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Anyone in the PHX area want to help me dial in my carb!? Will buy lunch!

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I have a PWK AS sitting here. And the stock TMX for my 03 250. Timing is set. Filter is clean. Fuel is mixed. 2 new unused plugs...

 

Tried setting the float height and it puked all over the place. Both probably need the float height set. I can't good response out of either carb adjusting them one way or another. I rebuilt the entire thing from top to bottom and I have 7 hours on it already... Its not like I am NOT mechanically inclined. I am starting to think so when it comes to jetting though...

 

I just cannot get this bike running perfect and it is driving me crazy. 

 

If there is anyone in the PHX area who would consider themselves a BOSS when it comes to dialing in carbs on these bikes and wants a free/dinner lunch and to help a fellow 2 smoker out... 

 

HELP! 

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Of you get the float set correctly,

Put a 175 main 42 pilot and you'll be all set!

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Except that the head is milled 20 thousandths. And so is the jug. So a total of 40 thousandths. Even on 100 oct. with 32:1 it still pings at WOT. There was a 180 main in there before I put the other carb on. Partial throttle sucks on both of them. 

 

Like I said, I need somebody who knows what is up with these carbs and will show me how they became a master in dialing them in, and keeping them that way. 

Edited by Blaze45

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40 thous. is quite a bit.  Did the tuner compensate by removing some material from the head to bring the CR down?       It might need more than 100 octane to get it to run right.

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I used to live where the elevation was 4500ft+. Now I am at about 1200ft. I didn't have any issues at higher elevation (other then I could never get it dialed in perfect carb wise) with pinging or knock. I am going to try some 110 on Tuesday and see how it likes that. Still would love to get the partial throttle dialed in thought since a majority of my riding is trail riding with some dunes mixed in.  

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You have 2 problems. Fix the carb first. Is the carb new or used. You may need a needle and seat. Float height should be easy to get close. Your bigger problem is like posted earlier is too much off the head and cyl. Without compensating on the head.

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The PWK is new and the stock one has all good/functional parts. Bought a new float and new hoses/gaskets for it. Put the jetting to stock (what the jetting chart recommends for my situation on it and the bike runs like crap. Used the recommended settings on the PWK and it isn't much more crisp then the stock carb. 

 

As for the float height, whenever I move the tang the float valve just slides back and it doesn't change the height of the float at all. I know for the Mikuni the height is 15mm and the PWK is 16mm.

 

When you say compensate the head, what are you referring to? 

 

This is the page I have been referencing to in addition to the manual for setting the float height.  http://www.allthingsmoto.com/forums/f-15/how-set-your-motorcycle-carburetor-float-level-more-commentary-13608/

 

 

My plans for Tuesday: Mix up a nice swill of 110. Attempt to set float height again. Mess with air screw. Pray for bacon. 
 

From what I can tell, really experienced riders who have ran both carbs say that once you understand the Mikuni, the differences are negligible. 

 

Keep in mind the level of performance I am looking to find is compared to my friends 02 that had the same carb and ran amazing. Always. I know they are not the same bike but they should at least be similar. 

Edited by Blaze45

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I just built an 01 cr250 with .20 off the head . Using the Mikuni ( pwk is a better carb ) my slow jet is a 30 and main is a 410 at 2 1/2 turns out on the air screw . I'm in GA. so between 800-1200 ft. also . I had trouble also because I bought a carb rebuild kit ( moose brand ) and the float needle hanger is too wide to drop into the seat . So it constantly ran out the overflow ( needle couldn't make contact with the seat ) . I put my old one back in and reset the float , started first kick . So done some tuning and plug checks and it runs awesome now .  :facepalm:

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Where in the valley are you?  Im no expert but I know my way around the PWK pretty well.  What needle are you running?  I have no time this weekend but might be able to help next week.

Edited by c-slak
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I am in Mesa, but I'll drive wherever. Next week I am open Monday or Saturday but I'll be in Vegas the rest of the week for work.

 

Today's plans:

 

- Attempt to set float height on both carbs

- Run 110 to see if it still pings/knocks at WOT

 

When I had the PWK on there, I ran the base setting/needle that they recommended from JD for this elevation. Both carbs, the mid range was garbage. 

