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44Dwarf SuperDork
3/20/13 4:02 p.m.

Nice. AirTech sells a nice light and small fiberglass fender called Blade1 it was used on TZ and RD a lot it would fit right in on the front of this and not look out of place. I personally hate airtech they screwed me big time when I was young and broke...but they have products.


Monkeywrench Reader
4/10/13 6:58 p.m.

Still waiting for a rear brake line, but I've put about 60 miles on it so far. Handles and rides great. I've gone up two sizes on the main jet due to the new exhaust and it could still probably go up one more.

Before and after:

Monkeywrench Reader
9/7/13 10:43 a.m.

Wow. I haven't updated this in a long while. Here is what has been happening....

This isn't as a complete rebuild as some of the others as the engine was pretty recently rebuilt. I blew a head gasket in late Spring (my fault) which caused me to do a mild top end rebuild.

Here is what's happening:

The previous owner had a 89mm bore (522cc), 10:1 Wiseco piston in the motor, but I'll be putting new rings on it since I broke a compression ring taking it off:

Moving up towards the head. The previous owner had some port work done. A quick measure of everything shows that it's nothing really more than a quick cartridge roll job. It sure does look nice, though. This time around, I had a valve job done on a Serdi by Leggett Engine Research. They do a lot of dirt modified / sprint car work. The intake valve has been back cut as well. They also did a light (.003") head skim.

On the cylinder side, I had Full Circle V-Twin do a 5 stud cylinder reinforcement.

Here it is with the through bolts slipped in to give you an idea: You can see the countersunk bores where the bolt heads sit. Curtis also added material (at the top of the photo) so the bolt can sit flush.

I'm replacing the stock camshaft with a Johnson J2 roller set-up. (soaking the rollers in Brad Penn oil) Advertised numbers are: I: .540" lift, 287 duration @ .040", 105LCA E: .515" lift, 280 duration @ .040", 105LCA

Like all roller cams, it features very fast ramps, which should help prevent any piston clearance issues.

Rounding out the valve train is R/D springs and Schumann Motorworks chromoly retainers and locks (lighter than stock, and hopefully longer lasting than titanium. I don't trust aluminum retainers).

On the induction side, I am adding a velocity stack that that fits inside a K&N. Also, per flow bench and dyno work Dale Lineawaver did, I'm making a filtered end cap to compliment it. The velocity stack pushed the intake tract length to about 11" from the valve seat. This is still a little short for a street motor, but would be perfect for a race set-up. Regardless, it's longer than stock which should help fill in some holes in the power band. It also dramatically smooths out the inside. There is a step where the carburetor meets the filter and the filter has a big flat area inside which causes turbulence.

The filter material is from Uni. You can buy a larger sheet for <$20 and it is available in several different mesh sizes. Naturally, I picked the largest mesh size.

What it fixes:

Inside the filter and end cap (needs to be siliconed on still):

All this is being paired up with an exhaust I partially fabricated this winter. It features a machined spigot that is port matched to the exhaust port (they're flush with one another) and slightly tapers out to the i.d. of the 1 5/8" o.d. primary pipe. The primary carries this diameter until it steps up to 1.75" o.d" after about 15.5" from the manifold face. Then it enters a megaphone/reverse cone before entering the muffler. Total length from the valve seat is ~60". It could be shorter for more peak power, but this set-up clears the kick start and should be faster in the mid-range. The megaphone/muffler and the spigot is a one off piece from Full Circle V-Twin. The shop owner there also did the tig welding after I tacked it all together. It's ceramic coated inside and out by H.M. Elliott out of Mooresville N.C. (they do a lot of NASCAR stuff).

Before ceramic coating:


This megaphone/reverse cone set-up actually tunes like a true megaphone set-up. The megaphone mufflers don't since there is muffler packing material disrupting the pressure wave.

I'm hoping for some pretty good power out of this. I don't expect anything earth shattering, but I expect it to be more than the typical performance build.

Monkeywrench Reader
9/7/13 10:44 a.m.

