Mikuni carb conversion questions for 73 125

[sdm]

I am considering doing a Mikuni carb conversion on my 125 but have a few questions. It looks like a 28mm would be the best size but Sudco
doesn't list that anymore on their web site. Would a 26mm be a good
option or would that restrict the power too much? I am really after
better response in mid range and low end for trail riding than top
end performance and a 30mm seems like it may be too much. The engine
is stock. I have checked with the local cycle salvage and they want
as much for a used carb as a new one. Any thoughts would be
appreciated.
Thanks
 Sam

[bentrims]

Sam,
I may (will)cause an uproar with many poggers but get a Mikuni on your 6 days even if you go down to a 26mm it will run great. To me "Bing" is the sound the carb makes when it hits my trash can.

I have been told numerous times that the Bing makes more power. If you sacrifice ajustability and you are trackside watching your race go by where is the power?

I am running a 32mm on mine and when I switched bikes to test ride another riders bike with a stock Bing last weekend I will never go back. He took down the jet specs given to me by Donny Smith and will soon have a Mikuni on his bike.

[dkwkid]

Clean up the Bing, replace the needle jet( it gets worn oblong) and you are good to go.125cc races are won with the shift lever-piston port engines arnt really all that flexible anyhow. Hold it open, use the clutch and gearbox if you want to win!

[tomale]

Bent, you made me laugh... that is just about all that bings are good for anymore. I hear that there is a guy up this way that will bore them or and fix them but why. They wear too fast and they are hard to tune. Not to mention the jets are almost twice as much. I still have a bing on my 400 and it cost me a few postions and maybe even a win. I had to pull it apart and clean it up at the race. Not my idea of fun. As soon as I can it is going away and is going to be replaced with a mikuni. They are cheap to buy and work really well. I brought with me on Saturday my 250 that has a mikuni and with it raining and temps in the low 40's it started on the 2nd kick. what else do you need to know?

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
78' 400 MC5

[Dave Withrow]

Do you have to do anything to adapt the Mikuni to the intake?

[firstturn]

Tom,
  Would you repeat what sound the Bing makes when it hits the Trash Can?[)]  They do look nice on restorted bikes[8D].

Ron Carbaugh

[bentrims]

Mikunis can be bought with a flange mount having slots on each side to allow the standard cylinder configuration to bolt right on. Look on ebay under the Mikuni listing. You should find one under $50. I paid $55 for my 32mm and it was in the box never having gas in it yet.
I did buy a flange 24mm for about $30 on ebay.  

Keep your carb on a shelf as Ron indicates. If you ever sell your bike or decide to make a beauty out of it the value is far better with original equipment as with show cars.

Tomale, Glad to hear I got you with that one. Humor has always been a high priority around here because life is just too short. Based on your signature closing I have always liked.

Make it a great day guys,
Tom B

[bentrims]

Tomale,
Based on your signature closing I have always liked, I think we share that priority.

[sdm]

I know that the Bing is problematic at least for me so that is why I am considering the change. I put a Lectron on a 1980 KTM years ago and it was a whole new bike after that. Thus the Mikuni consideration.I am not really racing the bike (yet) but who knows down the road. I mainly want clean running when it is off the pipe and may even teach a few newbies to ride on it. I'll definitely check out the possibilities you guys mentioned and thanks for that.
I'll let you know what I come up with.
Thanks
 Sam

[tomale]

Bent, we do...life is too short not to include humor. I love a good pun. my wife and I will go round and round adding one pun upon another. It drives my kids nuts. which is half the fun.
I seem to have a collection of Bing carbs. Not sure were they all came from. Maybe we should establish a home for wayward Bings, Is your home safe from Disfuctional Bings? [:0]
Ron very true and that is why I took the stock intake and Carb on the 76 250 and put it away for safe keeping. I bought a intake on Gee-bay (Gee they want alot)and modified it to work on my bike. Do a search and find my post on what I did. For anyone interested. I guess I allowed my frustration with them from this weekend to get to me. It nearly cost me a day at the races. To be fair though, part of the trouble could be my fault. The tickler is kind of funky and it looks like part of the brass sleeve that seals out crud from getting in is missing. I should have been more careful about my prep and figured out a way to seal that up better. Still most of my hard starting can be attributed to the Bing. I had nothing but trouble with the 250 until I changed Carbs.
Dave on the 125's you should not have to make any modifications to make it work. you will need a intake boot to make the connection but that should be easy to deal with.

Thom Green,Still crazy after all these years!
76' 250 MC5 (orginal owner)
78' 400 MC5

[DKWRACER]

Greetings from Colorado, just a side note:
I have an article titled " Super Sachs Secrets " in it are instructions for 28mm Mikuni retrofit....It does work.
Can send if you send me a SASE:
Tom Brosius
Talk to you on the outside?

[Tommy_V]

What are the challenges of converting a 74 175 to a mikuni?  Anyone?

Tommy

[deek]

Hi Sam

I have a 28mm Mikuni mounted on my 72 6 Day. It's fantastic!! Comes on quick and doesn't falter to the top end. I call it a clamp on. But I had a adaptor make local ($15) to fit into the Mikuni, of course you have to remove the original insert. I'm now looking for a 30mm to see how they work. Don't crop off the spiket!! I've seen that done. Try a Cycle salvage,usually the old Kawasaki's had the clamp on's.

Dake
72 6 Day

[sdm]

Thanks guys... DKWRACER I sent you an email..
Sam

[James]

Wow, granted bings are more expensive and more expensive to maintain.
Still, when working properly the tickle button make an easy starter-and you can run then leaner on the bottom due to this. They have also in my experience had more " punch" in the upper midrange. Maybe that is not a good thing but it make a 250 Katoom such fun to ride.
I put a mikuni on the Maico since it was missing a carb though and a new one for 149 is alot better than a used rebuilt one for over $300.
 They have their own advantages but a a mikuni is a whole lot cheaper.
you might remember that like the Pentons they are found on-they gave lot more years of service than most others the first time around. One usually does not find a Penton that was not ridden into the ground for sale. This is a a testament to their durability. with the exception of Tom Green's case, most of these Bings have been used more than a mikuni you find in a salavge yard.

 Tom B. the way you ride your 125 you can put a 38 on it. If only it were allowed in classic.  James


7" and 4" travel? Hmm-that makes 11" Hey! I can live with that.