rebuild

[chrisrider63]

I might have to do the crankseals on my v-max this year and if i did that i was thinking about doing the update porting on the MAX. If i do this will I compromise the reliability of this nice sled, also I would probably have to pull the oil injection off and mix the gas as the directions indicate for the mods. I just wanna have this thing as my reliable trail sled and looking to see if other guys did these mods and still had a reliable machine. Maybe ill just do a rebuild as it has lots of power to begin with when riding with guys that have 700 and 800 skaz-doos and I hang with them easily. What are the best pistons to run, like i said i just want the machine to be reliable so i can go for day-long rides with it.

[killerklown]

you cant beat genuine yamaha, but it will cost more.

[Bob Vehring]

I did it (porting) to mine last year. First just to be clear,, I was never happy with the engine that came in my sled, someone else had worked on it. I would say that yes it did pick up alittle top end power and never had any issues with reliability from the added port work. I didn't like the lose of low/mid power from having the ports bigger. Always seam a little "boggy" when you hit it below 6000, took a while to get fast.
I got new cyls for this year and welded up the ports to bring the timing down a little, then boring it out to be a 600. Still have work to do on that project but hope to have some answers in a month or so
BTW, my new pistons are from a 670 Rotax They are SPI's, so far look nice and the price is nice I'm not a fan of Wisco's have those in my SRV, only brand that make them the size I need.

[tyler440]

shit, bob i should have sold you my big bore motor parts... you interested in them? pm me if you are..

[Bob Vehring]

Mine are out to 77mm now, the real goal was to change the shape of the ex. port and lower them all some, so I would have had to have them stripped and do all this anyway. Haven't worked on that project in weeks. Have the SRV apart here at home, thats becoming a 550, waiting on pistons and gaskets for that and the 500 El Tigre engine and their ready to go together. Then back to the VM