[OldDD]

Just changed faUlty starter motor on my bike and checked to see if it was working with the body work (side panels and seat) removed. It fired with less than one revolution of the crank - Almost instantaneously time after time. However, with the side panels and seat on, the bike is less eager to start and it may take 2 or 3 revolutions of the crank to get it to fire...
The valves are good and the decomp is set correctly so I am guessing this is a mixture issue?? The question I have is do I turn the mixture screw IN to weaken the mixture or OUT??

[crfsonly]

A cold motor typically like a rich mixture (this is the function of the choke) to richen the mixture. If the motor is hot then it likes a lean mixture (this is the function of the hot start). With the seat and side panels off it would allow more air into the air box and if anything theoretically lean out the mixture. You didn't mention what the engine temp was but this should provide the information you need to judge where your jetting is.

Ken

[OldDD]

Hi Ken
The motor was stone cold with the choke on - I then tried it again when it had been run for a few minutes and again it fired instantly. I've tried it again today with the side panels and seat on and it just does not start as well as with the panels and seat removed.
I agree with your comment that removing the panels is weakening the mixture so do I simply alter the mixture screw (in for less air??) or try something else?

[JimDirt]

Its not less air , its less fuel , its a fuel screw not a air screw , , but in is lean out is rich , try going out a 1/4 turn at a time to see if it gets easier to start , then try going in 1/4 turn to see if it gets easier to start , this will tell you weather its rich or lean (i am guessing that if it starts easier with the panels off , then its a tad rich) , once you get it to where it starts easier then count the turns from all the way in

So go from where it is , 1 turn at a time IN (clockwise) and count the exact turns including 1/4 turns , if it needs to be over 3 turns out , then its too lean on the pilot and you need to go up 1 size , if you can turn it to less than 1 turn out and it runs better then its too rich on the pilot and needs 1 size down , anything in between can be done with the fuel screw (1 1/4 - 2 3/4)

That should get you where you need to be , but from your description it sounds like its a bit rich , either by the screw or a pilot jet size

[OldDD]

Thanks. Funny, the bike has run with the current settings for the last 7 years and don't get me wrong, it starts well but could not believe the difference with the panels removed...

[JimDirt]

The jetting can be off and the bike will still run , how well it runs and starts is different than "it runs with the current settings" , it could be that you were just used to the way it started , and never experimented to see if it would run or start better , by replacing the starter you found that it is a little rich ..... not really a bad thing ...

[Krannie]

Without knowing the state of tune of your bike (airbox opening, exhaust changes, fuel screw setting, jetting, etc), it's impossible to say how, but it doing what you describe is an example of how being 1% in better tune can make all the difference.

Remember, only adjust your fuel screw with a HOT motor....at least 10 min of riding.