Author Topic: Stuffed CB450 DOHC (Read 7636 times)

bill440cars · « **on:** April 21, 2006, 02:18:50 PM »

I know, I know, it's not a SOHC or a Four. At least I had the good sense to list it in "Other
Bikes".

Now that we've gotten past that, I've put this same basic post in the "cb450dohc.com"
site and I don't know if I've hit on something they don't know about or what. They've been
pretty receptive to my previous questions about the 450. Anyway, what I want to know is
(since the CB500T is basically a stroked 450), What displacement could you get out of it with a
healthy overbore (and I don't mean the last, maybe the next to the last and possibly the last)?
I read somewhere, if I remember right, that the cylinders were still marked as 450 cylinders
(444 or what ever it is). My thoughts are to put 500T guts in a CB450 crankcase so that it
would seem to be a 450, when in reality, it would be a 5??cc. I'm hoping that someone here
either knows the info or will be able to tell me where I can find the info. I've already checked
with HondaMan and while he's very knowledged in a lot of bikes to include the 450, he told
me that he didn't know that much about the 500T. I've got a booklet that has some info on
building a CB450 road racer by Jim Reed & I've checked out a site about one called "Fang" but,
they didn't really have the answers I am looking for either. Any input on this subject would be
greatly appreciated. Well, I've probably bent your ear longer than I should have, so I'll go for
now. (And this won't take me away from my CB550K project.) Later on, Bill

By the way, don't get the idea that I'm selling HondaMan short. No way! He's given me all
kinds of info on the 450 and the CB77 305, not to mention the 500/550s. He is one of those
people who have a vast amount of knowledge and experience in the subject. I just wanted to
make that perfectly clear. He's not the only one though. I have learned a lot from several of
you guys, either directly or indirectly. Later on, AGAIN. Bill

crazypj · « **Reply #1 on:** April 21, 2006, 03:15:31 PM »

Measure the stud spacing diagonal. subtract 6mm. thats the max bore size possible
PJ

cb650 · « **Reply #2 on:** April 21, 2006, 06:24:23 PM »

If you (we) had good sense we wouldnt be mop nuts.

Sorry
Terry

bill440cars · « **Reply #3 on:** April 22, 2006, 03:40:58 PM »

pj, I appreciate your response and all but, I'm trying to find out about what the
displacement would be? I don't have the bore specs handy but, the stroke of the 450 is 57.8mm
while the 500T is 64.8mm. Also I did notice the compression was lowered from from 9:1 to 8.5:1.
I'd be interested in what kind of power you could get of it.

Terry, Yeah, I do believe we're stuck in that rut, along with a few others on this site.
By the way, have you notice how many, on this site, are stuck in the rut of being mopar fanatics?
There are actually quite a few and they have or have had some pretty impressive cars too.

You guys take care.
Later on, Bill

Jay B · « **Reply #4 on:** April 23, 2006, 04:57:22 AM »

Hey Bill, to figure displacement you'll need to know bore size and do a little math. Take 1/2 the bore (in cm) squared times pi (3.141659) times the stroke, also in cm. Multiply by 2, for 2 cylinders. You can plug in different values to match the 450/500 parts. HTH.

Oh, BTW, the 450 I was getting for free turned out to be a 400 Kaw, pretty ratty, so I told him I wasn't interested. I had done enough research on the 450's that now I'm on the hunt for one.

bill440cars · « **Reply #5 on:** April 23, 2006, 09:17:49 PM »

Jay, I appreciate your response and the info you provided but, I'm kinda mathematically and formula challenged. Do you know what I mean? I've got the bore size, howmuch over youcan go and the stroke. Could I get a little help on the rest? I'd sure appreciate it.

