1983 XJ750 Maxim Build (Updates and Questions)

Recently I picked up a 1983 XJ750 Maxim with 33xxx miles on it with the plane to make a brat/cafe style bike. I started a thread in the hangout lounge forum but I am going to start posting here updates and questions I have to get some more action. I plan on rebuilding the forks, carbs, calipers, and changing all the fluids myself before I start making any customizations.

So I am working on rebuilding the front forks and I cannot remove the 19mm cap bolt to access the spring. Does anyone have any tips on how to get these off?
I also found why one fork was leaking oil like crazy, the washer the goes on top of the oil seal between the clip was missing. Also they used the wrong length bolt and stuffed washers on it and lots of locktite to make it work.

I was able to remove the air valve but I can't remove to 19mm bolt

Missing washer and wrong bolt

 

I always break then loose before removing from the triple tree. You could bolt them back in, it makes a handy clamp to hold them.
A air impact wrench will take it off, be sure to use a 6 point socket.
Last but not my favorite it to clamp in a vise with wood blocks to protect the inner tube. This method will sometimes does not hold well and the tube will rotate in the blocks. Don't clamp the tube directly in the vise jaws, it will mar the chrome finish.

 

it is threaded in place soak with kroil to loosen rust


haynes manual recomends soft cloth around tube and place it in a vise
leaving it in the tripple tree is safer

 

just remember to loosen the top triple tree clamp so you are not fighting the clamp.
its late you can also extend the tube section above the triple tree to be able to use upper and lower clamp

could be some thread lock on the cap maybe some heat to soften it

 

I don't recall mine being threaded... I do remember having to push it down to remove a circlip.

I do recall that the xj700 and virago forks are threaded, and the take a pretty good-sized Allen drive

 

Is that the one which can be substituted with a reversed spark plug socket? Where you use an extension on the ratchet and use the hex on the back of the socket instead of the normal orientation? I vaguely remember reading about the process, but not enough to recall the application.

 

That for at the bottom of the fork tube so you can remove the retaining bolt

 

The reverse spark plug wrench fits the damper bolt inside the fork

 

I haven,t done my 83 750 yet but the haynes manual does say that it is a change for that year and is threaded.
manual could be wrong.

with the torque spec at 6.8 ftlbs it shouldn't be that hard to turn unless it is frozen or thread lock compound was used by po when he redid the tues. it could also be stuck to the seal

 

Actually, that one fork tube has a spacer washer that shouldn't be there..........no spacer washer was used with original seals (or, aftermarket seals which have the same height as the original seals).

Cap bolt is threaded. Penetrating oil will (eventually) do the trick.

 

Quick update here. I followed most of the advice here and I was able to get one side apart after putting it back in the triple tree.
I let it soak in some liquid wrench and hit it with my impact gun.

On the other side I learned a very valuable lesson about the importance of six point sockets. I completed rounded off the bolt.
I am going to let it sit with the penetrating oil and try to weld a larger bolt on top. Unless any of you have better recommendations.

Thanks, I will discard the spacer as I have already purchased the correct seals from you.
I am going to replace bolt caps, do you happen to have any of those in stock?

 

I just don't remember unscrewing mine.....probably cuz I only had to do that set once, and have done a lot of the others.... Oh well, my bad.

 

you could try a bolt the size of the air nipple and lock it down with a nut then see if you can unscrew it using the inserted bolt

 

That bolt would just turn back out.

I would resign myself getting a new cap in advance, then either use a big easy-out in the Schrader hole, or weld a good-sized nut to the top and try turning it out that way. Maybe welding a nut on should be first choice-- if it turns out, the nut can be detached and weld residue ground off, allowing the plug to potentially be re-used

 

Quick update. I have tried welding a nut on top with no luck. The welds kept braking when I tried turning the nut. I had a bolt that fit into the schrader valve hole and tacked that into the threads. The bolt snapped in half. I picked up some kroil and let it sit overnight. I bought a set of extractor sockets which only rounded the bolt more.

I am going to try to find a more powerful welder and weld another large nut on top.

 

Oh that Kroil is good stuff!!

 

Pretty soon it's gonna be less expensive to get a different fork

 

When you weld a bit onto a fastener for extraction, making sure you get the best possible penetration into the piece you want extracted is key. Then once you have it stuck on there real good, let it cool for awhile before you start trying to turn it. Once you start trying to turn it, start by carefully working the fastener back and forth little by little, adding penetrating oil as you go.

 

Well I have tried everything in my power to get the nut to budge with no luck.

I found a straight pair of forks on ebay which I snagged for $50 +free shipping. I should have them in a week.

 

I might be interested in that fork just to keep trying

 

Masochist.

 

The issues continue on the new forks I received. I was able to remove the to cop with ease on this pair.

But the socket head cap screw on the bottom completely rounded off... At least this should be easier to drill out and the kit from XJbikes comes with a replacement screw. :/

 

After letting the bolt sit with some kroil I decided to take another crack at it with an extractor. I drilled out the head and got the extractor in place. It was not budging so I gave it some heat with a torch and it broke loose. I had to used the trick with the upside down spark plug socket and the extensions to get it completely off. The threads were packed with a hard black substance. After I get the forks back together I will be taking on the carbs.

