Topic: Rocker arms and needle bearings?

[lucky]

i dont know maybe modified head to use air operated valves. yeup titanium would be better but costs more. Anyone make an aluminum alloy cb750 frame? THANK YOU everyone for all the input any more ideas are welcome!

If I made an aluminum frame for a CB750 it sure would not be as flimsy as these sportbike frames are being made.

[lucky]

I do not know about the needle rollers for rocker arms but they did put needle rollers in a Honda CB350 for the camshaft and it worked wonders.

I personally have lightened the rocker arms on a Honda S90 from 4 oz. to 2.5 ounces and that seemed to make it rev much quicker and they did not break.

[Jim F]

I wounder if a coating would work better
No need to modify anything for bearings

There is a company called micro-blue.... http://microblueracing.com/

This is what an engine builder near me uses in his race bikes from WPC http://www.wpctreatment.com/

[Don R]

I think the honda ports have a little bias to one side to induce a bit of swirl, I ported our Briggs jr dragster engines and removed more metal on the right side and created a swirl inducing path to the valve and into the cylinder. I continued the  shape in the cylinder head, I used a ball mill and undercut the edges of the head around the valve area to allow the swirl to continue into the combustion chamber. We had a heavy car but it ran great for a stock block stock stroke briggs. My engine machinist said guys would kill for my set-up.
 
 I just bought shaft rockers for our 1,000hp 567" chevy. We had stud mount rockers but were at the maximum lift for that type. I'm taking out some beautiful steel rockers that auctually have less inertia than aluminum rockers. They are slotted and relieved in areas where steel is not needed and have a larger needle bearing than an aluminum rocker has room for.

[lucky]

Back in the late 60's Honda said the intake ports were rough for the very reason to increase turbulence and get better mixing of air and fuel.

Just like some sailboat racers insist on polishing and buffing the bottom of the boat to be smooth as glass, even after extensive tank testing of hull models proved that a
rough texture was better because it broke the surface tension and suction that slowed a boat down. The testers glued  a snake skin texture on the bottom of the boat hull and increased the hull speed. (C.A. Marchaj, The Aero Hydrodynamics of Sailing)

Even today many racers spend a lot of time polishing intake ports to a mirror finish.
Water is 12 times more viscous than air.

[spiritof67]

Oskar Leibmann (OL Performance/ Kurt Leibmann's dad) used to sell a needle bearing rocker arm conversion for SOHC CB750's...is it really better than running on a pressure-fed oil film?

Spirit

[gnarlycharlie4u]

Even today many racers spend a lot of time polishing intake ports to a mirror finish.

I didn't realize this was still a thing. I know that some people rough up or rifle intake ports to increase fuel mix. I've even heard of people scoring piston tops to better mix the air and fuel.
However I thought polishing was reserved only or the exhaust side of the head.

Besides not contributing to a good mix, polished intake ports will also cause fuel condense on the wall surfaces thereby detracting from a good mix of air and fuel.

[MRieck]

Oskar Leibmann (OL Performance/ Kurt Leibmann's dad) used to sell a needle bearing rocker arm conversion for SOHC CB750's...is it really better than running on a pressure-fed oil film?

Spirit

I don't think it makes a real difference and it adds another component to potentially fail. Treat the shaft and arm with a modern coating....it will be better than the needle bearings in terms of reducing friction.