'97 Classic Touring Maint Help / Manual Needed

[meburdick]

Ok... I was able to replace both of the plug boots and I swapped the plugs as well. The sled seems to idle slightly better, but it just does not want to come up off of idle still.

I had the air screw on both carbs everywhere between 1/4 turn out and 2 turns out. And, surprisingly, it was "the least sucky" at 1/4 turn out. Something very well might still be plugged. I'm going to pull the new plugs and see what they look like after being at idle in the sled for a while. The last time (before swapping parts), the PTO side plug was soaked and the other was fine.

[meburdick]

Ok... More testing, more symptoms (or, maybe just better understanding / explanation of the symptoms)

I ran the motor and sprayed carb cleaner on the motor behind the clutch and nothing happened. In fact, I sprayed it in a number of areas (around the crank case for example) and nothing happened.

I pulled the airbox off and removed the vent lines from the carbs (these are connected back to the airbox, so shouldn't matter). Ran the motor and it seemed no different. The "sound" of the bog was much more distinct, but it didn't seem to react any differently.

I covered each of the carbs in turn and the motor quickly revved down and almost died (I pulled my hand away before it could die).

I did a visual check of the carb sync, and it seemed they weren't quite the same at start but ended in almost exactly the same spot. I realized that it's because I had been adjusting the idle screws and they got out of sync with each other. So, I turned them all the way in and backed them out three turns each. The carbs were now basically in sync through the entire pull of the throttle.

I started the motor again and put my hand near the mouth of each carb to feel how much suction each was generating. My hand is not a gauge. I can't tell if they're the same or different.

HOWEVER: In the process of doing this, I had something interesting happen... On the clutch side, bringing my hand very close and restricting the air flow caused the motor to rev up and run more smoothly.

This would seem to indicate a lean condition on the clutch side at idle. However, the clutch side plug tends to show fairly good burn characteristics from idling while the PTO side shows that it's rich.

So, here are my questions:

- Is it possible that the leaner carb is slowing the motor down or is more correctly in sync with things like the timing and that's why the richer carb appears to be rich by comparison?

- Should I pull the carbs again and drop them in the bucket of cleaning dip overnight to dissolve any last residual crud and see what happens?

- Is there something here that I'm missing? Should I be looking now at something else?

[meburdick]

I think I may have a number of small issues that need to be resolved...

I've been some additional research on the Mikuni round-slide carbs. I found some information that says each of the Enrichment Plungers should have a neoprene seal / seat / ring on the bottom that should not be worn. I don't see this on the bottom of my plungers. New ones needed.

I'm not convinced that my cleaning job did an appropriate job of cleaning ANY of the jets, and I've now seen additional information on how to pull the needle jets and clean those. That needs to be done.

Additional thinking about the jets and their relative cost has made me believe that I should just replace them all. Period. What will it cost me? $10? Done. Besides - the previous owner admitted to storing the sled too long with bad fuel. Can you say varnish in the jets?

I need to pull the float arm, the needle, and the seat to inspect and possibly replace as well.

Everything that I've done so far seems to still be pointing toward a carb issue. So, I'll keep at 'em!

[meburdick]

I wanted to come back and update this thread so that there's some closure that might help others.

I ended up pulling the carbs again, completely dismantling them, and throwing them in the dip overnight. I also replaced the pilot and main jets, bowl gaskets, and the needle / seat assemblies. I rebuilt the fuel pump. I dropped the E-ring on the jet needle so it was one position up from the bottom (factory setting). New plugs, new plug boots, and fresh gas.

My total investment was probably somewhere around $100 in dollars, four hours of my time (counting ALL of my time, not just the last round), and an invaluable amount of learning.

The sled runs quite well now and I'm waiting for the snow so I can see how it will do on the trails.

Thanks to all for guidance and reassurance of things to check and do.