Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties flat tracer racers

flat tracer racers

Post Thu Feb 09, 2012 11:43 am

Posts: 13
hi guys and gals, glad to be a new member.
a bit slow with computers but i am getting there: )
what is a average neck rake for flat track racing? i was thing 25 to 30 but not opposed to leaving it at 35. the frame i am working with i been cut already been cut up ( swap meet find for this project ), so i am not screw up one ( i would not ! ).

also i know it as been covered and it seems the general thought is not to, but if i choose to convert this 45 to a WR can anyone supply info on the needed bearings?
maybe a source for them?
thanks all pan60

Post Thu Feb 09, 2012 8:12 pm

Posts: 693
Location: somerset, oh usa
A factory frame actually handles very well as is. Seated position needs moved forward slightly and I recommend 19" wheels for clearance.
It's not going to be the bearings that are used in the mill that will put you in the ball park with other racers in terms of power.
Cams and finding WR top end parts, or as the aussies and the americans that have raced them can attest, serious reworking of stock stuff can have remarkable results. has been producing some of the parts.
There is alot of info available via forum research or the purchase of pamplets with many ideas and insights for gaining power with the HD 45. If actually planning to race it then a full understanding of the sanctioning bodies rules is always good during the planning stages.
Racing is not for the faint of heart nor the light on general!

Post Thu Feb 09, 2012 9:59 pm

Posts: 13
i am not dead set on making the bottom a WR but do want to know what they did and maybe someone can post some pics.
for the bottom end that is.
i will probably run a K model top i have on hand.
the frame as to be de-raked as someone made a chopper out of it in another life or i would just stay stock.
i have a well made spring but it is a couple inches short so i thought i could suck this up a bit but i do not want to end up with something to unruly to ride.
i have some 19'' wheel i will probably run but not settled on it yet.
doubt i will race it, just rip around here on it.
are there many racing groups out there?

Post Fri Feb 10, 2012 8:04 am

Posts: 693
Location: somerset, oh usa
VDTRA, AHRMA, AMA, plus the series that is part of Wauseon and Davenport although I've heard that the first race in the series that traditionally kicked off the season does not have a sponsor after the debacle they started there a couple of years ago with the nicest and most dedicated vintage dirttracker i know and the resultant decline of participation. Lesson learned?????
The WR used a forged flywheel instead of cast that utilized a larger 1 1/2"crankpin but a dirttrack engine will spend most of it's raced life at a higher rpm than a stock engine will turn at all. Sprocket shaft was also bumped up in dimensions and the whole thing spun on ball bearings. Beauty of Speed has details and pictures.
I built a 45 / k hybrid a couple of years ago and it was a fun project.
Bruce at has most everything you'll need for for pairing the k top to your 45.

Post Fri Feb 10, 2012 1:32 pm

Posts: 767
Location: CA USA
A late friend of mine who tuned and raced WRs and Scouts always claimed that the all ball bearing bottom end of the WR was no better than a properly set up roller bearing bottom end when it came to actual on the track performance. The top end was what counted. I would check out the Truett and Osborne flywheels that take a standard set of XLCH rods and crankpin. Set up your sprocket and pinion shafts loose and think about maybe replacing the cam bushings with the XLCH needle bearings. There are several guys out there who are taking the repop cylinders and putting WR intake nipples in them, adding larger valves and then relieving and porting them with very good flow bench results. KH pistons with a relief cut into the heads similar to the later WR heads are part of the package. Cams will need to be carefully selected. Bruce has some nice offerings. In order to put on the K top end you need to add some more expensive valve gear and I'm not sure that the vintage racing groups will allow the use of the later top end in their hand shift class rules.

Post Fri Feb 10, 2012 1:38 pm

Posts: 13
i think this will be a fun bike to build. i need to decide how much i can safely de rake the front and what i should try to get for ground clearance.
any thoughts on where a guy might find the ball bearing and race dimensions?
i have a couple K's here one i am planing to part out.
we need more pics on the forum guys: )~

i looked at Beauty of Speed site i should probably look for my glass's?

Post Fri Feb 10, 2012 3:06 pm

Posts: 693
Location: somerset, oh usa
Do a forum search as the k top end requires some changes in your valve train for everything to alignthat has been detailed before. As B'dog alluded, it's rather expensive. He's also on track that if racing, the k cylinders would put it into a later class.
If your budget is a concern, I'd consider going with a W top end and KHK grind cam lobes, heavily massaged intake tract and unless planning to race a standard bottom end on rollers.
I find it more fun to go fast when i've not spent a ton of money getting there.
I would put the neck back to stock dimensions cause, as stated, it will work on the street or on the track.
The ground clearance will not be that much of an issue if you're careful with your front exhaust pipe. When flattracking the std 45 clutch would be a possible issue with grounding and lifting the rear end. WR's use a narrower clutch.
More frame clearance is required for hydraulic front ends as they have more travel than a springer so it's not a clear cut issue.
Plan your build asking questions when unsure and you should find all the help you need as it comes.
The conversion to K or WR top is pretty straightforward should you choose to go that way also.