Here is the assembled the head. Getting everything set up, I'm measured an installed height of 1.61" for both the intake and exhaust. This works out to be about 130lbs seat pressure, and 290lbs over the nose on the intake (more lift than the exhaust). A quick call to R/D, per past conversations with Harold at Johnson (cam grinder), and a friend of mine who has been building championship winning race engines for 50 years, says I'm on the slight high end for this set-up, but it's nothing out of line, so I'm going with it. I feel I could safely run around 115lbs with this cam. I'm justifying the 130lbs since it is a roller and the ramps are very aggressive looking (need more valve spring). I'm okay on coil bind, now it's just a matter of seeing if the retainer fouls on the stem seal.

Here are some photos of the assembled valves:

(I moved that lock over a hair before finally assembly. It'll probably move on a running engine, but it's annoying me to look at).

I also gapped the rings (Total Seal gapless top, conventional 2nd)... both top rings at .022", the second ring at .019", and the oil control rings are over the minimum .015".

To dial the cam in, I removed the inner valve springs, installed the grub screws to fix the rocker spindle deflection, and tightened the cam chain a bit more to simulate running conditions.

Using hole number "4", position "G" I'm getting:

Intake: 40 BTDC, 65 ADBC ... 285 duration and 102.5 center Exhaust: 64 BBDC , 35 ATDC.. 280 duration and 104.5 center

Total lobe separation is 103.5* .

Comapred to the published specs: Intake 40° BTDC 67° ABDC

Exhaust 64 BBDC 35* ATDC

I had to take .020" out of the intake valve relief on the piston to install it at the 40* opening figure.

Measuring the cam at .050", I'm getting 277 intake and 273 exhaust.

Monkeywrench Reader
9/7/13 10:44 a.m.

I assembled the motor for good Wednesday morning, and put it in the bike. Had it fired up by about 2pm. It almost went on the 2nd kick, but I had to fiddle with the idle screw and it lit on the 5th. It built oil pressure fast and accidentally had a mini geyser of oil coming from the oil filter bleed.

I put some heat in the motor and put about ten miles on it riding it up to 60mph or so at 1/4 throttle and then engine braking down to about 20 (without lugging it). I let the motor cool off over night, rechecked the valve clearances and chain tension, retorquedthe head, and then did the same at about half throttle and then full throttle. It sounds super healthy and pulls great. Now just to sort out the jetting a bit. I really want to get it on a dyno to see where things are.

Monkeywrench Reader
9/7/13 10:44 a.m.

The head is the next and most expensive project on this bike. It is something I'm going to farm out as well. I'm probably pretty far away from doing this though, based on my current work situation. :banghead:

Here is the type of work I would be looking to have done. This is a line of Royal Enfield Bullet heads that were modified by Joe Mondello (rip). Anything I would have done would be in the same 'spirit'. I have a short list of people to contact when I get to that point.

http://www.enfieldmotorcycles.com/fo...p?topic=6371.0 (post #6 is a good read). http://www.enfieldmotorcycles.com/fo....0.html(photos farther down).

Information on another Bullet head they did for racing (non raised port casting, but did a little welding, with the Harland Sharp roller rocker):

This is a very vintage(1950s) small air-cooled hemi single-cylinder with 535cc displacement and individual runner(of course), with slide-operated carburetor(Mikuni). Max rpms between 6750-7000 rpm. I'm contemplating flirting with some higher rpms by trying a few mm shorter stroke, but haven't tried that yet. There are some physical limitations, and the port itself has already been welded to close a break-thru to a head stud hole. Can't go much higher because the frame and tank are directly above. Stroke is 3.54, and is a 5-piece pressed-up crank. Bore is 3.425, and the intake valve is 1.84". 80 degree valve included angle. Port is 4.5" long, including the carb mounting flange which we flow-match to the port entry and pin it in place(shown in photo). MCSA is 1.5 square inches. (note: this works out to be 35mm round - Bob) Valve seat I.D. is 1.656"(90%) Seat angle is 50 degree. Max lift is .585". Max flow is 233 cfm at 28

I know they're making over 50bhp on gasoline with those specs above. To be competitive with the Minnovation G50 Matchless engines, they're going to need about 60bhp or more, which is why they developed this one...

