New to posting on this forum

Hi all,

I've lurked this forum for info so now I'm posting and possibly adding back knowledge from my experiences with these bikes.

Back story.

I bought a 1980 XS650 of off a farmer (from his front yard, $500) back in college (early 90's). I rode the snot out of that bike as a daily driver (until the snow would get too deep, then back to the car) for years. I was not kind to that bike, but it would not die. Usually had to clean the carbs every other spring. I would never winterize it and just leave it parked outside 365.

I eventually gave it some tlc, cleaned, painted, modified etc. and let a friend's girlfriend take my now fresh shiny bike for a ride. She assured me that she had ridden for years on a Goldwing. I live in the rural ag lands of Niagara, with big ditches. Her first turn led her straight into a ditch. About 1km from my place. We caught up to her, she was fine, but my bike was on it's side, half under water, still running. The above water cylinder just sucking that water in the carb of the under-water cylinder. Bluh, bluh, bluh, bluh...

After an oil change, it never ran the same. So it eventually became a dust collector in the garage and I eventually sold it for $300.

So this summer I caught the bike bug again. After getting sick and tired of hearing me blither on "It's a nice day for a ride", my wife told me to get a bike so she wouldn't have to hear about it any more.

I seriously looked at a 2009 Buell Blast 500. It was kind of fun to ride, but it sounded like a crappy ATV and it had previously been used at a riding school in Florida. Clutch crappy, brazillions of scratches etc. So I passed.

The next bike I looked at was a fresh listing on Kijiji, it had a ton of calls, but it was raining out, so I was the guy who showed up. It was a 1986 XJ750X... I never heard of one before. I just thought it was a regular maxim until I saw it in person. The guy was asking $650. It ran, had a horrible brush paint job, skull stickers on it, no baffles on the Harley sportster slip-ons.. which leaked at the joint, homemade vinyl job on the seats, ran, but was gutless, started right up though, needed choke to run even when warm, but it didn't smoke at all. All the guages worked, tires were ok, fork seals ok, brakes has lots of pad, rear drum marker showed a lot of pad left, plastic (chrome) around rear tail light was butchered for some failed custom idea, oil was black (no milk), rad drain had a drip leak, from marker light didnt work, brake lights were sketchy with the foot brake, front brake lever had a lot of play before it grabbed, the starter button would stick on after the bike started, all the buttons on the handle bars were stiff and would stick, etc.

So I bought it for $550.

Spent a week cleaning and lubing EVERYTHING, cleaning electrical contacts and coating them in dielectric grease, replacing light bulbs, replacing gas and fuel filter (with an 80Hp lawnmower one from the hardware store), changing oil & filter, cleaning air filter & re-oiling it, sourcing and replacing 5K Ohm plug caps, spark plugs, pulling the carbs. I never worked on a four carb system before, but this forum (and others) helped me out. So once the carbs were cleaned (full bottle of carb cleaner), reassembled, bench synced (using a pin under the throttles one at a time) and reinstalled, she ran great. Though a bit rich.

I pulled the Harley slip-ons off, made baffles using washers, nuts and threaded rod, welded them in. Cleaned the joint and used that exhaust gasket paste (I can't remember the name). No more exhaust leaks and the bike sounds a little throaty but has that Jap purr back. I hate loud bikes.

I also pulled the fenders, tank and side panels and gave them a tremclad overhaul.. actually I think it was rustoleum. Great for my purposes.

The biggest single expense I think was the plastic-chrome tail light piece, $40 from a wrecker... rape. I've since seen one on kijiji for $5.

I cleaned and adjusted the light switch on the back brake, tightened up the front, adjusted the free-play on the clutch, made a new plug for the rad from a bolt and nut. (FYI Canadian tire sells the perfect rad drain plug for the XJ750X in the generic oil drain plug area. Correct thread, shoulder and everything for $3.

It passed the Provincial Ministry Safety and runs great.

My only beef with the bike is that it sucks the gas hard. I get about 130km per tank. Though I haven't run it dry (stalled) it yet. I should get a little bottle of gas and push it to see exactly how far for sure.

I'm impressed with how quiet and smooth this bike is. It handles great. Doesn't have power until 3000rpm though. My XS650 had immense power out of the hole. But this bike is a lot fast than my my 650 was. Happy range seems to be 60km/hr to 110km/hr. It also doesn't pull as much as I would like from 60 to 100. But does pull once you reach 3000rpm, and again at 6500rpm. Though I usually keep it between 3000 and 4000.

