Surfriding stroked engines

Location
australia
just wondering has anyone tried stroking a standard bore 701 instead of going big bore because i heard alot of people are selling the big motors and going back to 760 but i know longer strokes make better torque then big bore and i know from racing motorcross a strong torque curve is easier to ride then a strong hpa curve more useable too as torque is usually lower in the rev range then torque. Just idea i have being thinking of trying to make a strong reliable engine, any info would be usefull
 

GIL

Power In The Hands Of Few
Location
Cullman AL
Here is MY experience...
5 mil Lamey stroker BigBore running Kawi flat top pistons,
New top end every winter-approx 150-190 gallons of fuel
Have 700 gallons on the crank and have been lucky so far.

My neighbor is running a 5 mil crank with 82 mm Yamaha/Wiseco pistons and follows the same pattern I do.
 
Location
dfw
just wondering has anyone tried stroking a standard bore 701 instead of going big bore because i heard alot of people are selling the big motors and going back to 760 but i know longer strokes make better torque then big bore and i know from racing motorcross a strong torque curve is easier to ride then a strong hpa curve more useable too as torque is usually lower in the rev range then torque. Just idea i have being thinking of trying to make a strong reliable engine, any info would be usefull

Your motorcycle engine experience does not apply unless it was squirting water out the back for propulsion. Good luck making more thrust at lower rpm.
 
Location
australia
Thanks Gil that's What I wanted to know.
That's why I was asking the question didn't know if it was going to be the same situation on the water most of the skis I have rode are all chasing the low end punch and low end punch comes from torque in most situations but didn't know if it was different with the jetski pump
 

OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
A strong torque curve is easier to ride then a strong hp curve, more useable too as torque is usually lower in the rev range then torque. Just idea i have being thinking of trying to make a strong reliable engine, any info would be usefull

You have described the first surf engine I built that now resides in my wife's SJ. It is a TLR ported 62T/62T stock bore 760. Essentially it is race ported but has strong pull off the bottom as well as excellent mid to top end. It has a linear power curve that is very predictable and very rideable. As far as reliability, I build the engine 4 yrs ago and haven't turned a bolt on it yet. I like the fact that it uses oem pistons and crank too.

I upgraded to a SS865 because it was the cool thing to do at the time but I still like riding the 760 and it holds it's own. Since I spent under $2K on the 760 and over $6K on the complete SS865, I have to say it was a hard pill to swallow and I would argue that it is not worth the upcharge.
 

OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
The stroker will always make more torque, I was just offering up that the OP could get the power curve he was after in an affordable package. I would not trust just anyone with the porting of a 62T cylinder though. Todd Lachance of TLR Racing did mine and has a very good reputation. Unfortunately I believe he has moved on to bigger and better engines including 4 strokes. I'm sure any of the big names in power can get you similar results.
 
By the time you add up the cost of a stroker crank / case work / on top of the porting etc you will have spent a pile of money and still have a stock cylinder . Even the resleeved big bore setups are expensive when you look at what you are getting compared to a Dasa top end kit , although there are some good deals on used big bore 62ts floating around.
It's all in how the thing is setup and dialed in . Doesn't matter who ported it , if you don't have all the other pieces in place and working right .
 
sj762 has a 760 done by XS that has a ton of low end snap and great power all the way up...Chuck cut the cylinder base down to lower port timing on the 760/62T cyl...this requires custom cut domes to compensate for squish relief...one benefit with the 62T is beefier cylinder casting. Very strong engine for the money...
 
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