Running sled motor backwards!?!?

[NINJIN]

Is it possible to run a sled motor backwards? In particularly a 1200 water craft motor? Would be with either a ultra, xcr or 650 ignition. It seems to me the ignition system wouldn't know the difference if you pulled it over in reverse? Not looking to do it for reverse, want to run the motor backwards in a chassis with pipes going out under the seat.
Just wondering if anyone has any experience doing this?
thanks

 

[600xc4me]

Saw a guy do it on a ski doo rev, not sure what his setup was or if it worked. Kinda interesting idea.

 

[m8magicandmystery]

i know i had a 92 440 prowler that would run backwards when some diesal fuel accidently got mixed with the gas...i would just pull it over kinda lazy and she would start on the backside and the sled would go backwards..i don;t know if the autolube pump would fail to delivar though..i just ran it backwards for a novelty for a few times..

 

[Wheel House Motorsports]

if im not retarted the doo motors run backwards to do the engine reverse.. same on polaris's with perc... and the new cats.... direction doesnt really seem to matter as the whole motor internally is symetrical.. the only thing I can think of is the oil injection pump and the water pump being spun backwards... just food for thought.

 

[t_thall]

you would have to move the pick-up for proper ignition timing. The ski-doo's with electronic reverse have two pick-ups on them

 

[NINJIN]

water pump and oil pump are no big deal. will be running premix and can make a bracket to get water pump going in the rite direction. Why does the pickup need to move? is that only to be able to have the motor go from forwards to backwards while running? Just to me it seems like the ignition and stator wouldn't know the difference if it was just pulled over in reverse

 

[clutch man]

water pump and oil pump are no big deal. will be running premix and can make a bracket to get water pump going in the rite direction. Why does the pickup need to move? is that only to be able to have the motor go from forward to backward while running? Just to me it seems like the ignition and stator wouldn't know the difference if it was just pulled over in reverse

When you turn the motor forward the pickup coil is set at an advance ( 28 at 3200 on a Polaris) turning it backward would make it 28 retarded.

 

[Idcatman3]

My dad and I have been toying with the idea of mounting a second timing sensor, wiring both sensors to a switch, and when the sled's not running, switch to the other sensor, then pull it over backwards. Timing should then be the same as in forward (provided you get the sensor location correct) and it should run. Sounds like you've figured out the waterpump. You wouldn't need to be able to switch, but you could, then you could have engine reverse also.

 

[NINJIN]

When you turn the motor forward the pickup coil is set at an advance ( 28 at 3200 on a Polaris) turning it backward would make it 28 retarded.

thanks thats what I was looking for. So its just a matter of moving the pickup on the stator plate to 28° on the other side of zero advance. That wouldn't be that hard to do. thanks guys

 

[0007]

I dont think it's that easy
The ignition system has no way of knowing which way the crank is turning
The CDI will still be advancing the timing but if the engine were turning backward then it will be retarding it

 

[Wheel House Motorsports]

seems like you could just switch the two coils on the crank the other way, on the doo's its got the two, and methinks there almost identical, if not the same, put em in the upposing position.... i havent played inside a 2 stroke enough recently to really think about it.. you just need to get the crank triggers in the right order for it being backwards!!

 

[winter brew]

Send a PM to fantom on this site....he checks in once in a while. I believe he has done this on a WC1200.....If I recall correctly he was somehow using a 800 twin ignition setup, not sure if he ever perfected it.

 

[NINJIN]

Send a PM to fantom on this site....he checks in once in a while. I believe he has done this on a WC1200.....If I recall correctly he was somehow using a 800 twin ignition setup, not sure if he ever perfected it.

did he do it for the sake of reverse or to actually run it backwards
I am going to be building a full chromoly tube sled and I am looking to put the motor in the chassis backwards, clutch on the right side, so i need to run it backwards all the time.
thanks

 

[ruffryder]

have you looked into a gear - gear drive unit? I know it isn't what you are looking for, but it would solve the problem of direction, though it might bring up other problems with reliability / building issues.

 

[0007]

How are you going to start it?

 

[Norway]

have you looked into a gear - gear drive unit? I know it isn't what you are looking for, but it would solve the problem of direction, though it might bring up other problems with reliability / building issues.

This would be my first plan. Same as FAST does on their Blade snowmobiles.
Doing this would solve everything from waterpump to pullstart, ignition and helix in the secondary.


RS

 

[Idcatman3]

have you looked into a gear - gear drive unit? I know it isn't what you are looking for, but it would solve the problem of direction, though it might bring up other problems with reliability / building issues.

The Blade sleds from FAST were built this way, with a 2-gear gearbox to reverse the drive direction. You could maybe find a gearbox from one of them, then you could run the engine forwards. To start then, you could just rotate the recoil around, and it would still start the engine correctly.

Edit:

This would be my first plan. Same as FAST does on their Blade snowmobiles.
Doing this would solve everything from waterpump to pullstart, ignition and helix in the secondary.


RS

Guess Rune beat me to it, that'll teach me to refresh the page before I reply

 

[turboDS1300]

I saw something similiar to what I think you are talking about this winter at some local ice drags. The racer's parked next to us in the 'pits' had a F7 chassis with a "stand-up" D&D 1010 in it on a A/C 900 twin case. I was looking the sled over and he had the exhaust running out under the seat so I knew I needed to pop the hood. The intake was in the nose cone and the engine had been flipped to accomodate the rear facing exhaust. Actually, the crank was still in its original position with the PTO out the left side and the electronics and recoil on the right side, just like "normal". They had modified the crankcases to allow the entire top end to be run facing the other way while still keeping the crank spinning forward. So, PTO was still out the left which allowed them to retain the secondary, jackshaft, chaincase, and recoil positioning, yet the direction of airflow from intake to exhaust on the chassis was reversed. It was a real cool setup they had and very unique in my opinion. I don't think they got the sled dialed in that day for 1000' but it sure looked and sounded mean.

 

[TRS]

On the timing issue you could cut a new keyway in the flywheel instead of trying to move the pickup.

 

[Idcatman3]

On the timing issue you could cut a new keyway in the flywheel instead of trying to move the pickup.

In our experience, it was easier to move the pickup than find someone who could cut a new keyway.