help with an older sled engine

[ice auger]

Hey everyone----
I needed a little help. A buddy gave me a 1996 Polaris XCR 600 with a mono block triple he had not ridden in 2 years. It was running terible so I cleaned the carbs and they were very dirty. It now idles and runs top end ok but it has a low end bog. Was this normal for the triples? When I rev it, the from the idle to wide open she bogs. My buddy did replace the throttle cable and i think the carbs are ok. I checked to make sure the slides were running at the same time. Took off the exhaust to see if the piston skirts were cracked. All ok, any ideas?

Thanks Ice.

 

[AzCats]

I'm not real familiar with your engine but I have an Arctic tripple that did that. It idled perfect but one of the pipes was cold. Even after repeated cleaning with compressed air, carb cleaner etc. it persisted. It turns out the idle circuit in one of the Mikunis was plugged and the only thing that fixed it was pushing a piece of guitar string thru the idle passages.

 

[ice auger]

Sorry for the double post

 

[go high fast]

My very first sled was the 96 XCR 600 SP but it was long ago so I will go with memory. It came with the rebuildable fox racing shocks, SLP ultra lite skiis and 136 track which I think was "long tracked" from something shorter.

I ride in the mountains so very first trip out I'm burning belts like nobodies business. Changed the gears, helix and secondary spring and no more burned belts. I think may have left primary weights and spring stock but we did a grind on the primary wieghts to increase engagement RPM. I dont recall the exact gear ratio or helix or spring.

I went with the:
1.) DG 3 into 1 silencer and kept the stock triple pipes
2.) Hot Seat hi compression domes


Perhaps the very biggest improvement was for the bog problem. I decide to call Aaen Performance after reading the carb tuning book and, no chit, guess who answers the phone....Olav. He recommends I carefully grind a bit off the bottom of the jet needle which has the effect of increasing air flow at low end......worked like a charm. I think the gear change and the higher engagement also helped eliminate the bog problem. Sled was a wicked screamer!

If the sled sat for 2 years I would go with new main jets and new pilot jets.

Although the sled was a bit on the heavy side the Agressive chasis style from Polaris looked incredibly cool.

I had a ton of fun on that sled. Sometimes I see it around town and the guy who owns it now hasnt taken care of it..........it's terrible upsetting.

 

[ice auger]

I can not firguire out if I still have a carb problem or is this normal for the triples.......low end bog......yuck

 

[Interceptor]

go high fast might be onto your problem - my old 600 triple was very finicky with mid range bogs and the needle position. Usually it was a lean bog so you might want to try raising the needles and see if it improves - its at least free and easy to try
good luck

 

[ice auger]

thanks any other ideas?

 

[Mt-Adams]

Check your clutching.Take the belt off and run it and see if it bogs if not it the clutch. Just don t slam primary clutch to hard. And watch how the clutch shift. That what i look for on my triples motor..

 

[ice auger]

I took the belt off and it still bogs.....

 

[Seeder]

That engine was a little on the finiky side especially low end, large 38 mm carbs, high porting and a short header pipe made for good peak HP but lousy low end response. That sled will not perform unless under load and the proper air temp. The engine will bog on the low end if you are "track stand tuning". With the engine under no load the pipe cannot get to operating temp and allow the engine to run as it is suppose to. Pipe heat and clutching is key for that sled to run good. A set of SLP heads will help out the low end it make it less finiky, varify 10mB weights, dark blue spring (may be light blue if original) and belt is tight to the point that it nearly wants creep when ideling. Wait until temps cool down and run it across the yard to clean it out and to properly heat the pipe and see how it runs then.

-Seeder

 

[sled_guy]

You can check if it is lean or fat on the off idle position by flipping the choke on when you crack the throttle open. If it helps then you know you are lean, if it hurts or doesn't get any better then you know you are fat.

sled_guy

 

[Mt-Adams]

What compression on your piston cylinder?