Author Topic: Some Info About a 550 Honda Called "The Mantle Piece" (Read 7157 times)

bill440cars · « **on:** April 10, 2007, 07:38:19 PM »

First, I'd like to lay some question to rest about whether this bike is for looks or will really run. The info that I'm about to give came straight from the actual article about the bikeThe electrics consists of: a Sebring pointless electronic ignition replaced the conventional Honda breaker points. As installed, the Sebring unit is comprised of 2 solid-state voltage regulators and recharging system for a ten cell, 6-amp, nicad battery pack. The electrical system is so compact that it would slip into a pocket of a hunting jacket. There was no electric starter, turn signals, no indicator lights, no horn and no gauges. The main purpose of that power pack is to excite the primary field of the alternator and provide enough juice for the headlight, to make it legal. The motor is now 590cc

There is more info and if needed, I'll be glad to supply it and remember, it's right from the article. The bike has nothing on it that isn't absolutely necessary. I downloaded this and the Gentleman's Express from online. I tried to use the info at the bottom of the page, to go back but can't seem to get there. I'm going to put this same info here and maybe someone can figure out how to retrieve the info and share it with all.

The Mantlepiece: http://mywebpages.comcast.net/roblloyd/Motorcycle/Mantlepiece.htm

The Gentleman's Express: http://wabisabi.swarthmore.edu:edu:9673/motorcycles/CB500/articles/GentlemansEpress/ge_1.jpg

Lots of luck to anyone who can manage to retrieve these articles.

There it is, Bill

cafe75-550 · « **Reply #1 on:** April 11, 2007, 08:53:03 AM »

I have both of those articles, found the magazine, "Cycle" from Nov. 1975, on eBay a while back. I'll see if I can't figure out a way to scan them in and post them here....

Awesome articles by the way...

csendker · « **Reply #2 on:** April 11, 2007, 10:10:03 AM »

Quote

I'll see if I can't figure out a way to scan them in and post them here....

That would be handy as neither link works for me.

cafe75-550 · « **Reply #3 on:** April 11, 2007, 10:26:51 AM »

Ok, here's the article. I had to downsize and reduce the quality a little $:-\$ , but I have the full size one's. If you have any issues reading these send me your email and I can forward you larger ones. Keep in mind that the full sized ones are almost 10 MB though

, and may not get along with your email server...

The site shows the scans a little smaller, to get the full size version just open each picture in a new window.

I also have scanned the "gentleman's express" article. This is the one that show's diagrams of how to cut 750 pistons to fit a 550 for your very own 590 kit with increased compression. I'll try to work with my photobucket album to get them up. Unless someone has a a better hosting option, or the moderators want to put the large files on the site somewhere

.

I bought this magazine a few weeks ago, but does anyone see a resemblance?

bill440cars · « **Reply #4 on:** April 11, 2007, 12:10:59 PM »

Hey thanks for posting that.

I've got them printed out but couldn't get them up on line to post them here.

I thought they would both be interesting for others to see also. And, yes I CAN see that there is a resemblance between the "Mantlepiece" and yours. Nice looking bike too, BTW.

Later on, Bill

cafe75-550 · « **Reply #5 on:** April 11, 2007, 12:55:46 PM »

No problem, and thanks!

When I first saw that article I had already bought the new tank for my bike. My first thought was "how did that guy get the picture of my bike out of my head?"

Of course, I didn't even have a head in 1975, so he obviously beat me to it

. But its pretty close to how I imagine my bike looking when I'm done with it. The guy spent a little more money on it than I hope to though, given that his frame is custom built. And I like the look of the shouldered aluminum spoked rims better than the mags.But its a beautiful bike, and there are lots of ideas to be had by looking through the article. I'll try to get the "Gentlemen's express" article up later, more good ideas there.

turboguzzi · « **Reply #6 on:** April 11, 2007, 01:24:58 PM »

very very nice! cycle was THE king of publications.
front end looks a bit flexy but in those times it was the norm.

length of the velocity stacks is quite impressive.

