61x cylinders on 62t cases explanation

[Patrick Star]

I think I have heard about this set up before. Can someone explain it a little more as I'm trying to weigh all my options as I gather parts for my SN hull swap and be pretty cost effective.

 

[steve1981]

basically the 61x are ported for more bottom end while the 62t cases have larger intakes and build more crankcase pressure. so you get the best part of each motor and put it together for a kickass final product geared for freestyle

 

[Patrick Star]

Thanks. Looks like that is the direction I want to go. Now to build or just try and buy one used...

 

[steve1981]

do you have any 701 stuff now? if not you'd be looking at around 300 bucks for cases and cylinders shipped, then just tear your 650 down for the crank.

 

[Patrick Star]

That would work perfect, but how long do cranks last? The 650 engine I have is the orignal from '93 and is kinda broke in, it had about 142 PSI in the cylinders about a year ago.

 

[go4it743]

if your worried about the the crank go to sbt. your crank and $198 gives you a brand new one trued and welded. all new then no worries.

 

[Patrick Star]

Yea.. I don't know with SBT, but I figure it would be better than running a 17 year old crank... Don't really feel like tearing apart a running 650 to get the core out though either. I would rather sell the engine as I feel it does have a few years of life in it and then buy a doner crank. The thing about a used crank is you don't know the hours on it. Oh well, maybe SBT it is then. I do have some time on my hands.

 

[Patrick Star]

On second thought... I just might go with SBT, seems that they have improved quality??? I really want to build my own engine and have a few months to think about this descision. Also building myself I can do what I want. Still undecided about the 61x on the 62t cases, but will run 62t cases for sure.

 

[jetski9010]

I would stay away from SBT. More then likely it will work but you get what you pay for. I would hate to put $1000 into a motor/ski setup and then something in the crank let go because you wanted to save $100-$200. I would get a good shop to rebuild your crank. Check out www.jetskimechanic.com he does really good work.

 

[jetski9010]

also if you have someone port your 61x cylinders before you put it all together you will be very happy with the upgrade in performance.

 

[Patrick Star]

Jetski9010 your probably right. Why skimp on the heart of the build?

I was thinking getting a stock 61x bore and having them bored and ported when I get my crank rebuild at the same time.


Guess I'll go ahead and get the cyl's and the cases.

 

[Boris]

Split that 650 motor and check that crank out.
For all you know it might be perfect.

I'm running a 20 year old crank out of the original 650. The thing was mint so it stayed.

 

[jetski9010]

Unless you have all the tools and the know how to check a crank out to see if it is all in limits I would just have the crank sent out to be checked/trued/rebuilt.

 

[Patrick Star]

It never crossed my mind to send it off to get it miced... Then if the crank is out of specs they will already have it for the rebuild.

 

[jetski9010]

yea that would be the best thing to do. The thing is most of the engine builders are perfectionist so more then likely on a 15 year old crank there going to go with getting the crank rebuild but you never know maybe you got a good one.