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Discussion Starter #1
As I previously posted my crank went bad on my 95 build so I installed the 103 crank with SE forged flatop pistons. I used the SBC Scotsman heads with .030 cometic hg's,Fatcat 2-1, PC111usb, and tossed in the tw55g cam that i had. I had it dyno tuned and the results show a gain of only 7hp and 7lb's of torque over the 37g 95 build.

103= 104hp 106tq (OVER 100 tq from 2400-5400 rpms, peaks at 4700) (HP peaks at 5200 and stays flat until 6000 )

95= 97hp 99tq


I am thinking of going with the Andrews 67g as per Grocks recomendation in the previous thread. (budget wouldnt allow it before)
I am still concerned about whether the Scotsman heads will flow enough for the 103. What would you recomend for the heads?
Mike
 

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I have seen significantly higher #'s with the 55's and different heads.
 

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Discussion Starter #3
HIPPO, Thank you for chiming in. What heads or headwork would you recomend? I value your input on this as it was you that talked me into using the Scotsman heads over the Vortechs on my 37g 95 build and they worked out great! When we were dyno tuning this current build It seemed to just go flat above 5000 rpms and nothing we did helped. The Dyno operator thought that the exhaust might be clipping it in the upper rpms and that a Boarzilla baffle might help but i was thinking more like the heads might be stalling out above 5000???
Mike
 

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My Dyna at 95" with tweeked SE heads and forged pop ups made 104 tq and 108 hp with Se 257 cam which IMHO is the best cam in the H-D line up. The HP didnt start to drop off untill after 6000. The 67g is as close as you can come to a gear driven 257.
So one alternative would be some cleaned up SE heads which can be had for around $600.00 or less right now.... But watch the compression as the 67g is going to want at least a true 10:5:1 to work.
My bagger..a CVO 103 E-Glide with slipons , a/c, and /sert makes just over 100/100. With those crappy CVO heads and cam specs. that would make you wonder "what were they thinking" Same thing though...the motor is all done at 5000.
I feel it's the heads on the build as it is right now..not the Fatcat. And as proof to what Hippo said..I run 55gs in my night train at 95" with stock ported heads and KB pistons and I'm making slightly better hp numbers than you are at 103" and the power does not flatten out at 5200.
And I feel with a heavier bike like yours....you would love 3.37 gearing if its not in there already.
 

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Discussion Starter #5
SYCLONE, I think you are correct about the heads being the bottleneck not the Fatcat. The heads are the SBC Scotsman II's with oversize valves, Revolution .600 springs, and 80-81cc chambers. With .030 Cometics we are estimating 10.5-10.6 to 1 compression? Compression test resulted in 190-192 psi cold. I think the 67g would help alot but i dont know which way i should go as for heads, Another set of stock heads ported or SE heads? Who knows how to get good results from a 103 build?
Mike
 

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Toyman said:
SYCLONE, I think you are correct about the heads being the bottleneck not the Fatcat. The heads are the SBC Scotsman II's with oversize valves, Revolution .600 springs, and 80-81cc chambers. With .030 Cometics we are estimating 10.5-10.6 to 1 compression? Compression test resulted in 190-192 psi cold. I think the 67g would help alot but i dont know which way i should go as for heads, Another set of stock heads ported or SE heads? Who knows how to get good results from a 103 build?
Mike

Toyman,

I think plenty of good shops can help you out on this, but since you're running SBC, you might start with Charlie and see if he can re-work what you have, and save you some $$ in the long run. Plus he knows his heads and has plenty of experienice with 103s. FWIW.
 

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That type of inexpensively reworked head is intended to pick the low fruit on budget 95 builds.

I have no idea what is "best" out there, all I can tell you is what heads I tend(ed) to use in more elaborate builds, and I will not say which ones I would refuse to work with at that level.
My personal preference would be to use BCG, HQ or John Sachs in FL on this type of build. My understanding is that T-Man heads also are very good but have not used them. Surely there would be others out there but one would tend to combine different heads with different cams depending on budget and objective.
 

