[metalheadman]

Hey guys I have gotten some great information from you suzuki owners on that it seems my bike is having carb issues. It is either a 1981 or 1982 Suzuki GN400 (the 400cc single cylinder kickstart). In my research it is a Mikuni BS 36 SS Carburetor that is a CV carb. Now my question is, is it a 36mm bore size because that is what my research has told me I would just like some confirmation on that and also I would like to put a new carb on it and not rebuild it. Possibly even an upgraded carb. So I am wondering since this is a CV carb what kind of carb would fit because I know constant velocity carbs are different than the mikuni carbs I can buy now. So I am just wondering what type of carb and bore size, if 36mm is correct I would just like to know, that would work on my bike. If there is an upgraded carbs that would fit/work and make my bike run really well.

Thanks Guys for all your help and knowledge any information on my question will be greatly appreciated!!

Peace

 

[WintrSol]

Definitely a CV carb: http://www.partsoutlaw.com/oemparts/a/suz/50d3edddf8700230d8b4b3a2/carburetor
You can measure the throat size; just pull it from the boot, and use a scale or vernier.

 

[OldVet66]

The only thing needed to rebuild that carburetor is gaskets, O-rings, check float height and a 24 hour soak in carburetor cleaner. Check with Robert Barr for an O-ring kit: www.cycleorings.com.

 

[marcohansen]

Hello guys!
Im new to this forum, and the site wont let me write a new thread since im extremely new here but I have a problem with my 1980 GN400, bike starts perfect up, idles ok and runs fine, until I hit around 1/2 throttle, then it completely stalls. I've cleaned the carb completely, checked float level several times and it doesnt change a thing. The weird thing is that there are three nipples on the carb and only one (larger one) is connected to the petcock...
What are the other ones for?
have photos but I cant figure out how to post them

 

[Unkle Krusty]

Carb.

I prefer the non CV type carb, having used many of the regular Mikunis. Non CV carbs predate the CV.
However my XS11 takes off like a haunted outhouse, and generally runs just peachy. It has four CV carbs. My XS400 runs fine with two CV carbs.
So a cheaper plan would be to buy a carb kit for what you have.
Measure the engine side of the carb, and the air filter side.

The cable will be different for a non CV carb. The choke will be different as well.
You might be able to find a used Mikuni carb.

Getting used to the CV carbs was not so bad.

Unkle Crusty*

 

[OldVet66]

Here is a link to the Factory manual for your bike markohansen. The line to the petcock is a vacuum line that starts fuel flowing, the other two are vents most likely. Routing of the lines should be in the manual. Your carburetors were not cleaned properly unless you tore them down completely and soaked them in carburetor dip for 24 hours before you started the cleaning process. The slides and diaphragms do not get dipped, that will destroy the diaphragms and they are not cheap. The only parts to replace are gaskets and O-rings. https://onedrive.live.com/view.aspx?resid=2370B62DDF9F0C6B!1334&app=WordPdf&authkey=!APM7hx6Q2ynLu-A This might not cover your model since it is a single cylinder. The carburetors should be similar though. It sounds like your main jet is still partially clogged.

 

[OldVet66]

I have had good luck with the carburetor dip at NAPA, and you can get the proper O-rings from www.cycleorings.com Z1 enterprises is a good source for gaskets. Stay away from carburetor kits, use only factory parts and they are still available. The only thing you might ever need is a float needle seat and float needle besides the gaskets and O-rings I mentioned. All the parts in my 37 year old carburetors were still good when I rebuilt my VM carburetors, and they are a generation behind yours.

 

[marcohansen]

Thanks alot OldVet! Ill give it a proper solid clean then, see where that takes me, its winter in Denmark soon anyways means less riding lots of garage time