• 2 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
     WR = 2st Enduro & CR = 2st Cross

  • Hi everyone,

    As you all know, Coffee (Dean) passed away a couple of years ago. I am Dean's ex-wife's husband and happen to have spent my career in tech. Over the years, I occasionally helped Dean with various tech issues.

    When he passed, I worked with his kids to gather the necessary credentials to keep this site running. Since then (and for however long they worked with Coffee), Woodschick and Dirtdame have been maintaining the site and covering the costs. Without their hard work and financial support, CafeHusky would have been lost.

    Over the past couple of weeks, I’ve been working to migrate the site to a free cloud compute instance so that Woodschick and Dirtdame no longer have to fund it. At the same time, I’ve updated the site to a current version of XenForo (the discussion software it runs on). The previous version was outdated and no longer supported.

    Unfortunately, the new software version doesn’t support importing the old site’s styles, so for now, you’ll see the XenForo default style. This may change over time.

    Coffee didn’t document the work he did on the site, so I’ve been digging through the old setup to understand how everything was running. There may still be things I’ve missed. One known issue is that email functionality is not yet working on the new site, but I hope to resolve this over time.

    Thanks for your patience and support!

All 2st Zip TY air screw... problems

krieg

krieg

Husqvarna
Pro Class
I thought long and hard about posting this. But now that I've experienced the same issue on two bikes, I had to tell the story.

I installed a Zip Ty air screw on my 2011 CR 150 this past Spring (April/May?). After installing the screw, I began to experience erratic idle issues. At the time, I thought this was due to a bunch of other jetting changes I made at the same time. Since then, I was never really able to achieve a stable idle setting on the CR, but I kept the ZT screw in because I thought the problem was related to float level and other jetting issues.

Yesterday, I installed another ZT air screw in my 2012 CR 125. I immediately noticed difficulty in achieving a stable idle. I futzed with the screw and the idle for about an hour and could never get a stable idle setting. I put the original screw back in at the original setting, adjusted the idle screw to the original setting and all was wonderful again.

Then I yanked the ZT screw on the 2011 CR and put the OEM screw back in... after a few tweaks, BINGO, stable idle.

Not sure what is going on here... but the results I've posted are real. After examining the ZT screw and the OEM, it looks like there is a substantial difference in the tip. The ZT screw tapers down to a flat. The OEM screw tapers down to a rounded end.
 
Nice to know. Too bad it doesn't work, as a quick no tool adjustment, for the air screw on a small bore would seem idea.
 
You may want to try rounding off the end of the zip-Ty screw to match the oem and see what happens.
 
+1 for the RB Designs screw. The RB Designs screw is machined brass (like OEM) and it's profile is be controlled better. It also has a tension spring to preload the screw threads. The aluminum screws tend to be like you described and more conical shape. Also, the aluminum threads are sometimes more sloppy fit. Both can lead to less precise metering of the air passage.

On my old SM610 with FCR carb, I noticed the same issue on the aftermarket fuel screws. The aluminum ones were junk. The brass ones from Scott or Merge Racing had a nice sharp tip like the OEM screw.
 
MattR said:
+1 for the RB Designs screw. The RB Designs screw is machined brass (like OEM) and it's profile is be controlled better. It also has a tension spring to preload the screw threads. The aluminum screws tend to be like you described and more conical shape. Also, the aluminum threads are sometimes more sloppy fit. Both can lead to less precise metering of the air passage.

On my old SM610 with FCR carb, I noticed the same issue on the aftermarket fuel screws. The aluminum ones were junk. The brass ones from Scott or Merge Racing had a nice sharp tip like the OEM screw.
Click to expand...
Will this wor with the pwk (keihin)
 
another RB user here... quality stuff, but I think it is only available with carb work?...
 
krieg said:
I thought long and hard about posting this. But now that I've experienced the same issue on two bikes, I had to tell the story.

I installed a Zip Ty air screw on my 2011 CR 150 this past Spring (April/May?). After installing the screw, I began to experience erratic idle issues. At the time, I thought this was due to a bunch of other jetting changes I made at the same time. Since then, I was never really able to achieve a stable idle setting on the CR, but I kept the ZT screw in because I thought the problem was related to float level and other jetting issues.

Yesterday, I installed another ZT air screw in my 2012 CR 125. I immediately noticed difficulty in achieving a stable idle. I futzed with the screw and the idle for about an hour and could never get a stable idle setting. I put the original screw back in at the original setting, adjusted the idle screw to the original setting and all was wonderful again.

Then I yanked the ZT screw on the 2011 CR and put the OEM screw back in... after a few tweaks, BINGO, stable idle.

Not sure what is going on here... but the results I've posted are real. After examining the ZT screw and the OEM, it looks like there is a substantial difference in the tip. The ZT screw tapers down to a flat. The OEM screw tapers down to a rounded end.
He makes a screw for the Mikuni?
Click to expand...
 
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