81 Maxim 550 ugh!!

This is my first post on this site. I have an 81 maxim 550, it's in great shape. I bought it cheap because it had an issue my dad and I thought we could fix. Well it turns out that its tougher than we thought. intermittently the engine will loose about half of its power and make a louder noise with out the acceleration to accompany it. while in this state the engine will make small revs in time with the turn signal or when I apply the brake. So I figured that it's an electrical problem. I have torn apart the carbs and cleaned the crap out of them. I have had them professionally synced. So I am going to tear it down to the minimum wiring possible and start to cafe it. Any help would be most appreciated. Thanks

 

Sounds like some kind of wierd grounding or power issue that involves the TCI. there are several grounding spots on that bike, have you taken them all apart and cleaned?

 

-what are you using for a manual?

-have you checked/adjusted the valves yet; and done a compression test? (Unrelated but equally important.)

You want some dead serious advice? GET THE BIKE RUNNING (and stopping) before you tear into it to "cafe" it. Otherwise when gremlins pop up you'll have too many variables to deal with.

 

I'm using the Clymer service manual. Mechanic said valves were A-ok and I haven't done a compression test yet. But do you think the valves and compression would cause the issue I'm having? Especially because it's intermittently happening.

 

I also haven't gotten to all the grounding areas yet but am making progress to it.

 

No, I said it was unrelated. I also said it was equally important. If you want to actually ride this bike, get it running first THEN start cutting it up. Otherwise you'll fight with it until you give up and part it out or sell it.

The Clymer is OK but the photography and diagrams suck. PM me with your email address and I'll send you some relevant stuff from the factory book, it sounds like you've got ignition or battery/charging issues.

Meanwhile, the bad pics in the Clymer is why I did this: http://xjbikes.com/Forums/viewtopic/t=14827.html

Don't trust the mechanic who said the valves were "OK." I've got $5 says they're NOT. Wanna bet? Check them yourself. CHECKING is easy (as is doing a compression test.)

You don't want to sink a whole bunch of time, effort and $$$ into a project only to discover you've got a burnt valve (or worse.)

Viable motor and solid rolling chassis first; THEN mod away. If you're at "ugh" then don't start trying to "build" the bike.

 

I just got an 82 XJ550 Maxim going well. Took the whole summer. Be prepared to spend some coin on the bike too. Carb kits are going to set you back about $120, but you will need them. I can't say what setting the valves cost as my Dad did those for me, but figure at least $30 for a gasket. Coils and wires if you need the total about $200. Fork seals are about $30, and a bottle of ATF for the forks can be had for $10. The engine side intake boots are about $100 too. You will need a YICS tool to balance the carbs; EBay that for $40ish. Spark plugs are probably the cheapest parts you will buy, $20ish for the set. And time. Figure lots of time into it.

I am really not trying to scare you here. Just relaying what all I could remember doing to the one I got for my girlfriend. It runs really well now, maybe not as good as some, but much better than when I got it. I am currently opening all the switches and cleaning them out, removing what corrosion I can, applying electrical grease and reassembling. The switches were all very stiff due to corrosion.

Its been quite an effort to get it this far, but man does it move! Nothing like the 08 Triumph Rocket I have, but still very fast and fun bike. I do still have a lot of tinkering to do, but most of the big problems are worked out. When she is finished with it as a learning bike, I may turn it into a full on cafe bike.

Stick with it, read as much as you can here, a and pay double or triple attention to those carbs! They will break you if you aren't careful.

Have fun, and good luck with your endeavors.

Matt n

 

That really sounds like your TCI and your coils are involved. The turn signal or brake is drawing off power but it isn't enough to effect a coil by itself unless it's related the signal coming from the TCI which is sensitive to small changes in voltage when something isn't right. You could try opening up your TCI box and using the tutorial to track damaged components or you could pick up a used one and see if that solves your problem. If not you could always turn it around and resell as they are always in demand. Just don't let someone rip you off they are all over the place on price and you don't have to spend $100 on a used one, but you will see those prices.

 

The problem is likely nothing more than a soggy battery and a corroded fusebox. But the point we're all trying to make is that there's more to this than just getting it running.

I paid $2 for my spare TCI (eBay mis-listing) and no it's not for sale.

If you're paying $20 for a set of plugs then go to AutoZone. I get NGK D8EA's (recommended plugs for the 550s) for $1.99 all the time.

Real fork oil works better than ATF, and isn't expensive. I'd recommend 15W.