SRX models

[Reimond]

SRX model info

Hello SRX fellows. Let's collect all technical info under this topic. I will add info under this first post when there is info available.

SRX 340//440 1976 8A7

-440 88hp @ 9000-9500
-340 65hp
-Cleated track

SRX 440A 1977 8F2

-98hp @ 9700-10,000
-VM40 mikuni carbs with power jets
-Cleated track
-Head volume 18,5cc

SRX 440 1978 8H1 (Europe)

-"oval racer"
-8H0 style tunnel with stabilizer
-8F2 cylinders
-Head 8H1 with a bigger chamber than the 8F2's
-8H1 pistons, 8G9 rings
-VM40 (42mm carbs) marked 8H1
-8G9 Crank
-CDI and magneto 8H1
-Head volume 19,9cc
-8H1 Pipes
-Rest is like 8F2

SRX 440B 1978 8G9

-80hp @ 9000
-Liquid cooled twin
-68,5 x 59,6mm
-Mikuni VM36
-Internal drive rubber track
-2515mm / 1010mm / 935mm
-Tank 7gal

SRX 440C 1979 8J0

-80hp @ 9000

SRX 440D 1980 8K2 (USA), 8K6 (Europe)

-75hp @ 9000
-Dimensions 2570 x 990 x 935mm
-Engine RT439
-Compression 7.0:1
-Head 21cc
-Butterfly carbs
-Piston pin 20mm
-Gears 18/29
-Fuel tank 25L
-Primary spring red/brown, secondary yellow

SRX 440 8K6 1981 (Europe)
-Like -80

SRX 440E 1981 8M6

http://www.totallyamaha.net/forums/attachment.php?attachmentid=26052

-88hp @ 9250


SRX 500 1982

http://www.totallyamaha.net/forums/attachment.php?attachmentid=26053

-92hp

 

[dynofun]

The '76 440 is a 9,000 RPM motor.

 

[YAMMIEGOD3:16]

AFEW CORRECTIONS.
1976 SRX 440 RAN AT 9500.
1977 SRX HAD .40 mm WITH POWER JETS. !! 3:16 (yammie tony)

 

[yamaton]

Accually that 1978 8H1 picture is of a 1977 model, I know as it is one of my sleds. No biggie though as they both got the rear stabilizer and look the same.

8H1 sled hade the same 8F200 cylinders with 8H1 pistons that took the 8G9 ring. Heads was 8H100 with a bigger chamber than the 8F200's, so there was a bit less compression. Carbs was mikuni 42 mm with power jet, same as -77 but marked 8H100. Crank was 8G9. The magneto was a 8H1 and the CDI unit was named 8H1 as well.

 

[Reimond]

Great info Yamaton. Sorry about the picture. I just found it from net. Let me know if you wish i remove it.

 

[yamaton]

No problem.

 

[YAMMIEGOD3:16]

PICTURE OF 1980 SRX SHOULD HAVE 8K2 PREFIX. 8G9 WAS 78 SRX. MAN HOW AWSOME IS THAT 8H1 SRX. 3:16 (yammie tony)

 

[dynofun]

AFEW CORRECTIONS.
1976 SRX 440 RAN AT 9500.
1977 SRX HAD .40 mm WITH POWER JETS. !! 3:16 (yammie tony)

The '76 440 is a 9,000 RPM motor. Look in the book. It says 9,000-9,500 but the Grass and Snow Racing '76 books and update sheets say 9,000. (9,100 tops) The '76 440 and '77 Carbs are similar. They say VM 40 but are actually almost 42mm.
Good idea on the thread.

 

[dynofun]

Accually that 1978 8H1 picture is of a 1977 model, I know as it is one of my sleds. No biggie though as they both got the rear stabilizer and look the same.

8H1 sled hade the same 8F200 cylinders with 8H1 pistons that took the 8G9 ring. Heads was 8H100 with a bigger chamber than the 8F200's, so there was a bit less compression. Carbs was mikuni 42 mm with power jet, same as -77 but marked 8H100. Crank was 8G9. The magneto was a 8H1 and the CDI unit was named 8H1 as well.

Yamaton, thanks for all the info you have given on this sled, now, and in earlier threads. I wonder if the pistons are a different profile than the 8HO's and that is why the Heads are different or if they just wanted less comp. to use cheaper and more readily available fuel for the type of racing they had planned. Also, any idea what the difference was between the 8HO and 8H1 ignitions?

 

[YAMMIEGOD3:16]

DYNO, SO WHAT YOUR POSTING IS 1976 SRX RAN AT SAME RPM AS 78-79- 80 SRX THAT HAD SMALLER CARBS, LARGER HEAD cc AND WAY MILDER PORTING. DUDE, COM,ON !!! I DISAGREE , BUT THATS WHAT MAKES THE WORLD GO ROUND. 76 SRX 440 RAN AT 9500. YOU ARE COREECT 76 & 77 SRX DID USE SAME CARBS .40mm pj. NOT .42mm !!! SORRY. 3:16 (yammie tony)

 

[yamaton]

Yamaton, thanks for all the info you have given on this sled, now, and in earlier threads. I wonder if the pistons are a different profile than the 8HO's and that is why the Heads are different or if they just wanted less comp. to use cheaper and more readily available fuel for the type of racing they had planned. Also, any idea what the difference was between the 8HO and 8H1 ignitions?

