What is really "needed"?

[kevbo]

It is no longer economical to port/bore a 650 cylinder with so many used 701 cylinders available.

 

[SXIPro]

If it ain't broke, dont fix it. I like your theory madmat! It would have just been preventative maint. anyway not really knowing what the previous owner has done. It has a prop - 7.4 Skat Trak which I am told is the old style sj 7/14 pitch. No pipe though. I have been told a pipe on a 650 doesnt make as much of a difference as you would think. I have a hard time believing that though...

Wrong. Our 650 was a complete turd until I piped it. If you don't decide to go the 701 route, a decent prop and a Coffman Sizzler will really wake that thing up.

 

[jetski9010]

It is no longer economical to port/bore a 650 cylinder with so many used 701 cylinders available.

I think it comes out to be about even it just depends with what you got. I know the 650 build I did the guys engine was super clean.
Yes you can find 61X cylinders for $100 somtimes but they might now be in the best shape so your going to have to get new pistons $180, bored to new pistons $90 crankcases bored to fit cylinders $80, 701 stock head $50, Gaskets $50 Now you are already at $550 and you have a 701 stock 701 top end that is not ported and has stock compression. You are also going to have to figure out what to do with your carb setup.
The Group K kit cost $880 and that includes the new pistons, boring, porting, shaving head and reshaping it, decking surfaces, dual cooling, Primer kit, Top end gaskets, and modifiying your carb. Like I said this might not be the best choice for everyone but I still think its a great kit and a good price for someone with a 650.

 

[jap7t8]

If it wasnt a 20 year old ski i would be more apt to upgrading the motor in some way (boring to a 701, buying 61x cylinders, buying a whole 701). But i think id rather save the cash for a rn when the time comes and have the 650 as the friend/learner ski. My buddy just bought a 93 650 with a sizzler on it so Im looking forward to seeing the difference in the two. That might push me over the edge to at least get a pipe for mine. I already have a worx 201 and a skat trak 7/14.

 

[jetski9010]

If it wasnt a 20 year old ski i would be more apt to upgrading the motor in some way (boring to a 701, buying 61x cylinders, buying a whole 701). But i think id rather save the cash for a rn when the time comes and have the 650 as the friend/learner ski. My buddy just bought a 93 650 with a sizzler on it so Im looking forward to seeing the difference in the two. That might push me over the edge to at least get a pipe for mine. I already have a worx 201 and a skat trak 7/14.

Holding out for a RN would be a good choice too. I think the sizzler pipe would be a good upgrade as long as your carb jetting is right.

 

[jap7t8]

Holding out for a RN would be a good choice too. I think the sizzler pipe would be a good upgrade as long as your carb jetting is right.

i was wondering about that too. ill do some digging. im thinking id have to go back to my stock flame arrestor too (currently has a k&n).

 

[jetski9010]

i was wondering about that too. ill do some digging. im thinking id have to go back to my stock flame arrestor too (currently has a k&n).

You have to think you are going to spend at least $200 for a used pipe. If you were to get that sleeper kit for $529 everything would be setup for you and there would be no guess work. I also think you would be getting a lot more power from that kit then just bolting on an exhaust. I know you were saying your just going to upgrade later but I think I mod like this would hold you over for at least a season or too and then when you want your friends to ride it it wont be a slug. Just my 2 cents.

 

[jap7t8]

You have to think you are going to spend at least $200 for a used pipe. If you were to get that sleeper kit for $529 everything would be setup for you and there would be no guess work. I also think you would be getting a lot more power from that kit then just bolting on an exhaust. I know you were saying your just going to upgrade later but I think I mod like this would hold you over for at least a season or too and then when you want your friends to ride it it wont be a slug. Just my 2 cents.

Do you work for them or something??? lol

You make a good point though. Guess i need to do some budgeting and see what i can make happen.

 

[jetski9010]

Do you work for them or something??? lol

You make a good point though. Guess i need to do some budgeting and see what i can make happen.

No but I have been done both roads before. buying mixed and matched used parts off ebay and slap them on. You will more then likely find yourself on the side of the lake with your hood off.