New to me XS, idles HIGH, hard to kick over

[ninskrillz]

Hey gang,

Just got myself a new XS! An early model too, 1971 xs1b! It's got its problems, and I need some help to find solutions. So lets start from the beginning... I bought the bike from the third owner. He says it was the perfect runner, started first kick every time, and the strongest he's ever owned (out of five). It came with a huge stack of reciepts for parts the second owner bought including: PMA, PAMCO, and Mikuni VM34's. When I go to see the bike, first thing he tells me is he has bad news. Some idiot who came and looked at the bike allowed the ignition to stay on causing the "Ultimate" coil to burn up. I borrow the guys meter; yep the thing is toast.

So after reading through the massive stack of new parts this thing has, talking with the guy, going over the rest of the bike, we come to an agreement on a fair price for the bike. Load it up, drive it home, cool. Order a new coil, and wait.

Fast forward to today, the coils coming! I ditch work a little early and just as I arrive, the UPS guy is pulling up. Meet him in front of my house, get the package, sweet. Rip that thing open and pull out the coil. Quick test with the meter shows 2.6 ohms. Sweet. Bolt it up, connect the wires, put the tank back on and go to fire it up. Did I mention this is an early model? No starter, ok lets sweat a bit. Kick it about 7 times to no avail. About the 8th or 9th time, its sputters alive a bit. 10th time the bike sputters some more then VROOOOOM. Out of nowhere the thing just roars to like 3-4k rpms and its not letting up either. The left cylinder coughts up a bunch of black smoke for a second then its clean. I turn the choke of, it sorta helps, not really. I try to give it throttle, not much happens.

Sooo. Is does this sound like just an idle adjustment or what? Ive never had a bike with roundslide carbs so I am a bit at a loss on how to adjust/tune them. The guy I bought it from lives in the mountains, and I at sea level, so he has about 1000feet of elevation on me, could that be causing air issues? Are the idle screw the brass screws with the springs on them on each carb? Thanks in advance guys!

edit: PIPES, forgot to mention the pipes. I believe they are 1.5" headers with mikes xs dunstall mufflers, and i believe the baffle material was removed for more open exhaust.

 

[fredintoon]

Hi ninskrillz,
like you I don't know nothin' about VM34s but here's what I'd do:-
First, read up all about them from everywhere I could.
Second, take them apart down to the last little piece and clean the bejasus out of them.
Third, put them back together, put them back on the bike and see how they work.
Hints on carb cleaning.
Work on one at a time so you'll have a clue about reassembly.
Work on them in a big cafeteria tray to keep those tiny parts from falling onto the floor and disappearing.
Any good carb cleaner will work.
Wear safety glasses rather than squirt yourself in the eye.

 

[weekendrider]

This may help?
www.amckayltd.com/VM34-36.pdf

 

[ninskrillz]

Alright I've a little update. I pulled the UNI's, to find the left slide was sitting way higher than the right. Pull the tank, fiddle for a sec, and it snaps back down. Apparently it was stuck on the tank. Kick her over, idles crappy from fidgeting with the idle screws like a noob, but it isn't waking up all the neighbors so thats a good sign.

Pull the filters again, bottom both of the slides out, and give each idle screw a full turn. Put filters back on a fire it up, still a little slow. Give another half a turn, still a little bit slow, but idles without giving it throttle. Another half turn and it's pretty good. At this point its nice and warmed up, give it some throttle, hangs at about 2-2.5k rpms then creeps back down. More throttle, more hanging, this time it doesnt creep back down. Dial back each idle screw 1/4 turn. Creeps back down to ~1k and holds.

At this point im just ready to take it for a quick spin, regardless if im pushing it back or not. Take it around the block, and when I get back its idling at about 2k again. Another quarter turn of the idle screws back and it seems good.

Take it out again and everything seems ok. Left side is kinda sputtery, and smooth delivery of full is come and go. It seems smoother at higher RPM's, and the left side issue isn't as severe.

So, guess this wasnt avoidable. I'll pull the carbs this weekend, give everything a through cleaning and set the idle properly and hopefully this thing will be good to go.

 

[ninskrillz]

Cleaned out the carbs, well carb, the right side carb was immaculate. the left side, on the other hand, had a bunch of gunk in the float bowl, main jet, pilot jet, and needle. Got that all cleaned up and put them back on the bike, still waiting to set the idle, as I ran out of daylight.

It also occurred to me that i probably need to clean the needle jet as well, but I'm stumped as to how to get it out. Any tips on getting it out?

I also was unable to remove the retaining plate for the needle, so I just let the slide/needle/top dangle as I cleaned everything. Any guidance on how to remove it? I tried turning it with a small flat head as I compressed the spring, but was unsuccessfull, it got to a point where the cable wasnt thin enough to allow the plate to move any more.

 

[ninskrillz]

a picture to motivate the helpers!

 

[figure8]

For the needle jet, screw in a main jet and gently tap the needle jet up out of its slot..If you look close you'll see the needle jet just slides in there, the slots in the needle jet match up to the little tabs in the port. Once you work it up a little just grab it with pliers. Don't seat the main jet, just a turn or so. The main jet will have to come off before the needle jet will come out.

 

[ninskrillz]

For the needle jet, screw in a main jet and gently tap the needle jet up out of its slot..If you look close you'll see the needle jet just slides in there, the slots in the needle jet match up to the little tabs in the port. Once you work it up a little just grab it with pliers. Don't seat the main jet, just a turn or so. The main jet will have to come off before the needle jet will come out.

does it come out through the top or the bottom? any tips for reseating it?

 

[figure8]

It comes out through the top. You can push it back in most of the way with your finger, the main jet will help seat it when you put it back in.

 

[ninskrillz]

It comes out through the top. You can push it back in most of the way with your finger, the main jet will help seat it when you put it back in.

Thanks amigo

 

[figure8]

No problem.

 

[ninskrillz]

Okie dokie. Got the bike to idle pretty good. Still has a few issues.

Firstly, choke doesnt do much for first minute or so, have to hold the throttle open slighty to keep it going. After it warms up a bit the choke kicks in and it sits at ~2500rpm.

Second, after the bike is warmed up and idling, it sometimes hiccups down to ~750-800rpms and if i dont give it a blip of throttle it dies.

Other than that the motor runs strong through the whole powerband. These symptoms sound familiar to anyone? Any input obliged!