Do you prefer to keep a lower compression ratio or bump the compression ratio up for more power?

It's amazing what a slight bump in compression, minor headwork, and a cam will do for performance. Top that off with a great dyno tune and it's like a new engine. The sad part really is that they could and should be built this way.

Turned my stock 88" twin Cam into a 95". 585 S&S easy start cams. And 10/2 to 1 compression piston Dyno at 110HP. And 117 lbs. Baby really moves.

I finally pulled the trigger on my stage one upgrade. I went with a more budget friendly configuration. Screaming eagle heavy breather, FP3 tuner, and V&H straight shots. That's it for this season. That's give me another year of watching your videos before I decide on my next upgrade. 👍😎👍

Did my 2009 fxdf with the SE stage 4 race kit with yellow race SE tuner, 10.5 to 1 compression, ventilator intake and SE slip on mufflers. My year had no catalytic. Ended up with a reliable 111 HP and 110 TQ. Bike runs great!

Your right on with more compression ! I don't even do stock rebuilds with out using Cometic MLS gaskets back in the day we always milled Evo heads .020 to wake them up but now we got thinner gaskets lots easier ! Your also right about checking valve to piston with stock pistons Back in 99 TC motors there weren't any good pistons & we had to machine the pistons for deeper & wider valve pockets for big valves & high lift cams !

Good info man. I had my screamin eagle motor done last winter, kb domed pistons, heads were ported, andrews 57 cams, crank has 2 thou run out, which surprised the mechanic and me as well...10 over bore, hone, and decked gasket surfaces, hpi throttle body, bigger injectors, bassani 2 into 1 road rage 3 pipe, arlen ness velocity stack air filter, tune liscence from dyno jet and a proper dyno tune...runs awesome now for a 19 year old bike...2003 cvo road king.

As always, great vid, great info and not too long. I like the positive approach you use in your productions.

After seeing this build I'm excited to see what mine is gonna do on the dyno . 100" S&S kit with 10:5:1 S&S cam plate and pump Woods 777 cams Woods lifters Fuelmoto pushrods Heads ported and polished with oversized valves and beehive springs , roller rockers and decked. 040 for about 11:1 compression. Tuned with a thundermax tuner. Appointment with dyno tuner next month. Not sure what the Hp and tq is but this thing is fun😁

Just remember. The more duration the intake cam has the later that valve closes which lowered dynamic compression. 12:1 static compression could be perfect for pump gas if your cam has enough duration.

Great info, as always. I wouldn't tear a motor down just to raise the compression, but if I were doing other work and had it mostly apart anyway then it is definitely worth it.

Raising compression was the way to go in the old days before all these kits.....

If your running that low why not kick it up. We used to run cars at 11.5 to 1. Wrist pins, crutch assembly , valve springs needed to be increased and maybe a better oil pump. Why not when it’s time to rebuild it have some fun? If you are like me and a gear head be it bikes , cars or trucks it’s a no brainer. It’s something I like to do with my sons and pass the knowledge I have from my father to myself. When I was kid in the late 60s -70s the gas shortage hit. We used water injection as the gas was crap. Texas 93 octane is all over

Awesome. Love the content. I used a .0030 gasket when I did my heads. Dan Vance Racing did the work. I would recommend him any time. Talking my book, but he might be the best HD head guy out there. His back ground was racing. I use octane boost all the time. I don't have any problems, but I notice a significant increase in power. I think the gas we get today cut with ethanol is not that great. Not only an increase in power, but gas mileage, so it's a win win. Left the stock 103" pistons in. Someday I'll upgrade to a drop in 110", but the motor runs so good, I'm afraid to touch it now.

I have kept my 88 standard, apart from a change of exhaust cam which makes it run cooler. I like the fuel consumption of standard trim suits my riding. But I know a lot of guys up the power and that’s their right, it would be boring if we were all the same.

KZfaq buried your channel on me but I'm back. ✌️😎 Also, I wanted to thank you for your recommendation of the spherical bearing kit for my swing arm that was on a previous video. (That I can't find) I did the install on it and it works great. It took that torque kick out of the ass end of my bike when I get in the throttle. LoveLoveLove ! I appreciate all your uploads and your sound advice.

Gixxer, just viewing your video. Just returned home from week at Myrtle Beach Spring Bike Rally. Thanks for the video.

I’ve got a Ducati as well as an FLSTN, so I don’t typically worry about peak HP or Torque. With all these videos, though, I’m starting to migrate over to the Dark Side. Thanks for all the awesome info!

EVERY engine loves compression

Once again. This is true for all engines.

Every time I got a question no shit here you are talking about what I need lol

Great job as always brother! thank you

Nice upgrade to the shelf brother!

How you gonna mention woods 777 and not give me a shout out! Lmao! I’ve been praising those cams for a longggg time! High compression over low compression any day!

