Quick Tuning Question.

Hey all,

Just got my Del. 17.5mm carb fitted, and i can feel the difference.

BUT... I have noticed when my bike reaches about 85kph it starts to stop pulling and will slowly start bogging. Then about 10 seconds later it will start pulling, then repeating the sequence again.

Could this be a needle position in the carb slighty off, or maybe a 1 or 2 size jet too lean?

Any help please ?
- Setup below -

 

is 85kmh around 35mph? i have exactly the same problem but ive put it down to carb icing as i have a runner 125 carb, think it had a heating element but i took it off

sorry i cant help futher, interested in a solution also though

 

85 is more then 30mph, its about 50mph

 

my aerox does the exact same thing i just put a malossi 22 carb on as well.

 

hi

you need to uplet your carbs i would try 5 lower and 5 higher
Thanks

 

Could it be a spray setting on the carb?
But thinking that, it is only an "idle" spray right?

I got the carb tuned by the Yamaha Dealer and it took them a while to get it the way it is now, so i really dont want to be screwing with anything until i know it may work.

I am currently using a 75 size jet.

 

I have just been speaking to the Yamaha guys,

They said that i should try moving the needle position about 2 positions leaner.

So i will see how that goes.

Anyone else with suggestions?

 

UPDATE:

I have tried playing with the spray and the needle setting...

... Did fuck all.

 

clean out your fuel tap and filter, i think it's just starving the carb of fuel.

 

Ok thanks i will try it and let you know.

 

UPDATE:

Tried cleaning out the fuel filter, intakes etc and did not find anything.
After cleaning i took it for a ride and it still crap.

There 2 things that it is doing:

Very Unconsistant revs going through from about 35kph (20mph) to about 70kph (43mph).

Also

Its hitting a big wall at 82kph (52mph), with the engine bogging down, andnot reving higher or further.

Its REALLY pissing me off now!

Help Me!!!!

Im starting to think its the jetting.

 

UPDATE:

Just Threw some 4.1g rollers in.

Engine revs alittle more constant than the 4.5g's BUT, I could feel it was slightly slipping (not as much punch) until the higher speeds (60kph + )

Tommorow I will try the 5.0g and see what its like.

Thanks for you help Minor.

 

Last Update:

Bike is going really well.

I put the 4.1g rollers in and it made a hell of a diffference, bike is performing beautifully.

Last night i couldnt really get the chance to test it as of the cold air.

Anyways thanks heaps.