What is the best throttle assembly and cables for Mikuni smoothbores ?

[maicojoe]

I am switching to a set of 33mm Mikuni smoothbores for my 1982 GS1100ez. It has the stock throttle assembly and single cable for the stock CV carbs. It looks like the Mikuni smoothbores are designed for a double cable, push/pull throttle assembly. Any advice on the best available throttle assembly that will fit my bike? Thanks, Joe

 

[storm 64]

I am switching to a set of 33mm Mikuni smoothbores for my 1982 GS1100ez. It has the stock throttle assembly and single cable for the stock CV carbs. It looks like the Mikuni smoothbores are designed for a double cable, push/pull throttle assembly. Any advice on the best available throttle assembly that will fit my bike? Thanks, Joe

Good evening Maico Joe,
I used a throttle assembly from a 1978/79 Suzuki GS750. It looks just like your original but with the push pull design. There are others that will work like say the GS550... anything using VM Mikuni carburetors. Ask around in the parts wanted section of the website, something should come up.

 

[maicojoe]

Hi Storm 64,
Do you have Mikuni 33mm smoothbores on one of your bikes? Any jetting specs?

 

[storm 64]

Hi Storm 64,
Do you have Mikuni 33mm smoothbores on one of your bikes? Any jetting specs?

Good morning Joe
Yes I have 33mm Mikuni Smooth Bores on my 1100e. I'm pretty sure I have my jet sizes written down, if not I'll pop one out and give you the size. I'll do it later when I get home from work. The carburetors work great on my 1100 its kind of like riding a Maico 490....

 

[maicojoe]

Do you have a Maico 490? I have been riding, racing, collecting, restoring Maico's since 1986. Have 7 Maico 490's currently. Prefer the 1981-82 piston port 490, best mx engine ever made. Kinda like a GS1100/1150 or 426 hemi, fast and fun, with lots of room to hot rod them.

 

[storm 64]

Hello Joe Maico, and whoever wants to know some of my carburetor jet settings. I don't know my needle number, and I'm trying to make out my pilot jet size. I may need a magnifying glass. It looks to be a 125?? (I'm near sighted but geez oh man) I'm going to need to magnify it at work tomorrow. I remember putting in a size smaller pilot jet because I was having to back out the air screw to much. I put in a smaller pilot jet to get the air/fuel mixture ratio more in range of the air screw. If that makes sense. The main jet is definitely a 135... Now for my motorcycle, I have the K&N style individual air cleaners. My exhaust system is a Star Racing street header. There is a baffle but no "packing". Private message me if you have any questions. And I'll get back to you with a positive identification of the pilot jet. I hope this helps you get into the ballpark... Norm

I have confirmed the pilot jets that are in my carburetors. #25.0

 

[storm 64]

No Joe, I don't have a 490 Maico. But I remember watching Mickey Kessler hammer up the back stretch at Unadilla in the 500 support class. I think it was 1980. I always liked them Maicos. Those were the days... My brother had a 79 YZ400. He put the 426 kit in it with the second gear option. What a hand full that was. Now you have my reminiscing...

 

[maicojoe]

Hi Norm,
Thanks for the info. Funny, but the 135 main jets for a start is exactly what RapidRay recommended. The carbs came loaded with 130 mains, so will go try finding some 135's tomorrow, especially since I am at sea level most the time, with lots of cool moist weather. I did start the bike with the 130 jets in it, it started easy, idled pretty good right out of the box. But, when I revved it up after it was warm, just sitting in the driveway, it would want to hang or stick past about 4000 rpm, every time. Could definitely feel the slides hanging up, not the cable. Would shut it off, and it would act normal, open the throttle wide open, and take my hand off it, just let it snap shut. Would snap shut completely every time if the engine was off. I kinda thought the same thing, that I might be able to get by with just one cable, as the throttle return spring on the carbs is pretty stout, but looks like it has to have the dual cable set up. Would not want a stuck throttle at the wrong time. So, for right now, ordered up a generic push/pull throttle from Motion Pro, and stock Suzuki cables with new stock Suzuki grips. Looks like I will be able to retain the stock kill switch/start button. I am going to get the bike dynoed this Friday, see what the AFR looks like across the rpm range. The engine is totally stock, just the bolt ons, MotoGP pipe and silencer, K&N pod filters, and the Mikuni smoothbores. Wonder what the HP and torque will be? Thanks again for your help, Joe

 

[rapidray]

If you don't want to convert to a 2 cable system you don't necessarily have to. The return spring on your smoothbores is huge and it sure as heck doesn't need the help of a return cable.

PLEASE don't comment with things that can get people KILLED!!! ALL smoothbore carbs NEED a return cable to ensure the slides close all the way!!! Simple as that!
Ray.

 

[Guest]

PLEASE don't comment with things that can get people KILLED!!! ALL smoothbore carbs NEED a return cable to ensure the slides close all the way!!! Simple as that!
Ray.

Not trying to purposefully "get people KILLED!!!" Ray. I do remember reading about others doing away with the return cable on VM carbs, now those might have been on 26mm VS smoothbores but I 'think' the process of slides is the same. I guess I'll have to read up on smoothbores a bit more understand the process completely.

 

[Sandy]

I can't remember exactly what the issue is but I thought I read something at one time that they'll actually flow enough air at high rpm to hold the slides open. Could have been all BS too. Ray???

 

[Pedda]

Mikuni flatslides have a pushpull assy for a reason! The slides can stay open under certain circumstances.

 

[limeex2]

How about slingshot carbs? Push/pull needed on these?

 

[Pedda]

How about slingshot carbs? Push/pull needed on these?

These are CV carbs as well, so no pushpull assy needed. The reason is: they are worked by the throttle flap which will close securely, no matter what the slide behind will do.