500cc pushrod bike project

[Stainless1]

Sock, they don't want the exhaust pointing at the surface.  Something that exhausts against the surface 10 inches away is a no no.  One that intersects the surface 5 feet away should be great.  Those in between are probably up to the inspector.

[JimL]

Thanks for the comments, folks.  The pipes are not yet mounted at the rear, so are hanging down a little.  Even at this angle, a straight line from the bottom pipe would probably hit the ground about 5-10 feet behind the pipe.  The picture is a little deceptive, actually. 

Megaphones also have remarkably cool "end of pipe" temperatures, with slow outlet velocity (I had thermal stickers on the megs on my CB450 I ran in 2007, and it didn't even darken the 250Farenheit sticker!)  This, even after I made a pass jetted too lean (had to back off the throttle to speed up).  I know that modern exhaust systems are all about velocity and keeping gas inertia high, but I love the sound of long megs...and this is MY toy to play with. 

Regards, JimL

[panic]

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[willieworld]

jim   you still working on the bike     willie buchta

[Dean Los Angeles]

I love the sound of long megs...and this is MY toy to play with.

I'm sorry, you are going to have to share. There may be more than one of us that likes the sound of a good megaphone!

[JimL]

Yes...still working but little progress.  I have the pieces to machine for the jackshaft (had to change course a little). 

I'm up to my ears in an old Toyota flat-bed dually...gotta rebuild the engine, replace the trans (switching from auto to manual), fix the efi, etc.... I bought it to fix, but the plates run out in November, so I'm really hustling.   I'll get back to bike real soon.

Thanks for the interest!
Regards, JimL

[sheribuchta]

Hello  anyone there ?


                                       Sheri Buchta

[landsendlynda]

not likely Sheri, it's New Year's Eve .... in fact......HAPPY NEW YEAR!!!!          

Lynda

[sheribuchta]

Hey Lynda,
Happy New Year to you as well. Hope it will be a good one.

Sheri Buchta

[SPARKY]

Sheri,  Tell Willie its a NEW YEAR---it's time for him to come out of posting retirement.

[JimL]

Hi folks....getting onto the bike project again.  Engine coming apart....I'm REAL unhappy with the jackshaft "deal". 

I've got to prove to myself there isn't some way to fab a new trans countershaft and seal setup to get chain directly to the rear wheel.  I may have to build a solid shaft that carries between the original output bearing location and inner countershaft bearing.....to get rid of the flex coupler buried inside that case.  I'm pretty sure I can build a bolt-in pocket case to carry seals and allow sprocket changes.

I'll keep you posted if I find a way...otherwise I'll move forward with the jackshaft arrangement and water spray for chain cooling.

Meanwhile, the roadster project hangs over my head (literally...it's hoisted to the ceiling on a chain hoist....and I'm working under it!)

Regards, JimL

[JimL]

Opened up the engine, took apart the flywheel/stator bucket, and checked alignment for a direct countershaft sprocked.  It looks good, if I cut off the outer edge of the remaining flywheel (see picture).  I'll still have enough for the back-side starter drive, after turning down the flywheel.  I always run constant loss battery systems, so no problem without the alterator (they are a lot of drag on motorcycle engines, because they are permanent magnet....just like an exercise bike).

I'm planning on making a steel case to carry a countershaft seal plate, and an outboard pillow block bearing.  The steel case will seal to the cut-away original outer case.

I'll cut down a CB500T output shaft, then make a coupler using the original part seen in the photos (on the end of the countershaft).  The steel case will also serve as a "case saver" for the front of the chain run.  There is a pic of the approximate area to be removed from the outer case (along with the original output shaft bearing).

The main case countershaft bearing (behind the coupler) is a full sized part, not the "mini-bearing" used at the outside of the outer case.  This will be a lot of work, but a lot less power loss than going around 3 small sprockets, with two chains!

More soon,
JimL

[JimL]

Since I decided to eliminate the jackshaft, and it's attendant power loss, here's where I'm at:
- I removed the alternator drum and magnets from the flywheel then a friend turned the flywheel down as small as we could go and still have an electric starter.  There are before and after pics of the flywheel below, and one showing where the sprocket has to line up.
- I'm dropping the left case off for millwork, tomorrow, then will have plates welded in to allow my countershaft sprocket to run "outside" (photo below).  I'm planning a bolt on seal carrier, and a sleeve on my output shaft.
- My CB500T shaft will be cut down, mated to the driveshaft inner coupler, and a single pillow block mounted outboard to reduce the load on the countershaft output bearing.  the pillow block will have to unbolt for countershaft sprocket changes.
- Shown in the photo is my largest countershaft sprocket (17 tooth), and I'll start off with 41-42 teeth on the rear sprocket.
- I'll try to run about 9500-9700 RPM at top speed, which gives about 4300 RPM on the countershaft sprocket.

Tonight I cut away the left "swing arm" and part of the frame, to make clearance for my new chain angle (since I won't have the jackshaft to lower the front of the chain).

More to come!

[oz]

Good to see you are sticking with it I am sure you will get there. nothing is ever straight forward or it never seems to be!!will the smaller flywheel make a big difference to power delivery more revvy / less torque
Good luck are you going to run this year?
Oz

[JimL]

Thanks OZ....so far it looks ok for this year.  I got the left side of the frame reconfigured this weekend, to make room for the new chain run.  Parts are at the machine shop for rework, case milling, etc.  I'll carry the end of the output shaft extension in a single 20mm pillow block.  That bearing will be mounted on a steel cage, supported by main case and engine mount bolts.  The welded up case won't have to take any load.  Tomorrow I've got to order 8 feet of chain....

As far as the flywheel issue, I can't say whether it matters a lot.  These small engines stay pretty far revved up, and the clutch basket package is geared to the crankshaft for a little flywheel effect.  On my old CB450 with no flywheel, we had a lot of trouble starting it (my dad towed me off the line, on the door handle of his Chevy Van because it didn't have a starter). 

Gordon Jennings (Cycle World) had found out that the 450 advancer wouldn't stay in place on it's weights, when run with radical cams, "one-spline twisted" torsion bars, and 12,000 RPM.  I learned about it in a magazine article, in time to fix the bike before Speed Week '69.  Curiously, that "door handle start" routine led to the only time I ever got my picture in a motorcycle magazine, which was back in the early days of Hot Bike.  They didn't know who it was....it just made an odd picture at the bottom of a page.  Below is a pic of Jeanne and I in 2007....I'm still hanging on the driver's door, but the bike has an electric starter now.

Personally, I like to run without alternators, on cars or bikes.  Straight 12 volt is easy to diagnose, and doesn't run the risk of popping a diode and becoming an AC generator where it shouldn't.  This pushrod bike will run two batteries, one for starting and cooling fan, and one for ignition. 

Perhaps if my wallet doesn't collapse, I'll have the old 450 out along with this bike.  I've got some friends that would like to make a pass on the old girl, just to see what it's like.  It seems to be pretty indestructable, and the old chassis wiggles enough to entertain you (oh man....Kent's gonna make hay with that one...).

Regards, JimL