mix and match xs parts

[dr mac]

Ok I have a 8/72 ? TX650 with over length tubes and drum brakes. Then one with the standard length forks and front disc brake and W type aluminum wheels.
Can I use the disc brake forks on the TX with the drum brake wheel.
Also since I need to clean the carbs on all . wich carbs to use on the TX . I have the following carbs off a 72 model the TX the 75,76 or what ever it turns out to be .And then two 78 carbs.
Also can I use petcocks off a 78 on the TX tank.

Also plan on lowering the front of the TX and installing rebel shocks on the back .

Guess what I'am saying is I want to lower the TX front and back , remove about 3 inches of seat foam and recover ( already removed the foam as seat was in bad shape ) in brown leather ( well I hope in leather) .
then ride the wheels off it untill next one is done .
So what is the best parts to use.
thanks
Dr mac

 

[angus67]

well.. you can use whatever carbs you want. an engine is just an engine. Ide use your 38's on the tx. if you plan on open pipes or pod filters, will take some tuning, but it will still run in stock needles/ jets. just not efficiently. take 'em off, clean 'em out, get new valve seats, set the floats, and take it for a spin.
Depending on how it runs after that, under load and all, we can help you with jets and pilots, so , go get dirty, breath some carb cleanr, and report back. good luck.

 

[650Skull]

The drum front wheel needs to have the correct set of forks. The forks have an oblong protrusion that sits into a grove on the drum brakes to stop them spinning.

 

[angus67]

oh yeah, I forgot the angle of the carb boots is different from the ealy to the later engines. still use the 38's though. just thought ide throw that in if you hadnt known that.

 

[5twins]

I think the '78-'79 carbs were the best of the 38s, '76-'77 set 2nd best. Either would have the single throttle cable and linkage to the other carb, easier to sync and keep that way. That's the main reason for using a newer set.

I think the mounting screw spacing on the later petcocks is different from the earlier ones so that probably won't work. Check to be sure but using a newer vacuum type would be a step backwards in my opinion. They tend to go bad, start leaking, and cause problems. The old manual style are pretty much bullet-proof.

 

[dr mac]

Was not sure if this post worked or not. Was on niece's pc in warrensburg . Darn thing froze before I got pics posted . Hope these work.
This is TX marked 8/72 forks are way long

.
this one is serial marked 447119xxx

.
And this one is a 78 it is a 11/77 marked neck tag.

All will start ( will run spraying directly into the carb ) .
Of course all the starters sound like they are coming apart .

thanks in advance
Dr mac

 

[XSLeo]

The date markings on the head if after about the 6th month are the next years model.
The 8/72 TX is probably a 73.
Using the vin and engine numbers and checking a vin guide will tell you better than the manufactured date.
Most of the parts sellers have guides, 650 Central, Mike's XS. Mike's also has pics of carbs to help identify them.
I like the 76 and later carbs, they use just the single throttle cable, as 5twins said easier to sync and stay synced better.
Your second pic, #477119xxx checks as a 75, best of the bunch IMHO.
I think Mike's sells stock length fork tubes for the TX, 34 mm tubes, You can tear down the 73 TX and the forks from the 75 XS, use the 75 XS tubes and dampers with the 73 TX lowers. Then you will have stock length forks and use the drum brake.
I would use the two sets of 78 carbs. They are BS38's, The 73 and 75 carbs are BS38's too, good carbs just a bit more tuning, as in sync.
The internal brass parts vary from the 73 to 75 to 78 carbs, mixing and matching the internals isn't reccomended but can work.
On my 75 I have a 76-77 carbs set with 74 internals. This has given me a bit more trouble tuning the carbs.
As you take the carbs apart for cleaning do just one set at a time, and write down just what each has for internals, main jets, needle jets, needle, pilot jets. Some off the jets from one set may fit another set, just different sizes. Once you have all the sets clean and know what sizes you have then you might be able to swap jets instead of buying.
Have fun with the cleaning and rebuilding the bikes. A very satisfing thing when you get one on the road.