Author Topic: If you were to go.... BIG  (Read 2447 times)

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Offline SB107

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If you were to go.... BIG
« on: March 11, 2021, 05:54:50 AM »
Hey guys,

Just wondering what you'd do if you were to do an overhaul of the M8 powertrain. I am buying one soon and would like to start planning the upgrade so I can start acquiring parts for it.

Here's what I want to do.

4.500" Bore
4.375" Stroke
Ward +1 Heads
HPI 70mm (or Ward SE)
Star 3/4 Race Cam (maybe wood 9F)
Billet Cat or KW 2-1
220+ CCP

Also driveline upgrades which I already have picked out.

Just dreaming for right now, but I would like to hear what you guys would do if you could!


Mutant Motors 124"
161/148 STD, 158/145 SAE

Offline JW113

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Re: If you were to go.... BIG
« Reply #1 on: March 11, 2021, 06:23:08 PM »
Isn't that a lot of CCP for pump gas?

 :nix:

-JW
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Offline Ohio HD

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Re: If you were to go.... BIG
« Reply #2 on: March 11, 2021, 06:34:15 PM »
220 ccp is doable with proper tuning. The M8 motors come with ccp in the neighborhood of 220.
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Offline SB107

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Re: If you were to go.... BIG
« Reply #3 on: March 12, 2021, 05:28:25 AM »
Isn't that a lot of CCP for pump gas?

 :nix:

-JW

For a Twinkie yes! GMR has done a few in the 230-240 range with no problems on pump gas, granted he is a great tuner.
Mutant Motors 124"
161/148 STD, 158/145 SAE

Offline rigidthumper

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Re: If you were to go.... BIG
« Reply #4 on: March 12, 2021, 06:45:28 AM »
Whose cylinders/pistons are you going to use? Goals for this combo?
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Offline SB107

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Re: If you were to go.... BIG
« Reply #5 on: March 12, 2021, 09:29:53 AM »
Whose cylinders/pistons are you going to use? Goals for this combo?

I'd like Star pistons, not sure about the cylinders though, definitely would have them done by someone who would use torque plates. Goal would be a tire roastin 150mi trip machine. Nothing to go cross country with. I have my dyna as the bar hopper.
Mutant Motors 124"
161/148 STD, 158/145 SAE

Offline JW113

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Re: If you were to go.... BIG
« Reply #6 on: March 12, 2021, 11:47:26 AM »
That's good info, thanks. Pretty impressive, actually 220+ on pump juice for an M8. Must be a combo of good tuning, and good combustion chamber design? Now I'm wondering if an M8 is in my future. Would have to leave my TC RK out on the street in San Francisco with a "take me" sign on it, and claim it got stolen. These days, they ain't worth a nickel on the open market...
 :emsad:

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Offline Hossamania

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Re: If you were to go.... BIG
« Reply #7 on: March 12, 2021, 01:45:17 PM »
Peruse the Dyno section, a lot of info there. A friend just did a 124", Fuel Moto pistons and cylinders, Cycle Rama 480 cam and heads. Fuel Moto Road Rage 2/1, which is holding it back, will be switching to a Billet Cat. He is having a lot of fun with it. I think he said he's right around 220 ccp.
150 lbs. torque, 134 horse.
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Offline yobtaf103

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Re: If you were to go.... BIG
« Reply #8 on: March 12, 2021, 06:04:30 PM »
Stock 114 M8 is around 230 ccp

Offline FLSTFIDave

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Re: If you were to go.... BIG
« Reply #9 on: March 13, 2021, 03:57:19 AM »
My CVO Road Glide is built to 130"  I am running a CR482 cam at 12.1 to 1 compression.  This yields a roughly 235 CCP, just barely more than stock.  I have put just over 23,000 miles on this build in 12 months.  I do have a dyno run and build details in the Dyno run forum.  Its fairly stout, 163HP and 167 torque. 
201 9CVO Road Glide, Red Pepper
2013 CVO Road King, Anniversary  03 Fatboy

Offline Hossamania

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Re: If you were to go.... BIG
« Reply #10 on: March 13, 2021, 06:50:44 AM »
Fairly stout? That is just straight up stout!
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Offline Hossamania

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Re: If you were to go.... BIG
« Reply #11 on: March 13, 2021, 06:57:58 AM »
As Rigid said, what are the goals for this build? Dependable long life multi duty use, or full on fire breather to kick everyone's ass and no worries about longevity?
Do you have a tuner once the build is done? Have you talked with him about your intentions? Have you spoken with Ward about the heads?
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Offline HogMike

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Re: If you were to go.... BIG
« Reply #12 on: March 13, 2021, 07:54:22 AM »
Whose cylinders/pistons are you going to use? Goals for this combo?

I'd like Star pistons, not sure about the cylinders though, definitely would have them done by someone who would use torque plates. Goal would be a tire roastin 150mi trip machine. Nothing to go cross country with. I have my dyna as the bar hopper.


You could do like Dave did and keep it fairly reliable. If you want more and donít care about increased maintenance sky is the limit. Clutch will have to be addressed.

My personal M8 is only 124 and detuned to handle reg gas when I have to. AND it has quiet mufflers.  :smiled:
It my long hauler. It starts, runs like a stock 117 (on steroids).
Depends on your riding style.
JMHO  :missed:
« Last Edit: March 13, 2021, 08:09:54 AM by HogMike »
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Offline Nastytls

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Re: If you were to go.... BIG
« Reply #13 on: March 13, 2021, 11:55:39 AM »
Iím in the process of having a 148Ē built. CR pistons/heads/cam, Burns pipe, grudge box, etc. hoping to have it before the warm weather hits.

