Other 650 Superjet Eng..a relic of the past ? paperweight? or more

[sixfifty]

BTW, I enjoy my 650 for now. Its got mild porting a milled head, msd enhancer with a B-pipe and Factory waterbox and the thing moves pretty damn good!

 

[datonetti]

My little 650 will have to do for now. New topend, milled head, ported cylinder, B Pipe, match ported manifold, proper jetting, prop and I'm good to go for next season. I say run the 650 if thats what you have. This forum needs a 650 section.

 

[sixfifty]

^^^X2, Word!

 

[mthomps]

My little 650 will have to do for now. New topend, milled head, ported cylinder, B Pipe, match ported manifold, proper jetting, prop and I'm good to go for next season. I say run the 650 if thats what you have. This forum needs a 650 section.

Are you running the stock 44mm carb and what jetting? I may have a set up very similar to this late next spring. Interested to know more about your boat's performance.

 

[sixfifty]

I run what factory pipe has listed on their site for the 650, cant remember the jets off the top of my head.

 

[sixfifty]

its on here - http://www.factorypipe.com/media/instructions/yamaha/650sj01a.pdf

 

[WAB]

I rocked a 650 for the first 2 years of riding surf. I added impeller, intake grate, slightly milled head, Bpipe, advanced the timing, modded the OEM steering, turn plate & nozzle, etc. loads of fun!
Plus, you keep at least 1/2 those mods if you step up the motor size.

You can even use the upper case halves & cylinder from a 61x or 62t motor and bolt it up with the 650 crank and 650 bottom case half.

 

[mthomps]

I rocked a 650 for the first 2 years of riding surf. I added impeller, intake grate, slightly milled head, Bpipe, advanced the timing, modded the OEM steering, turn plate & nozzle, etc. loads of fun!
Plus, you keep at least 1/2 those mods if you step up the motor size.

You can even use the upper case halves & cylinder from a 61x or 62t motor and bolt it up with the 650 crank and 650 bottom case half.

Have you had a 701 set up longer than a 650 now? Is your 701 ported and higher compression head? Do you feel your 701 setup is better enough to be worth waiting longer and skip building the 650?

 

[powerhouseperformance]

2 good options to go with a 650 engine;
Because the port timing is low they make killer 4mm stroker setups by boring the cylinder out to 82mm's, porting, and adding the 4mil crank. This was great for the guys who needed a new crank anyway. Or keeping stock stroke and going 760 with a 62t cylinder. The intake tracts are tight which give good velocity and there are solid gains to be had with case porting. Either of these setups make for a nice budget engine with the stock single 44. Obviously huge future power is ultimately limited, but for a budget build or a good surf ski both are decent options. We did the 62t ported cylinder route for a bunch of SN guys and it was a great upgrade for low dollar$

 

[wydopen]

my first sj had machined 6m6 cases with a 61x topend, taper bored 44, milled head, lightened flywheel, modified cdi and a bpipe and it ripped..i could get 90% around on flatwater barrel rolls in a heavy square hull..i could run that motor right now and be happy..

 

[mthomps]

2 good options to go with a 650 engine;
Because the port timing is low they make killer 4mm stroker setups by boring the cylinder out to 82mm's, porting, and adding the 4mil crank. This was great for the guys who needed a new crank anyway. Or keeping stock stroke and going 760 with a 62t cylinder. The intake tracts are tight which give good velocity and there are solid gains to be had with case porting. Either of these setups make for a nice budget engine with the stock single 44. Obviously huge future power is ultimately limited, but for a budget build or a good surf ski both are decent options. We did the 62t ported cylinder route for a bunch of SN guys and it was a great upgrade for low dollar$

What size investment is that stroker option with the 650 and are the maintenance costs high? Is the performance for money better than a 701 based stock stroke big bore?

What about investment for a 62t on 6m6 bottom? I've heard from many including a builder that the 6m6 bottom is too small. I've also heard that there is little difference between it and a 61x bottom.

 

[mthomps]

my first sj had machined 6m6 cases with a 61x topend, taper bored 44, milled head, lightened flywheel, modified cdi and a bpipe and it ripped..i could get 90% around on flatwater barrel rolls in a heavy square hull..i could run that motor right now and be happy..

That's encouraging to hear because I'm pretty satisfied with a stock 650. Maybe I have a good one but I can't recall ever hearing of or talking to anyone with a bad running 650 motor. Realistically my fun comes from the waves andchasing boat wakes. Flatwater rolls and flips are not in the foreseeable future for me. I feel like I'm close to all I need to be completely free of equipment limitation.

 

[High Speed Industries]

I came across a couple 650 cylinders for free and I think I will be getting a complete motor sometime soon. I was to try and learn how to port with these cylinders. It's a cheap way to learn and if everything goes right I should make good reliable power. But if you want more power out of a 650 I suggest mill the head and lighten the flywheel.

 

[High Speed Industries]

honestly my 650 SN all it has is a pumpstuffer tall prop (unknown) full coffman exhaust jetted carb and milled 10ths on the head and shes a quick little b@stard beats my friends stock sxi pro it gets the job done for a backup / loaner ski

I hope you are not talking about my sxi pro. . .

 

[orangefinger]

thats what i wanted to hear !!! PHP great advise

 

[NVJAY775]

Awesome thread! I think it would be a good idea to have a 650 Forum too. From previous posts there is a lot that can be done with them budget wise and It would be nice for more guys to have access to that info.

My son has a 650 in his BG2 carbon and it hits VERY hard for what it is. Limited b pipe, xmetal water box, enhancer, 9/15 hooker, dual cooling. That thing is SO snappy.

 

[River Rat]

Awesome thread! I think it would be a good idea to have a 650 Forum too. From previous posts there is a lot that can be done with them budget wise and It would be nice for more guys to have access to that info.

My son has a 650 in his BG2 carbon and it hits VERY hard for what it is. Limited b pipe, xmetal water box, enhancer, 9/15 hooker, dual cooling. That thing is SO snappy.

could you post vids of it while hes riding it? sounds interesting

 

[ajmps1]

I work with a guy who builds up custom golf carts with 2 stroke engines. I keep telling him about the old 650's and how cheap they are to pick up. He says he wants the next one I get my hands on. Just need to figure out a closed loop coolant system and they are some good cheap power that should run damn near forever.

could you put them in a snowmobile?

 

[NVJAY775]

could you post vids of it while hes riding it? sounds interesting

This is about all I have of it. Hard to see a lot of him riding, because he's so far away. Mine was having needle and seat issues and a broken motor mount, plus I was suckin this weekend. Could have been all the beer,,, I dunno. Hopefully this link works.https://vimeo.com/47146402

 

[River Rat]

thx for the post nvj...great family time!