My test ride wasn't great, can anyone spot the fault?

[Wes51st]

Thanks for all your help Chuck, you're a gentleman.

The colourtune tool looks really helpful, I'm going to get one. Also that's very useful advice on how the idle system works, I didn't know it that well.

Can I just check; So the fuel mixture screws only effect idle up to 1/8 throttle turn. But the air screws effect at all positions on the throttle?

I think it's the idle which is out and I'm going to reset that back to 7/8 today and let you know how I get on.

[Wes51st]

I've done as Chuck kindly advised, firstly order colortune, then set my fuel mixture screw to 7/8.

I did manage to get my bike running and idling until I turned it off. Now I'm just making small adjustments to the air screw so that it doesn't burn too rich. I check the vacuum and I didn't hear/see any problems.

However, the bike does rev much higher as I close down the choke- does that suggest anything? I've noticed there's no hose attached at the bottom of the air filter- that can't be right, where should it go?

[chuck hahn]

Yes on the pilot screws. when i set up one of my bikes I get the colortune to show me that nice blue color at around 1500 RPMs. Then i run it up to around 4500 which is roughly where then tach would be if your doing 70ish MPH and see what it looks like there.

Youll also notice that as you roll on the throttle from idle..or give it quick blip..the color will go orange for a second. Dont worry about that as its normal.

As for the RPMs going up as you let off the choke..First see that the rear ( engine side ) throttle cable has some slack to it as well as the front on and isnt causing a little bit of a hanging idle. Also twist the grip closed well and see if a little extra pressure on the grip makes the RPMs fall. I once had a damaged throttle tube and it was hanging up inside the switch housing.

At an idle with the choke off can you adjust the big idle knob and the revs go down?? You said the bottom pilot screws are at 7/8 but where are the side screws at??

[chuck hahn]

Frayed cable ends can also make a cable hang up...especially up at the throttle grip tube.

[Wes51st]

Thanks for your continued help.

I have installed new throttle cables actually, as one was missing when I bought it, so thought it best to replace both. So, I don't think that's causing an issue, but will check.

Yes when I adjust the hand screw for idle (forget the actual name but you know what I mean), the revs to fall or increase depending on which way I turn it.

Air screws are currently at 1.5 turns, but I had sooty plugs so will make an adjustment there. However when I tried at 2, 2.5 the engine dies. Despite the sooty plugs, like before, I feel like it's on the leaner side because I'm still getting a slight rumble like backfire in the exhaust. Might be worth mentioning the bike came with a harris 4-1 exhaust installed (years ago apparently), and the previous owner had an extra piece of foam over the air filter lid.

Do you know anything about the hose for the lower part of the air filter?

[chuck hahn]

Its just a drain in case the carbs overflow and fuel gets into it basically..that and condensation. I would out some vacuum line on it nd run it down between the tranny and swingarm. Wonder if the exhaust might be a bit plugged?? Mice get in the can and build a nest...it has been known to happen.

Its hard to guess when youre not right there. All I can do is tell you what ive learned and what i have ran into over the years working on bikes.