Honda CB450 K5 Cafe Racer.. ish

This bike will not run with the choke fully closed. With these carbs, if the choke is fully closed, you have blocked off all air flow into the carbs. You need fuel, spark, and AIR for combustion to occur. When I start my bike cold, I only close the choke about half way.

A cold bike tends to run lean because the fuel is not fully atomizing. A lean bike tends to rev up. Closing the choke lever partially restricts the air flow into the carb, causing the mixture to be richer. I only close the choke enough to keep the engine from revving up. I only have it partially closed for about 30 seconds.

Somewhat related to this, if you are riding and the bike starts revving up at a stop light or popping while you are riding, you are probably out of gas. A revving engine is a sign of your mixture leaning out. This happens when you don't have enough fuel in your carb bowls.

Next time you start the bike, tap the headers with your fingers. They should warm up about the same. Yes, eventually they will be so hot that you can no longer touch them.


I just pulled my pistons and found a broken ring. I had no idea. I just knew it was burning oil.

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I see.. Still.. whoever engineered the bike probably intended for the choke to work fully closed. The butterfly has a flap with two windows for it. Some air should pass.


I am still trying to get away without rebuilding the engine until next winter. If i'm not causing permanent harm to the engine, then i'll let it be for the summer.
Anyway, she will never do more than a couple hundred miles until the winter.

She does exactly what you describe. Revs up at stoplights and pops especially when maintaining speed or letting go of the throttle.
I can get it to calm down by letting go of the clutch a lit bit to force the engine to lower the revs and it maintains 1,5k revs until next stoplight.

I will do a compression test as soon as possible.

Thanks a lot to all that helpped ;)
 
I think I put them in in 2009? Put a few thousand miles on them.

My bike used to rev up all the time too. Not sure what fixed it. Maybe the electronic ignition or maybe the Uni filters.

If it is running and not making awful sounds ride that bitch. Just keep an eye on the oil.


end of line
 
My bike has under 10k miles on the clock. If it ran without it i don't know.

I will ride it as is, but that high idle has got to be fixed. The bike is loud, and revving like crazy on stoplights gets people to close car windows and cover their ears on the sidewalk. Embarrassing and uncomfortable.

Tomorrow i'll change the o-rings and washers on the carbs, tighten the exhausts a bit more and then make a video of how she sounds and rides.

Thanks again
 
adventurco said:
Are those EMGO pods? If so, throw them in the trash, or do some searching for the technique to mod them so they don't restrict airflow.

I read about why they suck, but mine do not block anything. I didn't even notice any difference between pods and no filters.

Where can i find that technique to modify them?

What i had there before starting the build was the same as no filters. Just a wire mesh stopping stones and (maybe) sand from getting in.

Should it run better without filters than with those pods?
 
Today i went over a few things.

Checked the right exhaust to see where the leak was coming from. Its oil coming from the exhaust.
There was no gasket there so i put a new one on.

Modified the baffles inside the mufflers to make them quieter. I cut it and bent the metal to make something similar to this.



When i opened the mufflers all the glass fiber wool had gone. And just after two short drives. I made less than 20 miles.
So i replaced it with stainless steel wool. Hope it lasts longer.

What is normally done in this case? Do you guys try to quieten down your exhausts? How?
 
I went over the points adjustment again and found that the right one was out of sync.
Adjusted it and now, not only it starts much easier, but I got it to idle properly at around 1200 revs.

No more spewing of oil after the new gasket.

Only thing now is that it still doesn't rev over 5000 revs
Where to look next?
 
New attempt... This time i just bench synced the carbs and replaced the spark plugs. Both pod filters are installed.

Its a little better now. Just looking at the plugs it seems the mixture is better. The right side is firing more evenly with less spewing.

It revs to 6k now and doesn't cut out abruptly. It just can't go any higher.


 
I have been putting a few miles but yesterday something went wrong.

The drive chain broke!! While i was doing 60!
Had to call the tow truck and got it home without a scratch.

For the last 10 miles i was felling something strange with the clutch lever. It was snapping at my fingers which was a warning sign. Then i felt that the lever had lost more than half of the travel.. weird.
Since i was on a motorway i tried taking it home without shifting until it completely broke.



This is what i found






The clutch shaft broke :-[
 
Damn! Glad you are OK. Had you put a new chain on it?

