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I have a 1992 R100RT with 30k. It is just about impossible to start when it is cold. I mean 45F or below. Where should I look for the cause of this problem?

michael wrote:I have a 1992 R100RT with 30k. It is just about impossible to start when it is cold. I mean 45F or below. Where should I look for the cause of this problem?

There are many things that can cause an airhead not to start. There is a sort of mantra that I have when attacking a problem. It goes along the lines that if an engine has fuel, compression, and spark at the right time, it HAS to run. It would seem to me that you first job is to figure out which of the three things are missing. Having said that, your brief question suggests that not enough fuel is available when starting from cold. The quick check for that would be to pull the plugs in both cylinders, squirt a small amount of gas directly into both cylinders, put the plugs back in and try to start the bike. If the bike doesn't start readily that suggests for whatever reason something other than getting enough fuel to start is the problem.

But really, since you're posting for help, the folks here can help you a lot better if we get more and better information about what all happens as you go through the motions of starting the bike. Although I'd suggested a scatter shot approach, sort of in alignment with your question, if the problem persists then we're going to need more information from you to be effective with our help. Extraneous information if fine. We are capable of setting it aside.

In addition to symptoms information a bit of information about how the bike is being used could help. For example, if you went out to start your bike after a year of not riding it, that would be one thing. If, on the other hand, the bike was starting and running fine yesterday, that bit of information would greatly help us to help you. With more information you will get more effective advice.

Ken

Ken in Oklahoma wrote:

michael wrote:I have a 1992 R100RT with 30k. It is just about impossible to start when it is cold. I mean 45F or below. Where should I look for the cause of this problem?

There are many things that can cause an airhead not to start. There is a sort of mantra that I have when attacking a problem. It goes along the lines that if an engine has fuel, compression, and spark at the right time, it HAS to run.

Actually, if it has enough fuel, compression, and spark. Assuming you have enough compression and your timing is correct, then the thing that can screw up cold starts is not having enough fuel or spark. A weak coil can make starting more difficult, and a blocked enrichening circuit will fail to provide enough fuel for a cold start.

My first guess would normally be that enrichening circuit, although it would be odd for both to get blocked at the same time. Timing or ignition are the only things that would effect both sides equally. Sorry, but I'm not as familiar with the 92 ignition system.

By 1992 I think they did away with the grey "crackomatic" coil. If not, it's something to check.

Yeah, these days "crackomatic" sounds like an automated crack pipe.

Major Softie wrote:

Ken in Oklahoma wrote:

michael wrote:I have a 1992 R100RT with 30k. It is just about impossible to start when it is cold. I mean 45F or below. Where should I look for the cause of this problem?

There are many things that can cause an airhead not to start. There is a sort of mantra that I have when attacking a problem. It goes along the lines that if an engine has fuel, compression, and spark at the right time, it HAS to run.

Actually, if it has enough fuel, compression, and spark. Assuming you have enough compression and your timing is correct, then the thing that can screw up cold starts is not having enough fuel or spark. A weak coil can make starting more difficult, and a blocked enrichening circuit will fail to provide enough fuel for a cold start. . . .

Quite so, except I can't remember a mantra that long.

Ken

I have only had the bike for a short time. I have put about 1k on it myself. I has always been hard to start when even slightly cold. It sat outside last night and this morning around 9:00 at approx 40 degrees I almost killed the battery (a full charged good battery) trying to get it started. It will fire once per push on starter button but just wont keep firing. Starts and runs very well when warm.

Let's start from the start(er). Does the starter motor turn the engine over vigorously, or not?

So no obvious binding of the starter motor (hit the button, engine starts to turn, but then stops completely or nearly so, and maybe turns over more freely on the very next push of the button)?