Harley Davidson Forums - Custom 124" build questions

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Custom 124" build questions

So I dropped off a set of 103 cases I picked up to the machine shop, going to do timken conversion, darkhorse crank, cases will be machined and it will be a 124 when its all done. Builder says 140+ hp but we'll see about that. My questions are, what other components do I need to upgrade to support that sort of horsepower? I don't want to slap this thing in, break it in and then put a beating on it and start breaking all sorts of parts every time I take the bike out. Id rather put a shopping list together and get everything I need, or most everything atleast so I can swap engines and do everything all together. It will be a winter project so I should have everything by then. Other question is, builder is recommending thundermax tuner, which is fine I dont mind paying the money if its worth it. But correct me if Im wrong, thundermax is sort of old technology now isnt it? Compared to whats out there today. He swears by it, says it will be best tuner for the build. I didn't question him he's very knowledgeable but I'm just looking for peoples opinions who have been here before. Trying to cross my t's and dot my i's with this thing. Any help would be great, thankyou.

We average about 8-10 custom built, 124"s a year here, plus the constant multitude of many, many other builds, upgrades, and repairs.
If 5 speed equipped, then you'll need to replace the trans mainshaft primary bearing race with an S&S unit, to prevent the race from walking/migrating into the maindrive gear seal.
Also, a solid comp sprocket, a VPC95LT lock up hat with a Barnett spring, and if auto chain chain tensioner, a Baker adjuster to replace that.
That is the short list.
Scott

we also do a lot of 124" builds,i assume since your having darkhorse rebuild your OEM crank your going 4.375x4.250,you didn't mention headwork.HD 110 heads are our go to heads for most 124" builds as their a very good foundation and we end up in the 320@28" area when done porting,ide also look into a BANDIT clutch and a powervision for tuning,58mm HPI would be the t body choice.140/140 is not a big deal on even a fairly mild 124"

We like stay with 4.625" stroke X 4.125" bore to insure good cylinder base clamp loading, to prevent any weepage on the 4.250" base gasket.
Yes, CVO 110" heads can achieve great flow numbers and we witness that here, but an S&S Super Stock casting, or OEM HD casting with intake seat replacement, are very good platforms.
The mac-daddy is a set of S&S B2 heads, if looking for that type of peak-oriented power.
Scott

The bike is a 2014 so it has a 6 speed, he said something about a bearing in the tranny not getting enough oil. Not sure if that rings a bell for anyone. He also mentioned s&s castings for heads with his port/valve job. Its a complete build starting with literally just a set of cases EVERYTHING is being installed new. Not a single part/bolt being re used. I just bought a set of bare cases so I can keep riding the bike now while the new engine is being built. Whats the long list of parts needed to support this thing? Anyone recommend a set of cams to pair up with heads flowing 300cfm+?

Quote:

Originally Posted by Hillsidecycle.com (Post 17437272)

If 5 speed equipped, then you'll need to replace the trans mainshaft primary bearing race with an S&S unit, to prevent the race from walking/migrating into the maindrive gear seal.

Scott

What about that All Balls Heavy Duty primary bearing that presses into the inner primary cover and you have to remove the original race from the drive shaft?

We do not see the bearing itself being an issue whatsoever.
The race, is in fact a problem.
Scott

Quote:

Originally Posted by clp13294 (Post 17438221)

Unsure of a transmission bearing not being lubricated correctly.
Probably best to consult with the cylinder head facility in regards to the camshaft requirements.
Scott