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Discussion Starter #1
I just bought a 94 zr 580, carb. It was running awsome in the cold weather but now that is warm out it boggs out so bad that it stalls, cant even idle. Now im told this is noraml but not from a reliable source. And also when running good in the cold once i hit 50mph the speedo went all krazy. Now would that be a drive bearing doing that? Any help would be appreciated, I havnt owned or dealt with a sled in like 15 years. If you dont use it ya loose it.
 

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On the bogging in warm weather, for a carb sled it isn't uncommon. In warmer weather the engine runs richer, and leaner in cold weather. To protect the engine from running too lean and causing damage, you jet the carbs for the coldest temp that you expect to ride in. Well if you are in weather that is significantly warmer than that you could be running so rich as to cause your symptoms. Racers will rejet the carburetor in the morning and again in the afternoon after it warms up a little to get that optimum mixture. In the past, I myself have rejetted toward the end of the ridiing season when temps were warmer because of too rich running.

On the speedo, what you describe sounds to me like your speedo cable is binding. I would remove it, pull the center part out and clean it with solvent. Then flush the insde of the outer part with solvent. If the center part has any frayed parts, even one strand popped out which you will find by running a cloth over it, replace the cabel. If everything is good and cleaned, re-assemble but wipe the inner cable with white lithium grease before snaking it back into the sheath.
 

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It is only "normal" for a poorly tuned sled. I expect you are jetted way too rich for the warm weather and that is why you are bogging out and it will get bad enough that the sled won't even move, BTDT. The 94's came from the factory with a poor calibration and they had a penchant for midrange burndowns. The guys that road them hard, throttle to the bar all the time did not have trouble, but those that did a lot of part throttle cruising melted pistons. The ultimate fix was to install a richer needle jet to fatten up the midrange.

The stock, or factory jetting chart is also way fat. When I did a baseline jetting set up on my sled, not long after I got it, I was 4 - 5 sizes smaller on the main jets from the factory chart. I could run 320 main jets down to about -10C(14F). I got my sled used and the needle jet (sometimes called the "tube") had already been changed out because I run the needle clip all the way to the top position, which is the leanest it will go. Each main jet size is good for about 10C in temperature and this sled, with the big carbs seems fairly sensitive to temp changes. I have a Tempa-Flow on my sled and I just love it because I don't have to watch the temperature, read plugs and change jets every day and during the day. You have to do a baseline set up to know what jets are right for your sled and to let you calculate the correct main jet for the Tempa-Flow, but you'll be amazed how much more fun the sled is when it is properly tuned.
 

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Discussion Starter #4
Thanx guys i leaned it out a notch and she ran wikkid. By the way my idle is around 1600rpm is that close to what it should be. I was told to have it around 2000rpm. And I think ill add a tempa-flow this summer.
 
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