Impending tranny doom???

[Firestream]

Just put 500 miles on the new cylinders, pistons, heads and 600 cam this weekend and started to feel a pretty good vibration above 2500 rpm and at slow speeds the bike felt a little jerky. Got back home and thought I better check all the usual suspects like motor mount bolts, tire pressure, tranny mount bolts and primary chain. Everything tight, so I decide to pull the bandit clutch pack and carrier since I had the outer primary off anyway and the clutch pack looked great. The backside of the bandit carrier showed no signs of rubbing the inner primary bolts. So then I figure I better check for any excessive end play and run out on the tranny mainshaft. No end play or excessive run out. I decide to shift the tranny through the gears, checking for shaft end play, no in or out movement of the mainshaft. Now, this is the part I need help with. While shifting into each gear and turning the mainshaft by hand, I notice 3/4" rotational play in the shaft. Meaning, I can rotate the shaft 3/4" before I see the slightest movement in the drive pully. Pretty much the same play in all gears. Anybody know if this is normal, or do I have some kind of internal tranny problem? I believe the jerky low speed feeling is due to this rotating play as the primary chain was correctly adjusted. Not sure what the symptoms are of a mainshaft getting ready to take a shit. Thanks in advance for the help folks...

 

[Raywood]

I would say loose coil cover/motor mount or loose primary chain but you say you check both so don't know what else to check other than tires.

 

[Firestream]

Tires in great shape, not cupping and only have 3400 miles on them. What about the slack in the tranny mainshaft? Does that sound normal to you?

 

[Raywood]

Tires in great shape, not cupping and only have 3400 miles on them. What about the slack in the tranny mainshaft? Does that sound normal to you?

Don't know. Haven't had an issue with the tranny on either of my BD's.

Need Dogvet to chime in on this one.

 

[bdmridgeback]

Gear backlash is normal like that, especially in a trans that has that many gears in it. Also with the bigger cam you are going to have more vibration and the low rpm cruising is not going to be as smooth. That is why BDM puts the smaller cams in them, to make them run out smoother and be more street friendly to all riders.

 

[alhall88]

I was going to also say thats what torque does. I know mine is a little tricky since my motor mods, if I even slighty blip the throttle it will lunge forward if the clutch is all the way out.

 

[Firestream]

Thanks for the info guys.

 

[Mickeetwo]

I know when the mainshaft brakes its usually quick with no symtoms and when my transmission failed (counter shaft had moved) mine stuck in third gear. Doesn't sound like transmission problem.

 

[Firestream]

Took the bike to the dealer this weekend after explaining some of the symptoms to the tech. He pulled the top cover and shift drum looking for problems. He will be tearing it down next week after BDM gives the go ahead. I would really hate to have the shaft break and tear up that pretty Bandit clutch and carrier assembly. I will let everyone know what's up after he gets it apart.

 

[Firestream]

Well, thought I would provide an update on my dog. It was the shift drum causing the problem. Replaced with a new one and good to go. Took it on a 100 mile shake down run this past weekend and ran great.

 

[MARV]

Well, thought I would provide an update on my dog. It was the shift drum causing the problem. Replaced with a new one and good to go. Took it on a 100 mile shake down run this past weekend and ran great.

good to hear.

i'm chasing a vibe now myself. all mounts are tight. while rolling during a vibe i'd pull in the clutch and it'd be gone. must be drive line related. so i was thinking crank runout would be the thing to check. pretty happy to hear it can be only a $200 shift drum!

did your bike ever slip into neutral between shifts?

 

[Firestream]

No didn't get there, but shifting was harder. I guess I'm just paranoid and notice every little change in performance, sound, seat of the pants feel, etc... Now shifting nice and solid and vibration is much less.