1982 xs400 pulsing idle

Hello everyone,

I just got myself an xs400j about a month ago (first bike ) and have been fixing it up. Been getting some great info and advice from previous posts and topics, but I'm stuck . I can get her to start fairly easy (1st, sometimes 2nd try) thanks to the wealth of knowledge on this site. Idles all day, but pulses :| . RPM's ok under 1300, but when I try to give her some gas (throttle or choke), she bogs down, lights dim, sputters, sometimes backfires and ultimately dies if I don't ease it back. :cry: A little info on what's happened...

Have done:
- I cleaned and rebuilt the carbs.
- Cleaned again....
- and again.
- Checked the wiring of the ignition system (seemed to check out).
- New plugs, wires, and caps.

Have not done...yet:
- Checked compression (don't have a gauge)
- Synced carbs (need the YICS tool)
- Figured out what to do.

Thanks for any and all advice/ help.

 

Maxim-umm,

You are asking a question in the wrong forum. This is the XJ Chat Forum. A Moderator should move this "other motorcycles" forum.

Someone there should be able to help.

MN

 

woops , thanks. Overlooked that. Must have got lost while browsing around. :lol:

 

I posted here tons for my 83 400, i think it's fine here.

The 2 cylinder 400 doesn't need a yics blockoff tool Max.

 

do a sync then play with the idle mixture, sounds like it might be lean

 

As long as it's the YICS "half an XJ" you're in the right place, and it is.

Borrow a compression gauge from an auto parts store like AutoZone that loans tools.

Check and adjust your valve clearances (again, same as the XJ just access is a bit different.)

KrS14 is correct, that motor doesn't use a YICS blockoff tool.

You need to sync the carbs; but be sure your valves are in spec first or you won't ever get them sync'ed.

THEN start fiddling with the mixtures as Polock suggests; does sound lean or way out of balance.

 

Thanks for all the great info and advice.

Unfortunately, while cleaning the carbs last night (after this post) I dropped them, had a few choice words and phrases, and found one of the float posts broke. Then I had a lot more words and phrases to say.

I just posted in the "other motorcycles" category asking about other carbs that I could swap out with mine, more options means easier time finding what I need. If anyone here has an idea I'm all ears. Thanks again.