Bike goes in reverse

[dovertim]

After starting my 55 Hummer I put it in gear and it goes backwards.
I thought it might be a fluke so I shut it off tryed it again the same thing.
Anyone got any ideas?
It's hard to ride bacwards.

[jim garrett]

Timing is incorrect.

[250_Sprint]

Yes, check the timing. You may have to make multiple small adjustments to get it working properly.
As you have found out, 2-strokes will run backwards quite successfully.
Harley-Davidson sold a 2-stroke golf cart. To go in reverse the operator would come to a complete stop, turn the engine off, move a switch to change the polarity going to the starter motor making it rotate in reverse and thus the engine in reverse.

I remember reading about Yamahas RDs running backwards and the suggestion was to stop the engine and restart it, placing in gear and slowly letting out the clutch.

Good Luck and let us know how it turns out.

[richard_blunk]

Same thing happened tao me on my 57 Hummer. Timing was set wrong. Simple adjustment fixed it. Hard to ride one backwards isn't it? I almost dumped mine.

[250_Sprint]

Going back through my notes,
I spent hours measuring and remeasuring Top Dead Center and Before Top Dead Center.
BTDC is where the points should just begin to open, causing a spark to occur at the spark plug.
I set, then rechecked when the points were just opening after rotating the engine by hand, in the direction of operation.
I set the point gap and rechecked the point gap after rotating the engine by hand, in the direction of operation.
I gapped the spark plug to its lowest allowable gap.
All values are per the service book.

I used a digital caliper to measure the piston distance at BTDC as mentioned in the service book.
I used a digital multimeter set on the continuity test setting and set the meter to beep when the two probes were touched to each other.
I placed the probes on the points.
Points are closed and the multimeter would beep.
Just as the points were opening the beep would stop.

I may have set, check, and recheck too many time in the eyes of some. All I can say is, the engine runs, runs good and responds to twist grip movement as it was designed.

Again, keep us posted.

[pumpguy]

Following are steps I use to set ignition timing:

First, set the points gap as recommended earlier.

Next, kick the engine over with the spark plug out to check it makes a spark.

Next, determine Top Dead Center.

Working from the ignition side, rotate the crankshaft clockwise until the piston is 7/32" (.219") before TDC. That's where the points should just begin to open. You can use a continuity tester. When you just loose continuity, thats when the points open and the spark happens.

Interestingly enough, for a 125 BSA Bantam with the same bore, stroke, port timing, and compression ratio, they recommend setting the spark timing @ 5/32" (.156") before TDC. When I was using George Todd high compression heads for racing, he recommended setting the spark timing @.100" before TDC.

I've never had an engine run backwards, but I would think if this were to happen, you would have the spark timing set AFTER TDC. That would mean if the engine were running backwards, (counterclockwise) the spark would then be before TDC

[hennesse]

The good news is that once you get the timing set correctly, you'll never have to change it again.

[dovertim]

Thanks guys. As soon as I get a chance I will reset the timing. My neck gets sore riding backwards.

[250_Sprint]

If you sit on the handlebars it will be easier on your neck.
Keep in mind though, the foot and hand controls are flipped and a passenger might make it difficult to see unless they slouch .
Good Luck.

[jdrench]

Hello, I think it has to be polerized? I don't remember how I did it. As soon as I remember I will let you know. JR