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Joined: Sep 19, 2008 Posts: 112 Location: Highland Park, Illinois
Posted: Sun Sep 28, 2008 2:16 pm Post subject: Where's the problem?
Having not ridden for many years (I'm an old guy),I bought this '74 CB450 as a learning bike, hoping to step up to a bigger bike soon.
I didn't pay much for the bike and I didn't expect much. I did a compression test, and both cylinders are slightly less than 150.
Working on a bike is new for me, but I'm enjoying it. I've worked on muscle since before most of you were born. Anyway, when I try to merge into faster traffic, the engine just won't keep up. When I roll into the throttle, the rpms go up, but the engine accelerates slowly.
What do you guess is the primary cause of this lack of power? If I were to rebuild this thing over the winter, are engine parts still available? Sorry this is so long. Thanks, Chris
Joined: Feb 15, 2007 Posts: 631 Location: LaPorte, Indiana, USA
Posted: Sun Sep 28, 2008 3:48 pm Post subject: Re: Where's the problem?
ChrisGarrett wrote:
Having not ridden for many years (I'm an old guy),I bought this '74 CB450 as a learning bike, hoping to step up to a bigger bike soon.
I didn't pay much for the bike and I didn't expect much. I did a compression test, and both cylinders are slightly less than 150.
Working on a bike is new for me, but I'm enjoying it. I've worked on muscle since before most of you were born. Anyway, when I try to merge into faster traffic, the engine just won't keep up. When I roll into the throttle, the rpms go up, but the engine accelerates slowly.
What do you guess is the primary cause of this lack of power? If I were to rebuild this thing over the winter, are engine parts still available? Sorry this is so long. Thanks, Chris
Yes, parts are still available - just rebuilt one myself.
Though 150 pounds is marginal on a 450, you should still get better performance than that.
You say the rpms go up normally, but it doesn't accelerate - maybe the clutch is slipping ??
bill _________________ Bill Lane
"When your only tool is a hammer,
everything starts to look like a nail."
Joined: Sep 19, 2008 Posts: 112 Location: Highland Park, Illinois
Posted: Sun Sep 28, 2008 6:04 pm Post subject:
Thanks for responding Bill. If the clutch functions normally when shifting, could it still be slipping when I'm accelerating?
Where do you get the parts for the engine rebuild?
Joined: Feb 15, 2007 Posts: 631 Location: LaPorte, Indiana, USA
Posted: Sun Sep 28, 2008 7:25 pm Post subject:
ChrisGarrett wrote:
Thanks for responding Bill. If the clutch functions normally when shifting, could it still be slipping when I'm accelerating?
Where do you get the parts for the engine rebuild?
It's a tight, durable tranny - drag racers even shift without the clutch many times.
If it is slipping, it would be worse under hard acceleration.
If the rpm quickly increase but you don't go any faster, that would be my guess.
But it may just need to be adjusted.
Some parts are still available from Honda - if so, that's always preferred.
Go to the Bike Bandit fiche - if they have a little box where you type in the number of the items you want, there's a good chance it's still availalbe. If there's no box, you'll have to start looking on EBay or other sources.
I see you are in Highland Park - that's not all that far from me, if you want to bring it over here.
bill _________________ Bill Lane
"When your only tool is a hammer,
everything starts to look like a nail."
Joined: Sep 19, 2008 Posts: 112 Location: Highland Park, Illinois
Posted: Mon Sep 29, 2008 5:23 am Post subject:
Thanks for the offer, but the truth is I'd be afraid to ride this bike that far and I don't have a trailer.
I'm a little confused. When you say it might be slipping or need an adjustment, are you talking about the clutch or the trans? I just installed a new clutch cable, and it seems to function okay, but what do I know?
Joined: Feb 15, 2007 Posts: 631 Location: LaPorte, Indiana, USA
Posted: Mon Sep 29, 2008 8:07 am Post subject:
ChrisGarrett wrote:
Thanks for the offer, but the truth is I'd be afraid to ride this bike that far and I don't have a trailer.
I'm a little confused. When you say it might be slipping or need an adjustment, are you talking about the clutch or the trans? I just installed a new clutch cable, and it seems to function okay, but what do I know?
Chris -
Ah, a clue, maybe ........
It's fairly common, when replacing the clutch cable on a 450, to lose the little ball bearing that goes in the clutch adjuster mechanism. The clutch won't work right without it. That would be part #23 in the diagram. It can be gotten at most auto parts stores, I think it's 5/16" (sometimes called #10). Can you check to see if it's there??
There's no adjustment to the tranny, it either works right or not.
bill _________________ Bill Lane
"When your only tool is a hammer,
everything starts to look like a nail."
Joined: Sep 19, 2008 Posts: 112 Location: Highland Park, Illinois
Posted: Mon Sep 29, 2008 10:41 am Post subject:
As a matter of fact, I did have to replace that little ball. My clutch engages kind of far out on the release. I didn't get around to adjusting it to the 1" of so of freeplay. Do you think that could cause the engine to rev to higher rpms without any real power? I'll try re-adjusting it tonight.
Thanks for your help and thanks for the diagram. Never messed with motorcycyles before and I need all the help I can get.
Joined: Feb 15, 2007 Posts: 631 Location: LaPorte, Indiana, USA
Posted: Mon Sep 29, 2008 10:51 am Post subject:
Adjust the clutch to your comfort point, not where a book says you should. I think I made a recent post about how to do it.
Some folks adjust so it's way out on the lever, others like more slop.
If the little ball is indeed in there, you may just have a worn out clutch. It's not an expensive fix, you can get a Barnett kit for less than $50, I think - I guarantee that won't slip. You'll need that cover gasket as well - no special tools are required, other than an impact driver for the case screws (around $10).
bill _________________ Bill Lane
"When your only tool is a hammer,
everything starts to look like a nail."
Joined: Sep 19, 2008 Posts: 112 Location: Highland Park, Illinois
Posted: Mon Sep 29, 2008 3:57 pm Post subject:
I contacted Barnett directly, and apparently they don't make a kit for my bike. So, I contacted Honda dealers and they said it is unavailable too. Do you think a 72 kit would fit?
Joined: Feb 15, 2007 Posts: 631 Location: LaPorte, Indiana, USA
Posted: Mon Sep 29, 2008 6:29 pm Post subject:
ChrisGarrett wrote:
I contacted Barnett directly, and apparently they don't make a kit for my bike. So, I contacted Honda dealers and they said it is unavailable too. Do you think a 72 kit would fit?
Yep - All 5-speed clutches are the same.
sorry you can't find a Barnett - can't remember where I picked up mine - I think maybe from one of the vintage places.
bill _________________ Bill Lane
"When your only tool is a hammer,
everything starts to look like a nail."
Joined: Sep 19, 2008 Posts: 112 Location: Highland Park, Illinois
Posted: Tue Sep 30, 2008 1:06 pm Post subject:
Honda dealer tells me the '72 and '74 clutch kits are the same. Barnett tells me they are different. Anybody have first hand knowledge? I would like to rebuild my clutch.
Joined: Feb 15, 2007 Posts: 631 Location: LaPorte, Indiana, USA
Posted: Tue Sep 30, 2008 1:46 pm Post subject:
From the Honda fiche(s) -
283 is the original CB450 4-speed (Bomber) number
292 is the CB450 5-speed number
When the 5-speed was introduced (K1), a change was made from 6 clutch springs to 4 - this also changed the clutch "basket" itself, the inner hub, and Plate A and the Pressure plate, as well.
But the actual clutch plates themselves did not change.
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