my 4pt kept cutting out at odd times, turned out it was a dodgy neutral switch (on the left side of engine under gear pedal) and a loose vibrating connector on the CDI (under the tail unit). i found out after spending a fortune on trying to mend it, and a tweak with some longnose pliers sorted it.

How do you get into the neutral switch? I can see where the wire is mounted with a screw (mine is kinda stuck:() Do you take the whole sidecase of? Can't really remember how it looks down there.

Mine is working from time to time, i figure its the switch itself beeing bad, not the connections, and I wanna have a look.

jens the wire to the neutral switch is hidden in the side cover but you dont need to take the side cover off as its just in front of the gear shift shaft they do wear out but wont affect running as when they wear out the stop coming on unless your really unlucky and it shorts out:(

cos it starts and idle's ok i doubt its the carb rubbers :innocent:

i'd try the needle first and you can check the inlet stubbs at the same time if you want to be sure :innocent:

Is it popping a bit between low gear changes, and upon deacceleration? It should if its lean.

This is exactly what happens. I will alter the carbs accordingly. I've yet to find a Dyno tuning shop with a 60 year old racer guru dude. I only know Dyno owners :thumbdown:

Right! I made a little T piece out of a screwdriver so I could adjust the air mixture screw without taking the bike apart. It worked like a charm! God-Damm! Its a whole different bike! A mate at work said if I need to wind out the screw so much, I probably need a bigger slow running jet. How many times can you turn this mixture screw? I dont know where it was before, but I turned it out 4.5 revolutions. Is there a chance the screw is holding on by just a thread and could pop out?

wind it all the way in and count your turns so you can return it to your current setting :innocent: then wind it all the way out counting your turns again and see how many turns in total you have before it comes out then you have a better understanding of how many threads you have left:thumbup1:

When stock, my screw was 6 whole turns out, i dont think anyone have ever messed with it, it showed nice fuel/air ration at a dynorun.

So that can be done. But for the peace of mind, you might want to consider a bigger idlejet

In the manual it say the standard Pilot jet is a size 48. How much do you think I should go up by?

One notch should be enough.

What's you're specs? (exhaust, airfilter and such)

K&N filter, Dep Silencer, DynoJet Stage 2, although I'm starting to suspect the installation side of that:thumbdown:. I think I need a bigger pilot jet. How many times can you wind the pilot screw out? I've got it out 5 whole turns. How many turns does it have before it pops out? I'm gonna adjust the needle when I get chance, but the pilot screw has made such a difference already, I suspect its the main problem.

like i said erlia wind it all the way in and count your turns so you can return it to your current setting :innocent: then wind it all the way out counting your turns again and see how many turns in total you have before it pops out then you have a better understanding of how many threads you have left on that pilot screw:thumbup1:

i'd try the needle adjustment first before going up one size on the pilot jet mainly cos its free unless you have a stack of jets in stock :rolleyes2:

you can drill your're 48 pilet jet with a 0.50mm drill... thats almost free.

As I said, when mine was stock, it was 6 turns out, so that should be within the safezone. Otherwise do as wolfzero explains.

You can make a rough idlejet adjustment at home....

Make sure the bikes is warmed up a bit. Rev the bike, and let if fall to idle, if it pops when the revs go down, you're lean. Adjust the CO screw out and try again, till its not popping/backfiring...


WHat did you're dynojet stage2 kit content of, what was "in" it?

My ride is just rejettet, with appropriate jets.

Whens the engines properly warm, turn the pilot screw in until the revs drop. Then turn it out until the revs increase, and keep going until they start to drop again. Count how many turns it is from each extreme then set the screw in the middle position.
SO, EXAMPLE: winding out 2 turns, carry on (revs go up) then keep turning and they start to drop - say 4 turns out. Set to 3 turns! If you have to turn the screw otu more than half a dozen then you need to replace the pilot jet.

Awesome guys. I commute on my bike, so I cant do too much work on it till I have a Saterday to play with, but my tinkering and turning of the pilot screw has fixed my bike a great deal. I still want to bump the needle up one notch, and then tune the pilot screw accordingly. I dont get any popping any more, but there is slight hesitation at low speeds. I must stress, after I turned the pilot screw, this hesitation is minimal. I've had to learn about this stuff quick, because my attitude before was, let the bike shop do the stuff I dont know how to do. But recently I've discovered that they dont know everything, and it would seem their knowledge is a bit thinner in the single cylinder category. They completely missed the pilot screw and it cost me HUNDREDS of pounds in labour. So now I'm gonna tinker as much as I can, because the bike shop doesnt have all the answers. Thanks very much for all your input!

The dynaJet kit came with a needle, and a couple of drill bits, which the bike shop now has.:thumbdown: I will see If I can get it back sometime and check the sizes.

Hey are a few pics of my bike, and the little T-piece I made to adjust the air mixture screw