Offline FLSTFIDave

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Re: If you were to go.... BIG
« Reply #14 on: March 14, 2021, 03:51:04 AM »
Iím in the process of having a 148Ē built. CR pistons/heads/cam, Burns pipe, grudge box, etc. hoping to have it before the warm weather hits.

Having cases bored then correct.  Whose cylinders I know Cyclerama has some for very big inch builds.
201 9CVO Road Glide, Red Pepper
2013 CVO Road King, Anniversary  03 Fatboy

Offline Nastytls

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Re: If you were to go.... BIG
« Reply #15 on: March 14, 2021, 05:06:38 AM »
Yup, 4.5, so the case is bored. Iím not sure where Wes sources the cylinders, I never asked. Crank coming from DH.


OP, Iíve talked to a few people, including FM, and they all say the Ward 64 out performs the HPI 70mm. I think HPI knows this, because they told me they have a new manifold in the works for their 70mm to improve performance, but that was months ago. Iíve reached out to them several times since then and itís still not ready, so Iím going with the Ward.
« Last Edit: March 14, 2021, 05:14:20 AM by Nastytls »

Offline Hillside Motorcycle

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Re: If you were to go.... BIG
« Reply #16 on: March 15, 2021, 04:16:51 AM »
The combustion chamber shape and dual plugs allow the increased cylinder pressure to be managed.
We commonly tune those in the 225-230 range.
We, however do NOT like to pound compression on a street engine arbitrarily.
We love it as our AHDRA Modified Class racer was 17.25 cr, and our 2-stroke Pro-Mod and Outlaw N/A snowmobiles carry 15.0.
Best to hedge to the safe side always for street use.
Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

Offline Billy

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Re: If you were to go.... BIG
« Reply #17 on: April 29, 2021, 03:17:20 AM »
Hey guys,

Just wondering what you'd do if you were to do an overhaul of the M8 powertrain. I am buying one soon and would like to start planning the upgrade so I can start acquiring parts for it.

Here's what I want to do.

4.500" Bore
4.375" Stroke
Ward +1 Heads
HPI 70mm (or Ward SE)
Star 3/4 Race Cam (maybe wood 9F)
Billet Cat or KW 2-1
220+ CCP

Also driveline upgrades which I already have picked out.

Just dreaming for right now, but I would like to hear what you guys would do if you could!

I just got a flashback to the 60's.
Lazyness is the Mother of Invention

Offline Ohio HD

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Re: If you were to go.... BIG
« Reply #18 on: April 29, 2021, 03:28:36 AM »
Star uses those "descriptions", 3/4 race and full race for their M8 cam selections.


https://www.starracing.com/star-cam-shafts
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Offline Billy

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Re: If you were to go.... BIG
« Reply #19 on: April 30, 2021, 04:45:42 AM »
Star uses those "descriptions", 3/4 race and full race for their M8 cam selections.


https://www.starracing.com/star-cam-shafts

Yeah, saw that, just thought it was humorous they use the same useless descriptions J C Whitney used in their catalogs back in the day. At least Star gives the lift and intake close though.
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Offline kd

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Re: If you were to go.... BIG
« Reply #20 on: April 30, 2021, 06:39:57 AM »
Star uses those "descriptions", 3/4 race and full race for their M8 cam selections.


https://www.starracing.com/star-cam-shafts

Yeah, saw that, just thought it was humorous they use the same useless descriptions J C Whitney used in their catalogs back in the day. At least Star gives the lift and intake close though.


I think it's a good indication of who they sell to.  Most of us that were hot rodding in the 60's and 70's understand the level of performance and street manners in those descriptions.

When you think about it, it's not much different than "stage 1", "stage 2"  etc..
KD

Offline HD Street Performance

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Re: If you were to go.... BIG
« Reply #21 on: April 30, 2021, 06:51:04 AM »
Me personally I would recommend compression a little less on a motor this big (bore). Have a few in the planning stages now.
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Offline Hillside Motorcycle

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Re: If you were to go.... BIG
« Reply #22 on: June 01, 2021, 03:37:52 AM »
We just completed yet another 128" here.
235 psi ccp.
152/159 with a table-top torque "line".
V&H Pro Pipe.
Dyno report on our company Facebook.
Transmission destroyer, if abusive riding is done.
Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

Offline OldMike

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Re: If you were to go.... BIG
« Reply #23 on: June 01, 2021, 09:47:22 AM »
We just completed yet another 128" here.
235 psi ccp.
152/159 with a table-top torque "line".
V&H Pro Pipe.
Dyno report on our company Facebook.
Transmission destroyer, if abusive riding is done.
Saw that graph, is this a Pro Pipe on a touring bike?

Offline Hillside Motorcycle

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Re: If you were to go.... BIG
« Reply #24 on: June 08, 2021, 02:26:37 AM »
We just completed yet another 128" here.
235 psi ccp.
152/159 with a table-top torque "line".
V&H Pro Pipe.
Dyno report on our company Facebook.
Transmission destroyer, if abusive riding is done.
Saw that graph, is this a Pro Pipe on a touring bike?

Yes it is.
The bike came in with it.
Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"