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CBR900 Starting trouble
eddyg - 7/2/10 at 09:46 AM

Hi guys don't know if this is normal but if i don't start the motor for a week it really strugles to fire, but once it has started it will restart fine? It also misfires when throttle is held open at about 60000 revs. I have not adjusted valve clearences would this be the next step?

Thanks Edd

zilspeed - 7/2/10 at 09:48 AM

quote:
Originally posted by eddyg
Hi guys don't know if this is normal but if i don't start the motor for a week it really strugles to fire, but once it has started it will restart fine? It also misfires when throttle is held open at about 60000 revs. I have not adjusted valve clearences would this be the next step?

Thanks Edd


I think my engine would misfire too of it was held at 60,000 rpm...

Sorry, can't help with anything actually constructive

Steve Hignett - 7/2/10 at 09:53 AM

Is this in a bike or a car?

What airfilter do you have?

What exhaust do you have?

What Jets do you have?

ATB
Steve

skinned knuckles - 7/2/10 at 09:57 AM

quote:
Originally posted by eddyg
Hi guys don't know if this is normal but if i don't start the motor for a week it really strugles to fire, but once it has started it will restart fine? It also misfires when throttle is held open at about 60000 revs. I have not adjusted valve clearences would this be the next step?

Thanks Edd
:

personally i have never taken any engine past 55,000 revs

seriousely though, my CBR was the same every time it went for a week or so without starting, never found out why though. what do you mean by a misfire? does it seem to hesitate to raise revs or is there a definate "lumpyness" to the engine. if its at just one area in the rev range it sounds like a fueling problem specific to those revs. how are you fuelling yours? as far as i know, valves would couse more of a problem than your relatively isolated one.

eddyg - 7/2/10 at 09:58 AM

the engine is in a locoblade it is jetted and set up by tts with thier air filter it has only started to do this after track day where i embarrassingly run out of fuel, have changed sparks,oil could it be the carbs?

eddyg - 7/2/10 at 10:02 AM

the exhaust just pops and bangs when the throttle is held open probably between about 4000- 11000 but not so much when driven under load more when in neutral ami worried over nothing or should i get it checked over?

Steve Hignett - 7/2/10 at 10:06 AM

Do you know where the float bowls are on the carbs?

I would definitely check them and clean with carb cleaner and a v soft brush that you can guarantee won't melt or drop bristles...

You could of pulled some shite from the bottom of your tank if you ran out of fuel...

skinned knuckles - 7/2/10 at 10:08 AM

quote:
Originally posted by eddyg
the engine is in a locoblade it is jetted and set up by tts with thier air filter it has only started to do this after track day where i embarrassingly run out of fuel, have changed sparks,oil could it be the carbs?


strip and cleant the carbs then work backwards through your fuel system. if this is happening since you sucked air and probably a bit of crap/sediment/waxy depisits/water from condensation through your fuel system, this should be your first port of call

eddyg - 7/2/10 at 10:27 AM

Cheers guys will get to work on carbs!

Mark G - 7/2/10 at 10:37 AM

Mine is the same for starting, I find that a little choke this time of year works a treat.

RAYLEE29 - 7/2/10 at 10:50 AM

sounds like a fuel problem especially as it was fine before you ran out.
check the pump is supplying fuel also the pump should energise for a little time when you first turn the ign on.
my blade used to play up after along lay up but just aweek is a bit short.
mine was in a bike though so the fuel line was short.
try cleaning the pump and also worth checking the float needles havent stuck.
Ray

ReMan - 7/2/10 at 11:32 AM

do you have the chokes connected?
mine always needs a touch when VERY cold or when sat for a week or more.
comes off agin after about 10-20 seconds else it will flood it

Mark G - 7/2/10 at 04:22 PM

I don't have a cable connected. I operate the lever by hand when required, like you say it's only for a few seconds.

mad-butcher - 9/2/10 at 09:03 PM

Deffo sounds like you've picked up the sludge in the float bowls and sucked it into the jets when you've run out of juice. generally the shit sinks to the bottom of the bowl being heavier than fuel and doesn't get sucked up.

tony