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You got a problem somewhere. Those are the results of just a cam change from the 37 to a 55 on a 95 build. Are you SURE that a stroker flywheel was installed?? Even a mild port job with oversize valves from SBC should flow decently for you. Should be in the teens on TQ. And not for nothing, but who tuned the PCIII and did they get to timing. Very important with the 4 3/8 wheel from the 4". It's either in the tuning or you got the wrong wheel in there, IMHO.
 

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Discussion Starter #9
Hippo, Thanks i was thinking of contacting either John Sachs or Headquaters.

Grock, I agree something isn't right! It is an SE 103 crank assy with 103 forged flatops I helped install them myself. Brian at BPA Mobile dyno tuned it on the same dyno that the 95 was tuned on. Not sure what was done as far as the timing but it needed a lot more fuel. Ihave a copy of the map on disk but the actual run is on paper and i dont have a scanner. The run was in fourth gear sae smoothing 5. 104hp 106torque!
I was really expecting more!
Mike
 

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OK, Toyman, the fourth gear run accounts for a few pounds and ponies. So you aren't too far off after all. Gotta guess that you need to break her in yet, so that is usually good for a few more points. And with a little more tuning to optimize it you will be close to where you should be. Not that bad after all!
 

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Discussion Starter #11
GRock, I still thought it would have higher tq and pull harder on top than it does it just completly flattens out above 5000 rpms like it hits a wall! The build had 1100 miles on it before it went on the dyno. The 95 run was also a fourth gear SAE run!
Mike
 

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Toyman said:
GRock, I still thought it would have higher tq and pull harder on top than it does it just completly flattens out above 5000 rpms like it hits a wall! The build had 1100 miles on it before it went on the dyno. The 95 run was also a fourth gear SAE run!
Mike
Fatcat and tw55 shouldn't run out of breath if the heads are decent! No way! Dewey's does heads for 107's we build (including my own personal bike) and uses 1.590 exhaust with 1.94 intakes and that, along with whatever magic he does, gives us great low end pull and still climbing at the rev limiter for the HP. Still hard to believe that the heads are holding you back that much, though, especially with oversized valves. But could be. Are you running the 55 straight up (no cam timing advance)??
 

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Discussion Starter #13 (Edited)
Fatcat and tw55 shouldn't run out of breath if the heads are decent! No way!]
GRock,Thats what i thought too! Yes the TW55'S were installed straight up. I know that it was hard to keep from bumping the rev limiter in the first three gears when it was the 95 build. It does not pull to the rev limiter like that now.
 

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I don't think scotsman heads were meant for larger than 95". With better heads and S&S .625 cams and the right exhaust 115hp is attainable. Large motors need to breath.
 

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GRock said:
Fatcat and tw55 shouldn't run out of breath if the heads are decent! No way! Dewey's does heads for 107's we build (including my own personal bike) and uses 1.590 exhaust with 1.94 intakes and that, along with whatever magic he does, gives us great low end pull and still climbing at the rev limiter for the HP. Still hard to believe that the heads are holding you back that much, though, especially with oversized valves. But could be. Are you running the 55 straight up (no cam timing advance)??
GROCK ,I have a bottle of L J brewing for your XMAS party. Happy New Year.
 

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SILVER BULLET said:
GROCK ,I have a bottle of L J brewing for your XMAS party. Happy New Year.
Thats very considerate, Bullet, but I would consider it a great favor if you could send me the bottle ASAP so that I can FORGET about the holidays! Hope all is well with you and yours.

Now why don't you have Dewey get in touch with the Toyman to fix his problem.
 

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Discussion Starter #17
Now why don't you have Dewey get in touch with the Toyman to fix his problem.
Comparing both the 95 and 103 dyno runs I see the exact same flattening out going on in the upper rpm's! It's just much more asthmatic on the 103.

I need some good heads that will allow this thing to breathe!!!

By the way, where's Doc been???
 
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