Author Topic: When is bottom end work required?  (Read 1826 times)

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Offline WMX124

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When is bottom end work required?
« on: December 12, 2017, 06:00:31 PM »
2007 Dyna with stock 96ci engine, 25k miles with stage 1.

Looking to increase displacement with a bolt on 107 or 110 kit from Fuelmoto or S&S. Considering head work as well but possibly just compression releases. At what point must you split cases and upgrade the crank? I've seen numerous build sheets on this forum with no mention of crank work. Is there a typical cut-off with displacement or expected hp/tq numbers that warrant mandatory bottom end work? Is run-out the determining factor?

Trying to understand realistic build costs with the different bolt-on kits available. Trying to build a strong street bike with usable torque.

Thanks for your help.

Offline Harley_Cruiser Rocker Lockers

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Re: When is bottom end work required?
« Reply #1 on: December 12, 2017, 06:55:20 PM »
Well there is no set rule, if you are just doing a bolt on. It's luck of the draw and how you ride that will decide. Yes run out is the problem when it gets real bad then it starts causing problems. Scissored crank is worse case scenario caused by hole shots. There are a lot of bikes running around with no problem on a stock crank, the ones that go bad are the one we hear of.
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Online kd

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Re: When is bottom end work required?
« Reply #2 on: December 12, 2017, 07:23:14 PM »
Check your runout first. If it's already borderline you'll be wanting to correct it before it gets worse and takes out the oil pump and / or everything else. That may make your decision and then you can get it Hobanized to bullet proof status.
KD

Offline sfmichael

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Re: When is bottom end work required?
« Reply #3 on: December 12, 2017, 10:13:49 PM »
both of these guys are right - I wouldn't be afraid to take a stock bottom end the the level where you are headed (105-125hp)

I probably wouldn't take one much higher - but a little bit depends on luck, and a whole lot more so on how hard you beat on it
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Offline Scott P

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Re: When is bottom end work required?
« Reply #4 on: December 13, 2017, 03:36:36 AM »
I'd be cautious leaning on that 2007 crank.
2004's were the absolute worst, some early 2005's, and 2007's in that order.
Not an opinion, or something I read on the internet....fact.
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Offline prodrag1320

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Re: When is bottom end work required?
« Reply #5 on: December 13, 2017, 04:29:16 AM »
if your planning on keeping the bike for a while,doing the lower end is a very good idea with any build,IMO

Offline No Cents

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Re: When is bottom end work required?
« Reply #6 on: December 13, 2017, 04:44:40 AM »
 all great builds...no matter how big or small need a good foundation to start with.
Bullet proof the bottom end...and you only have to do it once...and not regret it later.
08 FLHX 124", wfolarry 110 heads, CR630i cams, Burns pipe, 158/152 sae

Offline WMX124

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Re: When is bottom end work required?
« Reply #7 on: December 13, 2017, 07:17:20 AM »
I appreciate the input. Is reworking the stock crank adequate? Revolution Performance website notes issues with the tapered rod ends. Specifically, the lack of oiling hole and spun bushings that can't be replaced.

Offline GMR-PERFORMANCE

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Re: When is bottom end work required?
« Reply #8 on: December 13, 2017, 07:24:36 AM »
Here is a crank from them  Would hate to see this happen to you , as they did in fact install new bushings in this crank with tapered rods. Installed a aluminum plug in the crank . Stated tune caused the crank to fail ..  Customer had to pay for new pistons bore hone again and well a new crank . 

Build was running fine had a light vibration . Customer removed crank had them do the work he re installed it and it failed in under 50 miles .

With new parts tune was rechecked no changes where needed Bike has been running now for close to two years ,, without an issue .

If new is the way you want to go I would opt for S&S   If rebuilding yours is the way you choose I would get in touch with Hobans they are a vendor on here as well

http://harleytechtalk.com/index.php?board=69.0



Untitled

 by GMR Performance, on Flickr



Untitled

 by GMR Performance, on Flickr


Here is a dyna with the S&S kit on it stock heads DD fat cat pipe . clutch was slipping hence the curve being off a bit down low .  I would get with a S&S dealer near you get your kit and bolt it on . Great bang for the buck in my opinion . With over 39 of them done and tuned along with another one currently  of these kits now and they run very well . I like them and over all hard to complain about the end result.



dynorunShare

 by GMR Performance, on Flickr
« Last Edit: December 13, 2017, 01:33:20 PM by FSG »
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Offline WMX124

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Re: When is bottom end work required?
« Reply #9 on: December 13, 2017, 07:46:17 AM »
Thanks for taking the time to upload those images.

