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Posted by: Blaster668
In fact most older bikes do have adjustable timing.
Posted by: Raychalp
Fixing the timing on a two stroke? That doesn't really make sense. Let me say this since I just rebuilt 2 250R bottom ends. When you kick an R over(forward kick) the kickstarter gear forces the clutch to spin backwards which in then forces the primary drive gear on the crankshaft to spin forward. The mainshaft is connected to the clutch basket so it spins backwards and the countershaft(which the front sprocket is attached to)which is driven by the mainshaft spins forward. I don't see how the timing has much to do with that problem you described. It almost seems like when you kicked it over you kicked it the wrong way, but that doesn't make sense either. However, if it has a recoil starter, then I would say the it is either installed backwards or was rewound backwards. If this bike has electric start then I would say, check the electrical connections because reversed wires can make an engine run in the opposite direction. I think that the timing suggestion simply means that there is an electrical malfunction. Maybe somehow the polarity of the stator got reversed, I really don't know. I have never heard of this problem before so I can't really say what is wrong.
Posted by: Raychalp
dustness, your idea makes plenty of sense, but it sounds like you are referring to a 4 stroke and his question was about a 2 stroke. Unfortunately, I have only worked on TRX250R engines extensively, so I don't have much experience elsewhere. However, 2 strokes are all pretty much the same. I don't know any way of adjusting the timing on a 250R and I have never heard of doing this on anything else unless you have an aftermarket timing plate. I don't know about Banshees, maybe you can adjust the timing on a stock Banshee. In response to your theory, if what you say is what is actually happening, then I would say you are lucky that you didn't blow a hole in the piston because it sounds like a terrible case of predetonation. In that case you may have an air leak somewhere in the engine. I would then suggest checking for an airleak and then richening up the jetting. I just don't think that the timing is adjustable, especially on the older bike in question.
Posted by: P.J.
Witz is right. Used to have a CZ motocross bike a LONG time ago that did the same thing. Can be exciting.
Posted by: P.J.
Timing.
Posted by: Loofer
Yeah it is the timing...i have a banshee and you can do the same thing on it....jsut retime it like the manual says and you will be ok.
Posted by: Witz
The engine is running backwards. The crank is spinning the opposite direction that it should, that's why all the gears are reverse. I've seen this happen before on a Banshee and it's actually what Ski-Doo uses for a reverse "gear" on some of their sleds.
Posted by: Y2K300EX
Funny story. My friend had a 89 CR250 before he got his 300ex. I was at our friends track. He was going to do a holeshot so he fired it up. He did his holeshot but he went backwards! It was very funny at the time. Everyone was very surprise mostly him.
Posted by: Fireblade74
I have seen this problem posted somewhere before and think that someone referred to a snowmobile having problems like this. Maybe you might want to talk to someone who works on those to give you an idea. Only thing I could think of, is pull the side cover off (clutch side) and check the gears, maybe one has come loose and is engaging a gear it shouldn't?
Posted by: duster
Raychalp,
This is a very rare occasion at best. Here is my theory about how it can run backwards because of timing. Think of it this way...it's kind of opposite of when a car want to keep running when you cut it off. It can run forward or backwards.
This is the only way possible that makes sense to me after having it happen to me on an old trailbike. Agreed, the motor does begin to turn in the correct direction when you kick it. Now think of the shape of the cam and how it makes it's stroke. If you kick and the piston is on its way up, in that narrow window of time between the time the piston covers the exaust port and the time it reaches the top of the stroke, if the plug fires and ignites a charge already in the cylinder, of course the piston is going to go down, and in the wrong direction!! Thus it runs completely backwards as it would run forwards.
If you push down on a clock hand at the 11 o'clock position, does the clock not go backwards? It's all just a case of "perfect WRONG timing" in my theory. Make sense to you?
Posted by: duster
Raychalp,
I know we are talking about 2-strokes. I'm not saying it's a "TIMING" problem as in timing needing to be adjusted on a car. I'm speaking of it in the sense of "bad timing" or the wrong chain if events happening at exactly the wrong time.
I had this happen to me on my old CR125. I was really stumped as 1st. I couldn't figure out what was wrong or how to fix it. I am far from a master-mind mechanic.
A day of thinking about the laws of logic made me realize the problem. Logic was also my fix. I decided the only way to fix it was to force it to run the other way. So, I rolled it down the driveway and popped the clutch. She started right up in the right direction.
I never had any more problems after that. The engine was fine. I sold the bike to my uncle, who still rides it. To this day it still runs fine.
Posted by: Chawness
Not a ATV question but anyway. My friend has a older 185cc 2 stroke bike. Once we got it running (it had set a while) we discovered that no matter what gear the bike is in, it wants to go backwards. This motorcycle doesnt have reverse!! Thats right when you let out the clutch the rear wheel spins in reverse. Any ideas out there?
Thanks in advance!, email me sgmiller@transystems.com
Posted by: Chawness
Thanks, now what is the cure?