11.1 in my twinkie... Since 04... Has 34,000 miles and still does a wheelie plus i ride at 90mph cruzin speed.... I love my ol 95in motor with htcc heads , 11.1 compression, cam support plate , pump and tensioners with a big ol woods cam using a big s&s super g then pumpin it out the 2 into 1 exhaust... Forgot to mention its in a 04 street glide

For an everyday/road trip bike I like keeping the comp low. Never know what’s gonna be available for fuel. Rode to florida from PA hit a couple spots where the only fuel available was 87

I sure did wake my 103 up... I installed a stage v 103 - 110 kit with 10:5:1 pistons, 259E cams, cnc ported heads 58mm Throttle body ,S&S Cam plate and oil pump, RC head pipe , Dyna jet powder commander v, Getting ready to have it dyno tuned . I'll let you know what the results are.

My Twin Cam B is @ about 9.75:1 with S&S Super Stock 79cc heads, .040LD and an Andrews 37g

I put an EV-46 cam in a 1340 1990 fatboy, with a dyna ignition & coil and a few other tricks

Within a small super wealthy city of Piedmont, Ca in the middle of Oakland, there's a gas station that sells racing gas straight from the pump. However........? Not sure about riding in with a thunderheader? 😄

Currently getting my bike reworked. Had the 117 harley kit installed a few year ago on my 110 fat boy. Harley cams are crap. Also the kit advertised something like a 9.9:1 compression increase. I have a good 2 into 1 exhaust and used a power vision and I was not happy at all with the power as it was low for a 117. Was dyno'd at 108hp and 112 ft/lbs. So now my bike is with another guy re-doing the kit. I added a Tman 625ps cam and he cc'd the motor for more compression. He found that the 117 kit from harley makes a false claim on compression and is actually only making 9.5:1 instead of the claimed 9.9:1. So after he was done reworking the heads and all the motor is now making 11.1:1 compression. Of course this is static compression. Altitude where you live plays a huge role in what you set your static compression at and I'm at 2200 feet elevation and so 11.1:1 with my cam choice actually works out to 10.17:1 corrected compression so should be pump gas friendly. Waiting for the dyno results so I'll post them when it's complete and we will see the difference a cam swap and the added compression made.

Great information to know 👍 keep the videos coming brother and ride safe my friend.🇺🇸🇺🇸🇺🇸

+ Compression made my exhaust note pretty snappy in the old sportster

I have a completely stock 96 in a 2007 Road King - it has been a milkshake mixer since I brought it home new from the dealer. My 2003 Stage 4 twin cam Road King is markedly smoother - much less shaking. Motor mounts on both are fine. How about a video on how to cut back on excessive shaking and vibration? I’ve heard everything from “experts” on this subject (flywheel, idle speed, crank balancing, handlebar dampers etc.,). What’s the best way to cut the Shake?

Yes!

Now wait a second......the reason we use 93 octane is because that 87 causes knocking......it causes knocking because it burns too fast The idea of increased compression is putting the same amount of air and fuel into a smaller space......thus fuel molecules are closer together and will burn faster......more likely to knock Remember the cars, they'd put on turbo chargers, which put more air and fuel into the same space increasing compression, then they'd adjust the ignition timing to take out the knock......smart ones started using 93 and adjusted to that fuel.....that way they could still get max pressure at 20* atdc and complete burn at 70* atdc, which they couldn't quiet achieve using 87 But now you're starting with an engine designed for 93, then increasing compression The crotch rockets running high compression with 93 also have a short stroke in order to get stages of burn in the correct places The short stroke cruiser engines(not as short as crotch rockets) running 9:1 also use 87 to get a faster burn

Mate,i feel like we building bike together. Nice timing 👍🏻

Good video but, I’m assuming you’re talking about static compression not dynamic. The 10.5:1 never actually happens because of valve overlap etc. it’s the dynamic that’s important. Could you expand a little more on those numbers in a video some time. I was taught that a few point either side of 9:1 is the sweet spot for a hog that runs on pump octane of about 91-93

I has ever been watching your videos on the 107 and compression of 10.5 to 1 got my heads at 10 to 1 planing on going to 10.5 to 1 soon and going use tripple duece woods cam for low end tourque looking for video on installing pistons and heads with torque specks and adjusting pushrods

Hey dude no luck yet on fixing old bike or having cash to buy knew but I said I hit your like every time I saw you had dropped video so just keeping my word hope you an your are good B.

Happy life happy bike

Almost every Harley I’ve ever owned has been treated to a nice set of forged Wiseco pistons of 10 to 10.5 to 1.

And another thing what keeping it cool with the 107 inch Moter don’t like my legs getting burned

I went with s&s 585 and weisco 10 1/2 :1 pistons. Dyno 94hp 104 tq on 103 tc

Morning Strocker 103 h.d.204 cam recommend after market cam

Im all for hot rodding engines, but there is a dark side to performance mods. If you want your engine to run forever, anything beyond a stage 1 upgrade is going to decrease engine life.