Was the dyno sheet a 110ci bolt on kit with a stock crank or a 107ci? 110ci is the route I was looking to go. Slightly hesitant with stepping up to that kit with a stock bottom end.

Offline GMR-PERFORMANCE

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Re: When is bottom end work required?
« Reply #10 on: December 13, 2017, 07:52:42 AM »
If is on the sheet its a 110 kit . I do not recall at this time if the crank in that engine was good or if we replaced it sorry .
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Offline koko3052

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Re: When is bottom end work required?
« Reply #11 on: December 13, 2017, 08:21:06 AM »
To the OP, it's obvious that you're wanting more power. With more power, you will use it! To expect that stock crank & those "dick head" rods to hold up for any longevity is just a roll of the dice. By the time you have the crank reworked & full compliment rods added you are right next to a new S&S, just make sure to get the full compliment rods.
After that you can ride without worry for a very long time. JMO

Offline WMX124

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Re: When is bottom end work required?
« Reply #12 on: December 13, 2017, 08:32:23 AM »
To the OP, it's obvious that you're wanting more power. With more power, you will use it! To expect that stock crank & those "dick head" rods to hold up for any longevity is just a roll of the dice. By the time you have the crank reworked & full compliment rods added you are right next to a new S&S, just make sure to get the full compliment rods.
After that you can ride without worry for a very long time. JMO

Agreed. I'd rather do it right the first time. It's just hard to draw the line on an engine build as everyone here is well aware of.

Offline GMR-PERFORMANCE

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Re: When is bottom end work required?
« Reply #13 on: December 13, 2017, 02:43:31 PM »
No I do not feel that is correct . Being I build nothing but high performance engines and dyno tune them .

I feel that there are many that are not rock stars but offer great bang for the buck and hugely increased reliability .

Crank , is a first step the 110 bolt on offers a great set up and 1 year warranty From S&S . I would suggest leaving the heads stock but do a proper valve job . and that is it . tune the bike and go enoy it knowing that it will run for a very long time.  A Dyna making 110/120 is a extremely fun bike . and will out run most baggers short of those making over 130.130  ..
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Offline N-gin

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Re: When is bottom end work required?
« Reply #14 on: December 14, 2017, 01:24:13 AM »
DO the crank and do it right the first time. There are 3 very good options out there. hate to read about you reopening the engine for a scissored crank.
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Offline Scott P

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Re: When is bottom end work required?
« Reply #15 on: December 15, 2017, 04:10:30 AM »
Most HD cranks are just fine, so do not believe the sky is falling whatsoever, but that 2007 year crank has a notorious history.
Darkhorse Crankworks, in Newton, Wisconsin.(they are currently putting up a large addition to their shop)
Might want to place a call to those folks, ask for John.
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Offline Timinator

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Re: When is bottom end work required?
« Reply #16 on: December 16, 2017, 10:15:30 PM »
Dumping the clutch, hard downshifts and width(and stickieness) of the rear tire, change where the destruction crossover  occurs IMHO.  Seen a bunch of bikes over 130 last just fine with stock bottoms and some with 95-100 HP trashing the lower end. In my opinion riding style has more to do with where the breakage line is than most anything, other than shoddy aftermarket work. If you can't hook up the power, you have less chance of carnage because you don't have the shock load on acceleration. I also believe that hard downshifts are harder on most cranks than hard launches. Every one has their experience and opinions, those are mine. As usual, free advice is worth what you paid for it. Assess how you ride, and pick someone whose experience and reputation seem the most reasonable to YOU. If anyone disagrees, please feel free to ignore this post, these are just my opinions based on what I have built and seen.  TIMINATOR
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Offline 04 SE DEUCE

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Re: When is bottom end work required?
« Reply #17 on: December 17, 2017, 09:35:25 AM »
Locking the rear wheel in panic situations has been a long held theory. 

Offline Scott P

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Re: When is bottom end work required?
« Reply #18 on: December 18, 2017, 07:01:13 AM »
Tapered top rods, have been in the diesel industry for years, in severe duty applications.
Something to think about......
Otto Knowbetter sez, "steer clear of chameleons."

