drive shaft extention /test ride

howdy guy.i extended the drive shaft on my bike by 300mm using heat shrink interference fit and plug welding in then remachined .just got back from a 60km ride from 80kph up to 110kmp hour with no noticable viabration .time will only tell and i have prepeared myself to make another if the plug welds fail.needs rejetting. handles well but does need some effort around town.seat give not a bad ride .overall im very happy.cheers scruff

 

Hope you don't have to prepare another BODY for yourself if the driveshaft fails while you're going that fast.............

Dave F

 

howdy hotfiddles,you have got my attention and i really hope your wrong.the test ride was done at 50-70 miles per hour.i forgot to mention that the drive shaft is enclosed inside of 50mm nb heavy wall pipe plus part of the uni is covered as well.if the welds should fail the drive shaft has no way of seperating,should just lose drive .please let me know what you think may happen as when we create something our focus can become very narrow cheers scruff

 

I'd hate to see a weld break at speed........... theoretically, it should just spin, but spinning parts like that can cause a vibration.Vibration can cause a shake. Shakes can get uncontrollable. Uncontrollable shakes can cause blackouts. Some people have never woken up from certain blackouts.......

Not to be a downer, but I'm worried that a welded 'shaft could break. Especially a lengthened one. There's even more stress on it now......It's longer AND has a 'repair' in it already.

If you're really going to go this route, I'd recommend talking with some high quality metal/lathe shop and see about having one custom made for you out of the correct metal. That way you have a single-piece part, its new, balanced, etc...... maybe even have the length of the shaft thickened a little bit for extra strength.

my thoughts.............. $.02
dave

 

Spline cutting will probably be the main issue with a custom driveline.. the splined area is typically hardened (treated) steel. I dont see any reason this wont work fine long term - but please post if you are still alive and it doesnt! im about to do the same thing for one of my drivelines on my xj650, so im following this thread..

did you get any pictures?

shameless plug for my build: http://xjbikes.com/Forums/viewtopic/t=43716.html

 

scruff your good.... i have chopped a few drive shafts shorter and longer. i make my own axles and drive lines for the trail all the time. you good. if you ever want to know if it'll fail, you need to put a load on it. the best way to put a load drag on the shaft is to roast the rear tire and put all your weight on the back while its lighting them up... if it holds then f*** it, YOUR GOOD!

 

I also think you're "good"

My only gripe is, it seems you "balanced" it by turning it,
grinding away the excess weld to make it uniform.

If it were that simple, every manufactured driveshaft would be made "perfectly balanced" You should take it to a driveshaft shop.
Have them check it.

 

my opinion which stinks as everyone else's, weld the piss outta it, good and deep penetration. f***in bomb it. i like the sleeve set up cause if my welds breaks i get a shaft spinning inside a sleeve. dont have to worry about it coming unglued and hurting me or the poor bastard driving next to me lol. its like a burnt up clutch. simply re weld and good to go... if you can weld dont let the possers intimidate you. i know my welds hold cause i put them to the test over and over again. bomb it bro!

 

o and f*** vibration!!!! your on a damm hard tail. lmao.....

 

An out of balance driveshaft will kill the final drive in short order. That's if it dosen't tear up the U-joint first.