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Advice on 45's?

5K views 26 replies 18 participants last post by  Hopper 
#1 ·
I'm not a mechanic but I'm not braindead either... I THINK I can learn, or at least die trying! My grandpa rode a BT flattie back in '36 and I'd love to have one to ride now. I can't find an affordable BT but 45's are all over though I have no clue as to what they're worth in any of the varying stages I find them in.

Questions are;
-can a 45 be dependable as far as riding as a daily or at least on a regular basis?
-what sort of price range should I expect to pay for a complete or nearly complete 45 motor?
-is there anyone that just likes to talk flatties with total greenhorns and more specifically, anyone in Texas interested in the same?

Thanks in advance for your replies... I'm a sponge waiting to absorb all I can about these bikes!

Sincerely,
Scott McMahon
 
#5 ·
I have had a 1942 WLA for two years. Although I have not rebuilt it (yet), I have done a bunch of fixing. Rewired it, scraped carbon of the heads, rebuilt oil pumps etc. It is a real fun bike. Had to learn how to ride again because of the foot clutch. Mine will comfortably do 50 and a little more but I don't like to push it. Those in the know say they are very reliable and like Danisdad says above, you can fix it yourself. I see it like a big lawnmower engine... It goes slow and stops slow.
 
#6 ·
With a little work, they can be damn reliable machines. But you will never get a stocker to run more than about 50, unless you want to rebuild it every year. They are like all harleys, you can get a deal, or you can get fucked. Depends on how much you know about working on them and how much you want to put in to making it a daily rider. With enough money, you can get one, ready to go, but they can be a little pricey unless you run into a deal. A basket shovel would be a better fit, and it would not cost you any more than the 45, and would be much better for the money. But that is my opinion.
 
#7 ·
But you will never get a stocker to run more than about 50, unless you want to rebuild it every year.
This part is crap, If geared correctly and ridden like a vintage bike they will do 55-60 all day with spurts up to 70 with no ill effects. I built mine in '93 and it still runs strong. And I flog it!

This part is fact
A basket shovel would be a better fit, and it would not cost you any more than the 45, and would be much better for the money.
45s are now bringing prices that Pans did a few years ago. Go for the Shovel for same money!
Robbie
 
#9 ·
I can get 70 mph with mine. Pretty much stock rebuild, although I did shave the heads to bump up the compression. I still have the 1" Linkert and small manifold (that I did bore out and polish).

I have a 33 tooth motor sprocket. I think you can get 34 tooth, or maybe even 35 will fit under the primary cover. Plus, if you get a '41-up, you'll gain an extra tooth on the trans sprocket.

I wouldn't go 70 all day with mine, stuff starts vibrating off like tank screws, and I end up holding the tank on with my knees...........but with a stock 45" 70 mph is possible. The nice thing about a 45 is you can increase performance significantly without sacrificing reliability.

They are very reliable.....even for the outdated technology. Probably a bit too reliable. They'll run with poor compression from bad rings, worn valve guides, worn cam bushings, etc............I wouldn't want to ride on the freeway everyday to work.

I've seen titled motors go for around $2000-$2500. A bit high I think, but with the amount of parts out there, you could pick up some matching cases, buy some cylinders, buy stroker flywheels and have a great motor for less than that.

The 45's biggest pitfall...........the 3 speed transmission. Weak and poorly chosen gear ratios. To get any decent top speed out of them by changing the motor sprocket seems to magnify the terrible 'hole' left by the 2-3 shift.
 
#11 · (Edited)
victory library sells a 45 performance handbook also. and check out 45 restoration company in NY.
i've got a 54" that will run 90, and runs 70 all day long. i'm running a 4spd trans though. paughco now makes a frame, trans plate and belt drive to do it.

with a 45" engine with portwork and some epoxy in the ports and the 4spd trans i could run 70-75mph and i would run it for very long periods wide open. like 30 mile periods. i would run it to work (17miles each way) with one stop sign and one small town to slow down though. otherwise i would just run it wide open the whole way. it would speed up down hill and slow down up hill, but i rarely got passed by anybody and had no problem running with traffic.
 
