Tips on rebuilding your snowmobile engine

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harleysportster
Posts: 2965
Joined: Thu Jul 14, 2005 12:00 am
Real Name: Pat Scott
Location: Southeast Pa.

Tips on rebuilding your snowmobile engine

Post by harleysportster »

-follow a service manual for any type of repair
-replace worn parts
-replace gaskets,seals
-check the engine ring end gap, minimun of .012
-tighten hardware to proper torque specs(use lock-tite where needed)
-pressure test the engine before startup
-clean entire carb spotlessly( all jets and pasage-ways)
-follow factory specs for carb jetting
-check ignition timing
-install the correct spark plugs
-use the correct octane rating in the gas(see octane post in FAQ section)
-retorque engine head bolts before starting, warm engine(10-20 min.) and let it cool, and retorque the head bolts again.
-From '73 on, mix the gas at 40:1 for the first tankfull when re-ringing or new pistons were installed, then mix as normal at 50:1
-during break-in, don't run the engine wide open for extended times, you want to vary the throttle.
-check the color of the spark plugs frequently(cardboard color=normal, white=lean,black=rich), running lean will cause severe damage
'76 440 cyclone
'76 440 liquifire
'78 440 Cyclone
'75 JDX8 (sold to a member here)
'78 Liquifire(CrossCountry Clone)
'80 Liquifire(sold)
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guitardude081
Posts: 989
Joined: Sun Sep 11, 2005 12:00 am
Real Name: Jack Durand
Location: Brainerd, MN

Tips on rebuilding your snowmobile engine

Post by guitardude081 »

Also...
-On oil injected models make sure to bleed oil pump how it says to in the book
-On liquid cooled motors make sure to check coolant level after it has been run
-Don't forget to connect your impulse line
~Jack
Owner, Durand Motorsports
1980 Trailfire 340 (Grandpa bought new)
1983 Trailfire LX
1982 Spitfire (Grandpa bought new)
(3)1974 295/S
1975 340/S
(2) 1978 Liquifire
2003 Ski Doo Renegade 600HO
1993 Polaris XLT Special with AAEN pipes
2020 Polaris Indy 600 XC 129 40th Anniversary Edition
1980 Liquifire (currently in pieces)
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