Motorcycle carb

[Cbreiter]

So, I have a 1976 Honda xl350. I've been having carb issues with it ever since I bought it. I've taken it to several different motorcycle mechanics, and no one has been able to make it work correctly. They say it's good, but I've driven enough motorcycles, that I know when it kills plugs, and won't run smoothly at half throttle. So, anyway I've ordered a 34mm mikuni carb, and I'm hoping that'll fix my issues. Least then I'll be able to buy carb parts if I need them. If anyone has any ideas for me to try, I'd appreciate any ideas.

 

[mckutzy]

Well what about the lemon juice boil trick..
Complete tank cleaning...

That's all I can think of right now..

 

[Cbreiter]

I can try that, does vinegar work? I've cleaned the tank and put in a fuel filter already.

 

[mckutzy]

I'm not too sure if the vinegar works, but I know you can get L jugs of lemon juice at the dollar store,

 

[Cbreiter]

Ok, thought it might, cause it's an acid as well. Dollar stores here don't usually have that, but I can buy 4l of vinegar cheap. I'll see about getting lemon juice next time I'm in town.

 

[mckutzy]

Well I'd say it be worth a try...
Test on smaller parts first, carb bowl ect.

 

[Badot]

Clean the carb and rejet it if necessary? Not much to it beyond that. The tricky part is knowing which circuit goes to what load range.

 

[Cbreiter]

According to the mechanic, it's jetted to spec, though it's possible someone hogged it out at sometime.

 

[Joe-405]

If you move the needle down one click on the c clip it will run leaner. Should help on the plug issue.

 

[Cbreiter]

Ok, I'll have to give that a shot!

 

[Badot]

I've had my fair share of bikes that don't run properly stock (mostly old ones) so I'd be really hesitant to say "to spec" is an appropriate way to jet a bike.

What type of carb is it? Slide? CV?
Just for the midrange in general I'd first make sure all the air passages in the emulsion circuit are clear.

If not, I agree with Joe-405 that you should try dropping the needle. Especially if you're at a high altitude (and doubly so if it's a slide carb rather than CV)

 

[Cbreiter]

It's a standard slide style carb. I'll try talking a picture later and posting. I've made sure carb cleaner will go through all the passages. It smooths out if I turn the fuel off, otherwise it's running way too rich.

 

[Badot]

It smooths out if I turn the fuel off, otherwise it's running way too rich.

In that case if it's not overflowing when stopped then it sounds like you might just need to drop the float height. Pay attention to how the bike runs throughout the entire range when you do that though, sometimes changing float height can have some funny effects that varies wildly based on the individual carb design.

 

[Cbreiter]

I've tried that, however I need to take it all apart again cause the needle and seat assembly are sticking.

 

[that1guy]

Do you have stock air filter or aftermarket a lot of old Hondas are real sensitive to the fuel air ratio

 

[Cbreiter]

I have a stock air filter. It's that foam stuff, thats oiled and it goes over a kinda mesh thing, and pushes up against a seal.

 

[Joe-405]

Do you have stock air filter or aftermarket a lot of old Hondas are real sensitive to the fuel air ratio

This doesnt apply to him anyways. An aftermarket open style pod filter would actually make it run leaner.

 

[Poboy kartman]

the needle and seat assembly are sticking.

That'll do it....