randcracing
L1 Scorpion - The Great Snowmobile
Posts: 3
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Post by randcracing on Jan 26, 2021 0:20:33 GMT -5
I am hoping someone out there can help me! my 13 year old son getting into vintage racing and we went and looked at sleds. he fell in love with a 1980 scorpion whip. I'm hoping someone out there can give me tips on what to do to make this sled go. the rules for division he will be racing in pretty much don't exist. the ruling states the motor must appear stock. they don't do squish test or anything. the problem is I have no clue what to do with a points motor. I also do not want to let my son down, and I also don't want him to be way out classed. his class is 85 and older so he will be racing any 440 85 or older. I know these were decent sleds but I'm hoping someone can guide me to making this thing competitive. thank you in advance for any help yall may have
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Post by 80whip440 on Jan 27, 2021 20:01:23 GMT -5
I had an 80 Whip 440 for quite a while. It's a light sled, but that said the belly pan is fairly fragile. Remember it's 40 year old plastic, will crack fairly easily if it gets hit hard enough. The Cuyuna is a decent engine, I would replace the crank seals unless you know they've been done recently. Intake has plastic insulator blocks between the jugs and the manifold, if they're cracked it'll lean out and burn up. They need good airflow, the stock Whip setup needs to be complete (tool box air intake needs to be there as it draws in outside air on the right side). Track does not have alot of bite, but you can add traction aids if allowed. I put a Mikuni on mine with a primer and it started super easy. Points motors arent that hard, if it needs points try and get original Bosch ones if you can find them. Ribbed Comet Duster if allowed, and check that the spring in the secondary isn't weak. Mine was and it wanted to shift way too early.
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randcracing
L1 Scorpion - The Great Snowmobile
Posts: 3
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Post by randcracing on Feb 1, 2021 20:04:25 GMT -5
thank you im glad to know about the air/tool box because I would have removed it . ill also check for the insulator blocks . are there rebuild kits available for these still ? and possibly pistons ?
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Post by 80whip440 on Feb 2, 2021 18:07:35 GMT -5
If you put a Mikuni on it you can delete the insulator blocks as the Mikuni has the rubber mount which would isolate any heat transfer. Winderosa has gasket kits, bearings are common size and plenty of them around if you need parts.
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randcracing
L1 Scorpion - The Great Snowmobile
Posts: 3
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Post by randcracing on Feb 2, 2021 23:25:06 GMT -5
awesome thank you, do you still use the air/tool box with a mikuni ? also what size mikuni did you run on yours and where is a good place to start with jetting ? I appreciate your feedback
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Post by 80whip440 on Feb 3, 2021 21:40:05 GMT -5
The tool box/intake runs to the cooling fan on the motor. You need it to bring cold air in to the fan which then goes across the heads to provide cooling to the motor. I used a 34mm Mikuni off an Arctic Cat and ran a Unipod filter. The original Walbro mounted to an airbox which sealed to the hood and pulled in air thru the ductwork mounted on the hood panel. I'd have to look and see if I still have the carb specs somewhere. To mount the Mikuni flange to the manifold you have to remove the carb mounting studs and replace them with allen head bolts. The nuts on the studs are too big to clear the Mikuni carb mount (spigot) Here's a pic of the carb mounted on mine: You need to add a choke cable and a new throttle cable to use the Mikuni. You also need to add a fuel pump.
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Post by speedbuff on Feb 11, 2021 0:06:39 GMT -5
Ok if you want to go quicker get a mikuni from a 79-80 tk or sting 440. Grab the exhaust as wel it is good for some extra ponies . You could remover every other cooling fin in the mag side cylinder head that will cause a more uniform head temp . The paraslide suspension would a a worthwhile update as well depending what type of racing you will be doing . Wrap the pipe if youre donor pipe is from a 19i0 model 79's came with this although it may be missing . Thats it aside from some jetting if you wanna go fast good luck
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Post by vintageracer123go on Feb 17, 2021 14:43:28 GMT -5
When i built my race sled, i used a comet 102c clutch and it performed phenomenal. I dont know what your price range is, but its defiantly a very tuneable clutch. the comet duster is more of a trail clutch, but it is also cheaper.
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