Can I lower a shaft drive bike?

Question

Just started getting into customizing bikes this season, I like to find the older 70's style ones for a couple hundred and make them into bobbers or choppers, did a great job on a cheap xs I got a few months ago, saw an xs-1100 for sale the other day in mint, for only a couple hundred so jumped on it. My buddy said that since it was shaft drive, I may have problems lowering it because of the change in degree of the shaft, I'll be dropping it about 6 inches, just removing the shocks and using fender struts. I've seen plenty of pics of shaft drive bikes dropped and lowered, I just need to know what issues I will have and what do I need to do to prevent damage, cosmetics are simple, some ebay solo seats, drag bars, jesse james fenders, etc, but not much of a mechanic as far as internals go, what do I have to have done to be able to lower a shaft drive bike without issues?? if there are any?

Thanks guys, didnt think it was an issue, I've dropped an xs650 and a gs 750, no idea what the first idiot is talking about, it's as simple as putting a 1/4 inch shim on the back tire and unbolting the shocks, rear drops on the tire, drill up some fender struts out of what ever is laying around, and done. But these have been chain drive bikes so dropping and angle was of no concern, heard it may effect shaft drive, but I guess it's not that big an issue. And to the guy who says..... 6 inches??? on these older bikes, yea, they sit high, just measure the distance from your tire to the inside fender, usually more then 6. I've seen lots of xs pics dropped right on the tire, and dont see any problems coming up on searches, so it obviously must not be an issue. Thanks guys.

Answer 1

Yes you can lower it, but not much more than the lenghth of the suspensions travel.
By changing out the rear fender you can go a little beyond the travel, but there are limits as to how far the drive lines U-joint will work properly.

Answer 2

The second guy was pretty close talking about sighting a straight line, but not to the crankshaft. If memory serves be correctly, the XS1100 used a jackshaft in the tranny, so instead having the crank and two transmission shafts, you have the crank and three shafts. That's why the engine runs "backwards" comapred to most 4 cylinder Jap bikes. What this does is put the bevel gear at the front of the drive shaft back a pretty good ways as well as make the swing arm rather short. You should be able to remove an engine cover over the bevel drive and you should be able to get a pretty good idea of where the center of the shaft is. Do as he said and sight along the shaft, swing arm pivot and rear axle. With a single universal joint, 45 degrees off of a sstraight line is the maximum amount of deflection you can handle and you'll probably get a vibration at speed. At that angle, and since you only have one U joint, you'e going to get a speed variation on the driven side of the joint as well as accellerated wear. (Two joints like on trucks cancel each other out.) I'd try to keep the angle at about half that, or 20 some odd degrees. If you can get an idea of the angle at normal full compression, that will be a safe angle to stay at although you can probably go a bit more and be ok.

You might consider putting a lower profile tire on the rear to drop things a bit and you may also check to see if there is a smaller diameter wheel from some other Yamaha that will swap. I can't remember if you bike has a 16" or 17" wheel, 16" I think...

Answer 3

This is a real answer, and I know a Yamaha from a Suzuki, the guy before me does not. Yes, you can lower the bike, not sure it will go 6 inches without trouble. Look at the bike, on its center stand, if it has one, If no canter stand, lean it on side stand, and pull over a bit more, to extend the rear shocks. Mentally draw a line through the center of the crank, (center of the ignition housing) through the swing arm attachment point, past the rear axle. Note the distance the axle is below this line. You are safe moving the axle up to a distance about an inch less than the drop. IE, if 3" from line to axle on stand, can move axle up 2" above line. Would not do hard acceleration, or top end runs with such a bike, but can putt around without trouble. Of course, a bike modified this way has no right to be run hard, it is for looks and show. Some of us doubt the value of either. If you want to go really low without issues, then do frame mods, to effectively drop the frame around the engine so the drive train remains in its design limits. Would make a good old "Retro-Rocket" with a mild cam and 1200CC kit, good set of shocks, and some work on the front end.

Tomcotexas

Answer 4

he's partly suitable. once you strengthen up on any bike weight is transferred to the rear. On a shaft rigidity bike the pinion equipment tries to climb the hoop equipment. this would sell off the suspension even nonetheless ordinary weight is transferred to rear wheel. They stay "attached" however the guidance geometry ameliorations in case you're no longer tender. present day BMW & Moto Guzzis use hyperlinks and extra pivot factors to regulate this circulation. On older motorcycles it rather is controlled exceedingly plenty with severe overall performance shocks. in case you goose and chop the throttle on BMW's R1200c the rear end will bob up and down like a lowrider automobile. by no ability ought to get air.

Answer 5

That is correct

Answer 6

It depends..

Answer 7

yes, just do it.