I watch all your videos. Thx Question I have a 2017 Breakout i bought woods 777 cams and going to change all parts as you instructed. changing rocker arms to 1.725 roller type, 5.3 injectors, then Going to send heads to Hammer performance to get port and polished . what 4 in big bore kit you recommend for this set up. would like to do this all at once. but what to stay at 10-1 ratio

I have a 2003 dyna low rider anniversary edition that I get about one start attempt before the battery drains and it won’t try to start again .. what could be causing this ?

have you thought of doing a supercharger / turbo charger guide ? i know they are pricey, but if one really wants to get into engine mods lol. good vid

The 110s had to keep the compression low because the crankshaft couldn't handle the pressure

I watch all your videos. Thx Question I have a 2017 Breakout i bought woods 777 cams and going to change all parts as you instructed. changing rocker arms to 1.725 roller type, 5.3 injectors, then Going to send heads to Hammer performance to get port and polished . what 4 in big bore kit you recommend for this set up. would like to do this all at once.

I had to get rid of my harley, because I can't maintain, so now I've got a 900 Vulcan,and the cops love it .

Thanks to your video I’m now about to have a .027” MLS Cometic head gasket installed together with the S&S 570 on my 103”. Is this only gonna squish my compression a bit or should I retune with the FP3 and add something to it in order to make it run as good as possible?🤘🏼

Hey, my buddies think a new breather and exhaust IS hopping up your Harley!🤷🏻‍♂️

So if I wanted to use those gaskets your talking about how would I check valve clearance? Can I do it myself or do I need to take it in?

Can the crankshaft handle the power? What crank would you recommend to up grade? Thank love your videos!!!!!!!!

How would you no. I haven't seen you fix anything yet!

up the compression and then what about the crank?

I have noticed that you have the exact same accent as Mike Nesmith from the Monkees he was also from Texas I wonder if you guys are from the same town

How does higher compression impact engine life? I'm looking at a higher performance build that's still suitable for daily street use.

I have a twin cam 96 2008 Dina that I triked I’m putting a 107 kit with 103 calendars bored to 107 yoking water cooled heads that are ported shaved for 10.5 comp woods triple 2 cam what do you think I’ll hav in the end. I watch your videos on you too can I get some feedback thank you Rick

My buells new motor will be pushing the limits 11 to 1 comp ratio Nallin stage 3 heads N8 cams Hrs 42 carb And a full forcewinder induction system plus exhaust

All that with a pressed together crank ?

Have a 2014 Street Bob, can I have changed my exhaust with a V&H two to one pro pipe - I do not want to change original Air Filter

I got at 2017 fxdb getting MR103s put in thinking of going 10.5 comp while I’m at it, am I going to have valve clearance issues trying to achieve this by just shaving heads ?

Quick question, I have 2 2002 FXDWG'S and would like to ask you a few questions about them, just wondering the best way we could talk

I agree, Screamin' Eagle parts should installed as original parts from the manufacturer... and then thrown away when you upgrade the bike. There are much better parts out there than Screamin' Eagle.

I wonder how the twin cam 88 crankshaft holds up to higher compression...

Just had a 510 cam installed with gear drive, cam plate, oil pump, lifters and push rods but there is some noise i noticed from top end. What should I check? Should I check push rod adjustment and timing? But was wondering what the compression should be with the parts I had installed?

🛑🛑 Great Video Gix👍💯 Great Content as Usual😀👍

Just bought a set of KB 411 10.5:1 pistons sending heads in for Port n valve job. I already have Chris rocket 574 cams. Cams state up to 10.1:1 comp. .Do you think the 411's will work properly with the extra comp. I have a fxs blakline 103ho

I have a 06 road glide with a 05 engine and I don't know what pistons or compression ratio it has but if I run 93 octane it runs like crap If I put 110 octane in it runs great. It has a very mild tune and puts out 97ft lbs and 89hp and it's a 88c.i. any ideas ?

77K and change on my 2002 stage 1 RKC. Still getting me down the road problem free like the day I drove it off the lot. There's no free lunch. I'm guessing as HP and torque go up, engine life goes down.

Would Andrew's ev-27 cam work ok with 10.5 compression?...

So how much compression, requires compression releases In a T.C. 88?

Bro… can tw222 handle higher compression?

Im getting 10.25-1 pistons in my 103 with ported heads ... after this video i dont know if my starter can take it

Did a 117” S&S big bore kit on my twin cam 103, what would be the best cam for this set up. Bigger throttle body, S&S oil pump, S&S 585 cams 2 into 1 pipe etc.

Do you ever work on anything??

Who makes a good 103 TC lightweight piston with 10.5:1 CR?

Clicked on video to see Harley service information for customers... ..but as I watched I began to miss my '04 blue and white GSXR 1000. damn.. why did I sell that!

NO REPLACMENT FOR DISPLACEMENT, GO BIG OR GO HOME S&S HOP UP UR HARLEY!...😎 my twin cam 88 is now FULLY BUILT106 stroker on NITROUS! chain drive airshifter,🤣 LETS PLAY!.✌ 170hp n climbing! SHES A HUGE WHEELIE MACHINE!!. N I RUN A SLICK ON HER FOR HOOK UP!

I thought you’d want lower compression if adding a turbo.

Screaming mouse parts , not screaming eagle parts .

Turbski