heads for stroked flatheads

I'm now sorting through the various unused parts collected for my stroker project. The engine has T&O wheels and pistons to give a capacity of 54", near as spit.

I have several sets of heads, #5 and #6. As I see it, the extra stroke would have the effect of increasing the nominal compression ratio; #5 heads calculate out as 5.8:1 and #6 heads, 7:1 or something very like it. 7:1 sounds too much for a bike like this, I don't want to strangle it or overheat it... any comments?

what about ,using the 5# having them welded to kr shape, and see how they work. what cams are you using cos relieving above the valves for the correct cam lift will drop some combustion chamber volume.
regards jib
are you going pop up ?

There's no plan for any no fancy head welding. Frankly, I'd regard that as being too far down the path of diminishing returns.. my experience of old-bike tuning is that most of the time, you are best off to just get it running right and stop at that.

I don't intend to use pop-up, no. I was recommended against it by a VMCC member using a fast 16H Norton, as being not worth the decreased piston life and possibility of ring failure for a road bike.

Cams are WLDR. Barrels are stock with polished ports, close attention to squish distance and general racing-standard assembly. Carb is presently a concentric, but I may change that.

The bike weighs about 90lb less that a stock 45, the frame and forks weigh about the same as the 45 frame... the wheels and tyres weigh about the same as one original wheel assembly. I'll see how it goes and then worry about the next stage.

Jim Leineweber insisted I converted my k model head to KR combustion chambers,and when I say insisted he flatly and quickly shut me down every time I tried to ask him about other options for heads I had learned about.

Let me know if you lack the information on heat cycling times required for heads in our size range as well as oven temperature,best choice of rod though it tends to "bubblegum " when running a bead it's been found by one of the foremost aluminum welders the best end result ,specifically concentrating in Harley Davidson head,engine case,and trans cases for the last 3+ decades.The pro I speak of that gave me this information on request of a mutual friend we have.He also has always used an continues to use common house hold electric stove oven he has set up in his shop for all preheat and timed cool down of the items he repairs....

if I'd got K model port specs, and I was building a racing engine, I'd look at the heads but I don't believe it is a worthwhile use of time and funds for the engine as it stands.

I was attempting to buy some K barrels and heads a while ago but that seemed to fall through, a pity as it took my attention off some other good stuff I was offered and with being away so much it all fell through. Oh well, life's like that sometimes

Isn't the reason this engine can't use more compression then 6,5:1 is because you loose almost all flow from the back of the intake valve then you increase compression by milling the heads.
If you bump compression up by welding the heads to KR standard or stroking which doesn't affect flow in a negative matter you could have a lot more compression?

Like this? http://i244.photobucket.com/albums/gg3/ ... _kr_01.jpg

yes like that. , 45brit, damn sorry i didnt get back to you about the k barrels and heads, [have sent you pm] and they are yours if you want them. regards jib

pm sent. Last year was a very disorganised year for me so the whole project has slipped badly and various things I was trying to do, didn't happen for various reason

just been looking at your bike on flathead-bobbers.com

45Brit, My personal experience says that even if you don't go with the K head configuration, going for pop up is useful. The British flathead experience does not directly relate to HD combustion chamber design.
When I stroked both my UL's, I went with about .030" popup. The result appears to be more power than just the increase in displacement from 78 to 85" would create. Also, there is enough crown on the HD pistons to keep the rings in a safe location. Compression itself isn''t the enemy, as noted, it's the decrease in the size of the flow milling the heads causes.
Frankenstein is at 9:1 compression from stroke increase, and some milling to the heads by their previous owner. Piston life has been very good in that motor, although it does ping occasionally. And it appears to have adequate power.
However, if you get the squish distance to a close but safe value, then you will have achieved at least one portion of the value that popup achieves.
Just passing along my personal experiences, you should, of course, build your motor to please yourself
DD

ok noted, and thanks to all for your views.

