Preview of Coming Attractions

[maineSS]

I've been working slowly away at my Triple Carb project for the 230, and have made some progress. I decided to use CVK40 Kehein constant-velocity carbs from the 90's era Harley in place of the 38 Mikuni snowmobile carbs as they will be less "peaky" under acceleration. I also made up clear resin head castings for intake/exhaust valve flow work I'll be doing with the tractor-pull fellow in Tennessee.

Pic #1 shows the side view of the carb manifold, it's 4" long overall. Pics #2 and #3 show the carb and block ends, the interior tapers from 40mm at the carb end to 1 5/16" at the block end at a 2 deg taper. The tube was machined from hydraulic cylinder tubing with about a 1/2" thick wall to accomodate the diameter differences- they sure don't give that stuff away!

[maineSS]

Moving right along, Pic #4 shows the tube and base (for Cyl 5 & 6). Pic # 6 shows the assembled piece before fusion Tig welding.

[maineSS]

This was my first step into molding and patternmaking- you can believe it when they say "it's an art". I made 5 castings before things started coming out right. The resin is Polyester Mass Casting type, similar to layup resin used in auto/marine repair, but with a different formulation to allow thick layers without excessive heat buildup. I was casting layers 3/4- 1 1/8" thick, and had to really back off on hardener ratio- 2 drops/oz vs 10 drops! You can still feel the heat as it kicks, though.

Pic #1 shows a casting fresh from the mold. Pic #2 shows the top and bottom surfaces being cut to level with a flycutter, and Pic #3 shows the buffing process to achieve "see thru" clarity.

These transparent heads will be bolted to Cyl 5 and 6 on a 230 block, and used to observe airflow changes as the intake and exhaust valves cycle. I'm going to be trying different valve head shapes- tulip vs nailhead, to see which flows more air, and allows higher flow velocity. Flow velocity is what I'm hoping to improve with sidedraft carburation and better valves- that's what affects engine response, especially in an undersquare motor like the 230.

[QuantumJo]

Very interesting project.

[Gordon Maney]

Fascinating. Really.

[maineSS]

Some more progress on the Triple Carbs.

After looking all over Harley World, K&N, AEM, and various other filter manufacturers, I decided to use a custom backing plate to mount the RevTech Harley filter (pic#4). I needed to have removable hold down studs so I could install and remove the filter in extremely close space on the front intake port (pic #5). The studs are Stainless 1/4-20 Allen bolts with push-on black plastic caps my machinist had lying around. The spacers are polyethylene tube.

Pic #6 shows the RevTech backing plate. The studs are permanently mounted in the plate, and the black insert is quite an obstacle for airflow to jump over. I haven't flowed mine yet, but it should be more flow-friendly. The biggest problem was accurately locating all the holes on the backing plate- it took quite awhile.

[maineSS]

Here's the complete manifold, carb, and air cleaner (pic#7). It fits with about 3/4" to the engine compartment wall up front.

I was worried the filter might hit if the engine rocked on startup, but it doesn't seem to move. I even tried cranking in gear, but- no problems- yet.

[Matthew Ziegler]

harley filters

check out www.loudfastrules.com this guy is casting his own aircleaners, velocity stacks and some other cool one off parts, may be a good resource for you