Offline WMX124

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Re: When is bottom end work required?
« Reply #19 on: December 19, 2017, 06:05:36 AM »
....but that 2007 year crank has a notorious history.....

What's known to go wrong with them?

I'll certainly contact darkhorse before making a decision.

Offline rbabos

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Re: When is bottom end work required?
« Reply #20 on: December 19, 2017, 07:01:38 AM »
....but that 2007 year crank has a notorious history.....

What's known to go wrong with them?

I'll certainly contact darkhorse before making a decision.
Some were light in the press fits.
Ron

Offline GMR-PERFORMANCE

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Re: When is bottom end work required?
« Reply #21 on: December 19, 2017, 07:44:19 AM »
....but that 2007 year crank has a notorious history.....

What's known to go wrong with them?

I'll certainly contact darkhorse before making a decision.
Some were light in the press fits.
Ron

and the later years are better  ,... stock cranks are stock cranks . its a crap shoot no matter what . Unless a shop that only does a few engines a year can you say that there is no issue  . If your not seeing stuck cranks then you are either not checking or you just do not do many engines that simple . We will roll that crank 30 revolutions in one direction 30 the other 30 back the other way .  not like 90 is a huge deal . But if there is a issue with a stuck rod you should find it in that process . 

This year we installed 37 cranks  due to stuck rods , or massive run out  . 95% where stock con rods .     Now engine builds where the top end came off where over 175 .. So % wise you tell me if that is a  failure rate that one thinks is ok.     Years on the bikes where 07-16.

 Had a 16 in that had less than 1600 miles on it .. 
Bike was in for a 110 drop on kit . Stuck crank .   

Not saying that the sky is falling.. But again its a crap shoot .  On the other hand you have the builds that have the stock crank and are making mid 120 hp and over 130 tq and they have zero issues .. So its not a year thing , or driving style as i ask the customer many questions .. even the stupid oil one.. What brand do you run . Just data and what you end up with it  no direct realtionship to anything on failure . Other 1 of the 200,000 cranks that year failed .

this was a common site in the shop this year ...
15055631_1306739486024259_7196342330520406978_n by GMR Performance, on Flickr
« Last Edit: December 19, 2017, 07:48:33 AM by GMR-PERFORMANCE »
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Offline HD Street Performance

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Re: When is bottom end work required?
« Reply #22 on: December 19, 2017, 08:26:44 AM »
There is no hp level gauge to follow.
It is part of any high performance build in my opinion or you gamble.
Wheels slipping is one issue, pinched rods another with stock cranks in a built motor

Offline prodrag1320

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Re: When is bottom end work required?
« Reply #23 on: December 20, 2017, 04:31:09 AM »
one thing not discussed yet is the lack of races in the rod side of OEM rods.we`ve seen many cranks here that are not out of true that bad,not abused as far as riding goes that simply had the rod bearings/rods go south.a S&S F/W is a great foundation to any build,high performance or long distance touring builds

Offline rbabos

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Re: When is bottom end work required?
« Reply #24 on: December 20, 2017, 09:03:57 AM »
Not a crank expert at all but having a stock 96 crank, a Darkhorse unit and later a 120r crank, both Darkhorse and the 120r had the same rod clearances. The stocker was running fine and no stuck rods when it was pulled but damn the clearances were tighter then I like to see on a roller for rod big ends. Now if a company plays the tolerance game with +/- at some point those already minimum clearanced rods hitting below a safe clearance units could run into issues. Sticking the rods would likely be the result the way I see it.
Ron

Offline 02FYRFTR

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Re: When is bottom end work required?
« Reply #25 on: December 20, 2017, 02:30:49 PM »
Keep in mind that there is only one way to be sure a flywheel with miles on is 100% and that it to disassemble and check it, I see many flywheels and qll of them are "A" ok from the owner but upon disassembly the rods show defects that may survive or in many cases will not survive an increase in torque and horsepower or a change in riding style.

Offline Scott P

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Re: When is bottom end work required?
« Reply #26 on: December 26, 2017, 04:00:37 AM »
....but that 2007 year crank has a notorious history.....

What's known to go wrong with them?

I'll certainly contact darkhorse before making a decision.

Known across the industry, by folks that know, that many of the 2007 year cranks, did not have the correct wheel/crank pin, press-fit dimensions.
Otto Knowbetter sez, "steer clear of chameleons."