Post Fri Feb 10, 2012 7:37 pm

Posts: 13
i am slow at these builds i don't get in any hurry any more these day, just fun for me: )
like i say. i really doubt i would race it and i do believe that the difference in the roller verses the ball bearing bottom is minimal, but, building the ball bear bottom would be more fun.
if as else fells i will look at some going with the XLCH bearings.
i have a couple 45s so i may do one one way and one the other?
as i get a bit more info gathered and get close to starting the build i will get a new thread going with lots of pics.
i am not opposed to make lots of stuff here.

Post Sat Feb 11, 2012 5:14 pm

Posts: 13
does anyone know what the rake on the WR bike was?

Post Sat Feb 11, 2012 7:43 pm

Posts: 693
Location: somerset, oh usa
From an imaginary plumb line established through the centerline of the engines mountings, the neck angle that i found referenced is 23 degrees.

Post Sat Feb 11, 2012 8:23 pm

Posts: 13
that is steep?
i was thinking more around 30 would have been about it.
so i would probably be okay anywhere from 25 to 30.
i was looking at my old pan, and it looks like i have about 4 1/4 '' maybe 4 1/2'' of ground clearance from the bottom of the frame to the ground. that would be fine for this 45 wouldn't it? or should i shoot for a bit more?

Post Sat Feb 11, 2012 9:48 pm

Posts: 693
Location: somerset, oh usa
The reference point is not the ground so it's not what you're thinking. That 23 degrees would not necessarily reflect the angle of the fork stem when the bike is sitting on it's wheels.
I'm guessing that angle is closer to 30.
Reference line is established through the 3 mounting points for the engine and is per a factory manual. Centerpoint of lower engine mounts extending up through the center of the top mount.
The only factory frame i have set up with it's original front end is a 37 so i have nothing to check without somehow establishing a reference point, as like above.
It's my understanding that there are manuals available for viewing online to give further clarification.

Post Sat Feb 11, 2012 10:27 pm

Posts: 13
base on the frame drawing i have, the rake is the degree of what established square is.
so once the frame is set ate what would be considered level, the angle off a plumb line would be the total rake.
i am confidant in how to calculate the rake just not sure what the WR was.

the pan is 30 and the servi-car is 23
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Post Sun Feb 12, 2012 3:55 am

Posts: 1654
If someone brought me a bike for scrutineering with that kind of welding and re-welding around the neck, I wouldn't pass it... wouldn't ride it, either. Same goes for forks.
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Sun Feb 12, 2012 12:57 pm

Posts: 767
Location: CA USA
I have a WR sitting in a front wheel clamp that keeps the front tire on the same plane as the rear. I get 27 degrees unladen using a digital protractor on the front fork legs. Read the rule book about frame mods. The last I looked the standard was very subjective. Before spending time on this I'd check with a tech inspection guy from the racing group to be sure that you do this in a way that has a chance of being passed.

Post Sun Feb 12, 2012 1:25 pm

Posts: 13
i am not sure but i for some reason thought most of the Wl's were 30 or maybe even 35 degrees. i have not found in my stash any info other then the servi-car rake.

45Brit, as far as riding one that has been raked to each his own, i am a very confidant welder ( yes certified ) and i do see a repair front end if correctly done any more a hazard then that of a custom made frame.
some one welds the up.
i have seen some i would NOT ride, but i have repaired a number of big twin frames and rode-em.
i have a 60 model pan i had to redo the back end on and it look factory, repaired it years ago. it is tore down now to be freshened up and new paint, the he repair is solid.

i have a frame i have to rake somewhere degree wise, where i am not sure as of yet? i have a short spring i would like to use, but i do not want to de-rake the front end to much, and as i say i am not sure just where it should be.
27 degrees would work fine, 23 ( as with the servi-cars ), would be better.

Post Sun Feb 12, 2012 1:41 pm

Posts: 693
Location: somerset, oh usa
Could you accept that those are both the same and his engine is just 4 degrees off plumb sitting as it is.
I'm not aware of any neck angle changes on 45 solo, servi car, (or WR) necks and believe them to be all the same in that respect.
It's a matter of the reference utilized in measuring it.
How short is this front end and consider that a custom front end could have custom rockers made that would correct the length within reason.

Post Sun Feb 12, 2012 3:04 pm

Posts: 13
very possible.
the front end i was thinking about using is only 20'' from the bottom neck bearing to the axle center line.
i can machine the a recess for the top spring space the lowers and gain a bit more, may a inch? also i could get a inch out of some new rockers?
i may be to just use a different front end? i have a could sporty front ends i could use, or just make another front end. this one is done here and nice, since i need to do some work of the frame and the neck i figured i could use it.
so you think the solo, servi cars, and WR's were all the same.
not in a big hurry as i am also moving my shop to a old barn i have revamped ( still need to paint ), in my back yard, i have several machine to move yet.

Post Tue Feb 14, 2012 2:09 pm

Posts: 391
Most WRs used standard WL frame castings with the exception being the chrome-moly frame. Replace the neck with a stock one and you will be fine!

Post Tue Feb 14, 2012 4:38 pm

Posts: 303
Location: wooster oh usa
i have seen some "deraked" short coupled frames...all home made. all wr's that i have ever seen used a stock front casting section as robbie moly frames of the 40's era are brittle...not worth using in my opinion.most U.S. inspectors in ahrma will not pass a welded front section on a casting such as a wr has. kr's are a different animal and the de raking done on them was different. i think they made them 28 degrees as i remember.steve (37ulh) is the master of info. barry


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