Anyway, this post is a freaking novel. Kudos to anyone who has read it this far!

 

My XJ550 Maxim also really starts to pull above 5500rpm as well. Got to make sure I'm leaning forward when I am on the throttle or it will surprise me in that rpm band.

How big is the tank? If it is like mine, it is about a US 2.5g, so I get about 80-90 mpg before flipping to reserve, and then put about 2 US gallons in it.. Works out to 40-45 mpg, which isn't terrible.

Enjoy your bike. Is that avatar your bike?

 

I have a 700X and it only gets about 40 MPG maybe 42 MPG if I drive it easy. I think it is the nature of the bike. It does run good though.

 

sounds like you need to clean out the pilot jets
i wont go into compression test valve adjustment carb sync color tune.
check your rear brake shoes for delamination

my 5550 gets 50 mpg

 

550 will get better mileage than a 750x.

You DO need to check valve clearances and get them back in spec. That is a scheduled maintenance thing that must be done.

The "powerband" for Xj's is basically 6k-9.5k, so yeah.... As you cross 6k, the"x-factor" will kick in pretty good.

Worn slide needles or worn emulsion tubes will increase fuel consumption....

You didn't mention doing a running sync after doing the bench sync though--if you haven't done that, you need to, plus tuning the idle mixtures.

 

Yup that avatar is a picture of my bike I took at night lit only by the moon. (Sony A5000, awesome little camera).
My tank is around 13 litres, or 3.5 US gallons.
For slow riding I find that I get better fuel mileage at 3000 in 4th than lower rpms in 5th.. Must be pushing unburnt fuel out the exhaust or something.

 

Mine runs better if I have it running rich.
I backed my flow screws off to 1.5 turns and it's not as smooth as 3 turns. (stock jetting & air box, but homemade baffles in exhaust)

 

Carbs were cleaned. I synced them with a pin. At the garage the mechanics said they don't need to be synced as it was running well.. Perhaps fine tuning does make a noticeable difference.
No compression test or valves. I'm scared to look at the valves with their voodoo 5 valve deal. I'll check that out this winter.
I also never pulled the back wheel off to check for delamination, but it does roll/coast with no resistance at very low speed.
But perhaps there's a venturi thing going on at speed that causes some resistance? I'll feel the hub next ride for heat. Also I'll put the wheel off this winter and giver a once-over.

 

Valve clearances are scheduled maintenance? ... well I guess I'll have to. Because I'm sure the previous owner never did.

The needles looked and felt ok. What are emulsion tubes?

I think I may make an apparatus and do a running sync as well. Since you guys are mentioning it so much! lol

 

is this your bike
http://www.motorcyclespecs.co.za/model/yamaha/yamaha_xj750_maxim 82.htm

 

emulision tubes sit under the main jet and the slide needle sits in it. it has holes in it to asperate the gas.
re read post you have 1986 XJ750X

when the rear shoes let go you will stop hard and cold and unexpected.
you will be in a slide for your life

 

1.5 turns is lean.
3 turns is slightly rich.
Most of us end up at about 2.75 turns from a soft seat.

Get a Gunison Colortune. They are worth the cost.

The valve maintainance on the Maxim X is a bit more involved than on an airhead, but it is just as necessary (though the Genesis engine (yes, you have a Genesis engine, with a different case so it will fit into the frame) tends to go a long time before any valve adjustment is actually needed).

 

2.75 sounds good.
I'll look into a gunison colourtune.
Genesis eh?
The more I ride this bike the more I like it. It is a wicked engine with a small tank on two wheels.
I like the raked style, yet handles great in the twisties.
Beefs would be small tank and fuel eco, but for "short" rides who cares.

 

What do you mean when my rear shoes let go. You think they'll lock it up?
Well only a few weeks left of riding before they start salting the roads. I'll pull the wheel then.
Great ride tonight, my knees are still cold.

 

The emulsion tubes were pretty clean, but I cleaned them and soaked them in carb cleaner, blew them out etc.

 

http://xjbikes.com/forums/index.php?threads/15874

 

That would suck on a high speed bend.

 

Exactly, don't wait for a few more weeks . . . Check those rear brakes today!