I have the situation that I have been collecting parts over a long period, and by the nature of that process what you end up with isn't necessarily consistent. I have three sets of cases, three cranks ( one all-new ), #5 and #6 heads, several sets of cams etc etc.

I've rather come to the conclusion that I would be best served by building two bikes. I have a considerable selection of cycle parts and transmissions to hand.

Bike #1 will be the bike currently nearest completion, the bike I have posted pics of on here from time to time. Engine will be the stroked 45"unit with KNS-spec or WLDR cams, T&O 4.5" stroke wheels and pistons, zero pop-up and Amal Concentric carb which is already near completion. All-new WL rods and crank-pin, stock cylinder lubrication. Sleeved barrels to OEM bore. No significant porting or relieving but ports polished and smoothed. #6 heads to see how they turn out, change to #5 if they don't. Various odd parts such as belt drive and 12v electrics which have arrived in the parts box over time. Pretty much a WL with a bit more hair on its chest, and a bit less lard behind its belt buckle; the revisiting of the Ray Leon 45" powered Ariel which I owned in the 70s, which was the original impetus for this project.

Bike #2 will be the "clubman's bike" I have always fancied, but never built. An off-road machine with a competition flavour, for the occasional vintage hill-climb, demonstration track-racing rides, Mallory Park track ride at the 1000 Bikes, Saltburn Sprint... whatever amuses me, really.

Engine to be 45" using K barrels and heads, K type cams of some sort, 4-speed chain-drive transmission ( probably Albion because I have a good one I've used before in a grass-track bike, maybe a Norton box and clutch depending on what's in my loft ). 38mm Amal because I have several around the place. I can also use a total loss CDI ignition system, what's known as a "magic box" over here. Again, I have several available; I could use an electronic breaker from 45 Depot maybe so I don't have to find a mag, or maybe a front-mounted magneto, I don't know. Cycle parts to be much as for the original bike, probably with a set of braked and a set of brakeless wheels.

Again, this would be very largely a case of gathering together a number of parts and sub-assemblies already to hand. I have another Ariel frame with the mountings pretty much done from earlier work on the first bike. However the temptation to have a sell-off and fund a new frame along the lines of the twin-tube one discussed here recently is very strong and would solve a lot of the problems because the bike would fit together as built.

Sounds like fun, nice to have enough stuff collected to be able to go both ways. Couple of questions, are the 38mm Concentric something of a rarity? I picked up the only one I've seen years ago at a swap meet, it's the only one I've seen on this side of the pond, so I was interested to see your comment on having several. I've thought two might look nice on a dual runner carb setup. they're relatively narrow, which would help.
Also curious about the Albion box, I've got one behind the R.E. Fury motor, box seems o.k, but never thought much about the clutch. The box being so narrow should make it easy to fit into customs such as you're thinking about. I'm presuming there are ways to adapt the Norton or Triumph clutch to one?
Seems I also read once that the bronze bush in the main drive gear can slip if run low on oil, causing oil drillings in the bush not to align, and resulting in drag betwixt mainshaft and output gear, resulting in difficulties finding neutral. Ever heard that one?
You're lucky to be able to build no lights street legal bikes over there, New York laws require a headlight on at all times, period. Ugh.
It's good to view another's perspective on building one-off's, broadens one's horizons.
DD

the 34mm and 38mm carbs I have are Mk 2 Amals. I have a Concentric for the WL bike, because it came with a matching manifold, but that's about 28mm - "one and one-eighth", I suppose.

The Mk 2 Amals are still available new, supposedly. I still have a drawer full of them because they were at one time widely used for track racing - they had the same range of cut-offs and jets for methanol as the Concentrics and the only real alternative was the Dell'Orto which has mounting issues for certain engines. Anyway I'm not a great fan of them although my son prefers them.

the 38mm ones were the generic size for track racing bikes but then speedway was restricted to 34mm so the those became the default choice, these days people use various oddball East European carbs because the near-horizontakl engine layout means conventional float chambers don't work.

my feeling about Amals is that they are good racing carbs, good for high flow rates and very reliable - a stuck float interrupting the fuel supply will trash an alcohol-burning engine in seconds, so this is important - but nothing special for the road. I'm also not fanof dual carb set-ups anyway, I don't feel they are justified for any road application. I once had a single-carb Triumph T-Bird with stock pistons and E3134s that was at least as fast as the local Bonnevilles because it was always in tune on both cylinders and the rest was just careful assembly and careful maintenance.

