motor swap/ parts interchangability

[1lojet1281]

Hi, I am new to this forum and new to XS650's ( but i am learning very quickly) I have a a salvage yard bike for a bobber project and from the best I can tell it is a 72 XS2(306 engine), but it could be a 73 TX650(366 engine). for this query it should matter though as I believe both models have basically the same engine. anyway...

long story short, the engine is in rough shape, the lower case is badly cracked (probably by running into something) and all the oil leaked out so this leaves me with two problems; the lower case needs to be replaced and everything inside is pretty rusty/corroded. I think the internals would clean up but I dont know how interchangable the cases are. I guess I just need to know, what year (or code) motors have parts that will interchange with mine.

my other thinking is to ditch the motor and go for a 74-79 year range motor, as the replacement parts are much more common. my question with this is, will a 74-79 range motor mount up in the frame? I understand that there are some minor differences with the carbs but I am confident that i can work that out no problem.

thanks in advance for the help!

 

[inxs]

- if you replace the case you will need to replace both halves together, they come as a numbered matched pair where the bearing seats for the 3 shafts-crank, main and drive, are line bored...ie dont mix odd cases

- in any case the engine and frame numbers wont match anymore
- better by far to get another motor...may still be able to salvage some parts from this
- i believe engines will interchange when using the mounts that come with the frame

 

[cooltouch]

+1

I would also recommend going with a '74 or later motor. They're still plentiful and decent used ones are not all that expensive. As you mention, parts are more widely available for the later ones, especially those of the go-fast variety. If you think you might want to install MikesXS's OD 5th gear, then you'll need a '78 or later motor -- the shape of the tranny gears changed in '78.

 

[1lojet1281]

thanks for the replies guys, I picked up another motor from the salvage yard that sold me the bike. It's a 79, in good shape but missing the entire shift shaft assemby, alt housing, both covers and the clutch assembly. the guy let me have it with the BEAUTIFUL carbs that were on it for only $50!

I am going to see if the shift shaft assembly and clutch assembly will swap over... fingers crossed. if not, it'll be another trip to the junk yard.

 

[cooltouch]

The shift shaft assembly is the same for all years. You can buy a new one at MikesXS.

The "alternator housing" you refer to -- do you mean the stator?

There is a difference between the early and late clutch assemblies -- has to do with the number of disks, and as I recall the early one can be modded to work the same as the late one. I'm not the one to ask as to the exact differences and the modding procedure, though. Somebody else here can help you with that bit. Far as I know, though, all the other stuff should interchange.

 

[1lojet1281]

sorry, I do mean the stator. it was early and the term just wouldnt come to me, haha. I'm glad to hear that the shift shaft assembly will swap, and as far as the clutch, I also heartd that there was a difference in the number of disc's but I am hoping that it wont be an issue since I will be swapping the entire assembly. If not, the salvage yard here has LOTS of XS's and they have great pricing on parts.

 

[cooltouch]

Now I'm curious. What's the name of the salvage yard, and do you know if they will ship items? Whereabouts are you located?

Here in Houston, I think there is now only one motorcycle salvage yard left -- used to be two, but somebody was telling me the other day that the other one had recently closed down. Anyway, the surviving one usually doesn't have much of an XS650 collection, and their prices are not always what I would call "reasonable." A few years back, I bought an alternator rotor from them for my '81. Had to give $30 for it, and it lasted about a week before giving out. Never again will I buy a used rotor, unless it was a recently rebuilt one.

 

[inxs]

- 3 basic types of clutch, all are interchangeable as a complete unit..if replacing parts make sure they come from the same model

 

[1lojet1281]

the name of the salvage yard is Midway Cycle and it's in Madison, AL. they have a website I think, you should be able to google it. they also sell new parts and new bikes and seem like a very professional place so they would probably ship.

 

[cooltouch]

Thanks, I just googled them, bookmarked their website, and had a look at their eBay listings. Whoa! Over 2700 parts listed on eBay right now! Over 500 for Yamahas.

 

[1lojet1281]

yeah, thay are a pretty big operation, they probably have 40-50 XS's in varying states from almost bare frame to complete bike. I bet they have several thousand bikes total, thay have been in business for something like 30 years so they have had lots of time to accumulate inventory.

just dont buy up all the parts from my local honey hole though, lol

 

[cooltouch]

Sadly, with the current state of my pocketbook, that you won't have to worry about. Fortunately, I've been collecting the parts I need for my cafe project for quite a while, and there are few used parts, if any, that I still need.

Geez, it seems like to me like, with Barber's facilities and this huge source of used parts, Alabama is becoming some sort of nexus for motorcycles. Custom Rewind (they do XS alternator rotors) is located in Alabama too.

 

[650Skull]

Hmmm, $75 for the engine sidecover is a bit steep, wouldn't have payed that much for the bike

 

[1lojet1281]

I didnt see where anyone paid $75 for an engine cover...

 

[Ludlow]

Speaking of cracked gear cases, my 72 XS has a latteral crack just in front of the top rear motor mount. When I got the bike the crack was covered with caulking. I'm curious and didn't like the looks of the fix so I started peeling. I think the caulking would have held otherwise...

Anyway, I'm curious if any of you guys might know what would cause a crack in that spot only. Crash?? Bad mechanic?? I'm going with a JB weld temporary fix until I can find someone with a mig or tig welder.

 

[cooltouch]

I'm inclined to think it got T-boned. JB Weld will work okay if the area is not subject to much in the way of shear forces, and will probably work okay as a temporary fix. Will you be pulling the motor from the frame for the mig/tig repair? I'm thinking the mig/tig guy's probably gonna want the bare case half so he can go at the crack from both sides.

 

[Ludlow]

The plan at the moment is to JB weld for the summer and get on the road - keeping a close eye on it. I figure JB will show fatigue more than caulking. This winter will be tear down and patch up or case replace. Seems like a good time to be in the shop...

I have just never seen anything like this - no marks around any other mounts, just this one big crack.

 

[Ludlow]

Sure enough, JB showed signs of fatigue - and so do I. Due to the incredibly loud top end noise that I'm working through, which has me with the engine half torn down, I've decided to replace the case. By the time I'm done, I should have a solid confidence in this bike's reliability.

Please join me in thanking my wife. She said I should take care of it. (first ever)

 

[Ludlow]

- 3 basic types of clutch, all are interchangeable as a complete unit..if replacing parts make sure they come from the same model

Maybe I'm reading this right and maybe not. Are you saying that all the cases are the same? Will all the internals from my '72 XS2 fit in a '79 or '84 case? I'm working on returning the '72 case that turned out to be ebay crap. The seller has a '79 ym17 case posted. Maybe I can swap, but not if I have to buy a bunch of new parts. If all the bores and gasket faces are the same, I should be OK, right?

The devil is in the details.

 

[inxs]

The seller has a '79 ?? ym17 ?? case posted

- im missing something here?

- no, the cases are not all the same...there are differences with starter motor mounts, crank oil vent boring, strengthening etc...there are differences in the internals too-but in the main they can be interchangeable-the cranks as complete units together with rods and pistons-although there are differences in crank oil delivery between 447 and 533 models, the clutches as complete units, gearbox parts with similarly cut teeth can be shared with each other or swapped as complete gearboxes with other models...etc...

- save a lot of work by getting a good runner