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Discussion Starter #1
Hi.
I am totally gutted to have had to end my holiday traveling to the Alps due to a problem with my 1998 cbr 900 rrw.
I have used the bike for over 1000 miles with no issue apart from a low down hesitation that i put down to the exhaust I fitted.
Pic shows exhaust . Standard headers and fabricated stainless underseat with no baffling except in endcan. I refuelled in France, approx 300 miles into the journey, after having refueled twice already, and nearly straight away it began to run really rough. It would not rev cleanly, especially over 4000 rpm, and would feel like it was running out of fuel. I tightened down a slightly loose airbox and drained the fuel out and put new in as well as checking the fuel filter. This didn't help and I was forced to travel the 450 miles back at 55mph !
Since returning I have checked the plugs. OK. I have removed the carbs and would like advice as to what to look for that would give the symptoms i describe. Incidentally, it starts well and ticks over well and revs really cleanly when stationary.
Any advice would be welcomed.
 

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Discussion Starter #3
Thanks for the reply.
Have to easi out one of the pilot screws, as disintegrated the cross head as soon as it started to turn, but the jets all appear to be ok. bowls all clean and nothing blindinly obvious wrong ! Before anybody mentions the dreaded rectifier..I replaced that last year whilst in Marsaille as it failed then ! So many things it could be but is it just coincidence it happened after i filled up ?? :confused:
 

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I don't know where you are, but Steve Lynhams in Swindonia is your best bet, if you get no-where with it.
 

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Discussion Starter #6
Cheers mate. I live in Devizes but know Steve lynham ( used to live next door but 1 in Highworth ! ). My preference, as an absolute last resort, would be JHS in Bath. Would really like to sort it myself but dont like clutching at straws !. just taken all the jets out and all are spotless. Think I will test the coils and Ht leads next.
 

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Discussion Starter #8
Thanks for the reply Ian.
I have checked the hoses and all are clear including the breather hose. When I removed the tank I pulled the choke and it was free and returned to its correct position then i pushed it back in. The whole of the 450miles I travelled back was the same even though I filled up at least 4 times. Its starting to become a little frustrating !!!
 

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Cheers mate. I live in Devizes but know Steve lynham ( used to live next door but 1 in Highworth ! ). My preference, as an absolute last resort, would be JHS in Bath. Would really like to sort it myself but dont like clutching at straws !. just taken all the jets out and all are spotless. Think I will test the coils and Ht leads next.
No worries, i'm up the road in Chipp, no ideas, but if there's anything i can do, let me know.
 

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Thanks for the reply Ian.
I have checked the hoses and all are clear including the breather hose. When I removed the tank I pulled the choke and it was free and returned to its correct position then i pushed it back in. The whole of the 450miles I travelled back was the same even though I filled up at least 4 times. Its starting to become a little frustrating !!!
That was my next offering, suggesting maybe there was a vacuum created by a blocked fuel tank breather hose. Oh well. Any unusual noises as it starts to stutter? Like maybe a tossed rod bearing?:eek: I for sure hope that's not it.
 

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Discussion Starter #12
Cheers "Spaz" .
No unusual noises Ian. I pulled the clutch in when it started stuttering and it revs spot on. There are so many people on this forum that have had issues with fireblades that Im sure I cant be the only one that has experienced this problem ? The problem only arises when you try to rev it past 4000-5000rpm in any gear.
Whatever happens, I will definately post the solution when I find out what it is.
 

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I know next to nothing about carbs, but it sure sounds like your bike is starving for fuel. Hesitation under a high(er) rpm/load usually means starvation, while a bog usually means to rich.
No obstructions anywhere in the fuel system? Tank is venting properly, no pinches in the fuel line? How did you 'check' you fuel filter?
 

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Discussion Starter #14
I know next to nothing about carbs, but it sure sounds like your bike is starving for fuel. Hesitation under a high(er) rpm/load usually means starvation, while a bog usually means to rich.
No obstructions anywhere in the fuel system? Tank is venting properly, no pinches in the fuel line? How did you 'check' you fuel filter?
Thanks for the reply.
I have blown the lines through and no obstructions. The fuel "filter" on a rrw is a plastic tube which goes inside the tank behind the petcock, it has a series of gauze "slots" incorporated. all the gauze elements are clear.
I am with you on the fuel starvation route and was fully expecting to find an obstruction in the jets or blockage but...nothing ! :mad:
 

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Hi.
I am totally gutted to have had to end my holiday traveling to the Alps due to a problem with my 1998 cbr 900 rrw.
I have used the bike for over 1000 miles with no issue apart from a low down hesitation that i put down to the exhaust I fitted.
Pic shows exhaust . Standard headers and fabricated stainless underseat with no baffling except in endcan. I refuelled in France, approx 300 miles into the journey, after having refueled twice already, and nearly straight away it began to run really rough. It would not rev cleanly, especially over 4000 rpm, and would feel like it was running out of fuel. I tightened down a slightly loose airbox and drained the fuel out and put new in as well as checking the fuel filter. This didn't help and I was forced to travel the 450 miles back at 55mph !
Since returning I have checked the plugs. OK. I have removed the carbs and would like advice as to what to look for that would give the symptoms i describe. Incidentally, it starts well and ticks over well and revs really cleanly when stationary.
Any advice would be welcomed.

Did you replace the plugs?
 

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Discussion Starter #16
I put brand new plugs in when the bike was rebuilt. They are the original ht leads though. I have since removed the plugs and they have no signs of "damage". Gaps are set to 0.8mm as per Haynes manual info.
 

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Discussion Starter #17
So after much time ( and money ) I still have yet to solve the issue of my badly running 'blade. I am reposting in the hope of some new advice. Here is a list of the parts I have changed in trying to solve the issue. After each part, I have reassembled and tried before moving onto the next straw to grab !
Secondhand carbs with new 140 main jets and a dyno jet kit.spotlesslly clean.
New iridium plugs.
stick coil upgrade from a cbr 600 f4.( 2 Ht leads from 1 of the old coils showed a high resistance so upgarded to stick coils)
new petcock diaphragm kit.
new choke cable.
all fuel, breather and vaccuum lines clear.
fuel " gauze" inside tank clear.
The bike revs clleanly from standstill but runs Really rough under acceleration. It will not tickover now but i put that down to the carbs needing balancing !
I took it to a " Honda technician for 20 years". he cant look at it for another 2 months and said " I charge £50 per hour and I can't guarantee i can fix it, it seems you have tried everything i would have !!"
I am running out of ideas. Next step was to change the ECU but am certainly open to suggestions.
 
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