questions about 77 srx 440

rob jerico

rob jerico

New member
Joined
Nov 28, 2006
Messages
28
Age
49
Location
ontario
i just picked up a mint 77 srx 440, was wondering if anyone knows how much horse power these sleds made, how many were ever built? what can i expect for top speed on a nice flat lake? thanks
 

DUDE, NOT TO DOUBT YA. ARE YOU SHURE ITS A 77 SRX. PREFIX WAS 8F2. BEFORE I GIVE YA DETAILS, JUST MAKE SHURE. NOT EVERYDAY YOU JUST '' PICK UP A 77 SRX ''!! 3:16 (tony)
 
yes i am sure its a 77 srx, i just had to add a yamaha to my collection, i also got a 73 thunderjet 650, 75 thunderjet 440, 79 skidoo 440 snopro, 82 340 skidoo snowpro, a motoski super sonic, and a bunch more vintage pieces. the previous owner(original buyer) of the srx told me it came from the factory with 102hp, and then a bulletin to mod the sled was issued to bump it to 110hp. i am skeptical of those numbers thats why i asked those questions, anyone know what stock gearing would be for the srx, i want to do some speed runs and would like to gear it to run fast. thanks
 
thats sure is some rpm, how come they made so much power back then?what kind of fuel and premix ratio should i be using?
 
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they rev'd 9000 stock and were 96hp stock.
if your going to rev it 9800 or higher, you should be running mod race pipes.
i rev my 77 srx mod at 10,000 with Aaen wild race pipes and 44mm carbs. it was dyno'd at 101 hp.
with todays quality oils you can run safely at 40:1
yamaha sugested 15:1 back in the day. now thats smokey!
 
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Mine was 100% stock. Stock pipes with stock dump box. Stock 44mm carbs with air box. Stock cylinders(not ported) and stock heads. I don't have the dyno sheet any more. If I remember right it made around 88HP at 9000rpm. Made 98HP at 9800rpm.
Run 100 octane min. You've got to run them lean. Made 92HP at 9800rpm with stock jets at 35Deg. I only Drag raced mine on the ice,500ft.
Check your plugs color (No darker than cinnamon Brown) Check your piston tops for the correct wash pattern.
5500 engagment rpm.
 
can i beat a new phazer top end with this beast? i got a friend who bought a new one and would love to drive by him.

2stroke forever
 
Yes,I woke up at 4am, realized I said my carbs were 44mm. 40mm is what was on it.
Wasn't willing to get out of bed to correct it though.
New Phaser or old, the SRX will kill him. Just don't race him in the snow.Plowed road or on the ice. I rode my 77 in 6in. of snow once and and snow came up thru the belly pan slots and got on the belt.Didn't go to good!!

Mark
 
That's correct. 40mm. My drag 77 has a set of tricked out ssr cylinders and heads. The pistons also have some tricky dick modifaction to them. With Delaughters new pipes it's making 120 at 10,200. Ingagement is at 6,800. I need that snap out of the shoot when I'm against those 440 rotax's. Why didn't Yamaha make the 77 srx a reed with tripple port ex? That really would of done it. Dean-o
 
I HAVE EVERY BIT OF INFO EVER PRINTED ABOUT THE 77 SRX FROM YAMAHA MANUALS TO TECH BULLETINS, TOO OLD MAGAZINE ARTICLES. I RACED ONE FROM 1988 UNTIL 1996. THE 77 SRX IS THE MOST WINNING SLED IN THE HISTORY OF SNOWMOBILE RACING. THIS SLED WON AT EVERY RACE IT COMPETED AT IN 1977. THEY WERE LEGENDS. SOME INFO
WEIGHT - 337
HP - 98
FUEL- RACE - PREMIX
CLUTCHES- YAMAHA YP
PIPES FACTORY TWIN THAT WERE STANDARD AND COPIED FOR AAEN WILD PIPES
OPTIONAL STINGER UPDATE
PREFIX 8F2/ SUPER SEEDED INTO 8H0 WHEN 8F2 PARTS WERE GONE.
RPM - 9700 /10,000
CARBS- .40 mm / power jet
TRACK - STEEL CLEATED ( heavy )
GEARING- 18/35
ALUMIUM PARTS /
GEARS
BULKHEAD
SKIS
SUSPENSION
CHASSIS
CAME WITH 2 GALLON GAS TANK
HOOKED HANDLE AND PADDED SEAT
BACK SWAY BAR
!! 3:16 (tony)
 
Dean O what suspention are you running. I had to bump up to 7200 engagement to beat the Doo-s
 
i will get some pics when i get a chance, gota fix my wifes heating fan in her car today
 
Yamaha one,
I'm still using the stocker that's had some modifaction to it. I lay on the hood. I mean on the F&^^in hood. I'm going to run the vintage stock and mod class with it. I'm just switching pipes and jets at the last minute. I'd post some pics, but I never have any luck on this site. Maybe after Christmas I'll have more luck with my new camera. If I'm good......Dean-o
 
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