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Discussion Starter #1
rebuilt my carbs, first time since i bought the sled.(used) found some interesting things:

==>the mixture screws were all at different spots. one cyl at 1.25 turns out, one at 3.75 turns out, one at 0.75 turns out. The manual calls for 2 turns out. so what the heck??? i put it back the way it was, but shouldn't i put it to factory specs?

==>the clutch side cylinder, i can touch and hold the exhaust pipe, while the other two i can only touch for a second. i noticed there's an exhaust leak at the pipe to the muffler, when i held that as tight as i could the pipe got hotter, but not sh1t hot like the other two. there's spark, compression and the plug is wet a bit. it obviously burning something, but the burn isn't the same as the other cylinders.

which bring us back to the mixture screws mentioned before. should they all be the same, or wtf? i think that may be part of the prob here

help

--matt


btw sled & mods::

2001 Thundercat 1000
--Black Magic head
--Black Magic Pipes
--Boyesen reeds
--192 studs
--Tour buddy
--Clutch kit
 

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I would put 'em to factory, and all the same. Triples are harder to sychronize. You want all 3 cylinders to make the same power to have a smooth engine... Fine tune after you get a general setting. You may want to see about getting a Uni-Syn or other carb tuning tool to ensure equal air flow through the carbs...
 

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On my tcat the mixture screws are all 1 turn out. To synch the carbs I connect the throttle cables to the carbs and lay them on the engine so that I can see the gap at the bottom of the slide on the intake side. I set that gap by eye to one sixteenth of an inch on all carbs with the idle screws and then work the throttle lever watching that all slides start moving at the same time and bottom on the idle screw. If not adj. the cables until they do. Then I install them in the sled and start it up. If the idle is low I shut it off and turn all idle screws in the same amount. Maybe a quarter or half a turn depending on how low it is. Then I start it up again and check my RPMs. Then repeat until I get idle where I want it. It's not how the manual says to do it but I;ve tried following the manual instructions and I'm never sure where all the carbs are at. and I've never had a prob this way. Also your chokes may be misadjusted flooding your middle cylinder. Back them all off to make sure they're seating well. There should be a sixteenth of a inch of play in the lever.
 

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Discussion Starter #4
last night i put all the air mixture screws to stock on advice of my dealer. he said they should all be the same on that model/year. the throttle really snaps now, much more responsive.

that far left cylinder still seems to be cooler than the rest, although when i hold the exhaust pipe tight it seems to warm up a bit. so i'll have to get that leak fixed first and see how it is after that. at 1/4+ throttle it's the same temp as the other cylinders. wierd????

thundercat900, my 1000 only has the single cable going to a rail. the slides are sync'd with my eyeball, but as was mentioned i'd like to hook up a proper tool. anyone know if there's a way to hook up a unisyn or similar without having to drill a hole into the carb?

--matt
 

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The uni-syn goes across the face of the carbs, you pull the air box and put the uni-syn so the air in the carb flows through it then into the carb. They are pretty simple.
 

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Discussion Starter #6
The uni-syn goes across the face of the carbs, you pull the air box and put the uni-syn so the air in the carb flows through it then into the carb. They are pretty simple.[/b]
do you have a link for that tool? the only thing i can find is this


i think i found the problem btw!! wire/cap resistance was 4700/5300/5700 ohms, with 4700 being on the cold cyinder. moved the cap and wires to a different cylinder and THAT cylinder went cold. doesn't make a whole lot of sense to me, you'd think with lower resistance you'd get a bigger spark, but then again maybe it was sparking too soon, i dunno!?? funny, the lowest resistance was on the longest wire, the highest resistance on the shortest one.

NGK btw, not even 1000kms on them. no way i ever would have thought a small difference in ohmage like that could make sure a performance difference

--matt
 

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That's the one. I used one when I had a 1967 Triumph Spitfire with SU twin carbs, gawd that thing was horrible to tune. Twin Mikunis are a piece of cake in comparison ;) Easy to set things to get the same airflow through the carbs, it will definitely make tuning go faster on a triple!
 
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