85 Maxim 700 - Idle RPM/electrical issue

Hi everyone.

Just purchased my first bike, an 85 Maxim 700. Sorry for the long story, but here's some activity since I got it.

A friend did the initial test drive and said things looked good. We did an oil change right away and topped up the brake fluid. We noticed it idles pretty low, even when warmed up, so I tend to have to hold the throttle slightly at lights. It wants to idle at 700-800, even after adjusting the throttle cable. I was recommended getting a new one, which I did, but have not had it installed yet.

I got a bunch of practice riding in to prepare for my skills test, and things were fine, but when I went to take my test, the bike wouldn't start. Battery was dead. Jumped it, and it started, but when I got to the testing centre, it wouldn't start again. I ran to the nearest auto parts place and got a new battery. Popped it in, and it was good. Did my test and passed, then rode home.

A few days later, I was out riding with a friend. We stopped at a light that is on a slight hill. I wasn't holding the throttle enough and it sputtered and died. I tried to start the bike again, but got nothing. When I pulled off the road, I noticed that none of my lights were on.. I rolled the bike into a parking lot and tried to jump start it but it wouldn't. While waiting for my friend to come jump the battery again, I turned the key on one more time, and sure enough things lit up, and it was able to start.. Except now I have to really gun the throttle to get it going..

I have plenty of fuel. I have been running carb cleaner through it with each tank, and I've gone through about 4 tanks of gas now.

Was hoping someone out there would have some suggestions at what I should be looking at..

Thanks in advance.

 

Welcome to XJBikes! And congrats on your XJ, they are great bikes.

You say you adjusted the throttle cable, did that include turning the idle knob (big threaded knob behind carbs in between #2 & #3 carbs) to try and raise the rpm's?

Sounds like you might have an electrical issue like a loose connection, ground etc. Since it went from no lights, no start, to fine.

You won't get much benefit out of carb cleaner being run through with the gas. Although it can clean up light varnish, it CAN'T clean up clogged passages because it will never be drawn through them. Since they are clogged it will just go through what is not clogged and the rest will stay jacked. If adjusting the knob doesn't bring up your idle (it should) then you will need to clean your carbs. There are several good threads on here about how to do it, and even if they don't need it today they will eventually.

I would suggest getting a manual or two to help you with all the maintenance. Be sure and check over everything. Remember that bike is 27 years old and your life depends on it being 'right'. Start with your brakes.

 

Thanks MercuryMan.

Bike's going into the shop for some work tomorrow. Carb sync, new fork seals and boots, new throttle cable. When the existing throttle cable was adjusted, by buddy was adjusting it up by the grip. Pretty sure he didn't do anything with an idle screw.

Brakes are fantastic on the bike, was one of the things my friend commented on when he first test drove it. Needs new rubber come spring though.


Thanks for the advice, I really appreciate it.

 

If your jump starting from a vehicle, make sure the other vehicle isn't running. The extra amps from the other vehicle's alternator can damage your TCI.

 

Just a thought for you to consider:

I had a very similar issue that was very hard to debug, and it's possible you have the same thing. If you are having poor electrical system performance, you can find that the bike will sputter and die at low rpm, and that it will be very hard to start in general, and it will go through batteries rather quickly.

Go through your manual and check all the voltages for the alternator. This is what I did and I noticed that the connector from the alternator to the rectifier was shot, melted because of heat. The heat was from very bad connections, meaning that the voltage of the whole system was low. At idle, this is bad because it will mean you're running the electrical system totally off the battery, since the alternator doesn't put out much power at low rpm.

Check your electrical system, especially the charging system. There was a good flow chart for this from electrosport at one time, but I don't have the link right now. Charging system problems can make all kinds of problems appear that seem to be other things.

 

Be sure this shop knows the valve clearances need to be in spec BEFORE sync'ing the carbs.

It sounds like you need to catch the bike up on 27 years' worth of neglected maintenance. INCLUDING the brakes, no matter how "fantastic" they "feel."

You're going to need a manual, and to learn to do some of the maintenance yourself. Paying a shop to play "catch up" can get real expensive, real quick (unless they have no clue, in which case they'll just take your money and not actually do the bike much good.)