CB500T The bore is: 70 mm CB450 The bore is: 70 mm
Last factory Over Size is: 1 mm over Last factory over size is: 1 mm over
The stroke is: 64.8mm The stroke is: 57.8mm

What I'd like to know is, If I build a 500 and bore it 1mm o/s, what would the actual
displacement be? Could you, or someone, do the math for me? I would be so grateful.
Basically I want to build a 5??cc in 450 clothing. Later on, Bill

Jay B · « **Reply #6 on:** April 24, 2006, 04:14:12 AM »

Bill, figuring the 500's bore at 71mm I get 513 cc. A bored 450 would be 457cc. Looks like you'd gain about 56cc. If you could use the 450 pistons to keep the compression ratio up there, it looks to be a usefull gain.

bill440cars · « **Reply #7 on:** April 24, 2006, 04:53:30 AM »

Thanks Jay,

I had heard that a 450 could have been bored to almost 500cc (guess I heard wrong)and I
had visions that, if a 500 was created by Honda by stroking it then, maybe a 500T could be bored
to almost 550cc and that would be incredible. Imagine, a 550cc 2-cylinder! Oh well, I'm still working
on building at least a 500-513cc bike. with some head work, some cam, jetting and exhaust work,
it should still be a pretty good runner, don't you think? Also, HondaMan gave me some tips on
building a 450, that I should consider in building this one. Well, thanks again Jay and I'll catch you,
later on, Bill

Jay B · « **Reply #8 on:** April 24, 2006, 02:26:35 PM »

Bill, I don't know much about 450's, but just working the math backwards says that to get to 550cc with the 500's 64.8mm stroke you'd need a bore of 73.5mm. If the factory only goes to 1mm over, maybe somebody else makes a big bore kit to go that big. Like I said, I don't know if it's possible or not, but that's what the math says.

bill440cars · « **Reply #9 on:** April 24, 2006, 06:02:40 PM »

I know Jay, I'm just wishfully thinking out loud (or something like that). I've always had a
yearning to be able to build up a bike that nobody would guess, would be somewhat larger than it
was thought to be. Hence the 450 wanting to be a 550. I think though, with the ability of a 450
to start with, add HondaMans info, other bits and pieces that I have picked up here and there. I
hope to build a pretty good runner. Another thing I don't know is if the crankshaft of the 500T will
fit the 450 crankcase (different shaft bearings, 500T has ball bearings instead of the roller type
bearings.) There is a slight difference in the ratios of some of the trans gears. I've got a booklet of
info by Jim Reed on "How to Build a Honda CB/CL450-500T Vintage Roadracer" and it gives pretty
good info on the frame & engine. Only thing is, it doesn't give details of some of the things that
you need to do. Anyway, I'm still looking for anything I can find. Later on, Bill

Jay B · « **Reply #10 on:** April 25, 2006, 06:53:10 AM »

Sounds like a great project. Keep posting on it. Man I'm starting to want a 450 in the worst way, I'm gonna hunt one down this summer for next winters project build.

bill440cars · « **Reply #11 on:** April 30, 2006, 02:10:42 PM »

As part of this project, I'd like to put the 500T components in the 450 case. The main thing I
am not sure of is, will the 500Ts crankshaft fit the 450 case? The 500 has ball bearings on the
crank while the 450 has roller bearings and I don't know the outer races measurements. The trans
of the 500T has different ratios from one gear to another as compared to the 450 also. I'm hoping
the 450 case will accept the 500 innards to camouflage the motor so that I can pass it off as a
450. If things work out right, maybe I can start actually working on this project. Right now, I'm just
gathering info and ideas. So, any input would be helpful and welcome. Later on, Bill

CB925 · « **Reply #12 on:** May 01, 2006, 12:55:31 AM »

I have a pair of 1mm oversive pistons for my 450, the barrel and pistons etc are ready to install, but I haven't quite gotten around to it yet. I have been told these 1mm over pistons achieve a displacement of 462cc, but I'm not entirely sure where I read / heard that.

I'm pretty sure that I have also seen 4mm oversize kits for the 450 on ebay from time to time. I think that the 500T sleeves or cylinder need to be fitted in order to achieve this.

