OK so, I am thinking of doing a 107 kit. 88000 miles on my 2007 FLHTC, currently have cams in it but want a bit more... plus I am wanting to refresh the top end anyway... Just feels a little sluggish... This question is about the crankshaft.. Do I really need to address the crankshaft... Weld and true it..Is this really necessary? I am a mild to medium rider, I don't do burnouts, I get on it every once in a while but I am pretty easy on my stuff...
Some would have you think that the damn thing is gonna scissor out the door from the factory... Bike has been pretty reliable so far...
Just want some advice, suggestions, warnings...

 

I'm no expert but I would think you would need to tear it down and check your crank runout and end play to really be able to answer that question.

 

Check runout. If it is over .003/.004, I'd really think about doing the crank. If it is good and ya don't beat on it, I'd leave it alone. Of course, if ya do split the cases go bigger than 107...

 

I think 107 is gonna be pretty much where I wanna be....I want to keep it under $5000 with other stuff I am gonna do as well.

 

Absolutely necessary, a good crank job will include new H beam rods, Silvermoon cycle does excellent work at a reasonable price. By going to 107 you are going to be putting a bunch more stress on an already worn part, never a good idea.

 

I'm right with BVBOB. When I did my build I had about 10,000 miles and my runout was .007

I do ride real hard and wanted the added security, so I let Darkhorse do their magic.....no regrets! My entire build was a hair over $5k, but I also got some chrome rockers covers, tappet covers....etc sh?t I really didn't have to have. could also have saved a bit by boring my cylinders, but I really liked the S&S 106 kit. You'll definitely be in the $5k and below range with a solid 107".

 

Thanks guys.... I will be considering a lot withing the next 10-12 months getting all my ducks in a row..then deciding if I will DIY or let a Inpdy do it for me...

 

ide check your run out,if you do decide to do the lower end,dont just weld it.that really wont stop it from moving.have it rebuilt

 

I just went through this decision about 9 months ago. I had a crank run out of .006", which beforehand was the identical number I had come up with as my "go/no go" number for crank work. Well I put a thread out over at the HTT Forum on whether I should send my crank in for repair or just press on and do my 107" build. The replies were pretty much split 50/50, and I decided to go ahead and send it off to Darkhorse for repair.

Just wanted to bring out a few more considerations:

The bigger the build, the better the crank needs to be, so if all you want to do is a Big Bore, well that is a lot different than a Big Bore, big cam, headwork, big tb, and high compression build.

It is easier for some people to recommend crank work more than others. Somebody like BVBOB can probably split the cases, install the Timken crank bearing(s), and reseal the cases in his sleep and this saves a ton of $$$. But not so for most of us, so get ready to open your wallet for crank work - easily $1000 to $1500 depending on what all you do, ie Timken(s), H beams, balanced, etc.

The crank run out check is easy, just buy/borrow the Feuling tool (~ $100) and do the check before the build, then you can use this info to help you know what to do.

This is a risk/reward decision, there is risk/rewards on both sides. If you skip the crank work, the reward is saving a lot of $$, but the risk of course is damaging your engine with the increased power. If you do the crank work then the opposite is true, risk is spending unnecesary $$ and reward a crank that might save a failure.

Anyway there are a lot of other considerations that you and others have mentioned too, like how you ride, mileage on the engine, etc so you will have to weigh it all out and make a calculated decision and never look back.

 

Personally, I wouldn't consider anything more than a 103 on these stock cranks. I know they say a 107 can be done without, but no way would I push it.