Greetings to all, While it is a sad time of year for me here in New England, (the bikes put up for the winter). It gives one time to pursue modifications.
To the point, can anyone give me some info about boring out the stock carbs? Not very familiar with that mod and like to look into it. As much technical data or experienced usage insight is appreciated.
Max
RZ500
RD400
Ossa Pioneer
Triumph Sprint ST
Carb boring?
Moderator: rztom
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Retired 18E
- Posts: 30
- Joined: Sat Jan 28, 2012 3:45 pm
- Location: Poor part of Connecticut (eastern border)
Carb boring?
Let me ride on the Wall of Death one more time
Re: Carb boring?
While I've never done it, would be fairly simple as I'm a machinist, I did own a set of bored out 28mm mikunis (to 30mm), worked really well on a heavily ported RD350. I'm planning on a set of 33mm RS type for my 85 GSXR from the original 29mm. There's quite a bit of info online but the basic idea is to bore the carbs at the top of the inlet so you get an oval shaped runner, this is especially important on 2 strokes as it keeps the carb inlet smaller for longer off idle. You can't go bigger than the slide obviously but if you thin out the carb body on top too much you can use JB weld or some other epoxy to reinforce it (mine were like that). Any decent machinist should be able to offset bore the carb body in a lathe as long as they understand the end result you're looking for.
Here's a good link http://www.thunderproducts.com/media-carbboring.htm" onclick="window.open(this.href);return false;
Here's a good link http://www.thunderproducts.com/media-carbboring.htm" onclick="window.open(this.href);return false;
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Retired 18E
- Posts: 30
- Joined: Sat Jan 28, 2012 3:45 pm
- Location: Poor part of Connecticut (eastern border)
Re: Carb boring?
Thanks for the info. The explanation at the linked site was especially helpful. Please keep us (me to) informed here on the board as to how your's turns out. Sounds like it shouldn't be too difficult, I just don't have acces anymore to a lathe or bridgeport or grinder or anything. GRRRRR...
Max
Max
Let me ride on the Wall of Death one more time
Re: Carb boring?
You may be waiting a while, that's like project #123 in a long line of projects, a lathe would be helpful for you. This does work, it's been done quite a lot on the first gen GSXRs that have the VM29ss carbs (non-US model) which are actually just a rack of TM33 carbs with smaller bores. You may also want to check out 2 stroke world as this seemed to be done a fair amount on the RD350s.Retired 18E wrote:Thanks for the info. The explanation at the linked site was especially helpful. Please keep us (me to) informed here on the board as to how your's turns out. Sounds like it shouldn't be too difficult, I just don't have acces anymore to a lathe or bridgeport or grinder or anything. GRRRRR...
Max
Re: Carb boring?
I have a set of bored carbs , you can see the light on the side of the slides . Good for parts .
Re: Carb boring?
Yeah like I said you have to be very careful not to go bigger than the slide or bore off center side to side.ixe13 wrote:I have a set of bored carbs , you can see the light on the side of the slides . Good for parts .