Oh Hai! CB160 Build
- Thread starter 561design
- Start date
I'm glad to be back at it again as well. Travel for work has been heavy, so the build will come in spurts.
Good point, I was originally looking to bore it out to 200cc but I couldn't find the right kind of kit (sleeve less) to do it. This is my first motorcycle/scooter build, so I wanted to keep it simple. I never thought about bringin 175 parts over though. I'll start looking into it and see if there's anything I can incoporate. I'm more interested in acceleration over top end. The compression feels ok but it could be better. So I'll be replacing the rings and once I pull it apart, I may just get new pistions as well.
Good point, I was originally looking to bore it out to 200cc but I couldn't find the right kind of kit (sleeve less) to do it. This is my first motorcycle/scooter build, so I wanted to keep it simple. I never thought about bringin 175 parts over though. I'll start looking into it and see if there's anything I can incoporate. I'm more interested in acceleration over top end. The compression feels ok but it could be better. So I'll be replacing the rings and once I pull it apart, I may just get new pistions as well.
175 top end is a drop on. 200 also drops on but crankcase mouths have to be opened up and you have to use a CB200 crank and clutch and transmission which isn't all good news.
We have a full race 175 sloper and 240cc sloper both in 160 frames. They are a neat little bike. 5 speed trans from a 175 can be fitted but requires some welding and machining. 175 pistons don't fit inside a 160 head, so that's not a viable option. I built a 204cc motor for a guy a couple of years ago and that could be repeated. It went from 50mm bore to 56mm with stock 160 carbs and was a fast race bike. With a street cam it would make a nice street motor even with stock 4 speed. We fitted larger valves and spring kit etc, but a lot of things are possible on those motors. That frame will need to be braced now it's all bendy and flexible. Flexible is great in a human, but not so good in a motorcycle.
If you don't plan on using that front fender, I'd like to trade you something for it. I need a stock front fender.
We're just across the border if you need some inspiration.
We have a full race 175 sloper and 240cc sloper both in 160 frames. They are a neat little bike. 5 speed trans from a 175 can be fitted but requires some welding and machining. 175 pistons don't fit inside a 160 head, so that's not a viable option. I built a 204cc motor for a guy a couple of years ago and that could be repeated. It went from 50mm bore to 56mm with stock 160 carbs and was a fast race bike. With a street cam it would make a nice street motor even with stock 4 speed. We fitted larger valves and spring kit etc, but a lot of things are possible on those motors. That frame will need to be braced now it's all bendy and flexible. Flexible is great in a human, but not so good in a motorcycle.
If you don't plan on using that front fender, I'd like to trade you something for it. I need a stock front fender.
We're just across the border if you need some inspiration.
surffly said:
Yup! I look at it religiously. It is my first build, so I want to make sure I understand what I'm doing at a basic level and then I'll go back and make changes. It may take longer but then again I've been farting around with this thing for the past two years.
teazer said:
That sounds great. What's involved with putting a motor like that together? Yeah, I'd like to stop by and learn a few things if possible. I haven't found local resources to learn from yet. I plan on using the front fender, but I am heading out to the Crud Run in Madison this weekend. If I spot one, would you like me to pick it up for you?
At the right price for sure. As you may have realized already I'm a cheap SOB. We got our fist sloper for $25 and have had a few free bikes, so you can see where my price point is..
PM me when you want to come on down and I'll show you what works and what goes into those bikes.
PM me when you want to come on down and I'll show you what works and what goes into those bikes.
Teazer,
We're gonna need to talk about my motor options. I was at the Slimey Crud run today and they were talking to me about the same thing. One of the guys said the easiest thing to do would be a 175 sloper with the 5speed. But if I'm gonna go through the trouble of sourcing these parts, I might as well do it right.
For now, I think I'll continue with rebuilding this 160 for the sake of learning what the hell I'm doing. But I'd like to get a proper parts list together so I could start sourcing these parts.
These gaskets are getting to be trouble.
This impact driver is quickly becoming a favorite.
Now, where's that master link?
Found it!
Smooth
Also smooth
!#$%* Not so smooth. Anyone know how to pull this lower casing off easily? I only see one bolt on the backside and that's it. Am I missing something?
We're gonna need to talk about my motor options. I was at the Slimey Crud run today and they were talking to me about the same thing. One of the guys said the easiest thing to do would be a 175 sloper with the 5speed. But if I'm gonna go through the trouble of sourcing these parts, I might as well do it right.
For now, I think I'll continue with rebuilding this 160 for the sake of learning what the hell I'm doing. But I'd like to get a proper parts list together so I could start sourcing these parts.
These gaskets are getting to be trouble.
This impact driver is quickly becoming a favorite.
