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Another Cam Question

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Old Mar 31, 2015 | 04:47 PM
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I am going to change out heads and am looking for suggestions for a good low/mid range cam for my bike. It is 2001 95", fuel injected, 48mm modified stock TB, Fatcat 2-1 exhaust. Currently have TW6g cams and may try these out after installing new heads, but as much as others love these cams, the power kicks in higher than I want in the rpm band. Peak numbers were fine on dyno runs, but I want more torque down low. That is part of reason I am changing heads, as current heads had bigger intake and exhaust valves, and were not working with my build. I am going back to ported HD heads with stock valves, milled and cc'd to 82cc. Compression with .030 HG should be 10:1. Looking for a real strong low and mid range cam that revs up quick. When riding at 65 - 70 mph in 5th gear, and twisting throttle, I want the bike to jump. Right now, bike pulls hard, but you have to get the RPM's up first and there is a little lag in response. Here is the description of the new heads if it helps in selecting an approporiate cam:

Fully Polished combustion chamber
- prevent hot spots which lead to pre-ignition/detonation and it helps fuel economy
Full porting of both intake and exhaust runner.
Polishing of both runners to ideal surface finish.
100 grit intake for increased velocity
and better air/fuel atomization
Fully polished exhaust keeps velocity high and carbon build up down.
Retained factory guides and valves. (1.805 int. / 1.575 exh.)

Jim's Double Valve
springs with Dampener rated up to .600" lift.
Lapping of both Intake and Exhaust valves.
New Viton valve seals.
All gasket surfaces are lightly planed flat to assure proper seating of gaskets.

These heads will create greater Volumetric Efficiency (cylinder fill) and Velocity (faster air speed), in effect producing more torque, and at the end of the equation this means more horse power! Resulting in faster acceleration, more torque and a more efficient running engine. The Stage I heads velocity will be substantially higher than stock, thus allowing more cylinder fill which equates to more torque and horsepower. .


I have been considering the Cyclerama 575 cams, as I want to take advantage of the heads' higher lift springs, earlier closing intake, and less overlap (have been told my current build might be over-exhausting and losing torque down low). Also thought about TW5, Crane 302 (can't find any feedback), Tman 555 Torqster, Andrews 48, etc. Cams should work with 10:1 CR. I do a lot of highway riding and do open it up occassionally, so I don't want a cam that drops off too quickly. I don't need a cam to pull to 6500 rpm, but don't want one that stops pulling at 4000 rpm either. I have been researching this for awhile and am just looking for some real world feedback from some of you builders and tuners.
 
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Old Mar 31, 2015 | 05:27 PM
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Seems that I remember you posting this same question on another forum. I recall that the advice given there was very credible, something to the effect that getting heads done by a known porter that could also give you the best recommendations for compatible cams was advisable vs buying the heads you specified above and guessing at cams?
 
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Old Mar 31, 2015 | 06:17 PM
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My previous posts were trying to find what parts in my bike might be the cause of poor low end torque. I have done several things to narrow it down, and decided to try ported heads with smaller exhaust port to improve torque. Just looking for feedback on higher lift cams that would work work with the stock size valves for good low end torque in 95" engine.
 
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Old Mar 31, 2015 | 07:39 PM
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You might not have to De-tune your motor to achieve more low end torque. My 80"err is built pretty well and I just want to show you what different pipes can do. Check my dyno runs. Build is big cam, big valves,11:1 pistond etc. But check out the difference in low end torque. I see you have a supertrapp, can't you tune it to get better low end?

How many discs in your supertrapp? I believe the max useable is 24 and will improve on the low end.....
 
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Last edited by 98hotrodfatboy; Mar 31, 2015 at 08:19 PM.
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Old Mar 31, 2015 | 10:38 PM
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hotrod, OP says he has a Fatcat in first post. Hard to beat the Fatcat for big torque numbers...
 

Last edited by dynawg1; Apr 1, 2015 at 07:33 AM.
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Old Apr 1, 2015 | 01:04 AM
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I have Supertrapp on right now, but am going to install Fatcat when I install new heads and cams. I have had Bassani Road Rage 2-1 and Supertrapp on current build. Both had power coming in around 3500rpm. Supertrapps were tuned wth several disc configurations, but ended up with 20 discs and open end cap.

I think I am going to install new heads, ride bike with tw6 cams, and see if low end feels any stronger. If so, I may get bike tuned and see What tune looks like with just the head swap and Fatcat. If not, I am going to try the CR575.
 
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Old Apr 1, 2015 | 06:14 AM
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10:1 with TW6 cams should work real well especially with those supertrapps, take a look at this link to see dyno runs as to how they perform in a 95"er
http://www.woodcarbs.com/dynoruns.htm
 
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Old Apr 1, 2015 | 07:36 AM
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Originally Posted by txphatboy
...I think I am going to install new heads, ride bike with tw6 cams, and see if low end feels any stronger. If so, I may get bike tuned and see What tune looks like with just the head swap and Fatcat.
Roger on that.
 
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Old Apr 1, 2015 | 09:26 AM
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D&D has recently changed the head pipe design on the Fatcat and what I am hearing from tuners is that the new pipe doesn't perform as well as the old one; so buyer beware on the Fatcat. The other pipes mentioned are decent and the Supertrapp is probably the best of the lot; however, I would add the Rinehart 2:1 to the pipe list.

I think the OP is missing out by retaining the OEM valves, larger valves will only help facilitate velocity and cylinder fill which are not functions of valve size but of port design.
 
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Old Apr 1, 2015 | 09:36 AM
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I would not be so quick to discard that tuneable Supertrapp.
We've seen that pipe work VERY well over a broad range of engine sizes and configurations.
Scott
 
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