Help! Need advice on what I should look into to fix new old XJ750 Maxim.

Hey guys I just picked up a 1982 XJ750 Maxim for $80 CAD as my first bike (technically didn't even cost me that much since I traded it for some work I did for a guy), but it hasn't been registered since 2004 and I don't even know the last time it ran, it apparently would run for about 5 mins and then die when it did run, it's been sitting outside for quite a long time as well.
I'm just wondering what I should look into repair/parts-wise to get it going again, it has leaky fork seals, and I can't move either the front or rear brakes at all, but I have no clue about bikes or what I should look into to get it running so any advice would be greatly appreciated.

Here's the bike.

 

Hi @Elter - welcome to the party!

That bike looks pretty nice and complete to me (relatively speaking). I don't see any reason why it would not be able to live a good life again.

If it were me, I would want to hear it run first. For better or worse, that means bringing the carbs back to a good running condition, which is often the most difficult part.

How would you rate your wrenching skills in general??

 

Thanks Dan, I consider myself fairly competent, I've never been afraid to tear stuff apart on my (or anyone else's) truck but I've never worked on bikes before and from the thread I was reading on here about rebuilding the carbs it seems like a pretty decent sized undertaking, is there anything else I should look at to get it started that might have died from sitting (other than the battery, gas and oil)?

The bikes odometer says 58,000 km and I heard the guy who owned it wasn't much of a mechanic.

 

Of course you can always take the carbs off, shoot some starter fluid straight into the carb boots and see if it will run for a second or two. Its a little bit of a violent adventure, but that would tell you if the ignition is working, the engine has compression, etc.

The carb overhaul is a decent sized undertaking. However, there is plenty of information here to pull it off. I think the key is that you need to have meticulous attention to detail to make sure everything is clean - i.e. "The Church of Clean". These devices aren't that complicated, three circuits, but there are very small passages that all need to be free flowing to work correctly. Auto application carbs have enormous passages compared to these carbs.

 

Ok, might try and give that a shot, where would be the best place to find parts to (very carefully) rebuild the carbs? I figure they're probably pretty plugged up from 15-20 year old gas.

 

@chacal from xj4ever is the best place to get parts. See the link in the upper right of this page.

 

making sure the motor is not frozen would be a good place to start before spending any money on it

 

Well good news, I stuck it in a high gear and was able to roll the engine over from the wheel so at least I know it's not seized up.

Can I put a car battery on it for temporary testing until I can pick up a new battery?

 

Also looks like someone did some custom fuse box work

 

Yes.

 

That’s some real nice work. You will probably need to put that on the list of stuff to fix someday.

 

It's a beauty! I started with an '82 750 also and have been on a short and steep learning curve about these bikes ever since. The 3 biggest struggles I had (still have!??) as a newbie...carbs as already mentioned. They are mysterious and complicated, then all of a sudden make sense. Wiring - on a bike that has sat, you'll have corrosion in lots of terminals to clean. Get a wiring diagram, and learn the ignition circuit and the various relays involved and how to test them. Valve adjustment - first time is overwhelming, but after a few its old hat.

I think the '82 750 Maxim is one of the ugliest XJ's, but they've really grown on me. Oh, get a manual. The Haynes one is pretty good. Good luck!

 

Lol I suspect the issue I'm gonna have most of all is cash flow to buy parts.

 

No need to dump lots of money into it til you know what you have. The carbs are a fine place to start, and the cost might only be float needles and gaskets. You can get new, cheap carb boots between the airbox and carbs on ebay and they are actually well worth the cost for the hassle they save installing the carbs.

While you are reading up on carb cleaning, you could check compression to make sure you don't have any major issues, and check spark, but I bet since it was sitting outside all that time you will be fighting lots of corrosion. Again, that isn't necessarily new parts, just lots of labor.

Here's a link to the carb info. If you don't like to read that much, search for posts on carb cleaning with photos, ask questions, you'll get it.

https://www.xjbikes.com/forums/threads/in-the-church-of-clean.14692/

 

I figure getting it running shouldn't be too bad, but once it is running I'm gonna have to replace almost everything brakes-wise (which is gonna be the pricey part) and it's definitely gonna need new tires

 

Can I save a bit of money with an eBay gasket kit or should I just pay the little bit more and buy from Len to be on the safe side?

 

More good news, didn't even take the carb off I managed to get it running off a car battery, and some starter fluid sprayed into the carbs, it seemed to continue running after that (at least until the probably undersized fuse blew) but is burning pretty blue, but I'll have to see what that does after an oil change