Just found this website and I have some questions about my '82 750 Maxim

Hey there,


I am bringing a 750 Maxim back to its former glory. I have a lot of questions that I really hope you guys can help me out with. So far, I have...

Removed old gas and replaced with mixture of 87 octane and Sea Foam

Removed exhaust headers, chamber, and mufflers, swapped chamber with better condition one, and then re-assembled

Removed carbs, disassembled, cleaned very thoroughly, and re-assembled

Removed clutch cable, clutch cover, clutch plates, replaced clutch cable, and re-assembled


I am planning on...

Swapping my Seca 750 tank (I just prefer the shape) and modifying the stock seat to fit with the new tank

Painting everything that is currently sky blue a darker, fresh blue that will have no dents or chips (family friend has access to a paint booth)

Rebuilding/ replacing petcock (it's leaking right now)

Making a carburetor synchronizer and syncing the carbs/ honing in idle speed

Replacing the triple tree with an 83 so that I can swap lower handlebars (moving all stock hardware over)

Replacing license plate mounting plate (the humongous metal bastard between the license plate and the toolbox) with something smaller

Doing an oil change

After riding it a little bit, re-tightening the exhaust (I suspect the heat/vibrations could help it shift into a position where it could stand to gain from a little tightening)

Replacing the guages. Even after trying a new speedo cable, the speedometer reads zero. This could be the sensor thing on the wheel, but I'm not sure how to test it. Not to mention I'm not crazy about the big black boxy gauges anyway and the back-lights are very dim, so I am likely going to replace them either way. That said, I don't know how to find gauges that will work with the connections that this bike has (ie. speedo cable and all the other specific electric connectors) since I'm such a noob. How could I go about looking for stuff that would work on my bike?


So now that you know what I have done, here's a LONG list of things you guys might know about...

Bike backfires... quite a bit, albeit relatively quietly most of the time. I suspect this is because I didn't put the exhaust system back together as tightly as it should be and therefore backfires once every ten seconds or so at idle, but I'm not sure

I think the front suspension has a place to pump air into the forks to adjust the firmness. Right now, I can fill it up to be very firm, but as soon as I sit on it, I hear the air rushing out of the place that I used to fill it with air (it looks like thing to fill your tires with air). Does this just need to be replaced or can I fix it somehow? Either way, what is it called?

The bike is very hesitant to start, but I think that should get better after I sync the carbs and adjust idle speed

The connection from the switch for the rear brake to make the rear light brighter to the tail light is disconnected. I think it has a short somewhere, because when I connected it and tried it, the main fuse broke. How do I track/find/ fix the short?

The turn signals turn on when I move the (very sticky, gummy) slide on the handlebars, but I have to force the slide to return to the center position, and even then, the lights don't blink, they just stay lit. Nor do they cancel, although I can turn it off by turning on the other side. What might I replace/ fix to get the turn signals in working order?

My clutch is also acting quite funny. I believe it was user error (aka I put it back together wrong) because before I took it apart, it worked just fine (just a very, very heavy clutch lever). However, this is the second bike I've ever worked on and I was curious/got over-ambitious. Regardless of why I messed it up, I need to figure out how. All I know is that no matter the position of the "arm" from the clutch cover or the clutch cable/housing or the clutch lever, I can't disengage the clutch. Side note, the lever feels REALLY light now, so it might be time to change out the spring as well.

This is less XJ-specific, but I'll give it a shot. The oil drain plug at the bottom of the bike is pretty well stripped and the screw between the exhaust headers to access the oil filter is unmovable. How can I get these off so I can do a proper oil change?

If you were to follow the "passenger bar" behind the seat that goes around the toolbox/ license plate, there is a thin component that looks like it bolts to the rear suspension and ends at the battery cover. It doesn't feel quite like plastic or metal to me, but I'm not sure what material it is (I might need to upload a picture if you guys/girls don't know what I'm talking about). This component is perfect on one side of my bike, but cracked right where the bolt goes through to the suspension. First off, what is this component called, and second of all, is it cosmetic or structural? If its structural, I will have to buy it, but if it's cheap, I will get a new one either way.


