XJ700 water cooled

:?: well i was able to get my xj650 running so good a friend talked me out of it.
now i inherited a xj700 to fix for another person. same freekin story one of the carbs has a broken float stand !!!!who broke it tryed to fix it with ?. so the story goes on.
but this time i am having trouble finding carbs on ebay.. i had to make 4 out of 8 carbs last time. the main problem with the carbs i have {as a hole} is Idle mix screws are goofed up and i can't get em out. any Idea's ? they are different than my 82 650 so no extra parts here!!!
I was able to get it to run. enrichener works, mid range great, wide open (hold ON) so i synced the carbs but of freekin course it will not IDLE!!!!
lb

 

You and me both, friend. I too, have a 700 MaximX.

I had my own carb bank apart for the X to change out throttle shaft seals and whatnot, put it back together, had a hell of a time getting the fuel levels set right, put them back on the bike, refused to idle without choke. Now I've got them back off and apart again, seeing if the idle fuel passages are blocked or something. Even though I soaked the bodies in carb dip.

I know for a fact the idle jets in the float bowls are open, so that's not the issue. My big thing right now is trying to shoot carb cleaner up the siphon tube -- it's got those little holes that make things difficult. RickCoMatic suggested using the squeeze bulb from an ear wax removal kit, but the drawback is that the cleaner eats up the plastic bulb.

As for finding a carb... you know which one you're looking for, right? Mikuni BS33? As for removing the mixture screws, someone who's had to deal with that problem would be better able to help you than I -- but I can tell you that Chacal has replacements available -- part number HCP3745. Hell, ask him if he's got another carb body floating around... you might get lucky.

 

the floats can be a pain . the siphon tube your talking about is for the choke if it idles with the choke thats not your problem. I have a feeling its your float levels.if they are to low can't suck up the idle circuit properly Yamaha sure doesn't make it easy to do it either. I have an extra float bowl i am going to see about tapping and putting a nipple in it so you don't have to hold something in there while you try to set the level. I found on the later mikunis you have to get all the air out of the plastic tube or the height will not show right you wouldn't think 1 little air bubble where the hose turns would mess up the float height setting. Unfortunately in a few weeks i am going to pull my carbs rebuild them and change the shaft seals.
Something that works for me when cleaning out the siphon tube pull the choke plunger i have a rubber tipped blow gun for my compressor fits on the tube snug you can hear it whistling if its clear

 

I'm sure I have a spare body or two laying around.
Which one you need?

Those floats are a B I T CH to get settled in. I believe the book says 1mm below gasket face but my buddy has my first one and I think those levels are a little low ...and it seems to run BETTER at that level.

I had a square(ish) glass that fits right where the bowl is supposed to go. Hold the glass up to the gasket surface and turn on the gas....watch what happens inside. If glass overflows, shut off the fuel line and adjust. Pour a bit out of the cup and re-try. Saves a lot of screwing around with the bowls and clear tubes. If you are using the bowls, I only use one screw since if the bowls overflow the floats are too high anyway.
I clamp the rack in a vise to keep it level.

 

All the years i have been messing with carbs would have never thought of that. The glass is a great idea learn something new everyday thanks Mike.
My x is finally in peices starting to clean and paint ect

 

3mm, actually. For the X, at least.

Yeah, there was that thread last year where people were asking about transparent float bowls... you were going to ask your machinist about it.

Maybe if we can find some transparent aluminum, we wouldn't have to worry about finding which plastic wouldn't turn yellow.

I was thinking the same thing; the first time I had them apart when I got the bike, I used the squeeze bulb. I couldn't get the plungers all the way out of 2 and 4 without breaking the rack, but the bulb did push them out, so I took it they were open.

I'm beginning to suspect you're right, but I wonder why they came in on spec the last time. As for saying the siphon tube is for the choke, I'm thinking that's not the only place it goes -- if it was, then there wouldn't be a need for an idle mixture screw, yes?

I think we need a bad carb body so we can chop it up and see where all the passages go. Take lots of pictures. I've got a roommate that's taking machinist classes...

 

The cold start circuit only ads more fuel to the mixture pilot screw ajusts mixture from the pilot system only. Choke system does not even flow thru the same hole in the carb body. If you look up mikuni carbs there are diagrams that show what does what in the carburator

 

Yes, that's right. I did ask him about transparent bowls and never got back with anyone here.

We didn't find any material that we felt would stay clear enough when exposed to gas and making them was pretty expensive. I'll have to figure out where I got my square cups and post the link I guess....maybe I should sell them :lol:

SO, the levels are supposed to be 3mm??? DAMN, now I can't remember where I set them. BUT that would explain the somewhat poor mileage and non-responsive feeling until I crack the throttle a bit more.

What a pain in the backside just because I can't remember...and/or looked at the wrong book. ARRGGGHH

 

I Have not had that much of a problem using vinyl tubing stuck in the drain hole and curved up to float level. as far as setting floats. a clear vessel would be even easier.
LB

 

Maybe use it just for setting the floats and not as a permanent replacement for the existing bowls.

Hell, why not? Or maybe point Len in their direction... there was one piece he was going to talk to someone about fabbing some up, until I found a site that actually had them in stock.

Of course, those add-on float bowl nipples make using the tube SO much easier. If you haven't seen the file on setting the fuel levels (I referenced it a couple of posts up), you'll see them listed in there, along with the part number.