CB750 - 836cc Big Bore Kit Piston Comparison, Honda Motorcycles Restoration and Repair Classic bikes

Vintage Motorcycle
Rescue 750 Presents:
Comparison between big bore kit pistons. This is great. There is a huge difference between the big bore kits that you can put on your Honda 750 Motorcycle restoration. In this video we compare the Wiesco 836cc Big-Bore Kit to other 836cc Big-Bore Kits and the stock Honda motorcycle pistons. There is such a difference in the kits that it's amazing.
The forged Wiesco Pistons really changed the way that I'm going to think about pistons. Now, I will only buy forged pistons and forged rings, no more cast pistons and rings. The ability to shine the Forged Pistons as compared to the Cast Pistons was amazing. I had a mirror finish on the Forged Pistons in just five minutes, where, after two hours of polishing on the cast pistons, I could never get a mirror finish.
The difference between the forged and cast pistons was really the pore size, and grain of the aluminum. When polishing the cast pistons, I would polish and polish, removing minute amounts of metal with every polishing attempt, only to find that I was removing the metal and exposing the rough pores and grains at lower levels, therefore, I could never attain the true mirror finish that I was wanting. Cast Rings, when I used the cast rings, there are times that I have broken them when installing and other times I broke them by extreme over revving. The cast rings just crack very easily. I remember the old forged Wiseco piston rings that I used in my two stroke MX Bikes. When we replaced the rings, I took the old rings and twisted them in knots. I could not break them. As I mentioned above, it takes almost no effort to break a cast ring. There sure was a huge difference, so much so, that I will never use cast rings again, or cast pistons.
The polishing of the pistons makes a huge difference in the amount of heat that goes into the combustion process and how much heat goes into the engine. The higher the polish, the more power that you will produce. With the higher polish, the engine and oil stays much cooler, preserving the engine life. This is one factor that keeps motorcycles running longer with less wear.
Classic Motorcycle Restoration and Motorcycle Repair makes a great hobby and a great way to enjoy your time.
For Vintage Motorcycle Parts and Accessories go to
yellowairplane.com/Motorcycles...
Thank you very much and have a nice day,
C. Jeff Dyrek.

[@ivangonella1]

You really know! Remind me My uncle's doing repairs!

[@vintagemotorcyclerescue7506]

Thank you very much for watching. Have a nice day. I hope that your uncle is successful.

[@CeeBee1979]

Hello! It's been a while since you posted this video but I have to ask anyway. I recently opened a 1975 CB750K motor and to my surprise I found these big bore pistons inside. They look exactly like the one you hold in your hand when comparing with the Wiseco piston and they have the marking AP on the side. Would you happen to know the maker of these pistons? Thanks a million in advance!

[@JCcanU]

Forged is pounded into a bloch and CNC machined, Cast is poured into a cast mold and cooled , then machined , cast open more under extreme heat , forged do not . forged cylinder wall to piston is tighter , that cast . by .03 thousands Why Buff out a used piston ?? I have a shelf with used pistons . nothing wrong with the pistons they can be used in a other engine that need to be 5 , 10, 20 thousands over . if its from the same engine 1300 cc

[@vintagemotorcyclerescue7506]

I never realized that you can run a tighter clearance with a forged piston and that the expansion rates were different, but after reading what you have written and some thinking about the materials of forged vs cast, I can understand that what you are saying is true and it's very interesting. The polishing is good on new or old pistons for the reflection of the heat back into the combustion process and increased cooling of the piston itself. I also polish them because it's a good way for me to ease any stress. Thank you very much for your comments and have a nice day.

[@mikeford5106]

You will NOT gain ANY HP by polisting a pistin crorn ! but it will slow the carbon buildup, ..... 2% Increase in power ? Hahaha