They just completed a factory raised port head. Here are the details: http://www.enfieldmotorcycles.com/fo...c=16411.0(flow results on page 2).

Information on the valves they're using: http://autos.groups.yahoo.com/group/...s/message/3386

And here are the beehives they're using on the low lift set-up: http://www.racingsprings.com/1200%20...-1223/item/209

I think they're using a longer stem on the racing stuff, not sure what PAC spring number they're using for it.

I would like to go to a beehive set-up with a tool steel retainer. That would be ideal, imo.

Monkeywrench Reader
9/7/13 10:57 a.m.

Forgot to add, I changed up the instruments a little. Went to a single gauge for the speedo and had to go to a digital tach since the new cam billet doesn't have a drive gear on it.

44Dwarf SuperDork
9/8/13 6:50 a.m.

Bruce from Enfeild racing is a great guy and a hell of a racer to boot. Very smart guy and has the machine shop knowhow to make some great ever expanding line of vintage parts.

Bikes looking good!

benzbaronDaryn Dork
9/8/13 1:08 p.m.

Thats a neat bike good luck with it.

Appleseed UltimaDork
9/9/13 11:48 a.m.

God, I hate you.

Monkeywrench Reader
9/11/13 12:06 p.m.

44F, I just realized the links were bad. The work is from Tom Lyon's outfit. Bruce is the guy that does a lot of flat head Harley stuff, correct?

Monkeywrench Reader
6/5/14 7:24 p.m.

So this winter, as a college graduation gift to myself, I'm having a cylinder head developed for my bike. I'll also be changing the head pipe when I get the motor back in the frame.

For the cylinder head, I got a hold of a top-notch V8 cylinder head guy who has a lot of experience with Chrysler Hemi's (Nick Smithberg, https://www.facebook.com/pages/Smithberg-Racing/224572780930205 ) and he said he was interested in working on the head as a nice break from his typical stuff.

Things are progressing very nicely with the head. Unfortunately, he had a flowbench issue when he recorded the base line on my cylinder head and forgot to re-base line it before he started making changes. I picked up a junk head for cheap thinking it was stock (had it dropped shipped) to set a new base line and just to use for experimenting purposes. Turns out it had been ported previously, but I didn't realize this until he had it in his hands. Oh well. Here are the flowbench results for the intake on the junk head:

We're pretty confident a stock head flows in the 185-190cfm range based on the results of that. That jives up with other flow bench data at 28" depression.

The plan is to make the port as efficient as possible without resorting to making a huge port that is all but unrideable. The port face has been opened up to 38mm (1.50") from the just slightly bigger than stock 36mm (1.42") that my head was previously. Racers tend to open this up to 40-41mm or so. Then most of the work was focused on the short side radius as the port angle enters the head low relative to the valve seat, so it makes for a tight radius and the valve seat / profile.

Here is the finished chamber and valves. The head has since been blasted and decked to get the combustion chamber volume where we need it.

a photo of the intake port:

Valve retainers to fit the 7mm valves:

So as you can see above, we flow tested the Mikuni VM-36 (36 mm venturi) with a more traditional style velocity stack.

and the flow numbers at WOT

After that test and testing the combination on the head (was losing almost 30cfm at .600" lift), I decided to pick up a Mikuni TM-38 flatslide (38mm venturi), which works out to be an increase of 11% in area. Now the venturi matches the spigot and the port entrance diameter.

Here is the TM-38 attached to the spigot and being flowed: and flowbench figures:

So a 11% more area and 12% more flow, and that's without a velocity stack of any sort.

Here are the final flow numbers with the spigot attached (but without the carburetor):

Went up from a 1.85" valve to a 1.90". The port actually lost about 1.5% of flow by doing so, but made the port VERY stable on the bench. I'll take some flow if it means a smoother and more stable port.... especially when you start thinking about the kind of depression is actually occurring in the engine.. If the port is starting to break up at 28" H20, it'll be a mess at 3x that.

The right side is the exhaust. Those numbers are without a pipe. The .800" number is .700 valve lift but with a pipe. Was just really looking for the port to sound clean, which it did.

