"dont use washers, jet it right."


How is not using washers not jetting it right?


Chris

these mikuni carbs seem awefully complicated.  why do they make us disassemble and rejet for a simple inake setup???  why aren't there any external mechanisms to control air/fuel like 90% of all the other carbs out there!?

Quote from: Chris2P on July 19, 2006, 06:46:43 PM
"dont use washers, jet it right."


How is not using washers not jetting it right?


Chris

See Alpha's post. 

Quote from: Egaeus on July 19, 2006, 07:24:11 PM

Quote from: Chris2P on July 19, 2006, 06:46:43 PM
"dont use washers, jet it right."


How is not using washers not jetting it right?


Chris

See Alpha's post. 

Then see joedude's post.

The pre '01 carbs are a 2 circuit design, meaning to mess with the midrange you will need to use washers.

Gotcha!  I forgot that the 01 and up carbs have the midrange jet.


BTW,  I added a lunchbox after an initial rejet and adding a slip-on.  I went from a 125 main to a 140 with the lunchbox and an extra washer.  And really didnt notice that much of a different in performance.  The initial rejet was 40, 1 washer, 125 with a yoshi slip on.  Do you think going to a 150 main would make much of a difference?


Chris

Quote from: Chris2P on July 19, 2006, 07:37:09 PM
Gotcha!  I forgot that the 01 and up carbs have the midrange jet.


BTW,  I added a lunchbox after an initial rejet and adding a slip-on.  I went from a 125 main to a 140 with the lunchbox and an extra washer.  And really didnt notice that much of a different in performance.  The initial rejet was 40, 1 washer, 125 with a yoshi slip on.  Do you think going to a 150 main would make much of a difference?


Chris

YES! because you are jetted too lean with the current setting (at 140) you aren't getting all the fuel in there that you should - furthermore you are running HOT which is BAD BAD BAD! if you run for too long you could bend/break stuff! The 'perfect' setting for the setup you have without the slip on is 147.5 Main 40 pilot.... and 150 Mains with both.

to answer you question, yes you will get more power, regardless because you're goint up from a 125 to a 150, which is a huge difference!

Get those Jets Changed!

Quote from: Chris2P on July 19, 2006, 07:37:09 PM
Gotcha!  I forgot that the 01 and up carbs have the midrange jet.


BTW,  I added a lunchbox after an initial rejet and adding a slip-on.  I went from a 125 main to a 140 with the lunchbox and an extra washer.  And really didnt notice that much of a different in performance.  The initial rejet was 40, 1 washer, 125 with a yoshi slip on.  Do you think going to a 150 main would make much of a difference?


Chris

140 to 150 is a jump 4 sizes. I'd say go up 2 sizes, a 145, then see how that feels.

I agree Alpha, if he was the first person doing this ever... but he isn't. Lots of people have tried it one step at a time and bought all the different sizes of jets... its been done, In my opinion, if you wanna save a few bucks just go to the tried and true 150.

Thats just my opinion, take it as you will 

Quote from: crispy5 on July 19, 2006, 06:05:15 PM
So you put on the lunchbox, 40 pilots and 147.5 mains with the exhaust remaining stock, right?  Sounds like what I want to do.  Any problems since?

Yep, that's exactly what I did (except one of the previous owners drilled holes in the exhaust, but I don't think that should make much of a difference in this case.)

At first, there was a 'flat' spot from just after I turned the throttle to about 1/8- to 1/4-turn, then it kicked in.  I adjusted the float height (I think I may have thrown it off when I had the carbs apart for the rejet) and turned the mixture screws out another half turn (for a total of 2.5) and that made it feel a lot better.  After taking it on a long ride since then, it seems like it could be improved a little more, so I'm gonna try turning them out a little more to see what happens, but that's the only issue I've noticed. 

Good luck, and if you have any more questions, let me know

Mike

I have the same setup, previous owner drilled holes.

Lunchbox with 147.5's - after some fiddling with mixtures and proper synching.... no complaints at all!   

I got a set of 150's.  I figured I would try the 140s first because going from 125 to 140 seemed like a really big jump.  I'll pop them in and see what happens.  Thanks for the info.

Chris