m8 stage 4 upgrade

[rosey]

I'm not too educated with all this forum stuff so please bare with me here, I might not be in the right place. I have a 17 Rd Glide Special with the Screaming Eagle Stage 4 114 upgrade with factory HD race tuner. Now HD has offered a stage 4 128 kit. Does anyone know if I can simply upgrade to the bigger bore pistons & barrels from the 128 kit & reflash the module? I understand that the aftermarket world offers better options but I want to keep all HD parts. I have nothing against the aftermarket stuff, I'm sure most of it is as good as the guys installing it.

[Sunny Jim]

Do your research! Listen to the professionals! The after market options are well worth it.

[rosey]

The reason I want to use HD components is because I do a lot of out of state touring & if I have engine trouble any HD dealer can get the parts ordered in to get me running. Again my question is can I put the larger bore 128 cylinders & pistons in my stage 4 114 kit?  My research hasn't provided my any answer so far, that's why I'm on here asking.

[PoorUB]

If you break down on the road the dealer probably will not have the parts in stock, and will want to order them on a stocking order which will take a week or more. You or the dealer can order aftermarket and ship it next day air. IMO, if the dealer doesn't have the parts on had, your trip is screwed, rent a car! An HD dealer can order any aftermarket part out there. A friend of mine has his Sporty in the dealer right now, needed a couple things, plus a clutch cable, Harley is out of stock on his cable right now. The service writer just shrugs his shoulders and says wait. He went and complained to the manager. The manager said they could order and aftermarket cable to get him on the road.

I had a problem with a rebuild, my fault, not the suppliers, and tore the engine down Monday night, ordered parts, next day air, Tuesday, put it back together Wednesday evening. Went on a ride Thursday evening, changed oil and filter, Friday evening packed for a 3,500 mile vacation, left Saturday AM. I asked the dealer if he would do that and he just laughed at me, and said a week or two.

IMO, order the best kit for you money. Relying on HD parts is a false security.

Also your factory HD tuner will tune the new build, as long as it is a HD build, but only within EPA requirements. An aftermarket tuner will do a better job, and get you a better tune.

if you have a 114", my understanding is you will need the 131" kit. LINK- 131" Stage IV

Plus that is a $3,500 kit and not available right now! Not a very good deal IMO. Fuel Moto can sell you a big bore kit for a $1,000, do your heads for $900, then add what ever exhaust you want, and air cleaner and you will have money left over for a proper dyno tune and not a simple, one size fits all, dealer flash.

[Nastytls]

The 114 was the big bore for a 107 in 2017, so he would be ordering a 128".

I know the old and new SE heads are different. What you have is designed to work with that 114. Bigger pistons and smaller chambers means lots of compression. You might be the first trying this, so you're going to have to do some mocking up and measuring.

[Hillside Motorcycle]

I'm not too educated with all this forum stuff so please bare with me here, I might not be in the right place. I have a 17 Rd Glide Special with the Screaming Eagle Stage 4 114 upgrade with factory HD race tuner. Now HD has offered a stage 4 128 kit. Does anyone know if I can simply upgrade to the bigger bore pistons & barrels from the 128 kit & reflash the module? I understand that the aftermarket world offers better options but I want to keep all HD parts. I have nothing against the aftermarket stuff, I'm sure most of it is as good as the guys installing it.

We converted an anemic S/E 114" to a 124" with our headwork, S&S .550.
Dyno report is on our Facebook.
Taps on 150/150.

[rigidthumper]

I'm not too educated with all this forum stuff so please bare with me here, I might not be in the right place. I have a 17 Rd Glide Special with the Screaming Eagle Stage 4 114 upgrade with factory HD race tuner. Now HD has offered a stage 4 128 kit. Does anyone know if I can simply upgrade to the bigger bore pistons & barrels from the 128 kit & reflash the module? I understand that the aftermarket world offers better options but I want to keep all HD parts. I have nothing against the aftermarket stuff, I'm sure most of it is as good as the guys installing it.

Simple answer? No- as there is only one SEST map available for your bike with a 128 kit- you could add the SE517 cam, 128 jugs & slugs, and SE heads, and 2020 oil pump, then use that map.
HTH

[rosey]

thanks rigidthumper. this is pretty much the same answer I was finally able to get from an HD dealership. only took 3 to get a complete explanation of what parts are needed,lol. just a shame I spent for the 114 last spring & now they offer more power!