reliability of big bore kits

[Goopdienes]

just wondering the people that have done a big bore kit to your m8 has it been reliable or not. what size did you go to, dyno numbers and mileage since doing build.

[Vision]

My stage 4 ran great until it sumped just prior to 3000 miles.  My guess is that the new oil pump cover from Harley will help the sumping issue that's seen mostly with their stage 3 and 4 kits, but I'm not convinced it's the silver bullet. T-Man is putting out some nice kits and has a great solution for the sumping issue by splitting the case and installing a scraper with 3 oil pickups vs the 1 that comes in our M8s.  He stated that the bike can be leaned at any angle With no oil pickup issues. Revolution and Fuel Moto have nice kits as well.  My kit is Harley,  but if I did it all over again, I'd go aftermarket and forget the warranty.

I'm sure there are many folks who've had no problem and loving it.

[prodrag1320]

just like the TC motors,the M8`s where designed to sell a million big bore kits (cylinders with very thick sleeves,so they can be bored or cylinders bought and still be a bolt on with no case boring),as long as install & tune is done properly,reliability will not be a issue,

[Goopdienes]

thanks

[Hillside Motorcycle]

I agree.
As far as the mileage(longivity?) question, that is dependent, on the build, tune, maintence, riding habits, etc.

[Sunny Jim]

So I think a 117 , CP pistons and my cute little cyclerama 460
Will sort me out. PV, A/C, oil pump mods  and mufflers.
That enough for me!

[HD/Wrench]

So I think a 117 , CP pistons and my cute little cyclerama 460
Will sort me out. PV, A/C, oil pump mods  and mufflers.
That enough for me!

The 117 kits with a small cam do very well , Not a HP monster but very nice tq curve . Making 135 tq with a 117 is very simple .

More BB kits coming to the market I have one that will be released to the public very soon 124 bolt on kit that is less than just about anyone else at this point. We will be doing a install, dyno tune shortly . have to get the photography guys over here etc  . I like the fact that we can go from 107 to 124 as a drop on HA HA who would have thought that was coming 

Just saw a STD pull on FB  with a 124 build making big tq  with ported heads and the HP is JUST dead early on , you can see it was only pulled to just over 5 G on the RPM  and the HP makes a turn heading South .   

So its clear that with the M8 its going to be some time until we see kits that are really a done deal ready to go in the larger CI kits  . Its just testing , and it will take some time to see how it all shakes out .   

The M8 is a showing to be very easy to make massive  TQ  the Hp though is still being sorted out if you want a balance of Both HP and TQ .. Its getting there though .

Shops that are building testing you can see its getting better all the time .

[yobtaf103]

So were can it go, in bolt -on?

If H-D thin steel liner tech is applied, guess nearly a square motor on 107's

[Ozbob]

Star Racing seem to have the HP sorted on their M8's

[pwmorris]

No one touching the 150 SQUARE 124" M8 Zippers kit......(yet).
An absolute animal in a bagger, (or any bike for that matter).
http://harleytechtalk.com/htt/index.php?topic=106880.0

[No Cents]

Star Racing seem to have the HP sorted on their M8's

  George Bryce @ Star Racing has it going on with these M8's 
I've been watching what he has been doing closely.

[pwmorris]

I saw this Star Stage 3 124" kit (their top of the line) for sale,
http://starracing.com/images/m83dyno1.jpg

and while impressive.....it doesn't touch the Zippers torque shelf kit 124" at 150 square-unless he has something verified with more for sale (NOT a test mule).
The modern bagger with this kind of N/A early, instant, massive hit to move that load like a rocket,  and that keeps hitting and pulling, till you back off and quit, is absolutely awesome...
http://harleytechtalk.com/htt/index.php?action=dlattach;ts=1543291295;topic=106880.0;attach=90313

[Nastytls]

Fuel Moto's 124" has more peak hp and torque and also has a nice broad torque plateau. Not as flat as that one, but very similar nonetheless while having higher #'s.

[BigT]

Fuel Moto's 124" has more peak hp and torque and also has a nice broad torque plateau. Not as flat as that one, but very similar nonetheless while having higher #'s.

I have this exact setup ordered. It will be interesting to see how close the #s are when done.