#12 ·
I appreciate the information and suggestions so far! What I'm looking for is a reliable(daily would be great) rider and from what I gather that isn't a problem. The big thing for me is I'm in Texas and nothing is really "close"... my daily roundtrip is right at 70 miles so running 50 or 60mph sucks. I've been told you can't run a flattie(45 or BT) 70 for anything but short bursts or they'll fall apart or sieze up and something in the back of my conscience just doesn't buy that. I'm not looking for a racer, but I'd like to be able to keep up with a pack running 70 on the highway.

I've seen a few numbers thrown out there, can anybody give me an idea on what an "average" price is for a decent 45 motor? I've seen a nearly complete backet offered for $670+ and an assembled motor missing a few spare parts for between $1500 and $2000... what's reasonable? I know I"ll need to have any motor I buy rebuilt but the idea is to learn to turn a wrench on the bike motor myself for maintenance and repairs.

Somebody had already suggested the Victory library which I need to go ahead and buy... are there any other publications that y'all might suggest?

And I'm just throwing this out there, but I've never done a build before... I ride a stock Sporty(please don't drive me out with pitchforks and torches) which is why I've come to a site like this one... to hopefully learn what I can from those who have gone this way before me. At this point several friends are strongly encouraging me to buy an Evo Sporty and do a build on it and THEN move on to a flattie... is there any real reason to go this route? I mean, aside from working on the basics of putting the bike together I can't see that there would be alot of knowledge gained from dropping a Sporty motor into a frame I've hardtailed and working on building a flattie from the ground up.

Anyway, I'm interested in learning what I can and I'll take some time out to check out the sites and leads y'all have mentioned on go from there... thanks again!
 
#15 · (Edited)
It's just like the old saying you can go as fast as the amount of money you're willing to spend,of course that's up to a point.I'll briefly describe my bike to give you what I feel is a realistic point of reference.I have WL cases with 4 5/8" stroke flywheels,ironhead sportster rods,KHK cylinders which come off the top performing street legal K model based bike ever produced and utilize 1 13/16" intake valves and 1 9/16" exhaust valves.The cylinders are 3/8" taller then any other 45 cylinder and have the biggest ports and valves of any comparable size Harley flathead other then full on race bikes.I will tell you I have $600.00 in my 4 tappet blocks alone as they are a specialty item to line the KHK cams and valves accurately,which is a must if you run this topend.I have matching heads,The intake makes a stock 45 intake look 1/2 size,I'm running KHK cams with if I correctly recall are 288 degrees duration and .395" lift which isn't much in an overhead valve engine but approaching the max reasonable limit to run on the street in a flathead and according to many pretty much the limit,I'm running an M53 linkert carburetor with a bombsight venturi which was originally used for racing.heavy duty valve springs,and the small details go on and on.I'm near 50,have ridden steadily for 25+ years and have owned numerous Harleys.I didn't go into this blind.For reference I'm hopeful my engine I just detailed will effortlessly and consistently at least be able to keep up with free traffic at 70-75 m.p.h. Does that help put the flathead in perspective after spending a dollar amount I could've purchased a bike with just on my engine and pertaining items I will be thrilled if it puts out 40-45 horsepower.A relative has a late 90's 1200 sport that was advertised as putting out 80+ horsepower at the crank and doesn't even have $3000.00 dollars tied up in it.I will close by saying my drivetrain build alone easily eclipses the cost of his sportster,by a wide margin.I'm not trying to discourage you as I think everyone should own a flathead at some time.If the sportster you currently have is a healthy ironhead or a pretty much stock 1200 evo you'll feel like your walking compared to the typical speeds one gets accustomed to in metropolitan areas.I'm sorry for the long post but If you aren't being realistic with yourself about what a 50+ year old small cubic inch motorcycle will or won't do you'll not likely be happy..............
 
