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probably right and welding is just gonna warp it more..sometimes you just got to bend over and pay

Yep :)
Shipping a head from the US to Australia is pretty cheap so I can't imagine it costing any more to Canada, and it only takes a week or so. I'd be surprised if I couldn't have a head delivered to my door from the US for less than $250.

Remember, NEVER ship a head with the cams installed - unless you intend to replace the valves anyway, and always buy a head with its original cam caps.
 

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we have this thing called free trade between canada and the us ...sounds like a good thing don't it ? ..well it isn't ..you would get your parts faster and cheaper in the us supposing i lived ten mins from the border..china is easier to deal with then us for some reason..its our side of the border that charges tho not blaming the us at all..most ebayers won't even deal with Canadians cause of the border problems
 

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Had a class canceled, bored, trollin and this seemed interesting; thought i throw in my .02

First off, is the sound more solid and regular (think- tap, tap, tap), or random and kinda hollow (think shaking a can of spray paint)? To give you more time to listen, try a full throttle roll-on from barely moving in 3 or 4th gear. That way your in high load, low rpm, for longer.

I doubt it would be cam chain (which would be one of the random/hollow types), as you would probably hear that at idle too, but it you want you you can just pull the valve cover and take a look at the chain if you haven't already. Its free and fairly simply. Look for worn sprockets/links or if the chain is loose around the sprocket (same basic process as checking your drive chain/sprockets)

If its the tap tap tap sort of noise, its probably something mechanical like a worn cam/valve guide, piston slap, or even a failing crank bearing or wrist pin. If thats the case, you can sometimes narrow it down by recording it and timing the sound to compare to RPM. Crank/piston noises are usually faster than cam noises since the crank turns 4 times faster. Your options in this case are either a complete rebuild/blueprint, or just ride it till it blows up and wait for the rebuild till after the 'splode. Edit: as an afterthought I figured i'd mention thatI' me not say I think your in for an boom tomorrow or anything. If its something like a valve guide or piston slap it'll be years and many thousands of miles before that matters anymore than being annoying

If its more of the rattlecan noise (which i'm guessing is more likely) then its probably a lean misfire/detonation. Lean misfire would definately be load induced, and in my experience has to be REALLY REALLY bad before you can "feel" anything. The only real symptom is slightly less power, which on a literbike is still alot of power so it would be hard to notice. The good thing is this is pretty easy to fix in most cases.

In the order i would personally take:
1) Dump a bottle of carb/injector cleaner in you next tank of gas. This hardly ever works, but its really cheap and super easy.
2) Back out the mixture screw on your carbs 1/8 or a turn. Even if is doesnt help, you'll prob get a bit more power (FTR, if after you make the adjustment, it starts to bog down under load instead, then you are now too rich. Put the screws back where they were)
3) Change you spark plugs and wires. Doesnt cost too much, can't do any harm, and is fairly easy.
4) Clean and rebuild your carbs. This is either time consuming and cheap (DIY), or easy and expensive (pay someone).
Lastly) If you have done any previous work to the bike, mainly k&n filter, exhuast system, etc. Your carb jets may be undersized since it is breathing easier now, and a jet kit could be in order. This will be evident it turning out your carb mix screws helps, but doesnt completely fix it.

Hope this helps, good luck man.
 

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Hello folks I have exactly the same problem as per the first post. .....did anyone ever get to the bottom of this problem.....is driving me mad !!!!!!!!!!!!!!
 

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Hi Everyone

New to the group just got a 1996 -900RR fireblade which is at 36,000 miles and is in good condition with part history and is in good original condition but I am the same I have a top end rattle between 3-6000 Rpm does not do at idle its fine after 6000rpm, seen the posts but what the bloody hell is it? I was thinking Cam chain straight away but it was serviced by Honda 6 months ago they reported nothing untoward and I have not used it since just warmed it up the odd weekend. Thanks Andy :) PS- Before you all ask what is under the other cover its a 748 bispo I restored a few years back
106767
 

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Welcome to the forum Andy, dont think there's anything to worry about at this point in time ;)
By the way NICE BIKE
 

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probably valve clearances or CCT. I think some shops ignore the valves as its to much of a pita to check and on a Honda they rarely need doing. Sometimes new oil quietens down some noise - when was it last changed? Some FB motors are noisy - my 929 has and it only had something like 8,000 miles on the clocks when I bought it, but its not got worse and runs sweet.

the other option - get a loud end can and ignore it!! LOL
 

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Most likely cam chain. The chain itself is probably stretched. The easiest bit is just swapping out the tensioner and see if it quiets down. If not, it may be the valves, but I don't know of anyone doing a valve adjustment that got rid of a top end rattle (aside from finding obvious damage).
 
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