I stripped the engine right down and replaced all the gaskets and seals. It all looked pretty tidy when it was apart.

Gone through about 4 sets of plugs as keep changing them to elimate the chance of them.being fouled. Using NKG plugs. Checked each and they are sparking.

ve got it in my head its an air supply thing rather than too much fuel. I can't see how the engine gets that much air as the funnel seems pretty sealed. What with the rubber bit along the bottom of the air box bit that seals . I around the frame. Although they are obviously all like this.

If it were me id see if anyone has a known working set of carbs and try those, then assuming your intake system is as it should be you'd then know weather its the carbs at fault or the motor.

Well that was the idea with the ones I got off pauliealdridge69. Ive tried 3 different sets of carbs now, none seem to have made any improvement. Thought if I got some off someone who knew their stuff then they'd be set up correctly so Ive no doubt the ones I got off Paulie are spot on, as that rules out me being a fool having missed something obvious during setting the previous ones up.

What on the motor could cause the a/f mix to be so far out?

I believe my intake is normal looking at pictures of others it certain looks the same, no holes or bits missing.

Take the air filter out and run it... You certain that the filter you have is good?

CMSMJ1 wrote:Take the air filter out and run it... You certain that the filter you have is good?

Will give that a try, was brand new of Rick Oliver. Will rule it out. Ive checked a number of times to make sure the was no protective plastic on it or anything daft like that, that I had left on.

its funny that is was still producing a respectable HP reading on the dyno if it was/is an air intake problem though.....also, fitting good carbs but still having the same problems,so.......out the box...... could it be oil thats giving the rich symptoms, im not too cluded up on 4ts oil placing in and around the eninge tbh and leaking areas if seals are blowing!? could it be this?? basically, poor oil control!?

i need to read up on 4t workings as im a 2t geek lol but are you some how burning too much oil??

Its definitely fuel thats its using as otherwise I dont think the dyno would display the oil in the a/f mix. Ive done next to no miles on it as dont see the point until its running well. Think Im gonna take it round to the garage the tested it, he does a lot of drag races, has the highest power zxr in the country, seems to knows his stuff and see what he recommends.

sounds like a plan mate, as we are all a little lost on this one lol

Black plugs that are dry is a rich condition.

They'd be wet if it was burning that much oil, black / blue smoke could be oil though.

Burning oil with the fuel could throw off the O2 sensor on the dyno as it just reads the amount of air, it doesn't detect fuel present but lack of oxygen.

Also the oil would knock down the power a little.

Since you havn't rode it you can't really work out the MPG.. this would give you a clearer idea of if it really is using a lot of fuel.

Strange one for sure.

What were your compression readings? Are the cams properly timed up and the valve clearances all ok?

What plugs have you got in it? ER9s?