The Henning Honda article here is a good read: http://motorcycle.com/mo/mctext/henning.html

Also, some links on the following very basic site: http://www.justxr.com/cb450

Cheers, John.

bill440cars · « **Reply #13 on:** May 01, 2006, 05:26:17 AM »

Hey John,

I had seen the Tod Henning site which was very interesting to me. Keep me posted your
progress. I like to hear about buildups on most anything. I really like hearing and talking the 450
because it WAS a pretty big move to get Honda moving up to a larger bike and there were some
innovations used on the 450 engine. On that 2nd link that you posted, that looks interesting as well.
I'll have to check it out more thoroughly, when I have more time. I do appreciate your responses on
this and look forward to seeing if there is more out there and if it will surface.

HondaMan (here on the site)has some pretty detailed info on the 450 and lots of others.
SamCR and Greg (ohiocaferacers) has done good things with the 350 and has some good info on
the 350 and has talked about maybe doing a 450 later. There are probably others that I'm leaving
out but, it's not on purpose. Remember, I'm almost 60 and the memory is the 1st thing to go.

I know that this is a SOHC4 site, I hope I'm not pushing any bad buttons by doing so
much on the 450 DOHC and I am glad that it can be covered under "Other Bikes" because, I
personally feel it deserves a place and I seem to get more detailed responses here than even on
the 450 site. I am trying to work it over there and try to stimulate the conversation.
I'd better get out of here, Bill

dusterdude · « **Reply #14 on:** May 01, 2006, 06:08:49 AM »

well,you pushed mine damnit.

ohiocaferacer · « **Reply #15 on:** May 01, 2006, 06:47:23 AM »

Bill,

Kenny Augustine had contacted me a few months ago. Spoke with him a few times......seems like he knows his stuff. You may want to contact him and ask him a few questions......I would bet he knows. I have his contact info on my links page under:

Kinetic Analysis' Kenny Augustine

Later,
Greg

bill440cars · « **Reply #16 on:** May 01, 2006, 10:02:18 AM »

Thanks Greg,

I appreciate that, every little bit helps.

Later on, Bill

bill440cars · « **Reply #17 on:** May 11, 2006, 12:47:19 PM »

Well, I was just informed by a cb450dohc.com member, that the 500T crankshaft bearings
are too large and won't fit into the 450 crankcase. But, he did verify that the gear ratio spacing
on the 500T trans is noticeably better that the 450's. So,looks like the 500 encased in the 450
case is out. It's not over yet, I just have to decide what I'm going to do and how. I still have
some good info from HondaMan, the source from cb450dohc.com and the info that I already had.
So, the quest is still there. It's just being realigned, that's all. Later on, Bill

Oh and I'm not just looking for input on the motor. I'm also looking at ideas for the rest of
the bike and I'm going for the "Cafe Racer Style". So, anybody got any ideas/ If so, let's
here them.

GoatBaSS · « **Reply #18 on:** June 03, 2006, 08:32:03 PM »

I dont know if this will help, but the CB500t was the logical next step for the 450, but as I was told by several owners when I had mine in the early 90s the 500 was a lack luster version that actually performed worse.I also read some articles that echoed the performance stats. I never had the pleasure of a 450, but the 500 parts were a pain in the... to find. Part of the reason it was sent on. Was loud!!!Boy.

bill440cars · « **Reply #19 on:** June 03, 2006, 09:07:29 PM »

Thanks for that GoatBaSS, I have about decided that the trans, oil pump and the head might be good to have but, the rest either won't fit or be of benefit to mess with. The 500's gear ratio spacing is supposed to be better than the 450. Anyhow, with the info I have previously gotten, from here, will
be used to give the already peppy 450 a little more pep. Now all I have to do is get some other projects out of the way so I can get on with this one. Thanks again, Bill

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Author Topic: Stuffed CB450 DOHC (Read 7636 times)

CB925