I have a 3 day special permit to ride my bike and get police clearance. All of a sudden I find that the bike will not rev past 5000rpm in any gear. It is fine in neutral and in gear with the clutch in. It doesnt splutter or anything it just doesnt want to go. I'm assuming that because it is only when in gear (under load) that it is either an electrical or clutch issue. Please help me or I will have to take the bike out for a 40min drive below 5000rpm.

Okay just found something about the speedo sensor being missing causes the bike to not rev above 5000rpm. That is a relief because I just fitted a Trailtech Vapour and removed the mechanical speedo.

So how do I fix it without putting the speedo back?

Nothing like answering your own question with a simple search....

You know what, from now on just ignore me.... found out about the resistor bypass mod.

lol. i was just gonna post it :)
glad you found it.....

okay so I installed a resistor that was on the previous clocks which weren't original but it was a 1.5k resistor. She now revs out freely but I topped out at 127km/h or about 80mph. I guess I should just change out the resistor for a 2.2k but do you think this is definitely the problem or is it more likely jetting etc...?

Nothing to do with resistor at all..if it gets past the 5.5k restriction then you are either a fat bugger or your bike is not making much power...

What gearing is on it? Has it got restrictor washers in the carbs?

I'm not sure about gearing, I assume this just means counting the teeth on both sprockets? As for the restictor washers I didnt specifically look for them (as I didnt know about this) but didnt notice them in the intakes and have had the carbs off many times.

Some things to note:
The idle is very erratic but havnt had the carbs balanced yet.
The exhaust system is apparently aftermarket

Cammo wrote:That's an aftermarket system - it uses springs to hold it together. Looks like an ethos brand but hard to tell from that pic.

When I followed the DIY Carb guide the jets were stock so maybe its a problem?

And I am a hefty 100kg or 16 stone (Not sure what your wierd Imp-etric system uses) but I doubt that could decrease top speed so dramatically.

RegionX wrote:As for the restictor washers I didnt specifically look for them (as I didnt know about this) but didnt notice them in the intakes and have had the carbs off many times.

That's a UK aftermarket thing for learners mate, I doubt you have restrictors in there.

Your problem is a bit difficult to diagnose based on your description. Are you reading the speed off the new dash and is it calibrated properly?

What gearing are you running (the number of teeth is usually stamped on the sprockets)?

Is it revving out to redline in all 6 gears?

Yes reading the speed off the new clocks, measured the circumference of the tyre, fairly sure its accurate definitely wasnt hitting 160km/h like i should. It also gave me max rpm at 10600, not sure what gear I was in but in 6th it just wouldn't go any faster, flat out. Not sure how high red lining is but I wasnt trying to rev high in every gear.

Couldnt find a stamp, counted 40 teeth.

Not sure what other info to provide.

thanks for the help so far