35mm PWK jetting

[blooper]

I'm ready to roll this Blaster off a bridge. I have had problems jetting and nothing g seems to fix it.
From the beginning:
New top end Weisco
LRD pipe with pro circuit silencer
CFM air box Uni filter
Tuned with a 35mm PWK
DHG needle middle setting
45 pilot
155 Main
Air screw 1.5 out
Bike ran great strong all the way through. Decided to play around a little and put DMC pipe and silencer on. Bike still ran fine and quicker down low compared to the LRD. Switched carb out for 30mm OKO and tried every pilot and needle setting, could not get it to run right. Switched back to 35mm same jets, left DMC on and bike struggles to stay running. Barely idles, air screw has no effect and smokes like hell now. Thoughts of leaks and none holds 7 psi forever. Question is what
has changed and how do I correct
This. Any help would be great. Plug is black and soaked in fuel.

 

[jbuckster07]

Before you send it to its death, sell me that LRD lol.

But on a serious note. I am not familiar with either carb, so I cant say anything to help either way. But if it ran and was tuned with the 35mm PWK, why are you switching to the 30mm OKO? Is it better? Looks nicer? Just dont understand. To be honest, the stock carb would do just fine with your engine. Is there a reason you are wanting a bigger carb?

 

[dirtysquared]

The DMC doesn't need a 35mm Pwk. It works best with the stock 26 mikuni.

The lrd is more of a top end pipe, so a bigger carb will work better for it. The DMC is a Low/mid pipe. The smaller carb works better in that situation.

This is going to be hard to explain, but the jetting for the lrd pipe, is more than likely drowning out the DMC pipe....hense the smoking and no response to airscrew adjustments.

 

[blooper]

That would make since just didn't think it would make that much of a difference. I had the carb on when I switched to the DMC and it still ran, actually had more pep and snap down low. Now it is just a headache trying to get to idle correctly. I took the carb off again today and cleaned everything and adjusted the float to 16mm. I still need to hold the throttle slightly to get it to idle and still smokes. I put a new plug in because the other one was soaked.

 

[blooper]

Before you send it to its death, sell me that LRD lol.

But on a serious note. I am not familiar with either carb, so I cant say anything to help either way. But if it ran and was tuned with the 35mm PWK, why are you switching to the 30mm OKO? Is it better? Looks nicer? Just dont understand. To be honest, the stock carb would do just fine with your engine. Is there a reason you are wanting a bigger carb?

I just have all these parts sitting around and like to experiment on what carbs and pipes work well together see the different powerband. I am in the desert so I ride Sandy trails, hills and dunes. I enjoy the snap down low specially for hills, i rarely even see 6th gear.

 

[dirtysquared]

I just have all these parts sitting around and like to experiment on what carbs and pipes work well together see the different powerband. I am in the desert so I ride Sandy trails, hills and dunes. I enjoy the snap down low specially for hills, i rarely even see 6th gear.

If that's the case, put a stock carb back on with that DMC setup. You'll get the snappy down low, and maximize potential.

 

[blooper]

http://s1096.photobucket.com/user/B...160403_152352_zpsnufjrh12.mp4.html?sort=3&o=0

Back to the LRD with 35mm PWK. What to try next?

 

[blooper]

Thoughts anyone? Does the above sound similar?

 

[Awk08]

what # slide is in that 35 ?
you're going to need a #6 slide, or pull your hair out.
float height correct ? (16mm)

should be close with the 48 pilot and 155 main.
pilot confirmed with idles highest between .5 and 2.5 turns out of airscrew ?
plug chop confirmed 155 main ?
might want to try a CEL needle, it works on these 34/35 carbs for elevations under 1000' abs.
DGH is leaner needle and more suitable for higher elevations (1000-ish +).

 

[blooper]

#6 slide, I am at a 45 pilot and 155 main now, needle on middle clip. Problem is I can't keep it idling at all even adjust the idle screw. I read some where people had problems with the idle screw and had to modify it so the screw would go in further to push the slide up so it would idle. Double checked and it's at 16mm. I am at 1950 elevation.

 

[Awk08]

#6 slide, I am at a 45 pilot and 155 main now, needle on middle clip. Problem is I can't keep it idling at all even adjust the idle screw. I read some where people had problems with the idle screw and had to modify it so the screw would go in further to push the slide up so it would idle. Double checked and it's at 16mm. I am at 1950 elevation.

that sounds like it should run/idle fine.
the DGH should be the one at your elevation.

what turns out on the airscrew produces the highest idle ?
if turning the airscrew doesn't raise/lower the rpm's, you need a different pilot.
45, 48 or 50 pilots are all common. (I run a 48 on my 34mm, and know a few others who run 50's)
each bike is different., which one produces highest idle between .5 and 2.5 turns out is the one you want, the rpm's resonding will tell you which.


what you're reading about the idle screw not going in far enough, and filing the boss down further is on stock 26mm mikuni carbs, when deleting the tors and adding an idle screw.

thats not to say thats not your problem, I have seen/heard of the retainer spring on the keihin idle screws needing a ring or 2 cut off to allow it to run in further and hold the slide open further, it's worth a check.
take the spring off and try adjusting the screw without it on there just to test it, that will allow it to run in further to lift the slide further, and tell you if the spring needs cut down a little.

you need to get the idle screw working to turn it up a little while you tune the airscrew/pilots.
do the idle screw first, so it'll idle for you.