[HD/Wrench]

I saw this Star Stage 3 124" kit (their top of the line) for sale,
http://starracing.com/images/m83dyno1.jpg

and while impressive.....it doesn't touch the Zippers torque shelf kit 124" at 150 square-unless he has something verified with more for sale (NOT a test mule).
The modern bagger with this kind of N/A early, instant, massive hit to move that load like a rocket,  and that keeps hitting and pulling, till you back off and quit, is absolutely awesome...
http://harleytechtalk.com/htt/index.php?action=dlattach;ts=1543291295;topic=106880.0;attach=90313

I agree there are some kits that are doing it but not all and I like the fact you brought the test mule deal   Its getting there without a doubt but its not across the board yet .. But it will be just a matter of time .   Do you see the trend in EX system with the M8 

[CVOThunder]

Goopdienes, sorry to highjack your thread but I'm curious about bottom end reliability. I'm used to the idea of the Twin cam having to come apart for the Timken bearing mod and a better crank assembly but did they do something more robust with the M8 bottom end at the factory? I'm seeing lots of mods but nothing on doing bottom end upgrades. Thinking about going to an M8 someday and a beefier bottom end could save a lot of bucks later down the road. Big thing I'm watching is the new oil pumps to prevent the sumping issue.

Maybe I missed a thread where bottom end mods are discussed.

[rigidthumper]

Goopdienes, sorry to highjack your thread but I'm curious about bottom end reliability. I'm used to the idea of the Twin cam having to come apart for the Timken bearing mod and a better crank assembly but did they do something more robust with the M8 bottom end at the factory? I'm seeing lots of mods but nothing on doing bottom end upgrades. Thinking about going to an M8 someday and a beefier bottom end could save a lot of bucks later down the road. Big thing I'm watching is the new oil pumps to prevent the sumping issue.

Maybe I missed a thread where bottom end mods are discussed.

Crank work is available, Dark Horse and P3R, maybe others. 

[DTTJGlide]

Goopdienes, sorry to highjack your thread but I'm curious about bottom end reliability. I'm used to the idea of the Twin cam having to come apart for the Timken bearing mod and a better crank assembly but did they do something more robust with the M8 bottom end at the factory? I'm seeing lots of mods but nothing on doing bottom end upgrades. Thinking about going to an M8 someday and a beefier bottom end could save a lot of bucks later down the road. Big thing I'm watching is the new oil pumps to prevent the sumping issue.

Maybe I missed a thread where bottom end mods are discussed.

Well they're getting up to about 160hp & we haven't heard of any failures yet, & you know there isn't a failure on a Harley that we don't hear about.

[Hillside Motorcycle]

Used a .472 RS in the last 124".
Zippers does have a handle on the cams for these to produce big, useable, torque.

[Goopdienes]

ward performance just showed a 137 m8 that produced 191.92 hp and 170.96 tq naturally asperated. that is just insane

[1FSTRK]

They are starting to make twin cam numbers.
Where did you see that?

[yobtaf103]

HTT dyno section has it 188/167 sae

[HD/Wrench]

Do not forget that some of the big numbers have counterbalancer removed and the crank is lighter and back to a TC A style on balance factor .

As for the BIG scare in crank failures for one I am happy to see the stock crank taking the abuse thus far and not sticking rods or twisting up . Time will tell as the builds keep pushing further . But the 137 is making 1.37 + per cube that is outside of the TC on avg .  124 tc would need to be right at 170 HP  and there are a few but not many in NA form. 

[turboprop]

Aside from S&S and harley, are there any other companies that are manufacturing (vs relabeling someone else stuff) big bore cylinders for the M8?

[pwmorris]

Aside from S&S and harley, are there any other companies that are manufacturing (vs relabeling someone else stuff) big bore cylinders for the M8?

Not sure where Leading Edge V Twin sources their big bore cylinders.
Here is what they say about them...
"cylinders are made in the USA
from aerospace-grade billet aluminum. Our radically different fin design results in far more efficient air cooling. Inside the cylinders reside aircraft-grade steel sleeves coated with our proprietary mix of Nikasil nickel/carbide/silicon plating".

ward performance just showed a 137 m8 that produced 191.92 hp and 170.96 tq naturally asperated. that is just insane

LOL...
My EVO 131" made 201 HP 176 Ft lbs-N/A......on old B1 (non prostock heads)-
14 years ago.

Current 126" daily driven Twin Cam rolls on 91 crap pump gas all over SoCal with over 170.

Ward no doubt makes big HP, but...
Test mules with big comp, lift, and one off prototypes are coming out of the woodwork, so slow your roll and lets see where all the big inch numbers, reliability, and repeatability (reproducing SIMILAR numbers anywhere/anytime on any modern DJ dyno) shake out...
There is a lot of work to be done, impressive start so far, but it's just a start-