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snap1

Joined:

Nov 10

Posts: 21

snap1 says:

CBR 600 98 mid range power loss

Hi all, I have a Honda CBR 600 1998 (F3) which is suffering with mid range power loss, bogging etc. 


Symptoms:
Riding the bike at speeds over 30 and as soon as you hit 5500 RPM it just boggs down and looses power until about 6500, 7k when were back on the power. 

I have replaced, plugs, air and fuel filter and even had my local bike shop strip, clean and Ballard the carbs. Battery seems fine as it churns over for ages if required. 

Exhaust has a slight blow top of manifold but bike shop told me that is not bad enough to cause this issue.

Any ideas on what I can try next please.

Thanks

Paul

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  • Posted 4 years ago (02 February 2011 16:25)

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jaffa90

Joined:

Mar 09

Posts: 8895

jaffa90 says:

bogs

Does your bike have an exup valve,that`s a valve in the exhaust system,also the plugs you took out,were they coloured,burnt,clean,carboned,wet,can you explain the condition. 

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snap1

Joined:

Nov 10

Posts: 21

snap1 says:

bogs

Hey Jaffa,

Don't think it has a valve in the exhaust, looks like a replacement SS manifold and standard can.

The plugs looked healthy and were not that old by the looks of them, replaced them anyway. Going on a plug chart they looked normal not black, wet or blistered.

I have a feeling it's going to get expensive :-(

Really not sure what to try next.....

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jaffa90

Joined:

Mar 09

Posts: 8895

jaffa90 says:

bogs

Has this problem just started or is it a fresh bike to you?At 5500 rpm you say it boggs down and looses power until about 6500rpm,and at 7k it picks up,:unsure:. Have you ever experience clutch slipping at higher revs and had to shut off and re-throttle? All for now but i`m thinking your short of petrol just before the main jet is fully used.

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jaffa90

Joined:

Mar 09

Posts: 8895

jaffa90 says:

forgot

to ask,how long does your bike take to warm up from a cold start? How long with the choke on,how long is it before you can blip the throttle without hesitation?

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snap1

Joined:

Nov 10

Posts: 21

snap1 says:

Bogs

Have had the bike 3 months now and happened since I bought it.

Yes it's a weird issue and a lot of CBR owners seems to have issues but not like this where the power comes back on and it will always do this without fail so it's not temperamental which is good for diag.

No clutch slipping on the bike, If I go to over take now I always get the revs to 7k or over and it's fine just that horrible 5,5 to 6,5 range.

Warms up very quick even in zero, so would say full choke no throttle start maybe 10 sec crank. Then by the time I have my helmet and gloves on it will rev up nice!

The problem only exists with load so clutch in will rev up fine.


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snap1

Joined:

Nov 10

Posts: 21

snap1 says:

Tests

Have also been digging on Google and here is my list of things to try tomorrow:
1 - When on motorway to work, choke on and throttle through this range?
2 - Ride through range with tank filler cap open (Risky but can achieve this within 100 meters)
3 - Ride with lights off (in the day :-)) electrical drain?
4 - Squirt cold start in air ducts while in this range... may have to leave this one for the dyno

Any other suggestions to add to this list I am more than happy to try!

Thanks for your help so far!

[This Reply has been modified by the Author]

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oscarthegrouch

Joined:

Oct 05

Posts: 3143

i had a jellymould

cbr this started happening to mine turns out fuel pump was fekked one day it cut out completly so i put in a bigger fuse to get me home which melted the fuel pump relay.......ahem:shock: 

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jaffa90

Joined:

Mar 09

Posts: 8895

jaffa90 says:

bogs

I`m fresh now but try super unleaded petrol with a shot or two of redex in it,(you`ve no cat)if that improves the problem try lifting all the needles one notch/groove/slot.If it was a fuel injection i would reccomend a power commander.

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triumphrider600

Joined:

Feb 09

Posts: 550

I'm with

Jaffa on this one and think you have a feulling issue. I note from your posts that you have aftermarket headers. Exhausts really can effect the way bikes run incl creating flat spots where in the power curve they run lean for a specific rev range. Trying a higher octane fuel as suggested will be a good test. If it appears to make it better then you have a lean patch in the rev range. You may have to overcome this with a dynojet kit for your bike to up the fuelling,

 

Tom

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davidstowe358

Joined:

Jun 08

Posts: 185

just try this

The long pipe that comes from the carbs to the fuel pump connect it straight to the tank, gravity feed. take it for a spin and see how it works, it could be your pump or pump relay. this is how i run mine all the time due to the same problem and its fine, it will start to cut out at about 125 mph, but unless your at a track thats fine:lol:

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