Still have miss at approx 9 thousand revs upward. Any thoughts?

New plugs, leads, carb needlesand the carbs have been balanced. Using modified air box but with original K&N filter.(Engine dynojetted)

Where do I go from here?

dont go above 9K - my pinto doesnt and manages ok

A Honda bike garage have some kind of diagnostic link up if nec, what about coils?

Have you tried a different CDI? Rather than buy one - just try it.

If it's brown on the back it's been cooked... seems to be the achilles heel in a BEC.

ATB

agree with above answers....could be one off a cb500 or sommat like that that doesnt rev as high....they look identical and are the same plug type.....could be the rev limiter you getting - assume its in the cdi?

Did it used to run OK with that airfilter and jetting, or was it always missing at high revs?
Cheers
Ali

Things I'd check (in order of likelihood)

CDI Unit
CAM Sensor
Rectifier

It always has missed at high revs. Now carbs balanced and new needles it runs well low down.

Could do with trying another ECU then,,,,Anyone going to Exeter show?

If I go I'll bring mine...still not certain yet though...

I'm going - but not in the bl**dy locost in November

Sounds like fuelling to me. What jet sizes are you running? Try upping the jet size one or two sizes, I think there are different jet sizes in a dynojet kit, it doesnt usually just come with one set.

As a guide you would need to use a different sized (larger) jet on a BEC with a free-er flowing filter and exhaust than someone dynojetting the same engine in a stock bike, I think off the top of my head mine (with sausage filter) runs 128 mains.

Chris

Chris, I had thought of that.
The jets are for bike stock exhaust and K&N filter (DJ120). For through exhaust should be larger jets DJ124
The other thing I wondered was that the air box has a relativly small gap above the trumpets so to fit under the bonnet. Could be causing too much pressure drop as I suppose high K factor. Might try without bonnet and filter and see what happens. If improvement I might as well bite the bullet and cut a hole in the bonnet and put on a sausage. What do you think?

[Edited on 9/11/04 by Lightning]

try one thing at a time...like no bonnet first.....so you know what helps..

In my experience the blade will run OK if a little too rich but misses at high revs if too lean. The actual surround of the airfilter (the box itself with the two horns) makes a big difference when the car is moving, I'd recommend sticking it back on if you still have it.
My initial start point was getting everything running as it was on the bike.
As Chris says it sounds to me like a air/fuel/jetting thing.
All the best.
Ali

[Edited on 10/11/04 by alister667]

No I butchered the air box. I think, as Colibriman says I will try one thing at a time although my money is on putting on a sausage with increased jet size. Will let you know how I get on.

Although there are speed traps everywhere down here at the moment.
I got caught the other day in Cornwall by a "Safety van"...90 in a 70.
Thinking of investing in a Road Angel!

[Edited on 10/11/04 by Lightning]

road angel....there's a thing.anybody fancy a group buy?

I really should have one..just find it hard to swallow the price..

sorry for going diverse Lightning...

Thays ok.. In Macros this month there is a Radar detector for £69.99 + VAT not sure if its any good though. Will ask if anyone knows details in the Anything Else section.

One other thing Ive just thought of, are you using a bike pump or a Facet type pump with a regulator? If the latter, the regulators have been known to strangle fuel flow rate at the low pressures needed by bike carbs, so you might find although the pressure is OK, there just simply isnt enough fuel getting to the carbs when at high RPM - resolution is to use a bike pump.

Like you say though, just try it one at a time, run it without the bonnet etc first and see if it helps. You could even try it for a very short distance with no airbox on at all (usual disclaimers apply!) although if its not an airbox restriction and its running lean already this will make it worse not better.

Chris

[Edited on 11/11/04 by ChrisGamlin]

Thanks Chris, but using the bike pump. But thats not to say that that may not be the problem. It would certainly cause misfire at high revs....I'll certainly look into that also.

i had exactly the same fault as you lightning on my blade vortx,had it rolling road tuned by tuning japanese in aldershot,they fitted a dyno-jet kit and a feul pressure regulater,problem cured it revs fantasticly up to the rev limiter in every gearwow is that fast

i highly rcomend them if you live that way