Advice Needed - 650SJ Engine

[bassman215]

New to the boards... What an awesome place!!!

Been an avid SJ fan for years. Have a 91 SJ 650 w/ some mods.

Weastcoast head
Coffman's Pipe
Lightened flywheel
WW cone
skat-trak impeller
etc...

I have a dilema. I totally jacked up the lower starter mounting bracket that is part of the lower case of the motor. Long story. Dang cast aluminum. I don't think it is worth even seeing if it can be fixed...

Here are my thought's but wanted to see what some of you guys/gals think...

I am on a pretty tight budget but wouldn't mind more power. Who wouldn't right? My idea right now is to give a shot at the racelogic templates and port my cylinders I have now. I think it would be an interesting and fun experience. Never messed with that, but that's what the templates are for and a place like this right? Maybe hone the cylinder and slap on a new set of rings and call it good. I have been off the water for two years now and just am ready to get on the ol' SJ again.

Does anyone see any problems with my plans so far. I don't want to be spinning my wheels here, but would also like to keep this little project around the $300 mark.

I have thought about trying to piece together a 701 but that's going to get expensive. Seems like porting a 650 wakes it up quite a bit, at least from what I have read.

I am going to have to pull the motor apart any way to fix my original problem, so I though a little porting couldn't hurt...

Another question, is there a problem with using a bottom case half with the upper case half that I have now or is it better to find a set?

Thanks for all the help. This place is great.

BTW, my main goal is more low end. I enjoy just goofing around, jumping waves, etc. Not too crazy about just going fast.

 

[surfjetlouie]

I have some 650 6m6 cases here cheap $60 shipped to 48 states.
I also have the complete gasket set for the 650 motor.
PM me for detail.
Louie

 

[bassman215]

Until I have 5 posts I get an error message that says I can't PM. Shoot me an email if you would like. casey@wildhoghildebrandt.com

I guess I will have 5 posts soon, but until then...

 

[Mouthfulloflake]

to be SUPER cheap and fast..

just flip the engine over, and remove that lower case half, clean the case sealant, and stick another lower case half on there. ( careful not to spin the crank bearings, and this should be a really simple to do thing)

 

[bassman215]

Wow! That would be really cheap and fast! Thanks for the idea. Maybe I'm not quite that cheap.

I guess this case being screwed up gives me an excuse to try my hand at some home porting and I figured as cheap as the old 6m6 stuff is I wouldn't be at too much of a loss if I screwed up the port job... But if I did an ok job, which I am confident I can, then I would really enjoy the extra power.

I think it's that little voice in the back of my head that says, "You know you are not going to be happy until you take it completely apart and put it back together!"

Anybody else have that same little voice??

 

[The Penguin]

Wow! That would be really cheap and fast! Thanks for the idea. Maybe I'm not quite that cheap.

I guess this case being screwed up gives me an excuse to try my hand at some home porting and I figured as cheap as the old 6m6 stuff is I wouldn't be at too much of a loss if I screwed up the port job... But if I did an ok job, which I am confident I can, then I would really enjoy the extra power.

I think it's that little voice in the back of my head that says, "You know you are not going to be happy until you take it completely apart and put it back together!"

Anybody else have that same little voice??

yes - would it be illegal to kill the little bastard? :biggrin:

 

[bassman215]

He's a sneaky little sucker. Always seems to start messing with my head when my wallet is empty!! Dang it!

 

[wayne]

to be SUPER cheap and fast..

just flip the engine over, and remove that lower case half, clean the case sealant, and stick another lower case half on there. ( careful not to spin the crank bearings, and this should be a really simple to do thing)

i did this to replace my seals on my crank shaft. the stealer ship wanted to do a complete tear down. i got it back and did what mouth said.

 

[Matt_E]

Note that the Racelogic templates are not for the 6M6/650 cylinder.

They will work, but you need to be very careful not to cut into the waterjacket, as the casting is more narrow in that cylinder than in the 701.
It can be done, though.
Another thing you must consider is the small size of the transfer ports on that cylinder.

I am sure that just making those exhausts wider than they are stock would help a bunch.

 

[bassman215]

Really appreciate all the help. One of these days I'll move up and play with the big boys with a 701/760 setup, but for now I'll try and squeeze what I can with the least amount of dollars!! I will be very careful about the not taking too much and getting into the waterjacket also. Thanks.

 

[Mouthfulloflake]

I ran a 650 up until mid last year, with a pipe, lots of compression, rev limiter upped ( or removed) and advanced timing, it was good power.

 

[ATS_Scott]

I did the sportport (racelogic?) template on my 6m6. It is certainly a nice upgrade. Get yourself a dremel with right angle attachment and you can tidy up the transfers a little too. Little carbide cutter assortments are available too, that will chuck-up in your dremel.

I still have the template if you haven't bought one yet.

 

[bassman215]

Haven't bought anything yet...

One of the other memebers said he'd be able to hook me up with a paper copy of the templates. If those don't work or something I'll let you know, but I think it should work just fine. Thanks a bunch for the offer.