Power drop off on full throttle

[Badgerboy]

Afternoon,

Had an issue that started intermitedly, but now manifests itself on each ride.

Intially I noticed a complete lack of power when revving higher into the RPM band. This appeared at around 7.5k. The engine appeared to completely bog down, and the exhaust started to sound like a two stroke.

Today I took the bike for a ride, and kept part throttle on in a lower gear. It then managed to rev cleanly up to about 10k. As soon as I wound on more throttle, it bogged down once again.

Does this sound like a fuel delivery problem? I've replaced quite a few of the breathers, so wondering if this is as simple as something like the fuel tap? I initially though it was an issue with the limiter kicking in, but I've read this happens at 5.5k and across all throttle ranges.

Can anyone shed any light?

Cheers

[CMSMJ1]

What have you done to the airbox?

[scooble]

does sound like carburation though. Whats it like in the lower gears?

[Badgerboy]

Airbox is standard, no tweaks to it!

Gearing doesn't seem to make a difference. 2nd gear part throttle it revs cleanly, 2nd gear full it bogs. I can replicate this in 3rd too.

Assume first port of call is fuel tap, and then perhaps cleaning the carbs?

[skinnydog0_0]

Could be a number of things.
What size jets are you running?
Is it totally standard - i.e airbox, exhaust, CDI?
Is teh battery charging properly, and is the regulator/rectifier good?
Do you have good plugs all round?

[Badgerboy]

Well, I now have the carbs sat in front of me.

Upon inspection, they don't look too bad. (I.E the float bowls look quite clean inside, but the jets look quite dull. No blockages in them though)

I've pulled the jets, and it's running 120 all round. Someone has obviously been fiddling around too, as all the 5 hole ET's are on the left carbs, and the 4 hole ET's on the right. I'll rectify that when I rebuild them.

Skinnydog - Battery charged, new Reg/Rec, standard induction, plugs are about a year old, exhaust is a Yoshi Cyclone.

Although it looks like the ET's were put in wrong, to be fair it was running well up until the point it started playing up. (Which was intermittent at first, and only when warm, now all the time). In regards to the breathers, which ones should I check first?

[NZgatch]

120 all round ? Is it running a full exhaust system ?

It may be too rich and fouling up your plugs.

[Badgerboy]

No, it's a stock system with an endcan. Worth stepping down the front?

[skinnydog0_0]

Are the carbs 30 or 35?

[Badgerboy]

It's an NC30, and the pilot jets are marked '*35'.