Answers for a beginer's stupid questions.

Knew to site, first post, sorry if i messed up the format.

I bought my 82 xj750J last year, crashed it a month into having it cause of a previous owners "modifications" and my own ignorance to bike in gerneral. The front forks have been replaced with xj650 forks with just oil dampening and no anti dive, which is simplier and more reliable, but the brake caliber was bigger and they kept with the smaller rotor. so i crashed on my clutch side, and the head got scuffed up on the curb. Also i noticed before that exhaust was escaping from the front, i thought it was an exhaust gasket leak. And now a small oil leak, DEFF. from the head gasket, thoroughly checked.

Now I'm doing getting ready to do a head job. I got the gaskets, valve seals, and planning to check the clearences. My question is what are these cylinder head mounting rubbers everyone says to replace? where are they? and how many are there? I bought the four that go on top of the valve cover.
Also, i havn't opened it the bike up, and new to bikes, but not to engines. simple question, do these xj's have camshaft bearings that i need to replace?

Another question: Can I get rid of that ugly plastic semi digital display for a simple 2 guage, with the basic nutral, hi beam, and blinker lights, without causeing any issues with that digital part I'm trying to hide?

I got alot more questions, and have a great friend with a seca 750, so any knowledge is more than appreciated.

Also, I'm new to multi carb systems. is the proccess tune then sync, or sync then tune?

 

Lets start out by making sure of what bike we are dealing with. The 82 XJ750J would be a Maxim. This bike did not come with the anti-dive front forks (additional control body on the bottom of the forks). This feature was only available on the Seca. The Maxim did come with the air assist forks (air valve, and cross over hose at top of forks) though.

The 650 Maxim forks were only a single disk brake system with the caliper mounting being different from the 750 forks. This would change the alignment of the caliper to the rotor, and the bront brake would not funtcion correctly. To correct this you will need to repalce the rotor with a 650 rotor.

On to the rubber donuts.
These are the rubber pieces attached to the bolts that retain the valve/camshaft cover. There should be 12 total. 4 for the center bolts, and 8 for the outer bolts. These are compression seals that hold the cover tight to the cylinder head, and often the source for the assumed oil leak at the head gasket.
These seals dry out, and lose tension with age. Allowing the oil to seep past the cover gasket giving the impression of the head gasket leak. When you check the valve clearances. You will need to replace these rubber donuts along with the cover gasket to get it to seal properly.

The camshafts do not use a replacable bearing in the head. They ride in the machined surface of the head.

The atarti cluster can be replaced, but you will need to deal with the computer, and the several wires related to it to bypass the electronic sensors that operate it. There are sensors that will not allow the bike to run if not bypassed correctly. I have not dealt with the modification so I am not familiar with which wires to deal with.

As far as tuning the bike.
First make sure the carbs are perfectly clean, and the valve clearances are in spec. Then the process would be to vacuum sync the carbs. Followed by the color tune of the cylinders. The color tune will change the vacuum sync slightly. So it is recommended that the process of sync, and color tune be done twice.

Ghost

 

Yea, its a maxim, has the adjustable pegs that the J has, and i researched the serial number.

Its deff. the 650 forks, no air adjustment, and single brake. I switched to the rotor from a xs1100 and it fits like a glove.

thanks for the explaining the seals, the book wasnt clear how many there were, and for confirming my beleifs on the camshaft.

It seems all my warning lights are going off all the time anyways (lamps, no fuel, side stand, etc.) are always going off, so i beleive they may have been previously bypassed.

And as far as the color tune goes, is it really worth it? or can ear tuning and plug reading get me just as close? cause i dont have a dyno nor does anyone i know. Ive heard that don't make those plug to specs and can damage ur plug threads. I'm not against it, but i want opinions and details from people who have actually used them on there xj's.

Also, I currently have 4 into 1 headers, but is saw project VooDoo, with the 4 long down pipes and have been considering something similar for the flowing look, but doing that, do i need to get smaller jets or larger jets for my carbs?

Lastly for now, any advice on changeing the head gasket and doing the head job? I've got an extra set of hands helping, going to follow the manual exact, doing valve seals, reseating valves, checking clearences, replacing all rubbers, and gaskets i come across.

 

You'll never ear tune a 4 cylinder engine. Color tune plug works great on your engine (and there is no problem with its threads).

 

I know you said the fuses are ok, but did you check the fuse box itself? Common problem on these bikes from what I hear and read.

 

I don't know about the sensors for the HEAD or TAIL indicators, but if you don't have a sensor sitting in the third cell of your battery, then that's where the BATT indicator is coming from. The good news is, that can be dealt with.

As for FUEL, if you have a stock tank, there should be a two-wire (black and green) cable coming from the left side of the tank (there's a float in there), feeding back under where the rear of the tank bolts down, and plugging into a connector near the airbox. Possibly one of the wires is broken (had it happen to me).

STAND indicator is a no-brainer; the switch is, needless to say, next to the sidestand. Test the switch with a meter, and if that pans out, start tracing wires.

I'd worry about getting the carbs working as is and sorting out the instrumentation before worrying about modifications. You need a solid starting point to work from.

 

I bought the bike and it had no turn signals or taillight, and most of the wires have been cut back or tucked away, so i've been trying to sort them out. Today i found the wires inside the headlamp housing for the turn signals, hook everything up, and no blinking. Occasionally i get a springy sound, but no blinking, also front bulbs seem really weak compared to the rear. Last year i had the fronts and rears hooked up to the rear wiring, and it worked well (most of the time). Trying to hook it up proper and I'm stumped.

 

The Flasher could be bad.
Maybe.

The main reason Signal Lights don't flash is because:
A Bulb is burned-out.
A Bulb is not getting juice at the socket.
Bad socket.

Low amps.
Alternator Brushes too short. (10mm = Low limit)