I'd be more inclined to think it is a transmission problem

 

hope he's using M1 20W-50

 

By reversing the polarities on the starter...?
Obvious ly somebody is exceptional at working on thier RC51....

 

http://www.rcuniverse.com/forum/m_44...tm.htm#4430470

http://answers.yahoo.com/question/in...1185445AAkmP4V

I think the 2nd hypothesis is close; overly advanced ignition timing and keeping the revs low once started in reverse.

 

It really doesn't sound like he's going through the gears until he gets to 6th and it stalls... the rest of the take off's sound almost identical.

 

Yup, also if in reverse, the "exhaust" would be getting blown out the airbox and sucking air in the exhaust, and that'd sound very different.

 

I'de say the engine is running forward, but the transmission isn't assembled correctly.


Or the back wheel is mounted backwards.

 

 

You can not start a four stroke in reverse. You can do this with a two stroke, though. It is impossible because the fuel would never make it in the cylinder as it is injected before the intake valve (in reverse, after). On a two stroke, the operation is the same, the ignition advance is not.

 

with a very slight timing change, you can run a 2 stroke backwards all day long. but not a 4 stroke. the cams timing would have to be seriously modified which is easier to do than the transmission. I bet they simply switched the cams and degreed them correct to the ignition timing.

edit...they would also have to switch the plug wires. but the whole thing wouldn't take that long.

 

it's not a 2 stroke, it's a 4 stroke

 

ya think???

didn't say it was.

 

It's a two stroke X2= 4 stroke

 

since it is a 4 stroke and 2 cylinders in a V and 90deg, you could put front cyl cams on rear and vice versa, time them exactly backwards, switch the plug wires and reverse starter polarity. boom, motor turns backwards and will fire properly pulling air/fuel thru the intake and pushing exhaust out all proper like.

Thats my theory at least......

 

There are no stupid questions.
Only stupid people.

 

I think he put the key in backwards.

 

Sounds like a gear got switched in the tranny.

A few months ago I was able to get my firetruck at work to run in reverse. Its a Detroit Diesel 8V-92 2 stroke. It has a button that you push and hold to turn it off. I went to turn it off and released the button a split second early I guess so the engine was still cranking over. It fired back up when I let go and started smoking out of the intake. So me, thinking it got too much fuel floored it to try to clear it out kinda like a 2 stroke gas motor that loads up. It just blew out more smoke from the intake so I decided to take it down the road. I got about 500 feet away from the station and the little power it was making quickly dwindled to nothing. We called a tow truck and got it back to the station and the mechanic said it ran backwards. Unfortunately the fuel pump is gear driven off the engine so it ran backwards as well pushing all the fuel out of the line and when it ran dry it shut down. The mechanic reprimed the fuel line and it ran fine after that.

 

Owners Explanation:

The owner claimed he took the bike in for service at the dealer and when he got it back the motor ran backward.
Actually the motor was running correctly. The dealer's "mechanics" had routed the chain around the swing arm piviot bolt just behind the countershaft sprocket. There was just enough room for the rear of the sprocket to catch the chain as it was turning the correct direction, but pull the chain in reverse. Here is what the owner posted later...

The bike has been fixed What happened was when they put the chain (530)on the bike it must have draped in between the swingarm pivot bolt and the countershaft sprocket.And there fore the chain was being rotated from the top making it go backwards. If I had taken the time to do the nickey mod I would have noticed it right away. The guys at the shop (procycles) say the 530 chain fits perfect inbetween the counter shaft and swing arm pivot bolt. So if you thought this was a hoax I would say try this to your own bike and see if it goes backwards. All I know is my bike is now fixed and now it needs to stop raining so I can ride the bitch.

 

Sounds like a top notch shop.

Maybe I should bring my bike in for a big bore kit, and a race cam.

 

yeah sounds like a good repair shop, ride your bike in back it out!