495 Mikuni carb

[Mike Hufnagel]

Anybody know what size Mikuni I should run on a 82 495? round slide or flatside?

Don't really want to deal with bings as I have a ton of parts for mikunis and more familiar with them.

'12 Husaberg TE300
74 Yamaha TY 250
84 Yam IT200
75 Jackpiner w/ 250 eng.
82 KTM GS250II (import)
82 KTM 495 (2)
98 KTM 300mxc
04 KTM 125 SX
00 KTM Duke 2/rd. racer
06 KTM 950 Adv.
08 Suzuki DR70Z

[idiotboy]

I put a 38mm roundslide on my 1985 500mx

[brian kirby]

A 44mm if it will fit, thats what the Husky 500s came with, but thats a BIG carb, if not 38mm.

Brian

[adrian_goold]

I just fitted a 38mm TM Flatslide to mine with Powerjet.
I can give you some specs on jetting that i have put in it, but they are a starting point as i have not yet run the bike other than on the stand.



Regards,
Adrian Goold #101
http://www.ozktm.com

'73 175 Rebuilt.
'74 400 Now Racing!
'78 250 running soon!
'81 250 Now Racing!
'81 495 Engine Work stage.
'84 125 Now racing!
'07 300

[brian kirby]

The TM is a great carb, and if you do not care about AHRMA legality is a lot better than the round slide VM, but powerjet carbs are not legal for AHRMA if that is a concern.

Brian

[Big Mac]

Adrian, Mike - Please post your before and after impressions, and jetting conclusions.

I'm running a stock '81 495 Bing that's not too worn, stock jetting as suggested by Flash. Runs strong and pretty responsive right off the bottom, very strong on top. I rode a 495 with I believe a flat-slide Mikuni of Chris McQuillen(sp?) that Rick Doherty was running at Washougal a couple years back...felt like it had a big dead spot off the bottom, and had heard that could be a problem on Mikunis.

Another PacNW guy had a 495 with a flat slide Kiehn that I took a spin on. Very clean bottom to top and super strong. Some Maico 490 guys around here though have tried a bunch of carb variations and gone back to a good Bing and are sold on it.

BTW, AHRMA rules or not, the stock Bing on the '81 495 had a powerjet of sorts, at least as Bing termed it. Separate nozzle in the front intake for 2 "main" jets. I didn't note any real difference between it and the conventional single main jet Bing on the '79 420 I owned.

[tomale]

I am running a Bing off a 85 Maico 500 on my 78 440, It is a 40 mm. the unusual thing is that the throat of the carb is not perfectly round, but a bit more egg shaped. this allows for better throttle response in the first third and when you open it up, you have a full 40mm.
the thing with sizes of carbs have more to do with how much a motor draws than the bore and stroke.  The other thing is that flat spots in the middle of the power band can be caused by too lean of a needle jet so make sure you work on getting that right too.

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
74'250 hare scrambler (project)
74' 1/2 440 maico
78' 440 maico
72' cr125 Husky (project)
93' RMx 250 suzuki

[adrian_goold]

I have the same setup on my 81 250 (with porting changes).
And yes, they do need work with the slide changes, needle jet, needle changes etc to get it right.
My 81 495, is untested in the original bing setup (i did not have one), so have gone down the same path as my 250, as i have all the jets and needles to set this up.



Regards,
Adrian Goold #101
http://www.ozktm.com

'73 175 Rebuilt.
'74 400 Now Racing!
'78 250 running soon!
'81 250 Now Racing!
'81 495 Engine Work stage.
'84 125 Now racing!
'07 300