Mild Street Cams

[SkinHD1]

Hello.  I have a friend who picked up a '98 with low miles, and he wants to know what a good mild street cam is.  He isn't planning on doing the heads so compression will be stock.  He does have the SE aircleaner and plans on exhaust.  Also if anyone knows where I should start with jetting I would appreciate it.  Sorry for the easy questions, I usually play with Twin Cams.

SkinHD1

[ceduby]

I used to have a VT3020 on my fairly stock '97 Superglide, (pipes, jets and filter). It made a big difference. Really woke the motor up. Bolt on with no issues other than having to shim. He might want to go ahead and replace the lifters while he's at it. Stock pushrod can be used with the 3020. I jetted the carb with 46 slow and 180.  You'll probably get variety of cam choices here. you didn't say what model, Bagger would be different than a lighter bike. And where does he want the power? Low, Mid or High? The 3020 was good from around 1800 up to 4500-5000. Iv'e heard the the 3010 was good for down low as for a Bagger

[gryphon]

Everyone has their own ideas of course and you didn't mention what model (touring, softail?) but, the V-thunder 3020 is really popular. Good performance and very quiet.

[Reddog74usa]

3020, ev27 or woods W6. Take yer pick the'll all do the job. Mill the heads with just a clean up with the W6. best bang for the buck.

[TheSwede]

 


         

     





Cam Basics:

Correct cam selection is the single most difficult choice facing the performance enthusiast. And, unfortunately, we get it wrong about as often as we get it right. An incorrect cam choice can result in decreased real-world performance if the selected cam's operating range is not matched to riding style.

The operating range of any Harley engine is determined by a number of factors and the cam design is one of the most influential. If the cam design is not matched to the other components and is not matched to the desired engine power band (rpm range), then the engine's performance will be disappointing. No amount of carburetor tuning can compensate for having the wrong cam.

To get the "right" cam design, you need to do two things: First, decide upon the rpm range you want to improve. Secondly, use the list provided below and cam catalogues to select a cam design that begins to work at the lower rpm of the power range you have chosen. You'll probably be surprised to learn how few of the available cam designs fit your expectations. However, the list is accurate and if you follow its implied advice, you will get an engine that performs as you wish it to.

Cam timing: what matters

The most important cam timing event is the intake valve closing angle. The intake closing point determines the minimum rpm at which the engine begins to do its best work. The later the intake valves close, the higher the rpm must be before the engine gets "on the cam."

Long duration, late closing cam designs are necessary to drag the last bit of power out of an engine. Unfortunately, these same cams can perform poorly under more normal riding conditions. In the quest for maximum power output, many-too-many Harley owners choose a late closing, high-rpm cam for their engine. The problem with such choices is that the engine seldom spends time in the rpm range favored by such cams.

The majority of virtually any Harley motor's life is spent in the mid-portion of its rpm limits, between 2000 and 4000 rpm. At open-road cruising speeds, that range is more like 2500 to 3500 rpm. With current Big Twin gearing, top gear at 2500 rpm returns a road speed of 55 mph and 3500 delivers 84 mph. Riders sometimes "putt" around at 2000 or less. Even when accelerating to cruising speed, few of us use more than 4000 - 4500 rpm as a shift point. Very seldom, in day-to-day use, do our engines get near 5000 rpm, let alone 6000.

Even the mildest of Harley-Davidson's aftermarket cams (Evo or Twin Cam) do their best work above 3000 rpm. At 2000, the majority of these cams seldom perform significantly better than stock cam(s).

The rpm at which a Big Twin gets "happy" can be predicted by the closing point (angle) of the intake valves. The angle is expressed as the number of degrees After Bottom Dead Center (ABDC) that the valves reach .053" from being fully seated.

The following list predicts the rpm at which the engine gets "on the cam" based on the closing angle of the intake valves. These relationships are approximate but should hold true to within 200 rpm or so. They also assume that all other tuning factors, exhaust, ignition, etc., are operating correctly.


30 degrees = 2400 rpm

35 degrees = 3000 rpm

40 degrees = 3600 rpm

45 degrees = 4000 rpm

50+ degrees = 4500 rpm



If you have one of the late closing cam designs installed, say one that closes the intake valves later than 40 degrees, then you cannot expect excellent performance at 2000 rpm. No carburetor adjustment, ignition adjustment or exhaust system can change this.




Copyright (C) 2002, Mikuni American Corporation All Right Reserved.

[RLPOS1]

See this text for carb jetting
http://harleytechtalk.net/htt/index.php?topic=3700.0

[ClassicRider2002]

Hey SkinHD1~~~~

"........Hello.  I have a friend who picked up a '98 with low miles......"

A '98 what? ________________  model? ? ? ? ? ?

Hello.....

Is he a experienced rider or a new rider?  What would you say his weight is, what about passengers any 2 up riding?  What about riding enviornment ie: flat lands....straight line from state line to state line or mountain riding.....?  What about his riding style preference.....laid back and wants to go down the highway at 60 mph or wants to get from point A to B as quick as possible....country roads vs interstate highway riding?

Then  perhaps we can help you out here a bit.....based upon some other's experiences.....

Regards,

"Classic"

[Hillside Motorcycle]

Wood 6, good valve job, and surface the cylinder heads.
With a free-flowing air cleaner, and a pair of Harley or Cycle Shack slip-on mufflers, you will see it hovering just about 80 hp and 90 ft/lbs, tuned.
Biggest bang for the money spent by far.

[stroker800]

Talk to Bob Woods,,,he is the man when it comes to cams. Tell him want you want the motor to and what mods you are goin to make,,as stated very easy to throw in a cam , pipes igntion and have less usable HP. If you are gonna spend hard earned money,,,,make some power.
Dave

[shovelbill]

have him answer all the questions everyone asked honestly and he can make an educated choice. here's the monkey wrench i'll throw into the mix. leineweber E3S, great street beater as far as i'm concerned. cant help with the jetting, i used a super B and thats a different animal.

[Hillside Motorcycle]

Talk to Bob Woods,,,he is the man when it comes to cams. Tell him want you want the motor to and what mods you are goin to make,,as stated very easy to throw in a cam , pipes igntion and have less usable HP. If you are gonna spend hard earned money,,,,make some power.
Dave

.....................and if you do talk to Bob, alert him to what I said, and listen to his reaction.

[SkinHD1]

Thanks for all of the replies.  The guy rides a 1998 Super Glide, and he is about 250lbs.  Now I'm having trouble convincing him he needs a cam....