If anybody has any comments/answers/suggestions/insults etc. PLEASE contribute! I'm just learning this hobby and totally loving it, but I would love some direction, advice, and answers. Thanks

 

You don't need to swap the triple to be able to use round bars. The risers you have unbolt from the triple and the bar clamps from a Seca bolt right on.

You need to rebuild the carbs.

You need to rebuild the forks (including the schrader valves and the air collar o-rings).

Really, you need to be reading the thread below before doing anything.
The Information Overload Hour


I think the cracked component you're referring to is the side cover. Put up a pic (you need 4 more posts before you can link).

 

I would add check and adjust valve clearances to your list, may have something to do with the backfiring.

 

Glad I don't have to get a new triple tree!
Already rebuilt the carbs.
Adding to the list are rebuilding forks and checking/adjusting valve clearances.
Forgot to mention (not that it matters) that I'd also like to do bar end mirrors at some point as well.

This is what I was referring to...

 

I will be blunt. Everyone thinks they rebuilt the carbs, but very few really did.

Did you break the rack, remove all of the parts (including the pilot mixture screws), soak the carb bodies, and replace the throttle shaft seals (along with the float needles, float needle seats, and pilot screw o-rings)?

Did you inspect the slide diaphrams for pinholes, and make sure the slides clunk when dropped into their bores?

Did you wet-set the fuel levels?

IN THE CHURCH OF CLEAN

 

That is the grab bar. You'll need a replacement, or someone who is familliar wih welding aluminum.

 

Haha I appreciate the honesty, k-moe I really do.
I will look through your link tomorrow and see what I hit/missed.
Thanks for all the help!

 

Also have a close look at the carb intake boots. They will crack with age and cause vacuum leaks.

 

Yeah that's one other thing that I forgot from the list. Any good places to buy those bad boys?

 

Also, are the grab bars common to any XJ's besides the 750 Maxim?

 

Buying parts is easy we have a "buddy" chacal on the upper right corner click on xj4ever he has almost every part you need. His service is great AND it will be the correct part. His prices might seem higher be wary of some items you see for sale on ebay. Why buy used 30 yr old parts when xj4ever has new. Example used choke cable 10$ I bought new for 15 and was correct part. Good luck on your bike

 

Nope. That is a Maxim 750 only part. The 650 Max grab bar looks simmilar, but will not fit.

 

I think the front suspension has a place to pump air into the forks to adjust the firmness. Right now, I can fill it up to be very firm, but as soon as I sit on it, I hear the air rushing out of the place that I used to fill it with air (it looks like thing to fill your tires with air). Does this just need to be replaced or can I fix it somehow? Either way, what is it called?

Just chiming in on one of your segments here. I just replaced the OEM fork springs on my 1980 XJ650 Maxim with the progressives. Along the way, folks here were very helpful and informative. If you are going to break those forks open, I recommend these springs. Let me tell you, that upgrade was like going from a trampoline to a smooth controlled ride. According to the spring manufacturer, you can really forget the air pressure thing too. My XJ bike doesn't have the air option, so I can't speak from experience. But the improvement in handling and ride characteristics for my XJ was extraordinary. Good luck with your project. I'm about a year and @7K miles into mine, and loving every minute of it!

 

The adjustable air spring still plays a role even with new springs. It adds the ability to fine-tune the fork when riding with a passenger or luggage (or both).
Progressive brand springs have been reccomended here for years, but people sometimes confuse the brand name and the term. The stock springs are progressively wound, but in a slightly different way then the Progressive brand springs.

 

k-moe and OldFleetGuy, are you guys suggesting the brand or style? Would you suggest buying from XJ4Ever or did you get it from somewhere else? Also how do I know if the springs need replacement?

 

I always recommend parts from XJ4ever. May not be the absolute least expensive option, but it will always be the right part, unlike some other online providers that think they know XJ compatibility. Very responsive service as well.

 

I'm not suggesting any brand, or even spring replacement. That part is up to you. I'm just pointing out that the air system is still in play even with new springs fitted. Standard air pressure for a solo rider is 6 Psi, up to 17 PSI with a passenger and luggage.

 

Its your call, brand, to or not to replace, vendor. I am only sharing my experience. Good luck.

 

Personally, I ONLY buy repair parts from Len Chacal at xj4ever