 

Good job

 

That hard black substance is thread locking compound. Be sure to degrease the threads, and reapply a medium-strength thread locking compound before reassembly. Having the damper rod disconnect from the fork lower while riding may result in the sort of adventure that nobody wants.

Also get a new bolt. Chacal should have them in stock.

 

I definitely do not want that happening. Should I put any anti-seaze on the top cap?

I bought the full rebuild kit from chacal so o already have replacement screws.

 

Yaaay!!!

 

I figured you guys could use a good laugh on my behalf. After I finished rebuilding both forks and I immediately realized something was off. I had rebuilt the wrong replacement fork and now had 2 right forks on my bike.
I rebuilt the correct one and had the same issues with the bolt being stuck in the bottom and rounding off the hex head. I drilled the head off and swapped over the parts for the other fork. After that I put air in the forks, put new handle bars on, headlight, and horns.

I'm working on replacing the wheel bearings right now so I can take the bike off the jack stands. I also just got braided lines in for the brakes so I will be replacing those soon. Following the brakes I plan on doing the carbs and getting it running again.

 

2 wrights made an airplane-----

 

You could have just run two fenders..

 

Yes, but just a little.

 

I just got around to putting the front wheel and brake calipers back on after replacing the seals on the front forks. When reinstalling the calipers the right fork was too close to the rotor the fit the caliper on. I had to loosen the nut on the wheel to get the caliper to fit on. The spacer is on this side of the wheel. Is there something I am missing or can this be a little tight after changing the brake pads?

Also I have taken my carbs to church and reassembled the rack. I still need to bench sync and adjust the float levels. I am going to wait until I get a sight tube to take care of the carbs. Next I plan on checking valve clearances. I got a new valve cover gasket since there is a terrible mess all over my engine from the valve cover leaking all over. Is there anything else I should look for while I have the valve cover off?

 

Check the valve shim clearances!

http://www.xjbikes.com/forums/threads/bigfitzs-airhead-valve-adjustment-with-pics.116006/

http://www.xjbikes.com/forums/threads/valve-clearance-exhaust-side.94158/#post-522959

 

maybe get some donuts for the bolts if yours are hard

could be the fork tubes have moved the triple tree out of alinement

 

main jet washer looks cupped may cause you problems letting unwanted fuel to pass

 

Could you elaborate on this? I am not sure what any of this means.

Whats is the best way to check the alignment of the triple tree?

The main jet washer was definitely cupped on all 4 carbs. I figured they were supposed to be that way. Can I pick up replacements at the hardware store?

 

Just gently beat them flat with a hammer. Or we have new replacements available.

http://xjbikes.com/forums/threads/valve-cover-donut-tool-now-with-how-to-pics.40308/

 

Thanks chacal, I will try to flatten them.

This makes more sense. I thought XJ550H was talking about the front forks. I have definitely seen the valve cover donuts in other posts.

 

I got the bike put back together this weekend with the valve clearances in spec, a new valve gasket and donuts. I set the carb float levels and got the carbs on the bike. I was planning on doing the colortune and vacuum sync but my tach was not working.

All of the fuses are working and I have the ATC style fuse block installed. Is there a separate fuse for the tach/flasher? The bulb in the tach is working but the tach itself is not moving at all.

I have not wired any of my lights on the bike yet and it sounds like I am having a similar issues to this thread but I didn't find the resolution.
http://www.xjbikes.com/forums/threa...ach-and-others-not-working.66126/#post-463726

 

gray wire goes to the coil it is the signal wire to tach
black wire is ground
Brown wire goes to signal fuse
do a continuity test on the Gray wire from the coil to connector could be bad connector connection at tci or coil connector plug

so the ground should be good because the bulb works.
check for 12 volts at Brown wire at connector

 

It is possible for the tachometer to fail. Corrosion on the component board, or broken solder joints are likely suspects.

 

Thank you for the tips! I will try this weekend and let you know what I find.

 

I checked continuity from the coil to gray and it passed. The voltage on the brown with bike running was 14V.
I am testing the coil where it is mounted to the frame. Is this the correct way to check?

 

Well I disassembled the tach to look at the circuit board and connections. Everything looked good so I hooked it back up to the bike and it started working. I must have had a bad connection somewhere that got fixed when I put it all back together. Now on to syncing and colortune.

 

One thing to do is to go through all of the connectors, deox them, and apply dielectric grease to prevent future corrosion.

 

Yes that is on the list to do when I install the lights.

I did not have any luck syncing the carbs today. They were not drawing enough vacuum and the gauges stayed at "late valve timing or leak at intake manifold or heat riser"
The engine had a rough idle and when i would blip the throttle the rpms would hang at 4K and very slowly come back down. I have never used this tool before and I think that may be why I am having issues. I did build the yics tool I found on another thread and I had it installed during the process. Any tips would be appreciated.

I checked the compression on 1-4 and they read 120,90,90,90.
The valve clearances are in spec and the spark plugs are new. 1,3, and 4 plugs looked good buy 2 looked a little lean.

 

when using vacuum Gauges you have to put a restrictor in the hose to slow down the jumping of the needle. a hose splice with the red tube from carb spray epoxied into it works well.

 

The gauges I bought came with with bleeder screws and I was able to control the needle movement.

 

Did the gauges come with restrictors to put in the vacuum lines? The screws are for adjusting the baseline of the manometer (by connecing all of the lines to one vacuum port, and setting all of the gauges to read the same).