Jockey Journal Forum banner
1 - 20 of 37 Posts

·
Registered
Joined
·
933 Posts
Discussion Starter · #1 · (Edited)
Started this back in August. I acquired a pretty decent looking 45 U motor. Supposedly rebuilt and came from Dan Carr some years ago. It had high compression cast iron heads with a few chipped fins, a repaired front left motor mount, and the VIN is original and titled, but it looks like a "L" got zapped out with a TIG.

Once home I did check the top end, which indeed was fresh. 74" cylinders, +.050 cast pistons.

I decided to try Flathead power's KR-ish heads. If you're wondering, they cc'd to equivalent of med. Compression sized chambers. I smoothed out the chamber a smidge, and unshrouded the spark plug holes. Anders recommended NGK BP6ES plugs, but I think autolite 4265s would be good.

I also did the cylinder mods like in the factory KR manual. Why? Because why not.
 

Attachments

·
Registered
Joined
·
933 Posts
Discussion Starter · #2 ·
With the motor, came a 4-speed ratchet top trans in a nice '64 case. ratchet top is also oem, but I think the kicker cover is aftermarket (but no cracks...). The adjuster boss was shaved to fit in a VL frame, but I can live with that. It was in a not quite ready to run state, but a couple of misc parts and aligning the forks, and things were looking good.

My last 2 bikes (panheads) I ran the chain primary and run covers, and it reminded me how much I dislike extra hassle, parts, labor, and expense. So I'm looking forward to running nothing more than a 1.5" belt drive this go-round.

The last bike was a tank shift and rocker clutch, which was cool for awhile, but I'm looking forward to just plain foot clutch and ockey shift again.
 

Attachments

·
Registered
Joined
·
933 Posts
Discussion Starter · #3 ·
For the frame, I decided to try the v-twin hallmark frame. It's not terrible, especially for the $, but it needed a couple things.

1) I didn't love the way the rear legs were formed, but the frame was indeed straight, so that is what it is.
2) The motor mount holes needed a wee bit of enlarging with a pencil grinder. But I fully expected that.
3) The oddest part was that the foot control mount holes were a mix of 3/8 and 7/16", and we're FINE thread. I had to tap and helicoil all 5 of the holes.
4) the rear footboard mounts had to be drilled a smidge bigger.
5) the oil tank mount seems a tad low and/canted. And I'm not sure the cross brace is quite right. The bottom line is it makes for a super tight fit in the battery tray, and I had to trim the battery cover. If I had a stock battery, I'd have a problem.

I went through our own @mikevonwegener, and he was awesome. He went to bat for me, and v-twin acknowledged it was a little wonky, and to everyone's credit, we all agreed on a deal that was fair for everyone. So I'm not complaining.
 

Attachments

·
Registered
Joined
·
933 Posts
Discussion Starter · #4 ·
Now it was time for a carb. M51 linkerts aren't cheap, and I was also wondering if the fancy heads and cylinder reliefs wouldn't benefit from a different carb. I realize none of that may make any difference. I also realize it's an 80-year-old side valve motor, but it's still fun to experiment.

I had a linkert M74B ready to go. I was going to cut the flange off the stock manifold and weld on a pan head flange, but the original manifolds are hard to get and expensive. And the aftermarket ones don't fit as well either. So I decided to try the one from cannonball.de. I didn't love the fit or the look but I made it work. The smaller diameter and sharp transitions worried me, but I've been assured by people that know more than me that that is by design and intended as an improvement.

The spigots were a little short and off-center when mounted to the cylinders, But I got it to seal with new colony brass seals. Before that I put a smear of epoxy on any of the little pits in the nipples.

The bigger issue was how short the manifold was, so I had to use two insulators to bring the carb out to the stock position of the -39 manifold.

Then I had to massage a stock carb bracket to fit. I used a side valve fuel bowl, throttle lever, and choke. I had to rotate the needle/filter to the backside of the bike, to clear the exhaust. And that got a little tricky because the float could barely clear the carb body. And then I was able to use a stock OHV fuel line, with a little bending.
 

Attachments

·
Registered
Joined
·
933 Posts
Discussion Starter · #5 · (Edited)
The exhaust came with the motor and was unfinished, but I kind of liked it. Although the front pipe certainly complicated such things as mounts and clearing generator and carb.

I added a bend in the front pipe to clear the generator, finished off the welds, and added threaded bungs for the mounts.

Now I had to figure out an air cleaner that actually filtered air, and didn't look out of place. I flipped a j slot backing plate upside down, and with a little trimming of it and the cover, it fit over the exhaust pipe. Then I added a little shelf, to keep gas from dribbling on the pipe and act as a heat shield for the filter.
 

Attachments

·
Registered
Joined
·
1,339 Posts
you cant go wrong using a M74 on anything - M75 is the go to performance factory carb but the 74 will do anything you need - just my take

check the sip in the idle slot hole if you get a hot no easy re start as you can make it larger but you probably already know that
 

·
Registered
Joined
·
933 Posts
Discussion Starter · #7 · (Edited)
Aside from the motor, the most important part of a big flathead build is the tanks: it's the one thing you can't get in the aftermarket. I shopped, waited and waited for something that wasn't insane. These tanks came up, and they weren't terrible. When they arrived, they were definitely worse than described by the seller, but still not terrible. But then again I'm not doing a resto, and I liked the paint.

