Hello my 2 wheeled friends. Noob forum guy here with a 74 CB125 I'm building up. I started working on the bike last year, but haven't been able to work on it until recently (Broken arm via pencil rolling a go kart. I'm safer on two wheels....).
So here she is the day I got her. Was given to me for free so I was happy to take her home. Piston was seized up pretty bad. Like to the point where I started trying to cut the barrel in half. I was finally able to blast the SOB with enough heat and liquid wrench to bust it free.
First thing was getting the barrel, piston, and head replaced. I opted for the Chinese knockoff EBay special.
Main issue was the new head. The engine mount was in a different location and it was made for a newer cam that used ball/roller bearings instead of just the bearing surface being machined in. The mount I can deal with later, but I ended up buying another head, this time complete with valves, rockers, and a new cam. This cam however is setup for CDI so it didn't have the extended nose for the points system. I machined an extension piece, but I need to get it JB welded in and clock the roll pin that connects to the points rotor. I tried regular wire feed welding it, but the welds kept cracking. Not sure if it's the cam material or what.
Anyways that is where I am at right now. The pictures below will explain the rest.
Oh yeah, and I'm playing around with a velocity stack design that incorporates an adjustable shutter to control air flow. I love the look of a simple velocity stack, but I know they can be a pain to tune. The idea is by being able to adjust the airflow, I can tune the stack to the carb rather than being limited to tuning the carb only. I downloaded a student version of this AutoDesk software that simulates fluid/airflow so once I figure out the software, I should be able to see if it is a viable design.
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So here she is the day I got her. Was given to me for free so I was happy to take her home. Piston was seized up pretty bad. Like to the point where I started trying to cut the barrel in half. I was finally able to blast the SOB with enough heat and liquid wrench to bust it free.
First thing was getting the barrel, piston, and head replaced. I opted for the Chinese knockoff EBay special.
Main issue was the new head. The engine mount was in a different location and it was made for a newer cam that used ball/roller bearings instead of just the bearing surface being machined in. The mount I can deal with later, but I ended up buying another head, this time complete with valves, rockers, and a new cam. This cam however is setup for CDI so it didn't have the extended nose for the points system. I machined an extension piece, but I need to get it JB welded in and clock the roll pin that connects to the points rotor. I tried regular wire feed welding it, but the welds kept cracking. Not sure if it's the cam material or what.
Anyways that is where I am at right now. The pictures below will explain the rest.
Oh yeah, and I'm playing around with a velocity stack design that incorporates an adjustable shutter to control air flow. I love the look of a simple velocity stack, but I know they can be a pain to tune. The idea is by being able to adjust the airflow, I can tune the stack to the carb rather than being limited to tuning the carb only. I downloaded a student version of this AutoDesk software that simulates fluid/airflow so once I figure out the software, I should be able to see if it is a viable design.
Sent from my XT1585 using Tapatalk