I'm running a half Ethos system with standard jetting of 115f/118r. The engine feels a bit stifled over 11K, in fact it's hard to make rev above 11K. Should I be looking at changing the jets for 118f/120r or bigger?

Any help appreciated.

How clean is your air filter?

If it is bogging down then it normally would be rich.

If it made the revs but was weak with it it would normally be lean.

What does it do?

My filter is ok though I have a new one waiting to go in.
She just seems to run out of puff at the 11K rather than bogdown
Maybe I'll change the filter as it's there before doing anything too drastic

I would change the filter first and see how it goes. running out of puff in all gears at 11k or just struggling to go top speed..on your private road?

She wants to change up in all gears by 11K. it feels like theres nothing else there beyond 11, & as a result I don't feel top speed can be achieved. she'll do no more than 165Km, it's derestricted, in otherwise very good nick and a road bike.

Have you messed about with the snorkel and the rubber flap thingies? It should run fine. Fiddling with the airbxes make these buggers run poorly..

Where you at? not up a mountain somewhere with low air pressure?

Never touched the snorkel or other flappy bits and I wasn't up a mountain. The filter housing never closed snugly on one side, I've always sealed it up with duck tape. Think it's a badly moulded filter.
Think I'll just change the filter & see how it goes
Thanks for your help so far.

i would also get a air filter housing as well,always available on ebay at low prices and on here.........

like cmsmj1 says check the plastic cover in front of the carbs and if all seems fine then maybe consider changing the jets....

i did run full ethos system with 120/122 jets and it runs like a dream.i now have a different end can but the same jets



william

Throw some bigger main jets in, 118f/120r will do.

They don't breathe well in std form, and can run lean up top when teh exhaust system is changed. This problem is even worse on '89 models with smaller jets.

let us know how you get on fella,when you have your carbs off check the turns on the A/F as a matter of interest.

hopefully the airbox will seal better when the new filter goes in but if it doesn't get it changed as a few small problems can amount to one big one