Ironhead Cam question

[kitabel]

"TorqueMonster" is big twin only.

If comparing cams for torque range, 2 numbers should both be less than "P": overlap and intake closing point ABDC.

[Ferrous Head]

It's funny, most people are chasing that "sudden rush" of power they get by going with wild cams and open pipes.
It makes them feel like the bike is more powerful (generally, it's not).

The P's cams are actually quite good. Change the exhaust if you must but if your not running stocl exhaust and carb you really need to dial in the carb. That's done with an A/F gauge, not by guessing.
Too rich or too lean in the mid range will give you a flat spot there.
3 grand is where the main jet starts supplying fuel and it overlaps with the inter. Unless jetted correctly it's common to be too rich there. As the main jet starts supplying the bulk of the fuel ths will come back closer to stoichiometric.

If you have plotted the A/F graph and it's a flat line, that's as good as it gets.

If you haven't dialed the carb in properly the results are "unspecified".

[Tim The Grim]

Along the lines of doodah man suggesting changing sprockets you can also reduce the tooth count on your rear drum sprocket from 51 to 49 with one from these guys...

https://www.shop.pbisprockets.com/pr...c?productId=10

Running 2 less teeth on the rear will be like running a bigger sprocket up front. You might find your cruising around town more in third and then having a couple hundred rpm lower on the highway.
If your 48 year old scoot has never had its rear sprocket changed out it might be a good time to consider something like that.

I would not go under 18 up front due to angular issues with the chain at lower tooth counts.

As far as your vibration issues I like to toot my horn every now and then with this post I made about making sure your engine is set right in your frame to reduce harmonics and vibration.

http://xlforum.net/forums/showthread...1659782&page=3

[Ferrous Head]

That's interesting the 49's are still available. I read somewhere else they couldn't get them/didn't make them anymore.
I did think that was weird as I thought they ran them stock on the Pans.

A 49 rear is like dropping half a tooth on the front.

[RicThompson]

PICCOLLOB12 Vespas are cool. All the cool people inside the DC beltway love them. Keep the Sportster for the weekends so you can get away from that vile swamp on the weekends.

[Ferrous Head]

Wait ! Wait ! Wait !

PICCOLLOB12 - you live in Washington DC ? The District of Corruption ?

add 1 cup of sugar to your oil tank. It will make the bike run "Sweet".

[RicThompson]

Originally Posted by Piccollob12

Just so i can pass someone when needed in this DC and suburbia traffic.

[Heff]

I have a 21t sprocket. The wide 1st/close 4th andrews gear set. Og sifton hustler cams. 10.1 wiseco pistons. Balanced rotating assembly. Rivera timer with light springs. Points. Bendix carb. And...gasp....drap pipes, with wavy lollipops. My ch is a blast in stop and go light-to-light traffic. Revs quick. Pulls hard. I can get in and hang in the power band very quickly, and cruising at 6t-70mpg is incredibly smooth. Actually, I was really surprised at how comfortable it is and the in-town manners.
I did try my engine with p cams...and it didnt pull as hard. Or as quick. Actually sort of a let down.
Go with the sprocket change first.

[T. Clark]

I bought the headers as NOS about 10 years ago. You could probably pick up a set from ebay or perhaps you have a long established Harley dealer with a heap of used parts out the back. That balance pipe is what makes the magic happen. The pipes even came with a set of instructions stating that mid range may need to be richened up, I had to drop several sizes in the air jet in the S&S to get it to run. Just the different headers made a huge difference. Crossovers were very common on big twins, my Ducatis had them as well.