Thanks!
TG

MRieck · « **Reply #7 on:** April 11, 2007, 01:46:31 PM »

I like the 103 HP turbo Z1. I get 98 HP to the rear with a normally aspirated 915.

dminner · « **Reply #8 on:** April 11, 2007, 03:32:21 PM »

Dumb noob question, but where are they mounting their battery. Will it really fit under those low seat cowls? Thats my only guess to where they could be

cafe75-550 · « **Reply #9 on:** April 11, 2007, 04:30:10 PM »

There was extensive work done to the electrics of that bike, reducing the need for a large battery (no electric starter, no turn signals, no horn, no gauges..). I think they said they replaced it with a NiCad pac, so that would easily fit under that seat, actually almost anywhere.

But with modern gel-cell batteries, its not hard at all to put one under the seat cowl, I have a regular 12v 8ah gel cell under the seat of my bike posted above, which is plenty to power even the stock electrical system, and its only about 3"x4"x6", and can be mounted in any orientation.

Ricky_Racer · « **Reply #10 on:** April 11, 2007, 04:56:05 PM »

In the same vein, a question: Does anyone know of someone who has successfully minaturized the Honda electrical components (starter solenoid, rectifier, regulator and flasher) into a smaller, easier to conceal package? Inquiring minds would really like to know! RR

Geeto67 · « **Reply #11 on:** April 11, 2007, 05:16:57 PM »

my cb550 chop runs a bates box and a dummy oil tank. the oil tank holds the battery and all the electrics, the bates box holds the coils. Looking at the bike the wiring is hard to spot.

736cc · « **Reply #12 on:** April 11, 2007, 05:33:08 PM »

The "Gentlemans Express" and "Mantlepiece" were 2 different bikes. Both used the CB550 platform, but (if my memory serves me right) the "GENTLEMANS EXPRESS" had a KalGuard painted Kerker pipe, Muhlholland shocks, Action Four pistons and cam, Barnett clutch, CB750 carb springs (easier on the wrist), Lester wheels, single disc, used a stock front fender, flat cafe bars, original Honda paint, and K81 Dunlop skins.
I started going that route in 1977/78 with my CB500/4 but ended up saving $100 a week for 25 straight weeks and bought a brand-new 1979 CB750F DOHC instead for $2500 (and it was a very good choice).

Ricky_Racer · « **Reply #13 on:** April 11, 2007, 05:39:35 PM »

Thanks, Geeto, but I'm looking for a package that would replace the stock components. A package, let's say, about the size of two decks of playing cards or a coupla packs of cigs, or smaller...

If we can pack a veritable supercomputer into a new Yamaha R1, there's gotta be a solid state solution to reconfiguring our old sleds! Any electronics geniuses out there? RR

Geeto67 · « **Reply #14 on:** April 11, 2007, 05:59:57 PM »

Quote from: Ricky_Racer on April 11, 2007, 05:39:35 PM

Thanks, Geeto, but I'm looking for a package that would replace the stock components. A package, let's say, about the size of two decks of playing cards or a coupla packs of cigs, or smaller... If we can pack a veritable supercomputer into a new Yamaha R1, there's gotta be a solid state solution to reconfiguring our old sleds! Any electronics geniuses out there? RR

Well last time I thought about it, a battery for an LX50 vespa (things are tiny - about the size of a walkman), a combination regulator/ rectifier from a cbr600 (to replace the seperate units on our bikes) and a modern two fuse blade fuse holder (main and lights, delete the starter). that is about the minimum you need I think.

edit: I just realized that the tail piece on the mantle piece is a late kawasaki h1 unit with taillight (or a fiberglass replica there of). I kept saying that tail looks familar....

