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How long after cold start can you ride?

2K views 8 replies 6 participants last post by  vulcanpower 
#1 ·
I've got the bike to the point now that I can cold start it very quickly. The RPMs start to rise pretty soon after starting and the engine seems to run well. However, adding any throttle before the engine is really good and warm causes the bike to want to stall. Its as if the enriching the choke produces is only affected at idle. Once the bike is warm (several minutes of idling) then it runs well. Is this the "cold blooded" behavior everyone talks about or do I still have some carb issue?

-Robert
 
#3 ·
While a common problem, this is not normal. Try adding Seafoam to your tank and/or your carb and let it sit for a day before stripping the carbs completely. It's a real job the first time you attempt it and I recommend trying just about anything before you take it on. I'm no expert, but it sounds like your jets might be clogged.
 
#6 ·
That's how I got to the point I'm at now. The bike had been sitting with California gas in it when I bought it so the carbs were full of gum. They're all cleaned out now and the bike is now running well, other than this odd cold running behavior. In mild weather (say 60F) it takes about 5+ minutes before I can get more than about 3,000 RPM without it wanting to stall. Now, I also have a problem with the thermostat sticking (I've got it on backorder) so perhaps that's what's causing this (just though of that).

Do you typically see movement on the temp gauge before you try to ride?

-Robert
 
#4 ·
I never take off until the bike idles well without the choke. Seafoam always a good thing, but your bike may just be running lean.

Have you adjusted the fuel/air screws on the carbs? That might help.

How cold is it when you say "cold"?

You should not ride the bike with the choke on, and yes, it more or less only effects your lower throttle speeds.

Let the bike warm up..... If you are in a hurry you should not be riding the bike anyway...;)
 
#7 ·
With now perfectly clean & adjusted carbs, I can take off and drive 5 seconds after I start it. I don't hammer the throttle hard until it's warmed up, but if I asked for it, she'd deliver.

When you cleaned the gunk out, did you remove the needle jets and make sure all the little holes were clean & clear, or just unscrew the main jet? If you're not 100% sure the needle jets are clean, I'd start there. Takes me about 5 minutes to pull one: 7mm wrench to each of the bowl cover screws followed by an 8mm 6 point socket on a quarter drive ratchet to the needle jet. Presto, needle jet & main jet are both out in no time...
 
#8 ·
Well 5+ minutes in 60 F weather does seem a bit long. But if the thermostat is sticking....yeah, that ain't going to help.

I'd go with the SeaFoam treatments and see how it does after you replace the thermostat.

If you had a clogged jet, it should behave the same hot or cold. My thinking is the thermostat is stuck open and it is just taking longer to warm up.

KM
 
#9 ·
Not trying to negate your comment KM, but while I agree the thermostat should be replaced, I disagree about the jets acting the same cold/hot. After I last cleaned my carbs and let it sit overnight, the junk settled back into the jets the next morning and I was sputtering on one carb again. Once I rode it up to highway speeds I was able to burn all of the **** out, only for it to happen again the next morning. This happened for a few days and a few treatments of Seafoam before the problem went away.

So, while I'm not calling it a cold/hot issue, cold generally means the bike has sat for awhile and gunk has had the chance to accumulate in the tiny jets. If you have a carb problem to begin with, it could very well mean that the tank is rusty and/or dirty and sucking all kinds of **** into the carbs. Seafoam worked for me, but if the clog is bad enough and (perhaps) you have a small tear in your petcock filter, the problem is bound to happen again, maybe requiring a full fuel system cleaning. Just an alternative way of looking at it.
 
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