Well, I don't know why they used this 8H1 piston. Maybe profile was different. The combustion chamber in the 8F200 heads was 18,5cc (I belive) and the chamber in the 8H100's was 19,9cc. I guess they wanted the less compression as high octane fuels was banned from racing in sweden back then. Don't know what the differences between 8H1 and 8H0 ignition could be. Pipes look the same but is named 8H1 so I guess there could be some differences there as well. I don't have the stock pipes to make any comparions.

Again the 8H1 sled above is in fact a 8F2 1977 sled.

 

[yamaton]

DYNO, SO WHAT YOUR POSTING IS 1976 SRX RAN AT SAME RPM AS 78-79- 80 SRX THAT HAD SMALLER CARBS, LARGER HEAD cc AND WAY MILDER PORTING. DUDE, COM,ON !!! I DISAGREE , BUT THATS WHAT MAKES THE WORLD GO ROUND. 76 SRX 440 RAN AT 9500. YOU ARE COREECT 76 & 77 SRX DID USE SAME CARBS .40mm pj. NOT .42mm !!! SORRY. 3:16 (yammie tony)

My answer must differ I'm afraid, the 8F2 carbs I have measure 42mm and is the same to the 8H1 carb. Dont know about the 1976 carb though.

 

[dynofun]

DYNO, SO WHAT YOUR POSTING IS 1976 SRX RAN AT SAME RPM AS 78-79- 80 SRX THAT HAD SMALLER CARBS, LARGER HEAD cc AND WAY MILDER PORTING. DUDE, COM,ON !!! I DISAGREE , BUT THATS WHAT MAKES THE WORLD GO ROUND. 76 SRX 440 RAN AT 9500. YOU ARE COREECT 76 & 77 SRX DID USE SAME CARBS .40mm pj. NOT .42mm !!! SORRY. 3:16 (yammie tony)

Yep Tony, that is exactly what I am saying. '76,78,79, and 80 porting is the same except for the large intake port on the '76. Exhaust port height and pipe determine operating RPM. The '76 got all it's power over the rest from the bigger carbs and more compression. If you don't want to believe me you can read the factory Yamaha manuals.
By coincidence, I think my 4 cylinder drag sled has a cylinder from each. I didn't use 8F2 or 8H0 cylinders because they don't make as much power modded.

 

[YAMMIEGOD3:16]

DYNO, HAVE READ ALL THE MANUALS AND HAVE HAD ALL THE SRX,s. I TOTALLY DISAGREE SORRY !!!!!!!!! READ WHAT YOU JUST POSTED. EXHAUST PORT HEIGHT AND PIPE DETERMINE OPERATING RPM. NO WAY A 76 SRX 440 HAS THE SAME EXHAUST AS A 1980 SRX. THEY DON,T EVEN LOOK ALIKE. MATTER OF FACT INSTALL A 76 SRX 440 EXHAUST ON A 78-79- 80 SRX AND LET ME THE KNOW THE PERFORMANCE GAIN THERE IS OVER THE STOCK 80 EXHAUST. GO OUT AND RUN THEM OFF. AND AS FARR AS WORKING WITH THIS STUFF, WELL I HAD SRX,s FROM NEW UNTIL THE 1995 VMAX 4 800 CAME OUT. SO YEA I HAVE ALITTLE INSIGHT ALSO. TELL YA THE TRUTH, WHO CARES!!!!!!!!!!!! 3:16 (yammie tony)

 

[Reimond]

Good info guys, keep it coming and keep it clean, please.

 

[deanosmod]

The bars on the second 77 are not original....Just my 2cents. Hey the 78 looks like the one I sold Eric. It was that perfect. LOL. Dean-o

 

[deanosmod]

Tony,
Take a cold one from the frig buddy....We all know your the YammieGod. He made more power with 8J cylinders? He didn't use 8F or 8HO because they WHAT???? OK... I'll just take another pill. Dean-o

 

[Reimond]

Do you mean that the loop is different?

 

[yamaton]

The bars on the second 77 are not original....Just my 2cents. Hey the 78 looks like the one I sold Eric. It was that perfect. LOL. Dean-o

The bars look terrible I agree. I have replaced that one since that picture was taken.

 

[YAMMIEGOD3:16]

REIMOND, I INVITE YOU TO RESERCH ANYTHING HERE I HAVE POSTED ABOUT SRX,s 76-80. I HAVE ALL YAMAHA MANUALS, YAMAHA TECH BULLETIN,S. YAMAHA PERFORMANCE UPDATES, GRASS /RACE BULLETIN,S, DEALER BROCHURES, MAGAZINE ARTICLES, 20 YEARS OF OWNING SRX,s etc. IF SOMEBODY SUGGESTS SOMETHING DEFFERENT, THATS FINE. everything i have seen and read shows 40 MM carbs and 9500 operating rpm on the 76 srx. IF ITS 42mm AND 9000 , SO BE IT. 3:16 (yammie tony)