17th May 2007, 09:00

I have a 1982 Midnight Maxim which I love, except that it goes through time periods when it doesn't run well. During these times it will typically cut out and sometimes even die if I can't keep the RPMs up. If it dies, it will usually start back up in ten or fifteen minutes; then it usually runs fine. Any suggestions?

22nd May 2007, 08:57

I just bought an 82 XJ650J Maxim yesterday for $1600, and I am picking it up at the end of the week. I figured I would do some checking today, because the price seemed high for such an old bike. The current owner did put new front and back brakes on, as well as new tires. All the chrome is in excellent shape, it starts right up, and there are no electrical problems. I am extremely glad I found this forum. It sounds like a phenomenal bike and I can't wait to pick it up.

22nd May 2007, 20:43

Original reviewer here - as for the rear brake being "non-existent". I disagree, never a problem on mine.

24th May 2007, 13:37

I have owned an 81 650 Maxim for about 9 years now. I have had others during that time, but the Maxim is my favorite. As for the person who was "rapping it up" at 50000 rpm, not even close. Your redline is about 10,000 rpms. I have found 4500-5000 to be kind of a dead spot. Real power is made above 6000 rpm. Hang on though. Watch out for speed wobbles at 100+. I have owned hot rodded cb750's and they are not even close. You should be able to surprise anything other than a newish sportbike.

26th May 2007, 10:48

I owned an XJ650RJ for several years, and put lots of miles and work into it while I owned it. I hated to get rid of it, but didn't have any place to keep it anymore. Anyway, I'll attempt to answer some of the questions I've read on here.

The gas tanks on these bikes were notorious for rust. If your tank isn't coated on the inside, coat it. It will save you lots of head aches later with cylinders not firing, poor performance, carb cleaning etc.

Check the corners before wasting your money on a tank. Especially if one has been sitting. I've seen a lot of tanks look great on the outside, but still have rotten corners.

NGK makes spark plug boot replacements for when the old boots start grounding out, no need to replace the whole coil unless the coil itself is bad.

An oil leak on the top of the motor shouldn't be that bad. If I remember correctly, there were four half-moon plugs in the cylinder head at the ends of the camshafts, and are accessible by taking the valve cover off. You might start with them.

If you go deeper into the motor, have a good repair manual. The timing, although marked fairly well, can be tricky without guidance. Getting the cams, gears, chain, and tensioners all lined up to put the bolts in can be tedious. I recommend a second set of hands.

A bike that has been sitting for a while can have carbon flakes in the cylinders, causing poor valve seal. I noticed a big difference in performance after I did a valve job to fix this.

Also, I remember when I first started riding this bike, I shifted it like a car (3000-4000) RPMs, and constantly would be left by CX500s, CB750s etc. Then I learned to shift about 8000-9000 RPMs, and I never had that problem again! That bike went from a kitten to a tiger just by changing my riding style.

Also, for you guys looking for stock exhaust, I never found any either except for $800 from Yamaha. The best I could find in aftermarket was 4 to 1 pipes, but I wanted to keep the twin chrome pipes out the back. So, I decided to make my own mufflers. The headers where they attach to the mufflers are just under 1.5" OD. So, I took two 6.5" pieces of 3" exhaust pipe and made a couple washers for both ends. Welded the two headers from each side into one end of the 3" pipe, and a 1.5" piece of exhaust out the other end. If you 45 the end of that pipe, you can 45 another 1.5" and run it straight into the stock chrome pipes on the back. Get pretty welds on it all, and it looks very good on the bike. Got lots of complements on the sound, and performance was great.

The only issue I had after I made those mufflers was leaning. You can't lean quite as far, but enough for most riders needs. My headers were rusty. So, I painted them and the new mufflers flat black up to the chrome side pipes. Krylon BBQ high heat black matches the flat black on the motor perfectly.

Also, if I ran across good deals on electrical parts, I'd snatch them up. I noticed a lot of the plastic in the electrical system componets got very brittle with age, and new ones are very expensive. $22 for a new start button (no spring or housing) from Yamaha, and if you get in a position where you need to change fuses, the fuse holders will snap without much pressure at all. Be careful with them.

Hope that bit of remembering helped some of you.

9th Jun 2007, 17:16

I just bought an 82 XJ650 for $300, but one cylinder is not firing. Also, it is hard to start cold and does not like to idle unless the choke is on. I've cleaned the carb twice, checked the gas lines, and spark plugs and wires. The tank is very rusty inside. Does anyone know what the problem might be?

29th Jun 2007, 18:42

I'm looking at getting a Maxim 650... it'd be my first bike.

I want to check the oil. Maybe a dumb question, but how to I check it? Whereabouts on the engine would it be? I have a car, but can't think where I'd look on the Maxim.

1st Jul 2007, 02:46

Hey guys, love this forum. I didn't know anybody actually likes these bikes. I got a 81 Maxim 650, FOR FREE; this guy was bringing it to my shop that I work at to drop it off for our junk guy that comes once a week to pick up "scrap metal".

I just asked him if he wanted to give it to me instead of throwing it away like it was garbage. I had the title and keys in my hand a week later. I got it to start with some starting fluid the day I got the key. No luck running on gas just yet. I finally got it to my house today after it had been sitting at my shop for a month. I can't wait to ride it; from what I've read on here it sounds like fun. This will be my first street bike. I have grown up on dirt bikes. I am sure I will love riding this bike.