TrailDawg

Member
Sep 7, 2001
41
0
I'm been looking into getting my 220's carb bored out to 36mm, but am curious of which way to go. Having read through some threads discussing the RB-Designs bore/plate mods, it sounds like its the best option for the most power. My dilema lies in the fact that from what I've read here, this mod makes it extremely sensitive to jetting and a PITA to figure out. Is the performance increase associated with the divider plate enough to make it worth the additional headaches and cost over a standard bore job?

Additionally, has the jetting finally been figured out for the RB mods (the thread I am refering to was from last fall)? I really don't want to end up getting a mod that will cost me a small fortune in brass, give me constant headaches, keep me from riding, and possibly using my carb for target practice.

Any advice, info, and suggestions will be greatly appriciated!!
 

Fred T

Mi. Trail Riders
LIFETIME SPONSOR
Mar 23, 2001
5,272
2
Yes! The RB mod is the way to go and Ron will set it up with the right jetting. I think he sends you the CEK neede\le which is operfect. I had the carb done last winter and rode all this season with it and loved it. Really wakes the 220 up and the throttle response is awesome. Some folks like me have done some testing and that thread can be confusing and intimidating. The reality of it is that the bike will run better than before and if you do work on your jetting changes as the weather changes it will run great al the time. Same as your bike unmodified. It will run different at 90 degrees than at 50 degrees.
 

TrailDawg

Member
Sep 7, 2001
41
0
Thanks Fred T. After I posted this, I finally found the right word (design) to search for and found all the post/threads about the mod and am glad to see the jetting has been figured out. You aren't kidding about the one thread being confusing (the archived one with 7000+ views)....especially since I don't have the least bit of experience/knowledge when it comes to varying needle tapers or slide configurations.

I do have one other question though. I'm also going to have the cylinder and head machined...are the head mods Ron does basically the same as what any other shop will provide, or would I be better off having Ron also do the head to best match the carb mods? I'm relatively new to internal mods and have a good understanding of port work, but am unfamiliar with how/what the head mod effects (other than a slight increase in compression from the surface milling).
 

canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
0
Ask ron:

RB Designs
12025 NW Thompson rd.
Portland Or. 97229

Machinist name: Ron. E-mail address … rblack66@attbi.com

His website: http://www.rb-designs.com/

He's on this forum, too.

re: "I'm also going to have the cylinder and head machined.."

Wouldn't that be better done as a 'set'? Whoever is doing the cylinder work should do the head work I would think. One has to 'fit' with the other, and having them done by different people would lead to a question or two regarding that 'fit'.

re:"especially since I don't have the least bit of experience/knowledge when it comes to varying needle tapers..."

The thread you're referring to 'splains that well. Having at least a working understanding of needle tapers will put you far ahead in the jetting game. At least understand the 'magic number' part and how that relates to the start of the taper on a particular profile of needle, and how changing that profile can make a BIG difference in your bike's performance.

If you don't have JD's needle spreadsheet, and you are at ALL interested in aspects of different needles and how they will effect your bike, GET it. It's a nice tool!
 

fmfkdxrider

Member
Aug 24, 2002
10
0
I was just wondering around how much would this carb mod would cost. if it really makes a boost in power im kinda interested but money is a factor too. just wondering, thanks
 

simon1

Member
Oct 15, 2000
33
0
i recently bored my carb to 36mm, modified the slide and pilot and it made quite a bit of diference to mid and top .as your based in the us though i'd send the carb to RB
 

TrailDawg

Member
Sep 7, 2001
41
0
canyncarvr, thanks for the info. Where can I find this magical spreadsheet of JD's? I'm definitely interested. Also, is there any similar reference available for the various slides numbers and how their different profiles will affect things? To be honest, I didnt even know they had different slides, so any information I could get on this would be great learning material as well. Thanks in advance!!
 

kawaJawki

Member
Jul 17, 2001
9
0
had ron do my carb in june. was $165 shipped to my door. still waiting to see the results as our riding season wont be open for quite some time .
 
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