Need help with this blaster!!!!

[2StrokeThis]

ok guys i have a 2004 yamaha blaster this thing has me stumped. i cranked it up and it reved up good and everything but only one problem the engine is running backwards so all the gears are in reverse. it has a fresh rebuilt bored 80 over professionally. put it back together and it wouldnt start for nothing so i pulled the magnet off to look at the stator and found out that the woodruff key was sheared off so put another in and it sheared it so put another in an tack welded the magnet to the crank so it wouldnt shear it again and cranked it but it ran backwards and also was hard to start...any ideas guys im stumped

 

[Awk08]

the only way a blaster, or any 2 stroke motor will run backwards is if the timing is off 180 degrees
so you either welded it on 180 out of timing, or it sheared your tack weld and has slipped again

the solution to this is to use valve grinding compound on the tapers of the shaft/flywheel to increase the interference fit of the 2, thats actually what holds the flywheel in place, the woodruff key is only a guide to the timing mark

spread a finger full of valve grinding compound onto the taper of the crank shaft, place flywheel on and spin back and forth while applying pressure, you'll feel it start to bind
clean with brake cleaner, get the proper woodruff key from a dealer, or online, not one that seems to fit from the local hardware store, torque the nut to specs, i think it's 50 some ft. lbs. and try again

that is if you can get the redneck tack weld off

next time check here before rednecking anything, unless it's a very long walk home

 

[Blaaster]

Pull off the flywheel, lap the shaft, replace the woodruff key, and you may find all will be good.

The key is only a locator, the inteference fit of the taper on the shaft is what stops the flywheel from spinning.

That key has sheared again.

I am going to disagree with Awk here, but a 2 stroke will run backwards with only a little timing advance.

If the motor catches and fires on the upward stroke it may not complete the complete revolution in the desired direction.

If the kicker is at the bottom of the stroke, then it cannot push the piston over TDC, which results in the motor starting in reverse.

I have witnessed it happen on a motor without any mods to the timing, completly as if from the factory.

 

[2StrokeThis]

the only way a blaster, or any 2 stroke motor will run backwards is if the timing is off 180 degrees
so you either welded it on 180 out of timing, or it sheared your tack weld and has slipped again

the solution to this is to use valve grinding compound on the tapers of the shaft/flywheel to increase the interference fit of the 2, thats actually what holds the flywheel in place, the woodruff key is only a guide to the timing mark

spread a finger full of valve grinding compound onto the taper of the crank shaft, place flywheel on and spin back and forth while applying pressure, you'll feel it start to bind
clean with brake cleaner, get the proper woodruff key from a dealer, or online, not one that seems to fit from the local hardware store, torque the nut to specs, i think it's 50 some ft. lbs. and try again

that is if you can get the redneck tack weld off

next time check here before rednecking anything, unless it's a very long walk home

only tacked in one spot to hold and already grinded it off and pull magnet back off. but it seemed like it was backfiring and shearing the keys. i was told cdi box could make it run backwards as well?

 

[Blaaster]

The shearing of keys is caused by a poorly fitting flywheel, and backfiring will make it spin if the fit up is poor..

The backfiring is possibly caused by another issue, but I doubt the CDI.

I have never experienced a CDI defaulting into advance mode, but who knows, anything is possible with electronics thesedays.

 

[2StrokeThis]

its not really back firing just kicking back at the end of every kick if that makes any since. hard to start as well. it might be jus me but it looked like the fire was weak from the spark plug wire but again it did crank and run good and idled and reved good jus was running backwards. Lets say i put the woodruff key back in and put the flywheel back on and still the same thing? my stator only bolts on 1 way i think so it cant be on wrong. the pick up coil which is the lil black box on the stator is on the bottom which i think is correct. would i need to advance or retard my timing to fix it?

 

[Awk08]

pickup coil at like 5 o'clock if i remember correctly

and are you saying you left the woodruff key out last time ????

there lies your problem, the key sets it at the correct timing

and no advancing/retarding the timing

 

[2StrokeThis]

no it was in the last time but i pulled it out when i pulled the flywheel back off and the key was still intact so i really dont know how i could be off on the timing

 

[2StrokeThis]

and some guy just told me the flywheel needed to be moved 90deg counter clockwise,

 

[Blaaster]

and some guy just told me the flywheel needed to be moved 90deg counter clockwise,

Parcel up a lump of doggy doo and post it to that guy.I:I

 

[Blaaster]

Ok so now we know that the flywheel is out of the equasion.

Will it start an run forward, or does it run backward every time?

Could it have a gut full of fuel, and are the reeds in good condition?

If it has been flooded with fuel it can cause backfires.

 

[Larry's Shee]

What did you actually weld8-|? Flywheel to shaftX(? Magnets back into flywheel? Or what? Might consider a different wheel. Make sure you use correct key ONLY. I:I
Did you disconnect wires from stator BEFORE welding?

 

[2StrokeThis]

Ok so now we know that the flywheel is out of the equasion.

Will it start an run forward, or does it run backward every time?

Could it have a gut full of fuel, and are the reeds in good condition?

If it has been flooded with fuel it can cause backfires.

its hard to start but when it does it runs backward everytime. but when it was cranked and running backwards it ran good besides the fact that it was rnning backward so im guessing the reeds are good

 

[2StrokeThis]

What did you actually weld8-|? Flywheel to shaftX(? Magnets back into flywheel? Or what? Might consider a different wheel. Make sure you use correct key ONLY. I:I
Did you disconnect wires from stator BEFORE welding?

yes i unhooked wires and i jus put 2 tack welds on flywheel to crank shaft but i have grinded the weld off and pulled flywheel back off at this point

 

[2StrokeThis]

and yes it does have a little fuel in the gut but i didnt think that would make it run backwards. damn think has me stumped

 

[Blaaster]

Tow start it and run it for a while.

 

[2StrokeThis]

UPDATE!!!! i fixed the blaster and figured out why it was running backwards. i put a different flywheel in it out of a parts blaster i bought yesterday and fixed the problem. cranks first kick now and runs forward everytime.