Bogs down above 5500RPM

[CharlieK]

I have just put all my new shiny bits together and got the bike running for the first time in 6 months, having done a fair bit of work, (Carbs rejetted 120s all round, extra washer on the needles, 4.5mm hole drilled, set float heights, cleaned out all the jets, set the idle jets and reassembled) she starts a treat but under load on the road it bogs down at about 5500RPM and fails to accelerate any more with a bit of popping in the aftermarket can. Anyone got any suggestions? Fuel is getting through no probs, all cylinders are sparking nicely. I'm going to take it to a dyno to get set up properly but thought I'd ask here to see if anyone had any ideas?

[eamer1989]

4.5mm drill hole ? i thoguht it was 2.5mm or meant to be ?

what if you rev on idle does she go okey ? how many turns out have you got screw ?

[Drunkn Munky]

Is the speedo conected? it'll cut 2 cylinders at 5.5k if not, as will if the rev limit wire from the cdi is broken, i think its a pink wire.

[CMSMJ1]

Is the speedo conected? it'll cut 2 cylinders at 5.5k if not, as will if the rev limit wire from the cdi is broken, i think its a pink wire.

Yep - check your connections.

[CharlieK]

Yep sorry I followed the guide at the beginning of this section, it was a 2.5mm drill bit!
I have set the pilot screws to the recommended 2.25 turns out.
The speedo is connected and I haven't messed with it.
I have just tried revving it in neutral and it seems to rev past 6000 rpm no probs under no load?

[davepm13]

Hi there,

My money's on an electrical problem as I've had similar symptoms in the past.

Can you still get your NC to pull all the way through the revs even though it's boggy?

If so I'd say it could be generator or reg/rec. That's what mine turned out to be.

My advice is to check the 3 spade connectors (yellow, I think) and see what sort of condition they are in. Mine were virtually fried!

Dave.

[CharlieK]

Thanks Dave I'll check that now, the HT leads and pulse generator are OK, I have retightenend all the hose clips on the rubber intake pipes from the carbs and can be fairly certain that the carbs are sealing. I have just run it in neutral in the garage again, working up in 500 RPM steps through the rev range. Its clean to 3000RPm then starts to miss fire slightly at 4000RPM then runs really rough at 5500RPM. I have checked all the wires going into the back of the rev counter and sppedo, all are connected and seem fine. Im running out of ideas.

[CharlieK]

Oh dear! I'm ashamed to say CSMJ! and Drunkn Monkey were right, thanks chaps, I had plugged the speedo wires into the wrong connector, that only took three hours to diagnose!, Thanks for yor help everyone, I'm going to go and feel ashamed of myself somewhere

[Drunkn Munky]

we all learn the hard way, glad you got it sorted.