JAX71224
jax71224
Just got the 3mm O.S. piston kit from Cruisinimage and considering those pins from Mike's that are billed as lighter. Looking to keep balance close to original. Any thoughts?
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light weight piston pins
- Thread starter JAX71224
- Start date
How does the cruisn piston and pin compare to the stock set?
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JAX71224
jax71224
Have yet to weigh the oversize ones yet and the engine is still in the bike so can't check the stockers either.Just expect larger pistons to be a bit heavier.
JAX71224
jax71224
OK So going to a buddy's house to weigh the pistons and pins. does anybody know the weight in grams of the light ones from Mikes? He reloads ammo and has premium equipment for that purpose. Probably do this Sunday or Monday depending on weather.......It's snowing and blowing about 35 or 40 mph right now!
JAX71224
jax71224
THANKS! Now to get some numbers on these to compare with those. Might get the Wiseco pins if a significant difference and if not much difference just try to make both sides as close to each other as possible with the parts supplied........Hey, what base gasket and head gaskets are the thinnest assembled number? Just looking for any advantage.....but also want to use electric starter if possible because I have a prosthetic right leg.....Yeah, probably nuts but just me being me!
Try a forum search on "head gasket thick".
Lotsa chatter on the variations...
Lotsa chatter on the variations...
JAX71224
jax71224
Decided to use Wiseco internally tapered pins. They are billed as 60g weight vs 91.7 for the Cruisinimage pin part as measured. Pistons @ 280.7 and 281.1g. I thought that to be very consistent to each other being only 0.4g variance. From postings by others on here it looks like stock 447 std piston with pin comes in at 357g and my piston with Wiseco pin at 341g not counting clips or rings on either. .Isn't lighter by about 17g EACH a lot better than nearly that same amount heavier? Less reciprocating mass by more than an ounce should mean a lot at revs.....
Thanx, JAX. Added that to my list...
JAX71224
jax71224
And.............gonna send pistons to 650 central for the wrist pin oiling mod. Looks like a good enough idea that I'm sold on it!
Where do you get those lightweight Wiseco pins? I checked their website, but only pistons and piston pins came up for the XS650. Also, are 447 pins the same diameter as 533? I have a 533 crank/rods for my XS project.
Hey, arcticXS. Yes, 20mm wrist pins.
Coupla old threads of interest.
http://www.xs650.com/threads/big-piston-little-piston.32595/
http://www.xs650.com/threads/need-help-with-piston-id.42027/
http://www.xs650.com/threads/a-533-crank-in-a-447-engine.36548/
http://www.xs650.com/threads/best-conrods.52666/
JAX71224
jax71224
From Parts Unlimited dealers number S512X probably Dennis Kirk too.........Not sure about anybody in NORWAY But Heiden Tuning is in the Netherlands , maybe closer to you........
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JAX71224
jax71224
That kinda looks like the "knurling" process sometimes done on tractors and diesels....Anybody have thoughts on this?
My "256" 750 cast pistons, back in '75, grooved, skirts knife-edged, sharp corners rounded, oil holes relieved, domes polished. 298 grams.
After about 3 years and 10,000 miles.
After about 3 years and 10,000 miles.
Not to hijack this thread, but it definitely caught my eye. I'm also in the midst of rebuilding a spare motor, bored 1.5mm over with Cruzin Image pistons/pins, etc. Plan on doing a build with this motor as I do have an extra frame as well. 2M and Gary have been helpful (thanks again to both of you) in another thread re: crank question. Does this dimpling / weight balancing approach to pistons come highly recommended and proven to be a reliable approach to better oiling/cooling? Who has actually done it? Never heard of it before in any other engine builds, but that's not saying much. Not like I'm a full time engine builder....
Yeah, I saw that, sorry. Could have been more clear. I know the weight balancing is done from the inside. Just a general question between the two mods.
Tomterrific
XS650 Junkie
2M didn't explain but the rounded off sharp edges are to eliminate hot spots and help keep mixture motion going. Geez 2M, 1975? It was many many years later I learned this trick. 1986 Hot Rod, Soft Head article by Larry Widmer.
The dimpled skirt is an old idea but instead of drilling I used a punch to make the dimples on old pistons. This would raise the edges around the dimple to take up some skirt wear. A spring loaded punch is easy to use.
Tt
The dimpled skirt is an old idea but instead of drilling I used a punch to make the dimples on old pistons. This would raise the edges around the dimple to take up some skirt wear. A spring loaded punch is easy to use.
Tt
Hey, Tom. Haha, yeah, old tricks, huh?
To this day, whenever I see pistons with sharp corners on dome profiles, my skin crawls.
With respect to the grooving, I did a subtle copy of Forged-True's corrugated skirts.
Piston and combustion chamber design has come a long way since then. Modern coatings, flame notches, modern alloys, eutectic, controlled expansion, short pistons, slipper and non-symetrical skirts, anti-flutter grooves, squish/quench geometries, thin rings, gapless rings, ...etc. Personally, I'd pursue the modern coatings over the various oil retention mods.
My neighbor back in the '60s was the service manager at an auto dealership, and he told me about their practice of knurling pistons. Not for improved lubrication or performance, but to save a skinflint some money in an engine overhaul. Re-use old pistons in wore-out bores.
Looking into the Wiseco wristpins, found some complaints about receiving wrong lengths. The 20mm wristpins are available in various lengths. The stock "447" wristpin is 61mm long.
To this day, whenever I see pistons with sharp corners on dome profiles, my skin crawls.
With respect to the grooving, I did a subtle copy of Forged-True's corrugated skirts.
Piston and combustion chamber design has come a long way since then. Modern coatings, flame notches, modern alloys, eutectic, controlled expansion, short pistons, slipper and non-symetrical skirts, anti-flutter grooves, squish/quench geometries, thin rings, gapless rings, ...etc. Personally, I'd pursue the modern coatings over the various oil retention mods.
My neighbor back in the '60s was the service manager at an auto dealership, and he told me about their practice of knurling pistons. Not for improved lubrication or performance, but to save a skinflint some money in an engine overhaul. Re-use old pistons in wore-out bores.
Looking into the Wiseco wristpins, found some complaints about receiving wrong lengths. The 20mm wristpins are available in various lengths. The stock "447" wristpin is 61mm long.
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I acquired a Wiseco S-553 20mm wristpin, for a completely different project. Thought I'd post some measurements of the thing.