Keep in mind, this isn't what I would call a 'race' port. The goal with this was port efficiency and port stability. This is a nicely sized port with very good velocity. To take this further, we would go with a larger carburetor (40-41mm) which is where the port face would open up to. The intake valve size would be reworked a bit and the port just touched up to get it working better with everything sized differently.

Going forward, I'm looking to possibly get JE or Arias to update their dated piston designs. Something a little lighter and something with the top ring moved up to the .200" range to minimize crevice volume.

In the future, I'd like to ditch the pod filter and build an airbox with a flat panel filter underneath. This will help with some flow losses that are inherit to the individual pod filter design.

Here is the velocity stack I had made up for the TM-38:

Besides flow, it also aids in the effort to get the intake tract length where it needs to be.

I'm going to change up the head pipe slightly. I'm going to change the step length and shorten the primary as well.

Lastly would be camshaft development. We'd give back some of the low lift flow we too away and probably take 15-20* of seat to seat duration out of the camshaft.

44Dwarf UltraDork
6/7/14 6:47 a.m.

NICE! Full Circle does such nice work too. Amazing what a good shop with good people can do.

Monkeywrench Reader
9/29/14 11:22 a.m.

Custom RaceTec pistons

The piston is a 2618 alloy, machined with the Johnson J2 camshaft (.540" i, 515" e lift) in mind, a 49mm intake valve, and a 37.5mm exhaust valve. It also has dual pin oilers, and lateral gas ports. The dome volume will give me about 10.1 for my set-up, but will be around 12.1 for a stock combustion chamber. Rings are spec'ed for Total Seal's offerings for this bore size ( Gapless 1mm top, 1.2mm napier style 2nd ring, 2.8mm third). It also has a coated skirt and the top ring sits .220" from the deck which reduces crevice volume. The one thing that could take this piston further, and it's an option box I didn't check, is a tool steel pin (lighter).

In addition to the mold, there is a spec sheet that I filled out from the piston manufacturer. I also sent my Wiseco piston to them as well. Basically it was one of those, 'this is what I need, this is what I have / is available, make it better' kind of things.

Also, some history… Pankl owns CP pistons, which owns Carrillo as well. C(alvert)P(ankl) is a combined effort of the Calvert brothers, who started out working for Nick Arias, before going to JE. Wayne Brooks bought JE from Harvey Crane and Wayne and Barry Calvert became co-owners in JE. When Barry and Wayne sold the company to that owns Wiseco, Barry partnered with Pankl to provide high end pistons to the NASCAR world (and cherry picked the staff at JE). Obviously, they since have expanded. They later bought Carrillo and now the company overall is called CP-Carrillo. Wayne Brooks came out of retirement after his non-compete clause expired, and opened up Racetec/Autotec pistons with some of the former talented JE staff as well; Racetec being their custom piston line.

Monkeywrench Reader
9/29/14 11:25 a.m.

The finished head:

Monkeywrench Reader
9/29/14 11:27 a.m.

Final head flow numbers:

The left side is with a radius plate on the spigot, right side is with the carburetor and stack. Lost about 8% of flow at peak lift with the entire system in place. Nick said anything under 10% is acceptable. Still super steady on the bench, moving only .1 of an inch of depression at any given valve lift.

singleslammer GRM+ Memberand SuperDork
9/29/14 11:33 a.m.

Wow, you are serious about your engine building. This is killer.

Monkeywrench Reader
9/29/14 11:42 a.m.

Thanks! Think of this as a single cylinder Engine Master's Challenge type engine. Here is a great example of that. http://www.popularhotrodding.com/tech/1408_428ci_pontiac_engine/#.U7_ezzzi4g4.facebook

Nick Smithberg, who did the cylinder head, was heavily involved in this effort: http://www.popularhotrodding.com/tech/1211phr_388ci_chrysler_gen_i_hemi/

Basically, I've been tapping into what's going on in the domestic V8 engine building world, and applying it to this oddball vintage single cylinder. Most of the knowledge base and mods that I have seen people doing to these things are about 25-30 years behind the times, including the a lot of the parts offerings (like pistons).

Cheers, Bob

44Dwarf UltraDork
9/29/14 12:27 p.m.

Bob your going to have one hell of a monster under you!!
Looking good

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