New Air Filter - Again nothing fancy
Filters and Fluids - Rock Oil Semi-Synth / Hifiltro Filter

Here is what does not work:
The go I used to have above 70.......
Fuel Gauge - No sender in tank
Fuel Light - Again no sender
Tacho - Died last winter on the 25
Neutral Light - Died with the Tacho - but prior to dying it used to stay semi lit out of N.

Also i forgot to mention that a few ago in the morning when I was getting her ready to leave I went to start her and she decided that she WAS NOT going anywhere, When I pulled the plugs I was getting the lamest of sparks, to be honest I could of generated more by dragging my feet on the carpet. But after leaving her for a while the spark got stronger? not by much but enough to get her started and off to work - after this there were no problems until earlier this week.

I apologise in advance if this is abit long-winded and confusing, but im kinda racking my own brains on what it could be.

Hopefully we can get some clever'uns in here and maybe get some life back into my old donkey
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www.adrenaline-motorcycles.com.

[temeluchus]

To be honest you'll need to check the loom thoroughly a it could be the source of your various maladies.

Non electrical sources of the lack of horsepower include:

blocked fuel cap breather
leaky fuel tap vacuum hose
worn fuel tap vacuum diaphragm
blocked fuel filter if fitted
perforated carb slide diaphragms
float bowls full of shit and/or water
worn seals and gaskets in the carbs

Electrical issues affecting horseypowers can include but not limited to

poor earth to the igniter box (morons call it a CDI), the coils are also earthed by the igniter.
Poor positive feed to the coils and therefore weak spark
Some connector block somewhere is full of corrosion and needs a good clean.

Good luck.
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Some shite cruiser. Now with guns and FREEDOM!

[Aceslock]

If you are getting high voltage from the battery, it could mean your regulater rectifier is not functioning properly. Do your headlights go brighter when you rev it?
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Previous Bike: Skyjet SJ27
Sold: Yamaha YZF 600 R Thundercat. Sold: ZX636R
Current bike: R1 14B (Beast)

[MudSweatnGear...]

temeluchus, ive pretty much ruled out the mechanicals other than the diaphragms - both petcock and carb.

Silly question but would a carb balancer gauge tell me if my diaphragms are out? Im guessing they would as vac wouldnt be as high due to the slide not opening?

aceslock, I am leaning towards this possibly being the problem, my only reason for not believing in it fully is that the problem only arises on the motorways, and very sporadically round the town. for what its worth ill see if my cheap-o-nasto multimeter can check the diodes.

Cheers for your advice
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www.adrenaline-motorcycles.com.

[cormac83]

Let me know if you want to compare any readings as I have the same bike (1998 Model).
I know it can be a pain finding correct info on them.
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Suzuki GSX750 Inazuma

[temeluchus]

[MudSweatnGear...]

temeluchus, So ive found the root of the problem; turns out my float bowls 2&3 were full of what looks to be degraded fuel line... 1&4 wasnt too bad but you could see they were on the way to being mucked up.

Gave them a good clean out aswell as the carb passages and weheyyyyy all my ponies are back.

Strange to have the fuel line go on me, saying that though I have had ones rupture on me for no reason, I have been using DIN rated fuel line so gawd knows.

Looks like this fuel were using doesnt like it.

Thanks for all your help. Strange to think that something like this could cause all them problems....
____________________
www.adrenaline-motorcycles.com.