Engine replacement

[motoman]

I have gotten back an 81 xs 1100 H tour model, that I bought new then, and I was going to have to put another engine in it, as it smokes out the pipes and won't stat in first gear. As I understand it, I would have to split engine case to repair tranny, whether it be bent shift fork, or what ever, unless someone here knows an easy fix. That possibly being the case, would a 78 moter work, even tho the coils visually look a little different on underside, and have seperate wire plug-ins to electrical, as opposed to the one piece plug-ins on my 81? I presume firing sequence on 78 and 81 are the same, as long as rest of electrical is the same on both, other than some minor improvements on the ook-ups. Both have the same part number ignition box, But I'll take any help from someone who knows for sure, as it's been over 15 years not being around these forgotten about rockets..Thanks...Brant

[TopCatGr58]

Hey there Motoman,

The 81 engine uses a different module, starting with 4RO or 4RI. Much different than the 78. The 81 doesn't have centrifugal advance, it's in the TCI. The coils are also 3 ohm, the 78 are 1.5 ohm and use a ballast resistor inline.

The Tranny can be accessed and repaired from the bottom WITHOUT splitting the cases. You can replace shift forks, gears on the counter shaft, shift drum, etc.. YOu say that it WON'T SHIFT into 1st, or once it's in first that it chatters and won't hold traction?! See the tech tips for REPAIRS, Tranny section, you'll see lots of pictures!! Okay, just reread your post, you said it won't "stat", I think you meant STAY in first! The tech tips will will explain what the problem is and how to fix it!

As for your #3 and 4 cylinders not firing, both are fed off the same petcock and fuel supply line, so the problem is probably with the petcocks or the carbs and lines!

Good Luck. T.C.

[motoman]

Thanks!.....I'll try to explain a little better....and simpler......wanna put the 78 motor-tranny in my 81...will it work fine? Next: Tranny won't stay in first when load is put on it...2-3-4-5 shift smooth as glass, just like when I bought it new. Also noticed, probable reason being when I got bike back, clutch cable and housing were badly rusted, not adjusted(lots of free travel), consequently It was most likely tromped in first gear anyway, clutch slips badly(5th gear, any speed u can redline easily), pretty sad, but got it back after selling it 15 years ago, it went from Colo. to Ariz., haven't seen it all these years, and when I saw it back here again, it was ridden only occassionally, was headed for e-bay to be parted out, bought it for $100, still liscenced the owner rode it to my house(bout 8 miles, followed him on my ST 1100, and noticed it also smoked out right side, sometimes, not constantly, but did smoke). At home I first set cam chain slack adjuster as it sounded like a thrashing machine, which helped(likely too much too late), that's why the engine replacement, figured too costly to rebuild as opposed to a used one still in the bike, less carbs which aren't there for $200, and bring whats left back for them to sell as parts. It has 25,000 mi. as opposed to 55,000 on my old bike(and I'm sure hard ones). Also the right two cyl. are getting fuel, as plugs are wet. The tank is clean(no rust) as it was rode regularly, no leaky petcocks, all hoses good, including vaccuum hoses. All four hit good couple weeks ago, went and started it the other day, that's when problem started.....