Engine Bearing Upgrade

[cbinvb]

Ok, So I'm running a 155ZHO with a bbk for 185cc, Tak +R head with mild exhaust polish, a VM26 carb and a Two Bro M6 exhaust. I love the power. I am getting ready for the next round of upgrades which will include a stroker crank. I was thinking that while i have the cases split I could upgrade all the internal bearings. The list would include -

1 - 6000 (clutch basket bearing)
1 - 6001 (mainshaft bearing)
1 - 6002 (countershaft bearing)
2 - 6203 (main & countershaft bearing)
2 - 56×22×15 (crank bearing)

I would be using all ceramic hybrid bearings of at least Abec-3 and C3 specification. I went to bocabearings.com and tallied it all up to just over $300.

I'm hoping it will free up a bit of power because of reduced friction and add considerable length to the life of the internals perhaps even quieting down that all that busy noise it makes too.

Any thoughts?

 

[The_GDFP]

Glad to hear the project is moving forward. I still have the Photobucket of it's humble beginnings, if you ever want it.

Hybrids, or even quality steel bearings will quiet some of the racket inherent in these engines. Some is design of the head. Did you end up getting Tak rockers for the head? They're lighter by 70+ grams and absorb more noise.

Clutch pusher bearing spends so little time engaged that I doubt it's worth hybriding. Maybe if you convert to a thrust bearing, like what they should have used there? Cam spins all day, tooo

Mains are tough in the OE size. I've been swapping to 1mm wider 63/22 versions and a 14mm wide rod when stroking the YX/Z motors. Rods are available in 92.5-103mm length, depending on your stroker plans. Adding a base spacer and longer rod helps with R/S ratio, reducing side-thrust loads on the piston, allows an OE KLX cam chain. I run 6mm or 12mm depending on build.

Tumbling all the gears in ceramic media reduces friction, wear, and a lot of the debris on the magnetic drain plug. Plain steel-on-steel action in the trans, remember.

Techline Coatings has some good DIY products for friction reduction, thermal barrier & dissipation, oil shedding. Chamber, ports, valves and piston crown thermal barrier will keep the power in, heat out. Even removing the flash from the head casting around the airflow holes helps cooling. Air movement is all they have. SOHC design doesn't leave much room for cooling breezes.

Jamming the rubber pieces, like Tak jugs come with, in the fins, will quiet a lot of the engine noise. Fins amplify the internal racket.

You may want a 28mm, or bigger carb on a TB manifold. Worth a couple HP on that big an engine, with no low end torque losses. I prefer PE28's, but others seem fond of the OKO. Back-cut the valves, do a decent 3-angle seat job, pay attention to quench and total timing, degree in the cam. I like to cover the filter bypass port with a round magnet for more grabbing power. You can drill and tap the end of the cover, and run to the head from there, so it gets cleaned oil rather than straight from the pump, as well.

For street use, an added oil resivour/cooler under the engine would be a big help. I plan to try a pegmount attached plate and add some thing like:

I currently have a CM400A cooler:

Cheers!

 

[themountain]

wow..Terry...flawless info as always !!:first:

 

[Viceroy]

Terry, where do you get the rods from? I have'nt found any, except for homemade examples I've been thinking on a better R/S ratio as well. It is pretty horrible as OEM!

And thanks for good info! Must get some of them rubber fins, because I dont like the noise YX engines make.