Ricky_Racer · « **Reply #15 on:** April 11, 2007, 09:05:19 PM »

Thanks, Geeto. Maybe you've pointed me in the right direction; at least enough to go further. {sigh} I really don't know diddly-squat about electricity! $:-\$ RR

cafe75-550 · « **Reply #16 on:** April 16, 2007, 11:13:20 AM »

Quote from: 736cc on April 11, 2007, 05:33:08 PM

The "Gentlemans Express" and "Mantlepiece" were 2 different bikes. Both used the CB550 platform, but (if my memory serves me right) the "GENTLEMANS EXPRESS" had a KalGuard painted Kerker pipe, Muhlholland shocks, Action Four pistons and cam, Barnett clutch, CB750 carb springs (easier on the wrist), Lester wheels, single disc, used a stock front fender, flat cafe bars, original Honda paint, and K81 Dunlop skins.
I started going that route in 1977/78 with my CB500/4 but ended up saving $100 a week for 25 straight weeks and bought a brand-new 1979 CB750F DOHC instead for $2500 (and it was a very good choice).

Yep, they were definitely two different bikes, especially cool given the number of performance mods to both, to have them look completely different. The Gentleman's Express bike looks almost stock, but performance wise has been improved greatly, while of course "The Mantlepiece" is about as far from stock looking as you can get.

I've posted "The Gentleman's Express" here http://www.sohc4.us/forums/index.php?topic=20601.0, so you can check it out. It actually has shouldered aluminum spoke rims, not Lesters.

But thats pretty good from memory!

puppytrax · « **Reply #17 on:** April 18, 2007, 03:58:33 PM »

An interesting read, although Phil has/had too much Duesenberg history on his mind...

I thought the comment about using Honda 305 pistons was a good tip, until I saw the 14:1 CR...

The 750 pistons were a bit too much, if there's only a "razor blades" thickness of cylinder sleeve left...

Has anyone actually tried either of these piston swaps??

cafe75-550 · « **Reply #18 on:** April 18, 2007, 05:14:36 PM »

Quote from: puppytrax on April 18, 2007, 03:58:33 PM

An interesting read, although Phil has/had too much Duesenberg history on his mind...

I thought the comment about using Honda 305 pistons was a good tip, until I saw the 14:1 CR...

The 750 pistons were a bit too much, if there's only a "razor blades" thickness of cylinder sleeve left...

Has anyone actually tried either of these piston swaps??

No idea about the 305 pistons, but I know the 750 pistons have been used before. "razor blade" thickness is a little over the top, there's no room for a rebore and I wouldn't go thinner but the 750 pistons at 61mm are the same diameter as the ones in those "605" kits, which I know have been put into 550's without the sleeves included for the 500's. I'm pretty sure that both "bryanJ" and "crazyPJ" on these boards have done the 750 piston conversion.

TomC · « **Reply #19 on:** April 18, 2007, 05:33:11 PM »

Thank you cafe75-550
"The 750 pistons were a bit too much, if there's only a "razor blades" thickness of cylinder sleeve left..."
I think that there is a reason for the name "Mantlepiece" .
"An interesting read, although Phil has/had too much Duesenberg history on his mind..."
Phil does not seem to have a good knowledge of Duesenberg history.
TomC

Ricisan · « **Reply #20 on:** April 21, 2007, 08:18:48 AM »

I have had both of those stories in my head for 25 yrs. The GE was a middleweight UJM before it's time.
My 78 has alloy rims 18", CB 1000 forks and dual piston calipers, rearsets, 750 tank and a few other tweeks.
On the batt/elect I took the batt box and turned it around to the inside of the frame where the filter used to be. It makes the bike much slimmer w/roadster look. Now I don't need bulging sidecovers. I would like to find some PVC and make sidecovers that snug in close.
My torn rotator cuff is healing, should make some progress soon.

Ricisan

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Author Topic: Some Info About a 550 Honda Called "The Mantle Piece" (Read 7157 times)

dminner