Super Jet Porting a SN 650?

[SXIPro]

Would it be worth it as a 'free' upgrade/boost in power? Yes, I know i should drop a 701 in, but humor me, because this thing is rapidly draining my wallet. Has anyone done it? Was it worth it? Anyone have a template/instructions? It has a Westcoast head and a Coffman Sizzler on it if that matters at all.

Thanks for any input.

 

[Rushford_Ripper]

I plan on porting a 650 that I have for a square hull. @yamanube has the templates for porting.

 

[Quinc]

Groupk says they are able to get some decent power out of the 650 with porting. Throw a Zeel on it too.

 

[Storbeck]

EVERYTHING MUST HAVE A ZEEL!!

 

[SXIPro]

Groupk says they are able to get some decent power out of the 650 with porting. Throw a Zeel on it too.

I don't even have a Zeel on my own ski yet!!…….yet. The square has a lightened flywheel and a no rev limiter CDI, as far as ignition goes. I'm trying to keep the SN as cheap a build as possible since I have to save for my little girl's wedding. (Though she would probably rather have me spend it on a B Pipe for her Blaster)

 

[hornedogg79]

I've been toying around with a 6m6 since last summer while saving for a new top end. Not sure who ported it but it looks really nice. Ran great until my old westcoast head sprung a leak. Put a stock head on and now it's gutless. Compared to a ported 61x it had less bottom end but equal or more mid to top end. Pretty sure this was an old 701cc race cylinder. I've read some would port and bore these to 81mm because they could make the port timing higher than 61x. If you have the tools and time I say do it.

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[yurkanip]

I ran a ported 650 in my old square mostly ridden in surf and it was a good little motor. Had decent bottom end, with a good mid to top end. I ran that with a FX1 B pipe chamber and it was pretty close to a 701 at that point. They are cheap and can run well, with pipe and msd or zeel as others have mentioned.

 

[SXIPro]

Do you need to rejet after porting?

 

[yamanube]

Port it

 

[waxhead]

Port it with a 61x

 

[Jr.]

be careful if you go ahead and port the 6m6. The water jackets are very close, and easy to cut into, thus ruining the cyl. Have not ported one of these in years. They woke up nicely when done correctly. The next issue you will run into is headwork? No aftermarket heads avail for the small bore cyl. So once the cyl is ported, you will need to get the oem head custom cut to match the portwork on the cyl. If it was me, I would seriously consider going the 61x route

P

 

[SXIPro]

be careful if you go ahead and port the 6m6. The water jackets are very close, and easy to cut into, thus ruining the cyl. Have not ported one of these in years. They woke up nicely when done correctly. The next issue you will run into is headwork? No aftermarket heads avail for the small bore cyl. So once the cyl is ported, you will need to get the oem head custom cut to match the portwork on the cyl. If it was me, I would seriously consider going the 61x route

P

Thank you Paul. Maybe I will try to find a donor 701 then. Problem is up here we aren’t tripping over jet skis like down your way. Remember I had to drive to another country to get my RN that you helped me with a couple times. . Again i really appreciate the input!!!!

 

[mikidymac]

I had the same issue and didn’t want to spend much on my 650 since it was just going to be for the kids to learn how to ride a standup on. I just cleaned up and widened the exhaust ports a little and sent the head to Group K to be cut for 91 octane.

The little 650 really surprised me with everyone saying how much they suck and just get a 701 it was a blast. For $80 to have the head done it’s a great and fun ski.


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[mthomps]

I had an un-ported 6m6 motor with a protec pipe and stock pump with bored nozzle and a jetworks A prop that, while topped out at 32 mph, lol, had a stronger pull than bone stock 61x superjets

I would say go for it.