Carbs

I am thinking of just buying new carbs for my 1980 maxim xj650, but I'm not sure the right ones,

http://www.jcwhitney.com/mikuni-uni.../p2015670.jcwx?filterid=c51113d58162y1980u0j1

I have heard the best ones are the mikuni brand but I also don't want to change from stock if I don't have to I have gone through the " church of clean" bike still runs the same, so I'm not sure if I have done things wrong or not, on my first attempt I did snap off the float post on the #4 carb, repairs it but all the issues follow that carb.

 

I don't believe anybody sells bran new carbs for these bikes any more, and if they did they would be extremely expensive.

You may be able to mail your carbs to a member on this site that rebuilds them if you are not confident in your work. But you will still have to vacuum synch and coler tune them when you install them on your bike.

Used carbs are usually available on eBay or you can contact member Chacal if you need to replace the one with the broken tower.

 

The trouble with using the carbs you linked is threefold:

1. They are individual carbs with individual control cables. You will need to fabricate a linkage so you can use them with one throttle cable.

2. They are not meant to be connected together. toy will need to fabricate a fuel dilevery system to feed all four carbs at once, and to support all four carbs.

3. The jetting may not be correct for your Maxim. You will need to spend a fair amunt of time to get th jetting right.

What specific problem are you having with #4. How is the bike running?

You can get a spare rack of carbs to rebuild, or to just use that #4 body and rebuild it, but if the float post has been repaired and is sitting square and level then the problem might not be the post. We need to know what is happening before we can give advice on solving the problem. New carbs won't necessarily solve the problem, and may cause even more trouble.

 

Ok thanks guys I'm not horribly confident in my repair. Definitely not square. I'm worried when float bowl goes on it pinching it just enough to to not the the float move freely but no way to check that. I'll try and find a used rack somewhere.

 

Yes there is. Use a short length of clear tubing on the float bowl drain (same as you did when you wet-set the float levels (you DID wet-set, didn't you?)). Hook up a fuel source to the inlet and see where the fuel level stops relative to the carb body. Shut off fuel inflow, turn the tubing to dump the fuel into a container and repeat. That will tell you if the float is sticking or not.

 

Your 650 maxim should have Hitachi carbs, not Mikuni carbs. There's plenty of carb racks out there for these bikes.

 

china is 1200$

 

I think that xjforever.com sells little washers that go on the float pins of Hitachi carbs to fix a binding problem with the float and post.
I read to much sometimes

 

I should have a #4 carb in my box of carb bodies. If you can't get one from xj4ever let me know and I'll start digging.

 

Still have that #4 carb sitting here if you need it

 

Does anyone on here have a picture of what the carb float are supposed to look like while inverted, as if you were cleaning them. I think the guy I bought the bike from put them in upside down and I'm not sure what it supposed to look like. 1890 Yamaha maxim xj650.

 

Are they supposed to almost sit on the float bowl bottom?

 

And that is then there at there lowest point?

 

it would be obvious if they were in upside down now that you have a photo to compare to.look at the brass
the photo is with the floats at their highest sitting point ,the carb is upside down.

 

That pic is showing the floats with the carbs inverted on the bench.

 

All brass and metal in the bottom of the carb body faces towards the carb bowl........