XJ750J My bike runs for a mile then dies, carbs look great.

Hey! I bought my XJ750J a couple weeks ago and am having trouble keeping her running. I looked into the carbs and everything looks great, a little varnish but nothing bad. The floats jets needles and seals are all great. My dad had a 650 and it was an awesome bike! I asked him about the troubles I am having and he just said "hmm, sorry about your luck". I need your wisdom gang! Any ideas?

Sincerely

Omi-

 

Plugs/spark? Petcock/Filter?

 

Re: XJ750J My bike runs for a mile then dies, carbs look gre

I am getting good flow out of the petcock, and the air filter that was in it was filthy dirty, it was caked on there I should actually get you a picture. But anyway, I got a new filter in and it still runs for a while and once I get her on the road she putts out after a mile and I start pushin her back. The plugs look great and have good spark. Aside from a little timing chain slap under the valve cover this is the only problem... Think maybe it is a loose ground somewhere? I pulled the carbs and took a peak in the bowls and there really isn't much varnish at all, just a little in the corners.

Can't wait to get my baby back on the road, it might have been only a mile but man it was a comfy ride.

-Omi

 

Re: XJ750J My bike runs for a mile then dies, carbs look gre

Sorry I forgot all my other info for you guys.


1982 XJ750J
46,000 Orig. Miles
All stock
It's got that cool digital-ish dash
Inline 4cyc
Shaft drive

 

I have a little Suzuki 2001 LT50 4 wheeler that does the same thing. Goes about 50 ft then dies. Like its out of gas. fires back up again for another 50 ft.

New fuel line, petcock, floats and valve, plenty of fuel, adjusted the fuel level up and down... It's been a mystery for over 2 years now and the thing is still sitting, while my boys are out growing it.

 

Open your gascap, ride down the road, and post the results. Your problems sound like a classic case of a plugged vent in the cap.

 

In both cases I agree; sounds like a plugged gas cap vent to me. Either that or you've got a vacuum line issue; did you try it with the petcock on PRI?

I'm sorry to say my friend, if you can see varnish in the corners of the bowls, there is varnish and/or corrosion in places you CAN'T SEE.

While the cause of your immediate problem doesn't sound like the carbs themselves, eventually you are going to have to get them cleaned out.

Oh, BTW Omega; you can save a little space in your sig; pretty much everyone here knows an XJ750 is an inline four with shaft drive.

Get yourself a shop manual (factory preferred) and welcome aboard!

 

Yep you will have to get into the carbs, you can bet on it. I can't add anything on the stoppage as I'm fighting a similar problem on a 650. If the fuel vent is clear and running on prime fixes the issue than a petcock rebuild is in order. The 650 I'm working on runs for about 10 miles then it quits. Flip the Ignition switch from on to off to on and it will start right back up and run fine for the rest of the day. Ignition switch has been replaced with a new part. Its been doing this for the better part of a year! I just scored another TCI so thats the next experiment. Welcome to the fold and good luck with your new bike