Jerrod's 82 Yamaha XJ-750 Maxim

What's up guys, just bought my 2nd project bike. A 82 Yamaha XJ-750 Maxim. I started by removing the stock handlebar mounts, and took a set of stander mounts from a 87 Virago and installed them. Worked well, but now I'm to my broken Speedometer. It has this instrument cluster that looks kinda like a car dashboard, it's not in very good shape, and as I said the speedo is toast. But my Head and Brake lights run to a chip in the center of the cluster, and won't work without it. Is there anyway to delete the entire cluster, and install traditional gauge's?

 

Use an 83 750 maxim or 82-83 xj650 maxim wire harness and gauges is the quickest way.

 

I agree 100% with the suggested solution. As long as the recommended models also have electronic tachometers, it should be largely plug-n-play. There may be a different sub-harness required in the headlight bucket, check with XJ4Ever. Speedo is mechanical, so no issues there.

 

My neighbor has a 87 Virago that he is scrapping,

Copy that, thanks.

 

there is a thread on atari delete with wiring diagram.
or you could keep computer part and just tuck it away.

if you pickup a 83 750 maxim forks you could easily remove head light and replace with a round one

 

Hey what's up guys? So the instrument cluster on my 82 XJ-750 Maxim was toast, so I took the speedometer from a 87 Virago that I have sacrificed, and installed it. But no cigar, my assumption is that the XJ's Speedometer drive spins in the wrong direction to operate the Virago's Speedometer. So does anyone know of a good speedometer I can get that will work? I don't wanna spend money, and run into the same issue.

 

Try a 650 maxim speedo or 83 750 maxim will work

 

Ok, thanks.

 

have you checked the cable and drive unit in the wheel.
virago speedo drive is on left side of wheel it should be spinning the same direction.
Virago uses same drive hub on wheel as 650 and 750,

 

The Virago and all Yamahas of the period use the same speedometer drive. The problem lies elsewhere.

Make sure that the tabs on the drive coupling aren't bent and that they engage the slots in the wheel.

As mentioned: make sure that the cable is intact and lubricated.

Make sure that both ends of the cable engage their respective hubs.

 

What's up guys? I picked up an 82 XJ-750 Maxim last week, and the exhaust is toast, completely unsalvageable. So after searching online, I wasent able to find a stock replacement, so I settled on a 4 into 1 header, with a trumpet style slip on baffle. My question is, are there any signs I can look for, that would indicate that the bike is running too lean, or too rich, So I can then Jet my carbs appropriately?

 

Indication of running too lean and hot would be a blueing of the header pipes and the colour of the spark plug electrodes would be white-ish. Also the revs could hang up before settling down at tickover.
Too rich and the colour of the plug electrodes would be very dark and sooty in appearance.
Possibly other indications could be present.

 

-first point: most aftermarket exhaust systems are single-walled, so blueing of the pipes will be normal even if not running lean. (Get the tuning just right and they may "stop" at golden-brown and never make it all the way to blue.)

-next point: by removing the original exhaust collector box, you change the dynamics of the exhaust system enough that re-jetting may be be required. The "magic" of the XJ's exhaust system is in the collector box; the mufflers make very little difference tuning-wise. (There is a lot more magic in the intake.)

-as long as you retain the stock intake; that is airbox, stock air filter, etc., you may not need to re-jet, just adjust.

-you cannot hope to begin valid carb evaluation and tuning unless -your valve clearances are in spec; -and your carbs are 100% clean, float levels wet-set, etc.

-spark plugs are "read" by looking at the coloration of the "flame ring" and the ground electrode below the bend. Today's gas can produce some very interesting coloration (what does bright yellow signify?) on the insulator, the flame ring is the key. (The "flame ring" is that portion of the plug just beyond the threads that the ground strap attaches to.) You will probably be able to tell based on how the bike runs whether it needs to be re-jetted, as long as everything mentioned above is dealt with.

How many miles on the bike? Any history, has it been sitting or has somebody else been fighting with it?

 

I have to agree; compatibility is not the issue here, something else is amiss which means there is a good possibility your original instrument may be OK.

Flattened out tabs on the drive unit are very very common...

Simple diagnosis: disconnect instrument, spin front wheel in forward direction, observe exposed end of cable to ensure it is rotating.

 

Ok, this is interesting. Because my 74 CB-750/4 will hang RPMs like you described, until it gets warm, and then will run fine

20,000. And no it runs and rides, low on power though. My CB-750/4 will put it to shame as is. The collector box is roached, the tip had completely rusted away and was non-existent. It was basically running on the factory downpipe's. Very low on power, gets up to speed, but virtually no pick up to speak of. The header and baffle are due to arrive tomorrow, so I removed the rotten factory exhaust today. That's how I discovered the collector was completely rotted out.

 

The top* of the collector had completely rusted away. Not tip.

 

Oh, and the Header I bought is black. So discoloration is probably not gonna be a very clear indication.

 

I recently bought a 82 850 Maxim, and discovered today, that the Speedometer drive cable will only rotate when the Bike is rolling backwards. When the Bike is rolling fowards, the cable does not react, obviously resulting in my speedometer not working. Does anyone know what could be causing this? The only thing I can think is that the previous owner disassembled the speedo drive, and possibly reinstalled the gear backwards, if that's even possible. I'm Completely stumped, and any theroy's are welcome.

 

If your XJ is outrun by a 60s design Honda you may wish to undertake a compression test.

 

Please stop

Yes, I've learned that, what's happening is my cable is not rotating when the bike is rolling fowards. It rotate's counter clockwise when the bike rolls backwards, but does not respond when rolling fowards at all. The only think I can think is, the speedo drive was previously taken apart, and then reassembled backwards, if that can even be done. I'm confused lol. I have access to the Virago speedometer drive. Gonna try and see if it fits.