#16 ·
i rebuild my engine >did some work on the new cylinders /pistons and heads (size 6 with extra work done to them)

changed the intake and mounted a linkert M74B
made a custom exhaust
did loads of work to the lower end and renewed all the parts and bearings
BUT did re-use the stock flywheels and connecting rods

because i did some mild top end tuning and installed a joe hunt magneto
it already rev's better

but the main difference in speed is the gearbox i chose
its a BT 4 speed gearbox from a FL (shovel) from '79

highway speeds up to 84 m/h on the TomTom so that must be correct
and still have some throttle left over ....don't wanna floor it just yet
because i'm "still running in" the engine

normal cruising speeds are 70 m/h right now

not much money went into this engine and tranny ;)
 
#17 · (Edited)
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this flatty [ built by obsolete engineering] and myself, will run 75 all day long.......as long as you have fuel in the tank ! Like I told you before, throw out all misconseption about flatheads being inferior man !!! Geez. My buddy Brock rode his 1947 74" from Ohio to Mt washington 3 times ! Climed to the top and slugged down a bottle of wine . The 45 cubic inch models proved so dead nuts reliable, they were still in demand for traffic control etc. up till 1973
 
#18 ·
70 is not realistic, neither is massive building. Yes you can get more but your bike will be short lived. They were not designed for that,also as mention the transmissions are not the toughest and tend to fail before the motor will. With all the "speedy" builds by the time you get done all those alterations ,,find the bike at a deal is out the window with all the extra $$ you have spent,,that in the end only shortens the motors lifespan. 45's are for relaxing and taking your time. I'm sure so and so has done this ,,or the stories of you can do that, but ya know. Have had quite a few and they have been fun, easy to work on and reliable. The bigger Flatheads are another story,,

A good simple stock 45 will get you where ya wanna go for a long time,,as with everything,,it has its limitations
 
#21 ·
The basic 45 motor was around for a long time for a reason. The military and police departments (servicars) used them by the thousands and they're pretty tough to kill. Parts are easy to find, although unfortunately getting more expensive, like everything else. It won't get you there fast, but it will get you there.
 
#23 ·
Mr. Haney,

What year is your BT flattie?

List,

So I know everyone has opinions and that's great... but how does a noob like me know which opinion to take over the others? I mean no disrespect to anyone here, I appreciate all the input y'all will offer but the crowd is kinda split in reading over these posts.

Will the 45 do what I'm looking for or should I dig for a big twin?

Still confused...:confused:
SMc
 
#24 ·
BT vs 45. There's actually very little difference in performance. We have a group who meet up once or twice a year for rallies in Europe. Some on 45s, some on BTs. They're pretty evenly matched. Ok, the BTs have a bit more grunt but they're a lot heavier. I'd fan the flames and say that the 45 is more reliable than the BT - oil pumps are pushed to the limit on the BTs. Add to that the availablity and price of parts and initial purchase price and I'd stump for the 45. I also think that 45's make a better looking bobber - more compact. You can make a 45 go really well for little money if you're handy with a lathe and grinder. Convert to 12v for excellent lights and a modern charging system and avoid aftermarket points or go electronic. I also know of a reliable conversion using Nissan points.

Have a look at this:

http://www.jockeyjournal.com/forum/showthread.php?t=22069
 
#27 ·


It does not take much to get them going a respectable speed.
Not sure if you can read the writing at the top, but officially timed at 104mph.
Stock WLA motor with 2-inch inlet valves, big carb, 7/64" planed off the heads, ports polished and that is about it. Stock cams.
That engine is still going today, in a restored street bike.

You have to remember Harley had the 750 flathead KR going 150mph at Daytona in 69.
So getting more than 70mph out of a stocker is no big trick.

 
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