Now, where's that master link?
Found it!
Smooth
Also smooth
!#$%* Not so smooth. Anyone know how to pull this lower casing off easily? I only see one bolt on the backside and that's it. Am I missing something?
Remove the bolt from the rear and gently tap it to break the death grip that the gasket has on both parts. --Unless a piston is locked up solid and that's what's holding it on.
175 sloper was a one year anomaly . 5 speed bottom end in what are basically 160 cases. head is unique too. Deeper chambers like all 175s but with low level ports. 160 and sloper motors do not flow as well as as vertical heads but they flow more than the engine can use if you pay attention to the exhaust ports.
If you are tempted to buy a cam - get the mildest Megacycle cam. Our tests on track and dyno suggest it's best for a mild motor.
You can modify a 160 to take a later model 5 speed trans.
175 sloper was a one year anomaly . 5 speed bottom end in what are basically 160 cases. head is unique too. Deeper chambers like all 175s but with low level ports. 160 and sloper motors do not flow as well as as vertical heads but they flow more than the engine can use if you pay attention to the exhaust ports.
If you are tempted to buy a cam - get the mildest Megacycle cam. Our tests on track and dyno suggest it's best for a mild motor.
You can modify a 160 to take a later model 5 speed trans.
teazer said:
Thanks! I'll work on that tonight. Pistons are moving smoothly with no problems. I'll look into ordering that cam. I'll get the case cleaned up and see what I can do to fit/source the 5 speed. How can I tell if I need new valves/valve springs? I've read that I should just replace the pistons with new and I'm wondering if that's true with the valves and springs. Also, if I'm having to replace with new pistons, I might as well just get the larger pistons and bore it out.
This could start to get expensive - fast.
I just clean the valves and if they are pitted or the seat face is really badly recessed, I replace them. If not they go the our local machine shop to be ground and he cuts the seats on a Serdi machine.
Pistons:
Clean them and measure them when you get them out. If they are within spec (tolerance) I'd save the cash and re-use them. If the bores are gouged or pistons too worn, it's worth looking for larger pistons. I think Les Barker sells them or look out for a pair of HAp Jones 2mm o/s pistons. They haven't been made for years and they pop up from time to time. You could go with 175 pistons if you had a 175 head to go with them.
There are other options, but much larger than that and liners need to be replaced and costs start to rise. You could look out for a set of 175 barrels and head - vertical or upright and if you found a 175 sloper, that would save some time and cash, but they are not so common. 175 motors (both shapes) have larger valves and smaller carbs (go figure).
Time to work out a budget and shopping list. I usually make up a spreadsheet with parts on the left and columns for different options. They might be stock rebuild - low cost, rebuild all new, 160 core with big bore, 175 top end, replacement 175 sloper motor. Or whatever your choices are. You would be surprised how many ways there are to build a motor and how many options there are. for example - Ignition: Pamco, Dyna, Transistor assisted points or stock points. Then you add coli choices and HT lead choices and that's about the time they call for the men in the white coats to come and take you away.
It's important to think it through but don't get analysis paralysis and end up in an apoplectic fit
I just clean the valves and if they are pitted or the seat face is really badly recessed, I replace them. If not they go the our local machine shop to be ground and he cuts the seats on a Serdi machine.
Pistons:
Clean them and measure them when you get them out. If they are within spec (tolerance) I'd save the cash and re-use them. If the bores are gouged or pistons too worn, it's worth looking for larger pistons. I think Les Barker sells them or look out for a pair of HAp Jones 2mm o/s pistons. They haven't been made for years and they pop up from time to time. You could go with 175 pistons if you had a 175 head to go with them.
There are other options, but much larger than that and liners need to be replaced and costs start to rise. You could look out for a set of 175 barrels and head - vertical or upright and if you found a 175 sloper, that would save some time and cash, but they are not so common. 175 motors (both shapes) have larger valves and smaller carbs (go figure).
Time to work out a budget and shopping list. I usually make up a spreadsheet with parts on the left and columns for different options. They might be stock rebuild - low cost, rebuild all new, 160 core with big bore, 175 top end, replacement 175 sloper motor. Or whatever your choices are. You would be surprised how many ways there are to build a motor and how many options there are. for example - Ignition: Pamco, Dyna, Transistor assisted points or stock points. Then you add coli choices and HT lead choices and that's about the time they call for the men in the white coats to come and take you away.
It's important to think it through but don't get analysis paralysis and end up in an apoplectic fit
Yikes! Well here's what I'm thinking so far.
Keep the cb160 casing, bore for larger pistons, mild cam, 5speed from cb175 (if I find one) and port/polish. Use stock valves/springs if possible... And whatever else I can add to make it more "street-friendly". Is that a good start so far? I don't want to dump a ton of money into the motor but I definately want it to accelerate more than what it can do now. There's some stuff I want to do to the frame and wheels, so I don't want to burn all my money into the motor.
