My CB100 Cafe Racer exhaust

waldo101

New Member
Hello everyone, ;D

i am needing some help, I have almost finished my CB100 Cafe Racer build and i am thinking of changing out the exhaust from factory. I am keeping in mind that this is a small single cylinder engine and i am trying to see what my options are. I was thinking of cutting the end of the stock pipe off so it would be like a megaphone or putting a straight pipe set up on the bike. Would this increase the performance of the bike or am i wasting my time and being better off by keeping it stock?
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
Can you post some pix of it.

I have a CB100 too, and like seeing others.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
Bike looks nice. Reliability will depend on your mechanical abilities, as too, did you rebuild it yourself or had it done.

Exhaust IMO should stay original, however, if you wanted to put a CL type exhaust on it, it will give it a little more sporty look.

Like the one in the pix, (not my bike)

I don't ride it, I'm still building on it actually.

Has a leaking carb, and the kicker shaft is stripped.

So an engine tear down is gonna be needed, to replace the shaft.
 

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waldo101

New Member
I haven't rebuilt the engine just did the cover gaskets and the carb gaskets, seems to run okay, bike has left me stranded in the past but was due to electrical and i have fixed it up since then. Im not confident enough to tear into the engine myself unless i need too. i have no idea what miles this bike has as i didn't have a speedo when i first brought it. it does start on first kick and theres no knocking or unusual noises. but i do have that thought in the back of my head that its gonna leave me on the side of the road again.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
I've rebuilt this engine, actually just replaced stuff, had to put a new jug and head, cause the original ones was siege so that i had to break the piston in bits to take it apart.

bought a china carb for it cause the original was toast, i put it all back together, that's when the kicker crapped out. So i have it under cover in the storage shed til i get some gumption up to pull it out and work on it.

I think that if you keep her lubed and tuned you should be fine.

They can get a little finicky at times.
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
I do still need some stuff like a speedo, headlight, and fork ears to mount the headlight and turn signals.

Speedo mount I can make. tail light i can build as well., new tires, then maybe I can run her like I want.
 

coyote13

New Member
Waldo, you'd do well to combine your multiple posts into one cohesive/coherent post. You'll likely get a lot more (and better) feedback that way.

It looks like you decided to keep the exhaust stock, from what I've heard there isn't a lot you can do better than the original Honda factory equipment. It looks like you're running the stock intake/filter as well, also a good thing. Changing either the exhaust or intake can cause a bit of a headache with tuning, not to say it can't be done.

As far as your reliability concerns, I would suggest a compression test. That will tell you plenty about the health of the engine. Also, if you haven't already, pull the centrifugal oil filter and check for any sludge or debris. If your compression and oil both look good, and everything is in spec per the factory service manual, that's about all the confidence you're gonna need.
 

Popeye SXM

Also used for MX
From the pics I would you say you have a great little ride. As Coycote said if the oil is clean and good compression then ride it and enjoy. Worry about the break downs when and IF they happen. If ain't broke don't fix it
 

waldo101

New Member
thank you for all your replies, i put the bike back together today and cleaned the carbs. when i apple the throttle quickly it bogs down and starts spitting but if i apply the throttle slowly it revs up fine, what could be causing this?
 

coyote13

New Member
I believe that's just the nature of the carburetor, crack the throttle too fast and you basically flood it. Not uncommon on old motos.
 

waldo101

New Member
its just gotten worse, it starts after a few kicks but if I twist the throttle the smallest bit it tries to bog out and starts popping out the carb, does anyone know what would cause this? I've cleaned the carb 3 times and I have made sure every hole is cleared. could this be an issue with the timing or valves?
 

datadavid

New Member
coyote13 said:
I believe that's just the nature of the carburetor, crack the throttle too fast and you basically flood it. Not uncommon on old motos.
No. It does not flood, its fuel starved when you open fully at low revs. Flooded with air more like.
 

waldo101

New Member
i know nothing about jetting, the carby is stock, I ended up adjusting the timing and its worked good since then.
 

waldo101

New Member
If i pull throttle to fast it will try and bog down but i do it reasonable speed its okay and revs up good. The spark plug is black and i don't need choke to start the bike. will being too rich in mixture bog the bike? Im not sure what to do.
 

datadavid

New Member
Mechanical carbs do that, its normal.
Black plug and starting w/o choke indicates rich condition. You should do some light reading on carburator tuning before you do anything else!
 

irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
What datadavid said plus this is good guide to give you an idea what is where when it comes to tune.

 

waldo101

New Member
thank you, i will get onto that tomorrow. fixed one thing then another problem pops up, when the bike is idling every now and then it sounds like the cam chain is rattling around, i have got the tensioner on the max, could the tensioner be broken? i accidentally took the tensioner bolt out all the way last month on the outside of the engine and Im not sure if the bolt was supposed to clip into something inside the engine?
 
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