73 tx650

73 tx650-xs650 resto

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Hello finally figured this out I have a 73 tx650 or xs650 can't figure out the difference but I'm partially restoring it but rather putting everything back on it that shouldn't of been taking off and painted such as orig lights guages and ignition exhaust baffles air filters and a few other things one things is it is backfiring like an anti lag engine petrol heads use from the right exhaust and can't figure out why and sounds and looks unhealthy but it seems to run good but overall it isn't firing in sync like it should the throttle cable its abit kinked on the right side but fixed it somewhat because the cable wasn't pulling both sides of the carbs evenly correct me if I'm wrong or anything I have done this far I also put in new spark plugs and fuel lines from the tank to the carb and the previous owner runs 93 octane which I'm not sure at this point is good or bad anyone let me know what I can do thanks
Pulled new plugs after running for abit an a small spin left plug is dry an very light and right is dark and wet any help as to what carb adjustment I will need and it backfires multiple times in right exhaust pipe an then it seems the bike warms up an it stops when riding it I doesn't seem to be running right like the timing is off or the carbs aren't in sync. it has 93 octane in it

Clean, well adjusted carbs are necessary but carbs are often blamed for what may be electrical problems. If you have original or old sparkplug wires and caps, maybe replace them, better in the long run anyways. Test your coils, adjust your valves, check your compression. etc., etc., etc.

Has good compression will start just about every single kick I have not replaced the wires and caps and I have not tested my coils or valves I was told it still has the point's
First thing, get some different plugs. Get some BP7ES NGKs. They will burn better and cleaner. The B8ES you're using was the recommended plug for your model when it came out but that was revised to the BP7ES.

Your bike has dual points, one set of points for each cylinder. The timing is also adjusted individually for each cylinder. The timing on that bad burning cylinder could be off.
When someone mentions compression, the proper response is to give the reading in PSI's as a gauge shows, Good compression is a fairly meaningless term.
In the repair manual it explains how to set points gap and timing, if you don't have a repair manual I advise you get one. There are places online that have them as downloads, biker.net is one. The exact year isn't really that important on "how to" just get one that covers points models, 70-79. The procedure is the same.
In the repair manual it has the procures for adjusting the carbs idle speed and sync as well as cable adjustments. The Dead Cylinder Method is used for these things.
On your stock coils or fresh repop's, They were barely able to run an engine when new. Upgrading to hotter coils is worth it.
I would start by checking out the coils, input side ohms and output side ohms as well as to ground on both sides. A multi-meter is used for this. The primary side uses a low ohm scale, like 200 ohm, the secondary side uses a high ohm scale, like 20,000, or 20K.
As far as adjusting the points a screwdriver and feeler gauges is required, Adjusting valve clearances is done with metric hand tools, wrenches, sockets and such.
A place called MikesXS is our biggest 650 parts supplier. They have just about everything for the 650 but many of their parts are poor quality repops. It's best you ask here about any item you are thinking about ordering. However, their points sets and condensers are good.
Thank you most of that info I will need for later use and I was looking at mikesxs looking to get the clymer Manuel for 650 twins I was also looking to get new exhaust tips or just the muffler because the ones on it have no baffles and cannot get them from previous owner along with the front fender and have to deal with all the wiring from them removing all the orig lights and guages :(
Thank you that's very helpful I was looking to get the clymer Manuel for 650 twins an one a replica exhaust with the non removable baffles from mikesxs the previous owner won't give me the baffles for the exhaust it has now and he won't give me the front fender anywhere I can get a new fender?
Thanks it will come to use for buying parts later I downloaded the owner's manual for the tx 650 and has a few good points about the bike
Try this link for the fender and other items you need.http://speedandsportinc.com. If they have it it will not be cheap. However you may be looking for a while as they will be hard to find in good condition as will any other part. Careful on e-bay, make sure it is for the 73 as they may look similar but will have slight differences from other years
Here is a parts list and images for TX 650 A, I've found this very helpful in putting things back together again....if anyone has one for a 75B I would love to see it.....

Also I could chim in about the plugs too, but I think there is enough comment without my bit,


  • Yamaha xs 650.pdf
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A note/warning
In 1973 Yamaha sold the TX650
In 1974 they changed to the TX650A
In spite of the similar name there are probably more differences from 73 to 74 than between any other two years of XS650 production. There are many 70-73 XS650,Tx650 factory manuals kicking around, these are what the dealers used.
So Gaz, after 74-75 build dates was there many changes at all? I know Yamaha beefed the frame up after the early models flexing all over the shop, but after that, just subtle changes or were there major mods at all?
Sure, (mostly) improvements continued through the years the fork, brake change 76-77 was a biggie, TCI ignition in 80 another. carbs changed every year or two through the whole run,