Here's where I got to tonight. I was going to open up the bottom end but it's getting late.
You were right about the gasket. I never thought that it was going to come off!
A lot of carbon on the pistons.
First time I had to use the breaker bar on this motor to loosen up some bolts.
Keep the cb160 casing, bore for larger pistons, mild cam, 5speed from cb175 (if I find one) and port/polish. Use stock valves/springs if possible... And whatever else I can add to make it more "street-friendly". Is that a good start so far? I don't want to dump a ton of money into the motor but I definately want it to accelerate more than what it can do now. There's some stuff I want to do to the frame and wheels, so I don't want to burn all my money into the motor.
Here's where I got to tonight. I was going to open up the bottom end but it's getting late.
You were right about the gasket. I never thought that it was going to come off!
A lot of carbon on the pistons.
First time I had to use the breaker bar on this motor to loosen up some bolts.
It's probably too late already, but it's easier if you remove the rotor and oil slinger while the crank is still in the cases. To get the rotor off, you screw the rear axle into the rotor hard and smack the end of the axle with a large hammer and the rotor will pop straight off.
On the oil pump side, remove the center screw and use a longer 8mm bolt as a puller to get the end cap off after removing the circlip. Then bend back the lock washer and remove the castellated nut. Clutch and oil pump then come off together with one or both of the crank gears.
There's a couple of later model 175 transmissions on ebay and one 68-69 sloper trans. They are more than we paid for any complete bike, but ten years ago it was hard enough to give those bikes away. We got a couple that way at my favorite price (free) , but those days are long gone I fear.
On the oil pump side, remove the center screw and use a longer 8mm bolt as a puller to get the end cap off after removing the circlip. Then bend back the lock washer and remove the castellated nut. Clutch and oil pump then come off together with one or both of the crank gears.
There's a couple of later model 175 transmissions on ebay and one 68-69 sloper trans. They are more than we paid for any complete bike, but ten years ago it was hard enough to give those bikes away. We got a couple that way at my favorite price (free) , but those days are long gone I fear.
Rider52
Over 1,000 Posts
In the 60s, Bob Braverman/Cycle Guide magazine built a 160 based bike in a Van Tech frame. They used Honda 305 sleeves and pistons with a final displacement of around 240cc.
It requires an extreme bore of the cylinders resulting in the sleeves being visable in several spots. The cure was to weld aluminum in those areas to build up the existing cylinder and provide cooling surfaces for the motor. If I remember correcly they used a Harmon & Collins cam and 305 carbs. In the good old days, you could buy adapters from Racecrafters to fit the 305 carbs to the 160.
It requires an extreme bore of the cylinders resulting in the sleeves being visable in several spots. The cure was to weld aluminum in those areas to build up the existing cylinder and provide cooling surfaces for the motor. If I remember correcly they used a Harmon & Collins cam and 305 carbs. In the good old days, you could buy adapters from Racecrafters to fit the 305 carbs to the 160.
That was an interesting article. If you want to go to 61mm, it's better to start with a 175 block which doesn't break through. I ran a race bike with visible liner (bored through the fins) for years without any problems but I wouldn't recommend it. We run 305 carbs on a 175 motor but they are really way too large for the ports and that makes them a little tricky to jet.
sxecafe
You think the Carpet Pissers did this?
561design said:
This tripped me out pretty hard. I thought it was me for a second... hahahah tatts didnt match tho. This build should be really nice. Looking forward to it it.
Looks like you got some great inspiration! You get any ink while you were there?
sxecafe said:
You don't remember working on the bike with me?!?! lol
I got all my tats while I was living in Atlanta. I've had some work done by Jeff Paetzold and the rest completed by Tim Orth. My work from Tim has been in tons of magazines. I've been thinking about getting more, but one project at a time!
sxecafe
You think the Carpet Pissers did this?
Ah nice! I have a bunch of japanese work. Chris Brand at Good Time Charlie did the biggest one (a full chest piece) and then Horitaka and Horiken each have a thigh. Need to get the thighs colored in tho. I need to find some scratch and time to get work but... alas like you said, one project at a time.
Ok... back to bike building now.
Ok... back to bike building now.
Not much news. I've been traveling a lot for work lately and mountain biking because of the great weather lately. I did however order this nifty 2.0 piston set from a seller on E-Bay. I'm looking forward to the USPS fairy. ;D
With the long weekend coming up, I plan to have the bottom end opened up and start the cleaning processes.
With the long weekend coming up, I plan to have the bottom end opened up and start the cleaning processes.
