If you had to fab an intake

[Mother]

I have to fab a intake that will mount a S&S G to the Hurricane heads. not a really tough job, but the wheels started turning in my head. Intake is going on a 124 with 11.5cr, S&S 640g's, and going in a dresser. What would you want to see as far as runner length? Plenum? Has to be within reason and out of the way of the rider's leg. I have all winter to come up with something...

[Rollmeaway]

Eh Mother

As far as intake length goes there are various spacers available on the market these days. I have seen up to 2" but again its a tweeking procedure.

I would, if I could suggest that the intake when torqued up to the heads matches the head (intake) port without restrictions. What I mean by that is the intake inside bore matches perfectly to the bore into the intake port.

I have seen many that do not & restrict the flow of fuel to the combustion chamber.

[Mother]

Thanks Roll, I always make sure the ports are matched up. I don't want to relocate the gas tank, but I am open to ideas as long as it's out of the rider's way...

[frankie_b]

I use a 1" spacer on my RK and there is more then enough clearance for my super G carb.

[speedfoos]

You guys don't put a "stumble" in the head side of the intake manifold when port matching? I've been taught to do that when port matching and PnP'ing, but are air-cooled engines different?

[mccycle]

You will probably need to move your right footrest outboard 1 inch for what you will need for a 1 spacer and 3 inch filter depth.Leg room not as good as stock but a hell of a lot better than a D carb with big filter.There could be big money for doctors to put in a offset in the riders knee area.You could take up horseback riding which also may help.

[Mother]

MC, I ran a 1" spacer and a hi flow Green filter with my S&S teardrop no floorboard mod no issues.

[mccycle]

Your leg is younger and much more flexible than mine. You will be in good shape for your plans then.Try to keep same dimensions as before,with as much plenum volume as you can get within these dimensions for what you want from that engine.S&S makes a nice manifold for the old STD oval port heads,I do not know if it would work ,but you may want to look at it ,as manifold leg lengths are easily altered.It has lots of stock to work internal shapes with.

[nw_guy4_fun]

The HD SE manifold is a start, then cut and fab from there.

[disco]

Fab up something that makes it impossible to draw hot air off of the cooling fins. All engines have a huge HP derate based on intake air temperature (not to mention preignition problems). This is next on my list of fab projects.

[Knighty-Knight]

I'd start with the filter. Get a list of dimensions from K&N, then go from there. Calculated length wouldn't be hard to figure out, I understand the formula Vizard came up with is very good; as an aside, I suspect that there are very few HDs tuned to the second or even third harmonic. For the second harmonic the calculated length, from memory, was close to 2" at 6500rpm.

[TXCHOP]

Originally Posted by nw_guy4_fun

The HD SE manifold is a start, then cut and fab from there.

Thats the only/best way imho..Played with spacing a ton back in my carb days. Never seen a result worth the effort.

[Mother]

thanks Dan!

[torqueinc]

Still think you should try the Ultima oval port intake

[2wheelrider]

I managed to to put a mikuni 48 on my 126. I was dead set on having one. I had to raise the tank 3/4" at the and use a 1" adapter spacer plus one of the adapters that bolts up to the back of a mikuni for S&S two bolt flange. Motorway engineering makes them.