It's a 39 and down right tank and a later left tank, but they're both flathead tanks. The badge mounts were welded on after the paint job, so I had to repaint the white panels. The mounts have each been repaired at some time in their lives. There were some dings and chips.

Sherwin williams color matched ready to spray pints, and I used a pre-val kit to paint the fender and touch up the tanks. I suck at painting, but I didn't need a pro paint job in this case.

The raw fender and struts also came with the motor. It was fine so I decided to use them. I always weld nuts captive because I like being able to remove the fender without removing the wheel or squeeze my hands under the fender. I also welded the loops to hold the wires off the tire.

I debated what to do for a taillight. I like and always run a light on the fender with a license plate mount. But the vast majority of old photos of modified bikes I've seen don't have lights on the fender and use marker lights. So I gave that a try. And I used a bruce lindsay wiring harness. I use a 12v 5.5amp battery in a pvc tube, where I put a circuit breaker too. Then I can run a stock battery cover, and it resembles stock setup.
 

Attachments

·
Registered
Joined
·
933 Posts
Discussion Starter · #8 ·
I wanted the 41-46 tank trim, but didn't want to ruin the paint by welding mounts. This was my first time dealing with this trim, and hopefully my last. If there's a secret, I'd like to know it. I tried epoxying the mounts on twice, but by the time I'd try to get the trim on the strips, the epoxy would let go.

I finally put the trim on the strips off the bike, bent them for a nice fit on the tanks, then 3M emblem tape fit in the groove perfectly.

Then onto the dash. I have a nice replica switch with Briggs&stratton barrel. The aftermarket cateye dash is a hole filler only. But that's all I needed. The correct Colony hardware kit is almost a must. Twist/grind/drill/tap/space it until it fit half way decent. I won't run a speedo unless it's proper, and I have no need or desire for a $1000 speedo on this build, so I just cut the face off a junk speedo. Under that i can put whatever family photo, word of the day, or inspirational quote under the glass that I want.

The early dash doesn't use a rubber trim strip but I wanted something to protect the paint. It needs to be super thin, so mcmaster carr to the rescue.
 

Attachments

·
Registered
Joined
·
1,702 Posts
you cant go wrong using a M74 on anything - M75 is the go to performance factory carb but the 74 will do anything you need - just my take

check the sip in the idle slot hole if you get a hot no easy re start as you can make it larger but you probably already know that
Agreed, just added a 74b on to my 41 EL, just a solid carb, Retiring the M35 to the shelf!
 

·
Registered
Joined
·
1,804 Posts
Dang! Thank you for putting up this thread: it's a pretty good palliative for cabin fever.

I wish my grasp of flathead flow and f.h. design was a little better than the average four-year-old girl's. I get the fundamental idea. In a few cases I see the obvious connection between what Flathead Power, and then you, did and the advantage to be gotten from doing it. But a lot of your head pics, I just stare at them with no more comprehension than if I was a cow.

I appreciate your photos and words, though! Thanks again for posting them.
 

·
Registered
Joined
·
933 Posts
Discussion Starter · #12 · (Edited)
Forks: my last few builds have been springers. And on my long road trip each spring, I'm frankly tired of the vibrating bars and the springer ride. So I'm looking forward to a glide fork for a change.

I preferred the early trees, but I was wedded to my bars which were too narrow for the wider risers. So '60+ trees it is. The legs had the perfect shave job, and just the right amount of patina, but they were frozen solid and a mess inside. Many hours to disassemble, clean, fix; but I was able to salvage almost everything. And without the fender or tins, I had to come up with a brake line holder.

The aftermarket headlight brackets aren't my favorite, so I turned the headlight mount in the lathe to fit the socket in the oem mount.

My cycle electric generator (because what else do you run if you want to ride) had to be heli-coiled to 1/4"_24, so I didn't have to drill the cases. Fyi- it's NOT 1/4-28! The gen body is a little too big to use the generator strap, but it's sitting on the cradle so I'm not worried about it.
 

Attachments

·
Registered
Joined
·
162 Posts
Devotion and desire, very need project. I am very impressed with some guys here who really dig deep into the classic facts.
 

·
Registered
Joined
·
2,493 Posts
very nice job.
how does it run?
Flat is where its at!
 

·
Moderator
Joined
·
4,039 Posts
I had very good luck relieving my cylinders and running the KR heads. Finding a deep-enough plug is a bit of a challenge.

Very impressive performance boost, IMO.
 

·
Registered
Joined
·
1,569 Posts
Looks great, thanks for all the photos and explanations! I like that color
 

·
Registered
Joined
·
933 Posts
Discussion Starter · #18 · (Edited)
maiden voyage. Could have been worse, could have been better. After 4-6 heat cycles and a 2 laps around the block, I set out. 3 miles in (it's 30deg F here, so it's not because the motor got too hot), the rear exhaust valve stuck. I made it home on 1 cylinder, reminding me why I have no interest in 45" harleys.

The valves look like they werent new, so I'm doing all the valves with new kibblewhites, cleaning up the seats making them 3-angle, and cleaning up rough spots in the ports.
 

Attachments

·
Registered
Joined
·
1,702 Posts
Aside from that unfortunate issue, the bike looks fantastic, Scott. I'm sure it'll be back together sharpish and back on the right track!
 

·
Registered
Joined
·
2,493 Posts
Why did it seize ?
any idea ( i had a valve seize was inadequate oiling.)
 
1 - 20 of 37 Posts
Top