Trippy motor on Ebay!

[XJCrawler]

So is this motor build for bottom or top end?

 

[SUPERTUNE]

I guess that what the long boost port and also two small lower ports are for to get rid of some of that heat. Do you think this is an aftermarket sleeve from back in the day or did he do all the port work and window cutting by hand?

The long and 2 smaller ports are there because they ARE intake ports to get the air/fuel mix into the engine, having the cold fuel charge coming in directly at the piston skirt and getting under the piston is a side effect of a reed inducted cylinder.

So is this motor build for bottom or top end?

Being a non-powervalved cylinder it still depends on the port mapping of the transfers and the exhaust port.
Intake side reed induction is just another way to get air/fuel into the engine.

It's cool to see someone thinking outside of the box with this intake design applied to the 61X engine.

 

[SUPERTUNE]

The lighter the piston the quicker the engine revs ie: response or as the unknowing think of it, bottom end. Response and torque are two different things. When you get into the 87mm+ piston diameter the weight of the piston goes up significantly. Its a give and take thing, heavier piston/more displacement vs. engine rev. acceleration. Waterhawk, I think your right.

Not entirely true, when the R&D Dominator flattop piston came out, it is (was) a very light piston for a 85mm bore piston, under 400 grams for piston and pin.
The CR 500 piston is the lighter of the two 89mm and up pistons including the Seadoo 951mm piston for off the shelf Wiseco pistons. The Wiseco 951 piston is a tank stock, (560 grams/piston and pin) so a lot of special machining is required to get it in the ballpark. The CR500 piston is even taller than the SD piston and it's about 1 1/2-2mm taller than a stock 701/760 deck height piston with a very big dome (crown) to it's design. (old technology when compared to modern flattop designs).

With our SS 865 kits, we designed our custom Wiseco pistons to be the best for our engine setup. So with that in mind we could make the skirts wider for more support, make it a short CD (compression distance) piston and being a flattop and some extra skirt milling we save weight and have less piston rocking for added longevity in a high performance engine package.
If you start out with the 88mm bore @ 827cc, our complete piston assembly is lighter than a stock OEM cast 81mm 701cc piston assembly.
This really is a big plus for the proper match for use with a stock stroke OEM crankshaft balance factor.

 

[MADMAT]

Killer info!

 

[waxhead]

Has anyone looked at the crank and noticed how it looks like an oem crank
Im not sure where that 11mm of stroke went but i cant see any machining that actually accomidates it
And when you consider what the timing would actually be on an oem cylinder with a 11mm stroker on a stock cylinder.
I dont see a spacer plate and if you ran it with out one the piston would have to come out the top of the engine 4.5 mm
Yes its impressive art on the engine but its old school now and While it would look good on the shelf it wouldn't make the power that we are accustomed to nowadays

 

[waxhead]

The thing I would really like to see is the exhaust port and there is no pic of that

 

[egbrig]

Chuckie, I've never got to weigh one of your pistons, so I'm still right (lol) but your piston is designed to be lighter than whats been on the market before, so you've got big bore and light weight. You've push that tradeoff point higher. If we only had aluminumbyrilliam pistons like they used to in F1, 98mm bore 340 grms. with piston pin although minimal skirt and only $800.00 / piston.

 

[SUPERTUNE]

With 2 stroke pistons... they have a big and long skirt to cover the ports (especially the exhaust port).

 

[Flash-FX]

With 2 stroke pistons... they have a big and long skirt to cover the ports (especially the exhaust port).

Example..like you don't want this

 

[the WaTeRhAwK]

here's some "trippy" pistons......

 

[SUPERTUNE]

R&R jet tech grooved pistons! Made them for 440 superstock and 550 mod Kawasakis.
I got that beat! I use to use the die gringer and drawing squiggle grooves in my pistons.:wiggle:

 

[masterblaster]

I want some atimatium pistons for my big bore,lol I weighed my riva/R&D pistons and they were way lighter than the kawi weisco flat tops I was using before.

 

[waxhead]

R&R jet tech grooved pistons! Made them for 440 superstock and 550 mod Kawasakis.
I got that beat! I use to use the die gringer and drawing squiggle grooves in my pistons.:wiggle:

Were you trying to hold oil on the piston ??

 

[the WaTeRhAwK]

Were you trying to hold oil on the piston ??

less surface area to come in contact with the cylinder walls to better accommodate faster and sustained piston speeds. they hold oil too.

 

[WFO Speedracer]

Were you trying to hold oil on the piston ??

When you are twisting a high compression 440 10-12,000 rpm you need to hold as much oil on the piston as possible to prevent seizure, even at that they still seized and released during the races at regular intervals, the engines were good for about one race.

 

[the WaTeRhAwK]

When you are twisting a high compression 440 10-12,000 rpm you need to hold as much oil on the piston as possible to prevent seizure, even at that they still seized and released during the races at regular intervals, the engines were good for about one race.

what cracks me up is when you say 11,000 to 12,000 rpms, and most of the responses you get are like "huh!?!? wha!?!?"...LOL

mostly unfathomable to the "rec" minded


"rec" isn't much what it used to be...lol, I've got a "rec" setup in a boat set to back off at 10.5... : ) it gets a rebuild about every other season.

 

[WFO Speedracer]

Yep the 440 superstock engines were on the ragged edge of performance, they seized often and made lots of power, all of it at ridiculous rpms, you notice all of the old superstock riders were around 150 lbs or so, although the 440's had serious HP they had very little torque and couldn't carry much more rider weight than that , at least not and still be competitive.

 

[sjetrider]

Chuckey makes me re-think my ADA billet bigbore motor. its done but havent tested it yet. Will know soon how it worked out with the domes sea doo pistons.

 

[the WaTeRhAwK]

Yep the 440 superstock engines were on the ragged edge of performance, they seized often and made lots of power, all of it at ridiculous rpms, you notice all of the old superstock riders were around 150 lbs or so, although the 440's had serious HP they had very little torque and couldn't carry much more rider weight than that , at least not and still be competitive.

until after about 9000 rpms.. and some nitro and alcohol....LOL

 

[egbrig]

Wow Chuckie, those pistons bring back "the good ole days". I used to grind lines into the head. I keep saying it but when us "old" riders see some "new" idea we just say "seen it" and all the newbies get insulted. Thats ok because all the new guys will get to say that to one day.