Don't lose that little ball, you will probably need it.
 
glad you are ok could have been bad
previous images show chain way loose and front sprocket pretty badly worn and rusty chains are only good for scrap or art the rust can cause crack failures
what happened is the chain being very badly worn equals stretched no longer sitting on sprockets like it should
then the chain gets a big wave in it betwereen the sprockets and allows it to climb a tooth, which then it became whip-snap tight in an instant and broken
besides the chain, tires and brakes and suspension are really important things to maintain and underststand
its new chain and sprocket time, buy them as a set
if you need as clutch pushrod i have em
 
Flugtechnik said:
Damn! Glad you are OK. Had you put a new chain on it?

Don't lose that little ball, you will probably need it.
old rusty chain, worn sprockets,way too loose.....its like in the old movies ,when they cut somebodies brake line,'cept for he sabotaged his own ride :-\
 
You are all right. I have bought a new chain and rear sprocket months ago, but i don't have a chain breaker, so there was no way of installing it.

I tried buying a chain breaker, but my bank has blocked paypal as they believe it is unsafe.
I can only find one on ebay. There is no store that sells it.

The front sprocket looks to be in good condition. The rear doesn't and i already knew the chain was bad. I just pushed my luck a bit too far :-[


Now that it happened and the pushrod (i called it shaft earlier) is broken, how do i find a replacement?
How long is the pushrod? Those two bits that fell out are just a part of it right?
There is still a rod inside the hole.. It moves freely so i guess i could pull it out using a magnet.
 
bezugo said:
You are all right. I have bought a new chain and rear sprocket months ago, but i don't have a chain breaker, so there was no way of installing it.

I tried buying a chain breaker, but my bank has blocked paypal as they believe it is unsafe.
I can only find one on ebay. There is no store that sells it.

The front sprocket looks to be in good condition. The rear doesn't and i already knew the chain was bad. I just pushed my luck a bit too far :-[


Now that it happened and the pushrod (i called it shaft earlier) is broken, how do i find a replacement?
How long is the pushrod? Those two bits that fell out are just a part of it right?
There is still a rod inside the hole.. It moves freely so i guess i could pull it out using a magnet.

what do you need a chainbreaker for ?i know every body has a grinder just get after with a grinder it is the easiest method anyway just grind the head of of 2 pins in outer links and a small punch they drive out easy on your junk chain just severe that one side plate
the front sprocket does not look good you didn't know what you are looking for, ,thats ok now you do wrap the new chain around that sprocket and you will see
believe it or not a roller chain and its sprockets is a very precise mechanism
be sure and get the rear sprocket bolts secured the service manual has the torque specs and use loctite
yes a magneyt to fish the rod out get a new seal i have a rod you can have it for the cost of shipping and a cup of coffee
 
whats going on with the bottom shock bolt i see welding so somebody converted it to eye instead of clevis ?you dont have the rubber bushings like stock ?
but it looks like the eye is bolted up tight ?
 
xtop20A said:
whats going on with the bottom shock bolt i see welding so somebody converted it to eye instead of clevis ?you dont have the rubber bushings like stock ?
but it looks like the eye is bolted up tight ?

The shocks that were there before were the same type. That's why i bought these shocks not knowing that the stock ones are clevis. Didn't even know that term before.
Nothing was modified. It just bolts this way. I have bought new stainless steels bolts though.

Some may tell me i'm wrong, but i do feel it is safe (although not ideal) this way.
If i'm convinced otherwise i may get new shocks.
 
xtop20A said:
what do you need a chainbreaker for ?i know every body has a grinder just get after with a grinder it is the easiest method anyway just grind the head of of 2 pins in outer links and a small punch they drive out easy on your junk chain just severe that one side plate
the front sprocket does not look good you didn't know what you are looking for, ,thats ok now you do wrap the new chain around that sprocket and you will see
believe it or not a roller chain and its sprockets is a very precise mechanism
be sure and get the rear sprocket bolts secured the service manual has the torque specs and use loctite
yes a magneyt to fish the rod out get a new seal i have a rod you can have it for the cost of shipping and a cup of coffee

I know the grinder would work getting the old one out, but what about getting the new one to the same length? It has 20 extra links..

Ok.. since i'm putting in a new chain and rear sprocket i'll get a new front one as well. It looks ok to my eyes, but i've never had a proper bike before.

I went to the garage just now and tried using a magnet, but it is just slightly larger diameter than the pushrod so no luck.
While i was there i looked at it a little better and it really doesn't seem like it snapped.
Cleaned the two broken bits and took a few pictures



The sheared ends


And the other ends


What do you think? None of these ends looks sheared. Nor does the end on the rod still inside the engine.
 
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