Honda Twins banner
1 - 17 of 17 Posts

·
Registered
Joined
·
21 Posts
Discussion Starter · #1 ·
Hey everybody, I've been trying to search and find definitive advice or parts help but haven't been as successful as I'd like.
I currently own a cb125 twin (not sure what year) and I'm doing a cafe racer build. I want to know if anyone can help me with some subtle performance mods to just add some power and speed to the bike. I plan to do an exhaust and new carb with tune. But curious on higher compression, different piston, timing change, electrical upgrades, camshaft, anything really. Unless someone can tell me a larger engine will fit in my frame to build up that.
Any help from anyone would be greatly appreciated!!
Attached my bike just for sharing. Only just mocking stuff up. Need to modify forks for a drop, getting side number plates, and other stuff. Try not to judge my work too bad yet.
 

Attachments

·
Registered
Joined
·
13,085 Posts
That's going to be one wild 125 with a wheelbase longer than any 125 probably ever had. Not sure how it's going to handle with that setup, but it looks pretty cool. Sadly, it appears you have the single carb version and I also wonder how much high performance stuff is out there for that engine...
 

·
Premium Member
Joined
·
3,046 Posts
Wouldn't a CB175 or CB200 engine be a fairly easy swap ?
 

·
Registered
Joined
·
21 Posts
Discussion Starter · #4 ·
The front and rear end are actually off of a CBR150R. I'm not looking to build much of a track ready bike. But something cool and fun for a weekend cruise, but c'mon who doesn't engine some extra HP between the legs. I'm entirely up for a motor swap if it doesn't require more than some simple engine bracket mods.
And i was trying to pry the twin carb head off the guy who sold me the bike, but one of those times who holds onto everything because one day he says he will use it haha.
 

·
Registered
Joined
·
13,085 Posts
Yeah, I think most of us realized the forks and swingarm weren't OEM '60s gear... :lol: I was thinking along the same lines as Richard, the 175/200 twin would seem to be pretty straightforward as a swap, just wasn't sure if you wanted to go that way. I saw it done with a CL100 back in the day, someone stuffed a 175 engine into it (but did a below-average job of it)
 

·
Registered
Joined
·
21 Posts
Discussion Starter · #6 ·
Haha just thought I'd give the extra insight to what I used.
Oh I am entirely up for an engine swap, just wanted to avoid welding up the frame to make something fit. So what do you guys think is the biggest I could stuff in there?
 

·
Registered
Joined
·
21 Posts
Discussion Starter · #7 ·
Believe I read a 350 or 360 twin is taller of a motor so wouldn't fit. So I assume I better look up some 200 motors..
 

·
Premium Member
Joined
·
3,046 Posts
To my untrained eye, this CB125 twin, with twin carbs, looks uncannily similar to a CB200, which is why I suspect that the engine swap would be easy enough. Looks like a lot of common cycle parts there.

Land vehicle Vehicle Car Motorcycle Motor vehicle Land vehicle Vehicle Car Motorcycle Motor vehicle
 

Attachments

·
Registered
Joined
·
4,402 Posts
If someone could confirm this for me then I would definitely go that route.
What is the height of the area inside your engine compartment Baxter ? I ask because someone here with a CB200/CB175 can measure their engine mounts from top to bottom and then you could fab-up some custom motor mounts,etc. to fit.
 

·
Registered
Joined
·
523 Posts
if you're determined to have more power, adding boost to the single port head can be done: Small Engine Turbo Charger - Small Turbo Kits | RHB31 VZ21 Turbo charger
it'd be quite sophisticated in the parts required, esp exhaust, but it appears you're fairly handy and you can use the same carb, but in a blow through system. check 66sprint's LSR build for more info
 

·
Registered
Joined
·
21 Posts
Discussion Starter · #14 ·
everything from what i can see the cb175 or 200 will fit as long as i have the matching engine brackets. i keep seeing CB160 pop up, is this a faster motor than the cb200?
 

·
Premium Member
Joined
·
3,046 Posts
CB160 is a sloper motor, so engine mounts wouldn't line up.

Only 4 speeds.

Probably a touch slower than a CB175 or CB200, nothing to choose between latter two for performance. CB175 revs, CB200 chugs ...
 
  • Like
Reactions: ancientdad

·
Premium Member
Joined
·
3,046 Posts
It's all relative. CB200 delivers similar power to CB175, but at a 1000 rpms lower down. It's still a little screamer, in real terms.

I prefer the 'feel' of the 175 unit.
 
1 - 17 of 17 Posts
Top