"Sounds like fun, nice to have enough stuff collected to be able to go both ways"... says the man with seven bikes

I've been collecting this stuff for years and years. I did buy a deal of stuff a few years ago when the exchange rate was $2 to the pound, though.

Albion boxes, h'mm. Good solid box of thoroughly old-fashioned design with few bad habits if properly built and maintained, a right old bag of nails if not. This one is a known good one. Then again, I've never known an Albion box which DIDN'T have neutral selection issues of one sort or another, although there is a traditional fix whereby you lightly punch the end of the bush so it won't rotate... and of course you DO need to keep an eye on the oil.

I do like the clutches though, very light and strong. Popular for speedway bikes in the 50s because they would stand up to repeated clutch starts better than most and the central ring of springs under a keeper plate ( much like a 45 clutch ) are easy to set up for a good start, slipping just enough and no more. Not interchangeable with Norton or Triumph units due to incompatible shaft tapers. I do have a mainshaft for fitting a Norton clutch to a BSA 'A' series box somewhere about.

Norton or AMC units are better on all counts, though. My 350cc JAP has a Norton unit with Jawa plates and springs because they are half the price of Norton ones and you can get them from the spares van, no use on the road though due to rapid wear and they are pure "dry" plates which can't be run in an oilbath chaincase ( if such a thing can be said in respect of Nortons ).

Hi guys,

I thought this topic was a perfect place to give folks a preview of what we are going to be releasing this summer.


By moldthread at 2011-04-02


By moldthread at 2011-04-02



At this point I only have the front head complete and am working on the casting pattern for the rear. All fixturing and programming is complete for the WR combustion chambers.
As you can see the entire chamber is CNC machined into the solid casting. These still need to be polished.
Casting the bottom of the head solid allows me to put a riser directly in the middle center and this avoids the porosity common in the factory castings, and machine any combustion chamber into the head. Imagine being able to machine a chamber for a WR that uses the latest KR dome piston.
I can also make high quality racing heads for your WLDR or WL.
Castings are poured from certified 356 aluminum alloy, heat treated to a T6 condition.
Material thickness is increased over the combustion chamber only, which allows all critical dimensions to be the same as stock. Appearance is almost identical to the stock head. Will be available using 14mm ¾” reach spark plugs (18mm special order).
I will post more here when both heads are available.

I will have these at Oley on display along with my other stuff and can answer any questions.

BRUCE ARGETSINGER
http://www.enfieldracing.com

45Brit,
I have been flat tracking Royal Enfield 500 (1 of them is #1 in the classic 500/750 class this year beating Gold Stars and KRs) singles for the last 12 years and have found the Albion boxes to be very robust with the exception of the possible false neutrals between gears if not shifted with authority. I think the clutches STINK! The were all slipping on me coming out of the corners.
About 6 years ago I started using Bob Newby belt drives and clutches which I love.
They use friction plates from the Jawa speedway bikes and I think springs. Absolutely NO slip or problems on the starting line.

[Pa]

Nice work Bruce !! I was aw strucked when I looked over your other components at Oley last year. You do really nice work indeed ! Though a little off topic....Have you put any thought into reproducing the K, KH, and KHK heads ? As you well know, they were prone to cracking around the sparkplug hole. Pa

PA,

It's on the list.
I've got the K heads measured (I use a Faro Arm) and drawn up, but only have so much time.

Bruce

[Pa]

Awesome Bruce ! Make sure you shoot me an email when you get er done. I will link all I know who needs a pair to you.