 

[blooper]

Ya that's what I was reading was about cutting the spring down and they still had to screw it in all the way to get an idle. I have messed with the air fuel with no changes but kind of defeats the point if I adjust when I can't get it to idle. I have that cheap plastic screw in the idle so I ordered a brass one to see if it changes. I have screwed it in close to the end like 2 threads out with no difference. I guess I can screw it all the way in to see if it changes. It won't idle now without me giving it throttle, just the slightest throttle allows it to run rough.

 

[Awk08]

yeah, you gotta get the correct brass idle screw before going any further.
hopefully you bought the one spec'd for that carb ?

#17 & 18 ...........
http://www.carbparts.com/keihin/pwk_33_39expl2.gif

part# in this list: http://www.carbparts.com/keihin/pwk33_39parts.htm

 

[blooper]

Thanks for the diagrams. I bought off ebay and was a keihin part said to fit the 33 - 39 size carb

 

[blooper]

Once the Screw comes in I will try that and update. I can't stand how many posts are on here where they have a similar problem and I read through 3 pages with no solution.

 

[Awk08]

Thanks for the diagrams. I bought off ebay and was a keihin part said to fit the 33 - 39 size carb

should be fine with that

 

[Larry's Shee]

Once the Screw comes in I will try that and update. I can't stand how many posts are on here where they have a similar problem and I read through 3 pages with no solution.

Ya, that's quite common. The old "I got it fixed and don't care about you"

 

[nick20555]

Ya, that's quite common. The old "I got it fixed and don't care about you"

Yep, that's why I try to keep my threads well informed on the situation and come back with what I did that fixed it.

Ya that's what I was reading was about cutting the spring down and they still had to screw it in all the way to get an idle. I have messed with the air fuel with no changes but kind of defeats the point if I adjust when I can't get it to idle. I have that cheap plastic screw in the idle so I ordered a brass one to see if it changes. I have screwed it in close to the end like 2 threads out with no difference. I guess I can screw it all the way in to see if it changes. It won't idle now without me giving it throttle, just the slightest throttle allows it to run rough.

As for your idle problem, I have the 35mm air striker so I'm not sure the exact differences between the 2 carbs but I had the same problem about it not idling and I researched into the idle screw problem. What happened with mine was that I was able to take the carb off to look inside it while I turned in the idle screw. What is suppose to happen is that when you turn the idle screw in, it should push on the slide and raise it so if you have the carb off the quad and are looking in through the airbox side of the carb you should see the slide start to raise as you turn in the idle screw. With mine, the screw bottomed out the spring before it even started to raise the slide. So what i did was take the spring off the idle screw and reinstall the screw. I screwed it in until I could see it raising the slide. I found the spot where it just started to touch the slide and used that length to modify the spring length by cutting it. I just kinda cut a little at a time until I found a good length where the spring started to compress right before the slide started raising. By doing that you should be able to get your idle screw to screw in far enough to get your blaster to find a spot where it idles good.

Sorry for the long post but I figured this may get looked at in the future as a guide to fixing the PWK idle screw problem

 

[blooper]

Thanks, I believe I read your post on what you did above that's what I was going to try and do. I reviewed the idle screw in the mail just haven't installed yet. I snapped a spring seat on my inner clutch basket so waiting for a new one to come in the mail. Maybe I didn't put it together correctly but when I installed my kickstart and put everything back together the and now the kickstart spindle is too far in and it won't catch on the crank when you kick start it. Almost looks like I should have installed a spacer washer prior to puting the spindle on so it would push the spindle out further and be able to line up with the gears and crank when you engage the kick start. I have to take that part and see if I installed it incorrectly.

 

[blooper]

*UPDATE* the idle needle was installed and you have to adjust almost all the way in but the bike idles fine now. The metal screw is a lot longer than the plastic one and is pointier on the end so it allows the slide to raise more. I have a 50 pilot in and and 155 main, the bike is great up top and even through mid range. I am still messing with the air/fuel screw because it idles fine but not real high and kind of stumbles on take off. Bike smokes for a while at start up as well. I will update again whem i fine tune it and it runs perfect again.