zxr 750 wont start

[sunnydevon-2008]

Hi guys well iv got my self a new project a zxr 750,The bloke i brought it off said that it hasnt been started for over a year or so and as there was no battery in there i couldnt try it out.Anyway i brought the bike off him and put frech petrol in the tank cleaned the petrol pipes and tank and have stripped the carbs down and cleaned them.I put them all back on and i can hear that the engine wants to start but cant.Iv looked at the spark when turning over and one of the has a big think spark where the other 3 dont.Do u think the coils could be at fault.Oh yeh and theres brand new spark plugs in there

[Wafer_Thin_Ham]

HT leads? It's unlikely that 3 coils would go at once if it has individual ones.

Check the leads, then the coils, then the CDI.

You have changed the oil too just to be safe right?
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[sunnydevon-2008]

yes i will be mate once iv got the bike running

[sunnydevon-2008]

Got some new leads and coils from the breakers and fitted them and all four have a nice think strong spark

[sunnydevon-2008]

Got some new leads and coils from the breakers and fitted them and all four have a nice think strong spark

[sunnydevon-2008]

Right well iv sort of got the bike running today.i sprayed easy start in the air box and it started up on one cylinder or too it sounded like a tractor and as soon as i took my hand off the throttle it cut out and wouldnt start up again.but when it was sort of running it i moved the throttle it woundnt rev.its like there aint fuel gettin through.I cleaned the carbs and jets out about 3 weeks ago

[stu_m]

fuel tap blocked ?

check all fuel lines again

take a look in the carbs make sure fuel is getting in

it is definately a fuel issue

Stu

[sunnydevon-2008]

Hi mate yeah fuel is getting into the float bowl and iv had the fuel pump tested and thats 100 per cent fine

[stu_m]

have you checked all the jets ? they arent blocked are they

Stu

[sunnydevon-2008]

[sunnydevon-2008]

well i did blow them out with the air compresser at work when i stripped the carbs down

[Barry_M2]

[sunnydevon-2008]

Ok mate i`ll give that a try.with the pilot screw does that screw all the way in or does it have to be set like 2 turns out etc.as for the engine it has lighter wisco pistons,lighter crank been rebored has gsxr 1100 valves and some sports cams

[Barry_M2]

If you take the float bowls off, remove all the jets you can see and clean them.

Its the air screw that your thinking of.

What model 7 is it out of interest? I've never heard of fitting gsxr valves before!? Have you got receipts (or any evidence) of the work being done, it'll be interesting to know?


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[sunnydevon-2008]

The bike is an h1 model and yes i have the paper work for the engine mod it was done by nck racing i think it was

[sunnydevon-2008]

[Barry_M2]

I'm not too familiar with the H models, more so with the J through to P.

If the pumps working fine (you could always pull the fuel line off the carbs and turn the engine over, with a rag over the end of the line to check!!) and your are 100% positive ALL the jets are clear (even spray cleaner down the holes you took the jets out of too) then I'd try another set of carbs. It cant really be anything else.

Tell you what you could do. Tip a thimble full of fuel straight down the carbs, count to 5 and hit the starter. It 'should' fire up, maybe rev up a bit on its own, but it will more than likely stall again after a couple of seconds.
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[hmmmnz]

i am very familar with the h1's bastard bikes
it sounds to me that your valve clearances are too tight.
i had exactly the same symptoms on my bike, i stripped and rebuilt the carbs more times than you could shake a stick at it, and some times it would run completely fine for days on end, and then would refuse to start, i'd change the plugs and it would go again, like nothing was amiss, and then while riding it would feel like it was running on 2 or 3, if i kept the revs up it would sort it self out, if i didnt and let it die, then it wouldnt start.
after months of fucking about i decided enough was enough and did the clearances, (id put it off, because to change the shims the cams need to come out) i guess kawasaki were still finding there feet in relation to shimmed engines, as thats just a dum thing to do.
any way my clearances were so tight that i couldnt even get the feeler guage under 6 of the 8 on the inlet side, ended up having to do clearances 3 times just to get it right.

as i said ... bastard bikes


any way, save yourself the hassle and take it in to get the valve clearances done before you bother with any thing else.
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[dr_adams]

if you try to start it for a few seconds... not to long or you'll mess the started up... then take the plugs out and see if they are wet from fuel.... normally u would flood the thing and the plugs would have some petrol still on them....

[sunnydevon-2008]

hi dr adam after iv been turning over the engine for say 5 mins the plugs are still bone dry

[sunnydevon-2008]

iv tryed tipping abit of fuel straight down the carbs and its still does the same thing

[sunnydevon-2008]

hmmmnz when u said this problm did u have petrol gettin throgh ok as im not

[hmmmnz]

yep, try and clean your carbs again, soak all the jets in kerosene and spray carb cleaner all over the carb, then put them back on the bike,
don't pu on the air box, but put your hand over the opening of 1 of the carbs, try and start the bike, you shoud feel a vacume, and if you have an auxiliary tank then you should fell the fuel being sucked through,
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the humans are dead
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[dr_adams]

i would deffo think a carb issue.... have them to pieces entirely... don't use flash cleaner tho as it has a habbit of burning sheds down... ask phoenix... but completely strip them and then set as per manual....

[sunnydevon-2008]

ok guys i`ll try that.To be honest i think its a carb problem too