46u

My Feedback: (3)

Does any one know if Zenoah and CY wrist pin bearing are the same and interchangeable?

dc2 man

yes the wrist pin bearings should be the same,but you need to make sure the piston are the same displacment and that the roller pin is the same length......
allthough if the both engines are of the same displacment the roller pins will be much the same.

hope this helped some....

most internals are the same in a cy/zen example 26cc the bottom end is the same [apart from case matching on some] the crank/conrod bottom end bearing should all be the same.

one thing that anoys me is that crank cannot be stripped apart from the conrod,as i was once trying to build an engine from an old box of parts and realised that it wasnt going to happen changing rod to crank assembly......i had to as i had an old crank damaged and i was trying to swap conroads from another,i couldnt use the other one as conrod was too long.

slawhammer

There not the same.... and the cy wrist pins are 25 mm. Zen wrist pins are 27mm cage bearings are also different..asto the washers......Measure them....
do a search on them as well....I have used both.......The CY piston is better quality tha a Zen.....You can use a CY piston in a Zen cylinder....I have done this
and I have it in my present engine......Just my thoughts on this...Slawhammer

dc2 man

what cys are you talking about slaw?

every 23cc/26cc i have built were the same and fitted always for me........

maybe on some they may be differnt,cy engines i havent had.....

46u

My Feedback: (3)

From what I can tell all CY and all Zenoah no matter of displacement run the same wrist pin bearing. They all have the same part number. Now the Zen and CY pin washers look different.

I do not see why you could not disassemble one of these cranks? On 2 stroke motorcycles I have put many a rod kit in them using the old flywheels even thaw the local Honda dealer said it cannot be done. I even offered to do one for them for free then they did not want to talk to me! LOL [X(]

I have rebuilt MANY Harley cranks!!!!!!!!! I even can rebuild the rods if the core is good.

dc2 man

yes i think the washers are the same also 46.i never had any problems interchanging them anyhow.

you would have to have a crank there and look at it the conrod is litterly welded on to it.......it really would have to be cut to be removed...would be cheaper and less hassle to buy new crank if one was needed.

its sealed on to it.

man thats cool,i would love to be able to rebuild a harley...

nice work on them,

46u

My Feedback: (3)

I understand about the different lengths of the wrist pin but both CY and Zen wrist pins are 8mm OD according to DDM so why would the bearing not interchange? Is the small end of the rod ID different?

dc2 man

no sure im saying they would b the same and should fit.

some small ends are differnt all down to which engine,for example-a cy 29cc has a larger displacment,longer stroke,longer rod assembly and stroker crank.....this crank/rod wont fit a 23cc or 26cc stock cy.....on the 29cc the gaskets are stacked.....or nowadays they just machine the inner top of cylinder for squish clearnce.now the top end stuff might sure be differnt in these engines like the washers wrist pin/bearing etc etc...

i dint say it was litterly welded but its like its welded in there lol

its not possible to remove them.

46u

My Feedback: (3)

I am holding a CY crank in my hand and do not see a weld. I agree it would just be cheaper when you take your time into consideration to just buy another crank. Now on a 2 stroke motorcycle where a new crank is $300 and a rod kit is $75 cheaper to rebuild them.

I use to have a motorcycle shop some years ago and kept tall my tools and equipment since it was paid for and paid for its self. I would still have the shop if I could have found good reliable help but after 13 years of working 18 ours a day and raising 3 children as a signal parent I closed it. I can just about rebuild a Harley engine here at the house. I have a boring bar, a valve grinder, a seat grinder, Sunnen horizontal honing machine, lath, and a whole lot more.

46u

My Feedback: (3)

When stroking the rods are the same Leigh just the crank pin location is move more towards the out side of the flywheel. Now if you do not use a cylinder machined for a longer stroke you have to stack gaskets. Not in some cases on other vehicles on a very large stroke they make the rod longer to cut down on piston speed. I stoked MANY a Harley.

46u

My Feedback: (3)

I have a 20ton press and I bet I can get one of these little cranks apart. LOL

dc2 man

man thats cool.....fair play to you as a single parent raising your kids and running a buisness.....thats not easy.much more than a lot of others do....

its not easy to run any kind of buisness,me im a builder and its so hard to get crew to job early and actually try and turn over the work,its quite now i know but when it was busy it was stressfull too.....i used litterly work the whole time....3years ago in the boom i might be lucky to run my r/c once a month.....

times are sure changing.

man you have awesome gear there,would you set up from home,why not build repair from home???

im sure there are loads of guys who need rebuilds done,.,......you could advrtise online man.

when i have my own workshop done i sure will be doing this work part time........r/c machines/garden machines/ horticultural etc etc in my spare time from home...........

why not....

savagecommander

you can press the crank apart but ive heard they never fit right again- and there are a few motors you can run a stroker in without stacking gaskets(yes the squish is that much)

46u

My Feedback: (3)

DDM sells some cylinder kits that have been machined to accept a stroker with out stacking gaskets.

Might be more but here are some.
http://www.davesmotors.com/s.nl/c.88...t.A/id.1127/.f
http://www.davesmotors.com/s.nl/c.88...t.A/id.4755/.f
http://www.davesmotors.com/s.nl/c.88...t.A/id.4168/.f
http://www.davesmotors.com/s.nl/c.88...t.A/id.4169/.f
http://www.davesmotors.com/s.nl/c.88...t.A/id.4754/.f
http://www.davesmotors.com/s.nl/c.88...t.A/id.6259/.f

mooman007uk

if you have a dti and v blocks on a marking table i'm sure you can get the crank properly aligned, don't know where you'd buy just a con rod and big end bearing though

46u

My Feedback: (3)

Like I said I have done 2 cycle motorcycle cranks and big Harley. I have a crank truing machine which I do not think a crank from one of these engines would fit. But I all so have a lath I have used to check the true on small motorcycle cranks. You do not beat on the crank while in the truing stand or the lath you take it out first. But like mooman007uk said no one makes a rod kit.

rckiwi

The wrist pin bearing is different from CY to Zenoah.

The CY piston has wider distance between the pin bosses (under piston) to a Zenoah piston

So the CY wrist pin is longer and the washers are thicker, to say put a Zen top end on a CY motor you need to use Zen wrist pin bearing and washers to fit.

46u

My Feedback: (3)

I will be getting a Zen bearing to compare but if I am not mistaken the washers are what is different and the bearings are the same. But thanks for the input.