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-   -   Carb shim mod (https://www.superhawkforum.com/forums/technical-discussion-28/carb-shim-mod-9370/)

MessF4 08-20-2006 02:38 PM

Carb shim mod
 
Hey gang-
I have done a search for the shim mod, but have only stumbled across one or two quick rundowns on how to do it. My question is this...When you pull the needle out, the .020" shim goes underneath the small washer at the bottom of the needle, that is, the end that goes into the needle jet. Does that sound right? How easy is it to get the small washer out? And is it fairly easy to press it back in? Any help will be appreciated.

Scott V 08-20-2006 03:17 PM

That washer happens to be 20 thou in my 05 unit. another .020 made all the difference in how it ran. (stock unit) I am very happy the overall improvement.
It's easy to fit both back together. The slide spring in another thing altogether. LOL

Scott

superbling 08-20-2006 04:05 PM

You have it right. It's a circlip type washer. I pressed a flat blade screwdriver against it to remove/insert it. WATCH OUT: it can or will go flying if you aren't careful and will be almost impossible to find. BTDT. Do it over a big clean towel to catch it.

Great cheap mod for stock bikes (my favorite kind).

Hawkrider 08-20-2006 06:31 PM

The stock needles don't have a circlip. It's just a head, like a nail, with a washer under it. The additional washers go under the head, in other words slide the washers down the needle. With bafflectomized pipes you will want to add several washers, for a total of 0.060". Just to clarify: There is a retaining dealio in the slide with a threaded hole in it. You take one of the bowl screw and pull that plastic retainer out. Then the needle and washer will come out. Add washers. Spray little o-ring on the retainer with some WD-40 or something and reassemble.

superbling 08-20-2006 07:51 PM

DOH!

It's been so long since I did it, I forgot mine was/is a DJ kit. So disregard the circlip advice.

MessF4 08-21-2006 11:21 AM

Thanks guys, I appreciate the advice. I have aftermarket cans, so I think I'll start with just one washer, and add as I see necessary.

RonVTR 08-21-2006 08:55 PM

You may want to think about adding more washers as described in Hawkriders post... His advise was with the "bafflectomized" (or opened) stock mufflers. I'm shure your aftermarket mufflers flow even better... May save you a couple of trips into the carbs. :)

Hawkrider 08-22-2006 09:59 AM

+1.

MessF4 08-22-2006 12:31 PM

Okay, I'll try adding a couple of shims. I guess I just don't want to go overboard because it's only in a specific set of circumstances that the jetting is off. Thanks!

RickB 08-27-2006 04:24 PM

What diameter washers work well for this mod? Something standard size (and .020 thick) from a hardware store work? I haven't had the carbs apart yet so I haven't seen the size of the needle or any stock washers.

Thanks

killer5280 08-27-2006 09:00 PM

I have used #4 brass washers for this purpose. The ones at my local hardware store are .030" thick.

RickB 08-29-2006 05:43 AM

Thanks for the info, I picked up some .026 brass washers at the hardware store last night. As I was putting the bike back together the rain started :(




Originally Posted by killer5280
I have used #4 brass washers for this purpose. The ones at my local hardware store are .030" thick.


avramd 11-15-2009 07:50 PM

On my slides, the factory washers appear to be glued in place. Is there any reason to take them out? Or just leave them alone and add washers?

killer5280 11-15-2009 08:53 PM


Originally Posted by avramd (Post 243104)
On my slides, the factory washers appear to be glued in place. Is there any reason to take them out? Or just leave them alone and add washers?

They're probably glued in with the same varnish that plugged up your jets. It's OK to leave them in and just add washers.

VTRsurfer 11-15-2009 09:44 PM

But a little carb spray here and there might be well advised.;)

stebbdt 11-18-2009 04:26 AM

Just make sure ya don't get any carb cleaner on the diaphragms, and test the slide action on both carbs to be sure ya have em captured in the rabbit right.

nath981 11-18-2009 08:12 AM

I did the .40 shim (hawkrider recommended a while back) and set the air mixture at 2.25 turns out(also Hawkrider recommended), TPS 500, foam filter, cut airbox flap flush with top of filter, and the color of the pipes is perfect and it runs strong through the entire rpm range.

avramd 11-19-2009 10:51 PM

The color of the pipes? What are you referring to?

Syclone 11-19-2009 11:07 PM

probably the soot level / color on the inside of the cans

nath981 11-24-2009 05:14 AM

the color of the pipes can be an indicator of how rich or lean your engine is metabolizing fuel. Similar to looking at your plugs. Google spark plugs color fuel and you'll find that color can vary from white to grey to brown to black, the lighter being lean condition while black indicates too rich.


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