All 2st Terrible low speed running

surely though, an air leak would show up throughout the rev range.Also im having problems with a local bike shop willing to take on the task.Ive had the power valves out again,but still no improvement

Do you get sputtering in the low throttle positons or does it bog? Sputtering generally indicates an over rich condition on the pilot, a bog would indicate too lean on the pilot. You may have already tried this but sometime a pilot jet gets obstructed and it can make the bike run poorly down low, and hard to start. I have found that in-line fuel filters can prevent this and are generally worthwhile..

Its spluttering on low throttle positions,you can feel it clean up as it goes onto the main jet.Thing is ive got a 32.5 pilot jet in and the needle (which is one of three options according to the manual)is on the top notch,which should make it very lean.It has an inline filter on at the moment.The next pilot jet down is a 30.

i Im still having problems on the low speed circuit,and in convinced its the power valves,as i dont think they cover the exhaust port enough when shut at low speed running.In the manual it states that the clearence should be 0.5 of a mm between the piston skirt and the edge of the power valve,im erring on caution when using a piece of tie wire.The problem is i cannot get this clearence because the valves tighten up in the seats before i get anywhere near the corrrect clearence,i have to literally tap the ends of the vallves,surely they should drop through into the barrel! .Any of you guys had this problem before,its just had the bore nickasiled.On the main jet it pulls like a train however.

Power valves should slide nice and free all the way to their seated position (closed). I'd suggest you're onto something if they are being held slightly open. Maybe there's some "overspray" or imperfections in their bores. You say you have to tap them to close properly??

Disconnect the linkage, close the valves manually and then see how it runs.

Cheers for the reply Oldschool,i didnt want to take off the head Again,ill try your above method first,but it looks like im gonna have to.What is "Closed"as such.I thought the valves would travel along the length of the guide until they caught the piston,then the restrictor bolt would be adjusted for the final clearence(0.5).In picture 2 one of the valves is clearly lower than the other.Anyways ill investigate further

Yeah good idea, check and make sure the valves cannot travel far enough to contact the piston.
All the bikes I've had dealings with have had limiters of some type to prevent that but I've not pulled your model engine apart to see how it's set up.

Its just been stolen from the Sheffield S8 region,anyone with info or trys to sell you a bike similar to that of my avatar please get in touch via this website,btw it has no power valve assembly

Your kidding?! Bastards!!

No,six years of ownership,i think the only roadworthy of its age and size,complete engine rebuild and gone.smashed the garage to smitherines,still havent seen any police

My van ect was stolen off my drive last year with a small fortunes worth of tools bikes ect onboard | Guess what - over a year later I am still waiting for the police to turn up
Tracker did its job and I got the van back but not one item of the contents has ever reappeared so don't hold your breath waiting for them to turn up, you will die of lack of oxygen way before they will make any effort !