 

PWK:

 

Pilot 45

Needle was clip 3 on the blue 

Main was 180 (up from 170 since it was pinging @ wot)

AS was 1 1/2 turns. 

 

I am going to start fresh with both carbs today and see how upset I can make myself. Should be fun. Anyone want to join?!!! haha

 

Mikuni is currently

 

pilot 30

needle stock 3rd clip

main 420

As 1 1/2

 

If I can find that dang S7 nozzle I might even give that a stab as well. 

Edited by Blaze45
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I am in Mesa, but I'll drive wherever. Next week I am open Monday or Saturday but I'll be in Vegas the rest of the week for work.

 

Today's plans:

 

- Attempt to set float height on both carbs

- Run 110 to see if it still pings/knocks at WOT

 

When I had the PWK on there, I ran the base setting/needle that they recommended from JD for this elevation. Both carbs, the mid range was garbage. 

 

PWK:

 

Pilot 45

Needle was clip 3 on the blue 

Main was 180 (up from 170 since it was pinging @ wot)

AS was 1 1/2 turns. 

 

I am going to start fresh with both carbs today and see how upset I can make myself. Should be fun. Anyone want to join?!!! haha

 

Mikuni is currently

 

pilot 30

needle stock 3rd clip

main 420

As 1 1/2

 

If I can find that dang S7 nozzle I might even give that a stab as well. 

If you are running 110 try the blue needle in the 2nd (from top) clip position. 

 

As far as setting the height on the PWK.  I have found the easiest way is to lean it at a 45 degree angle and bend the tab so that the line on the float is parallel to the gasket surface on the carb.  Make sure it is parallel just when the tab hits the plunger on the float needle and that the plunger is not being depressed at all.  Everytime I would try to set the float at 16mm I would get fuel dumping out of the hoses.  This is the method all the KTM guys use and I found success with it as well.

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Got the Mukuni on there and dialed in today.

 

I used the acclaimed S7 nozzle and set the float height on the Mukuni. Seems to be running better then it ever has. 

 

Changes that I made today consisted of:

 

Set the float height (15mm on Mukuni and 16mm on the PWK)

Installed the S7 nozzle

Ran 110 leaded octane fuel (I can smell the lead in the exhaust is that weird? Probably my piston melting into the sleeve lol)

Adjusted the slack out of the power valve (it was minimal but hey, it was still done) 

 

I had to adjust the idle to bring it down some because it was idling way too high and I only got about six good WOT pulls in before the sun went down. Still loads up some with the 410 so I think I will drop it down to 400 the next time I take it out and see how it does. 

 

Seems to be running better then ever with the Mukuni. 

 

Anyone wanna buy my PWK? lol

Edited by Blaze45

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Sorry, I have been out of the loop for a while. I might be able to help ya out with it. I have been thru a lot of this. I am concerned with the 40 off the top tho. 30 is what most people do, including myself. Let me know if I can help, I'm in mesa gilbert too. BTW, riding single track tomorrow if you guys wanna join.

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Got the Mukuni on there and dialed in today.

 

I used the acclaimed S7 nozzle and set the float height on the Mukuni. Seems to be running better then it ever has. 

 

Changes that I made today consisted of:

 

Set the float height (15mm on Mukuni and 16mm on the PWK)

Installed the S7 nozzle

Ran 110 leaded octane fuel (I can smell the lead in the exhaust is that weird? Probably my piston melting into the sleeve lol)

Adjusted the slack out of the power valve (it was minimal but hey, it was still done) 

 

I had to adjust the idle to bring it down some because it was idling way too high and I only got about six good WOT pulls in before the sun went down. Still loads up some with the 410 so I think I will drop it down to 400 the next time I take it out and see how it does. 

 

Seems to be running better then ever with the Mukuni. 

 

Anyone wanna buy my PWK? lol

Actually, I am interested in the PWK if you are serious. In Gilbert and have an 03 CR250

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Got it, I will call you later this morning (Saturday).

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