Newbie buys a moneypit?

Greetings!
A little intro: I'm a moto newbie who purchased a 1982 XJ650 Maxim a couple months ago for $750. It was clean, sounded good to my ears, the owner spoke like a gearhead I met out on a ride (I'm a cyclist) around 25 miles from his home. I also met his wife and kid, so, based on my limited, unlicensed, superficial criteria, it seemed like a good deal.
Okay, so, bought the bike, got my license and papers, picked up the bike a couple months ago.
Started up fine, though the idle was uneven.
First thing I noticed is that the bike didn't track well. I couldn't keep a line. Then, the front forks shimmied when applying the brakes. I figured best case was bearing adjustment, then bearing replacement, and worst being an ovalized head tube. I also noticed that the forks seemed to bottom out every time I came upon an irregularity in the road. (To call them 'irregularities' in Brooklyn is laughable.)
I was riding around locally when I stalled at a light. When I tried to start her up again, I got nothing. The battery was new, so I checked the circuit box and found that the 20v main was blown. Replaced, restarted, but I decided to bring it to a local mechanic to go over the electrical system and etc. He's not a Yamaha dealer, but the mechanic is well respected in the area.
Sorry about being longwinded -- I'll try to trim down. The mechanic checked the steering bearings, the carb pack, and tuning.
It needs new shocks springs fore and aft.
He checked the carb pack, cleaned jetting and float bowls, and tuned it up. He wasn't able to adjust the MCU properly, and the spark plugs are running VERY lean. The idle runs at a hair over 1000rpms until I've been riding for half an hour or so, at which point it'll notch 1500.
Tom suggested that I have a Yamaha Dealer check the tuning, TCI unit, and valve clearances.
I've gained some quick familiarity with this stuff (through a Clymer book) I'm trying to gauge what I could expect to spend in a best case/worst case scenario. I vascillate between thinking I might be able to get new shocks and a new TCI unit and get lucky, and thinking that my distaste in cutting and running is the product of false hopes and injured pride in buying a lemon.
Thanks in advance.
Scott

 

Cheer up dude! Shocks can be had on ebay for a song. The front forks can be rebuilt and there are many on this site other than me who can walk you through the procedure. Sounds like your carbs need sync and your valves definately need to be checked. You can check those yourself in 2 hours. I don't know where you are geographically but a carb clinic is what you need. There are regular ones in Canada and the US.

While the clymer and haynes manuels are good the XJCD is the best. It can be purchased here: http://members.tripod.com/dave_jack/id47.htm#xjcd

Don't worry about the TCI. When they fail it is a case of not running at all or feeling like only 2 cylinders are hitting. First I would check the valves and see if any are tight. IF that checks out then I would sync the carbs. This is best done at a carb clinic where you have experienced help. On the front forks look for fork oil seeping past the fork seals. The chimmy you mentioned sounds like it may be the brake rotors. If these get to hot from over braking then they warp. This will make the front wheel shimmy when the brake is applied. If you feel the shimmy other than when the brakes are applied then check for front wheel bearing play. Put the bike on the center stand and place something under the engine to keep the front wheel in the air and move the wheel from side to side and back and forth. That's enough for now. Check back with us and let us know what your find.

 

Thanks guys, I'll definitely check out the cd.
Blue Maxim, I googled "carb clinic" but didn't see anything. I take it that there isn't a central location to find out about them. I'm in NYC for what it's worth.
Scott

 

Sorry, should have been more specific on that. The carb clinics are put on my members of this forum or the XJ owners mailing list. Rex Smith and I do one in Dallas Texas and there is one in Northern and Southern Ontario and the bay area of California each year. There was recently one in Vermont and I would like to have one in Memphis. Looks like the Vermont one is closest to you but it won't be held until October. Just keep a check on the forum and look for one near you.

 

I got some photos from my mechanic of the bike's internals.
http://www.katzinteractive.com/motophoto/index.htm
If anything catches your eye (other than the mucky brake fluid, which has been replaced) please pass it on!
Thanks,
Scott

 

One other thing that causes head shake - scalloped tires. Infact, I'd look there before I looked anywhere else.

Engine symptoms sounds like tight valves - as they warm up they seat slightly differently (expand) so that would explain the idle. You probably also notice that if it gets really cold the symptoms are more pronounced.

Steering bearings are a common thing - I have yet to replace mine but I do know they need doing - you can replace them with tapered bearings for not much more and they're supposed to stay smoother longer. To test the bearings put the bike on the centerstand. Have a friend sit on the pillion seat to keep the front tire off the ground. Move the bars back and forth - with no weight on them you'll feel notches if they're shot. Another cheap solution is to make sure that the head is tight - over miles and miles of irregularities they will loosen a hair (and wear)... snug them up and if it goes away good.

Suspension - make sure you've got the rear sorted out first - what the maxim will do is wallow/pogo in the rear when the rears get worn - that'll push the front of the bike around alot - very disconcerting. The rear shocks are adjustable, if you're a larger fellow like myself crank them up. You're aiming for about 2.5 inches of sag. If the shock is working properly 2.5 inches gives you enough preload that you won't top out, but will still have the best part of the range for absorbing irregularities. My bike is nearly bang on 2.5 and it's running pretty well. New and fancier shocks are available ( progressive IIRC makes some nice 2 or 3 way adjustable shocks with external resevoirs... if anyone is looking for a birthday present... )

To set the sag - stand over the bike - have a friend measure the distance from the swingarm shock mount to a fixed point ( like the grab bar). Sit on the bike naturally. Have them measure again. Subtract - if it's more than 2.5 crank it up, if it is less back it off.

After you do the valves a carb sync/clean might not be a bad idea. You can try something like seafoam but at a certain point the only way to get them properly clean is to disasseble and clean with a very soft wire like sodder ( the small holes are the most important ones to clean as they are the most affected by varnish buildup or rust particles).

As this bike is new to you also check it has a fuel filter and that it is clean. I don't think this has much to do with your current problems but it is a good preventative maintance thing to do.

Also check the inside of the tank for rust. Always keep your tank full when storing short term, or for long term ( several years) vacuum packed empty. Fuel stabilizer is cheap and buys you storage time. A full tank is less prone to rust as it doesn't get oxygen exposed - nor can water condense in the empty portion of your tank. No water or oxygen means little to no rust developement.

So the forks - it's not a big job. Unlikely the springs are completely worn out but if you want to do the work nows not a bad time. Do the seals look ok? If you see signs of weeping then perhaps a rebuild would be enough ( fresh oil and the right volume with new seals)... if the springs are shot then you'll have to decide if you have enough money to do it - I'd be hard pressed to do the whole bike in one shot on my bike budget. Especially after buying one.

What do the tires look like - if they look dry or near the wear bars make that your first purchase. You can get good tires for not that much... you can get really good tires for marginally more.

Anyhow - have fun and keep us posted - we'd love to see you on the road.

Woot.

 

One other thing - what did the mechanic say about the blown fuse? What caused that? While you've got the seat off check out the air filter...