I was told on two separate occasions by two different mechanics that the '98 -'99 era Evo crankshafts were actually too tight and the MoCo reverted to an earlier / preceding crank part # when fixing them. True? If so, how frequent were the problematic cranks and what symptoms / issues would they cause and how severe?
The rods were fitted tight on the crankpin to reduce noise. The more noise reduction they got from the motor the more noise they could let out of the exhaust. I fixed a lot of them by tearing them apart & honing the rods to size. Almost all the ones I took apart had nothing wrong with them. Rods, bearings & crankpin all looked like new. On the plus side there was a lot more power on tap afterwards. Those zero bearing tolerances would really drag the motor down.
Quote from: wfolarry on October 02, 2018, 04:31:44 AM
The rods were fitted tight on the crankpin to reduce noise. The more noise reduction they got from the motor the more noise they could let out of the exhaust. I fixed a lot of them by tearing them apart & honing the rods to size. Almost all the ones I took apart had nothing wrong with them. Rods, bearings & crankpin all looked like new. On the plus side there was a lot more power on tap afterwards. Those zero bearing tolerances would really drag the motor down.
Thanks for the response. Interesting re the power loss. So, a hopped-up / built Evo with the tightly fitted rods would more than likely show LESS power gain compared to same motor with honed rods?
Over time / mileage what potential problems, surfaced with the tighter rods?
Both of my 1998 evo's had tight rods. When the barrels are off you can get the rods to stand up in a V without falling away to the case. I had my wheels split and re-honed to a looser spec. I also took advantage of the disassembly and changed the crank pin at that time to the later (better oiling) version.
Quote from: JamesButler on October 02, 2018, 06:48:21 AM
Quote from: wfolarry on October 02, 2018, 04:31:44 AM
The rods were fitted tight on the crankpin to reduce noise. The more noise reduction they got from the motor the more noise they could let out of the exhaust. I fixed a lot of them by tearing them apart & honing the rods to size. Almost all the ones I took apart had nothing wrong with them. Rods, bearings & crankpin all looked like new. On the plus side there was a lot more power on tap afterwards. Those zero bearing tolerances would really drag the motor down.
Thanks for the response. Interesting re the power loss. So, a hopped-up / built Evo with the tightly fitted rods would more than likely show LESS power gain compared to same motor with honed rods?
Over time / mileage what potential problems, surfaced with the tighter rods?
They would destroy the pinion race that's pressed on the pinion shaft. Then I would have to replace it & mount that flywheel half in the lathe & grind it to size with a tool post grinder.
that makes sence why my 98 Heritage I bought new was the slowest EVO ive owned
Since I just bought a 99 bone stock FLSTC with 20K on it, this thread caught my attention. I've been digging around on the net looking for more on the subject. Thought I should share what I found. I certainly don't discount what is in this thread (don't want to ruffle feathers) just wanted as much info as I could find. Still looking....I hope more people chime in with additional stuff.
Found this on another forum, it was regarding a 97 Evo that a shop recommended replacing the entire motor on:
FYI everybody ... 1997 was the year of the tight connecting rod ! Assembly line procedures were changed for crank setup for the '97 big twin engines !
A couple symptoms associated with the tight con rod issue are : Hearing a couple squeaks from the bottom end when shutting off a hot engine and once the top end is off the rods will stand up when positioned in a less than vertical position with the pistons removed . The rods should always fall off to the case and not stick in any position .
The factory resolved the issue before the end of the '97 model year but paid out a ton of warranty cash for the mistake !
and this in the same thread:
so if this tight con rod issue existed straight out of the factory, and its been running for 13 years in that condition without a problem...what kinda problems would there be with running it as is?
That's kinda what I was getting at , a fairly stock '97 could go forever in that condition . Problems arose when they started showing up at shops for top end rebuilds and the rods were found to be tight . Now the shop has to address the situation because they're liable if the rods sieze after they do the rebuild . Some '97 owners wanted hopups seeing as how the engine was apart for the top end rebuild anyways and that caused more problems .
If I were looking to buy a '97 big twin I'd get the engine hot to see how it sounds when I shut it off . If I hear a couple squeaks coming from the bottom end the last couple revs , I steer clear of the sale or negotiate for a couple grand less . IMO
Also found a Tech Service Bulletin that seems to be for a lot of years:Purpose: technicians have been falsely identifying connecting rod bearings as failed due to a perception of resistance as the rods are rotated.
So, 97, 98, or 99? Which has the issue? Or all have the issue? Yikes! Gotta love the internet....
One of the reasons I bought the 99 was that the engine was so quiet. Really like that. I'll keep an ear out for any squeaks when I shut it off hot. So, takeaway for me is all of this is good knowledge but only requires action if there is noise or you are tearing into or building up a motor. That leaves me out. For now.... :up:
:up:
Quote from: kd on October 02, 2018, 07:27:16 AM
Both of my 1998 evo's had tight rods. When the barrels are off you can get the rods to stand up in a V without falling away to the case. I had my wheels split and re-honed to a looser spec. I also took advantage of the disassembly and changed the crank pin at that time to the later (better oiling) version.
nice
QuoteAlso found a Tech Service Bulletin that seems to be for a lot of years
you have a number ?
I'd delete that sentence from my post if I could. Future readers ignore the TSB reference. Too many bikes listed in it.
if you don't want to post the TSB Number then send it to me in a PM
Hmmm, When I pulled my jugs off my 97 wg the rods were not tight. ?
Why does the pinion race get destroyed?
What crank pin is recommended?
Thanx
Quote from: thumper 823 on October 30, 2018, 06:21:54 PM
What crank pin is recommended?
Thanx
I use the S&S 2 hole pin. Have had very good luck with them. Don't use the 3 hole. Don't like them at all.
Quote from: choseneasy on October 26, 2018, 08:46:50 PM
Why does the pinion race get destroyed?
The thrusting action caused by the tight rods can force the race off the pinion shaft or wreck the bearing. if the race wasn't damaged a little green Loctite & press it back on. Hone the rods & put it back together. Did a lot of those for guys on the cheap.
Ok, continue as I need a reason you don't like a 3 holer.
I am always looking for an education.
Quote from: thumper 823 on November 01, 2018, 07:04:45 AM
Ok, continue as I need a reason you don't like a 3 holer.
I am always looking for an education.
On a three hole crank pin the rollers pass over the holes. On a two hole crank pin the rollers straddle the holes.
I have heard of others not liking 3 holes too , but I can never fond real reasons.
The "skating " used to be a big rumor, but I guess that has been disproved.
Two holes, three holes the bearings hit the holes in a different spot.
The third hole does add one more spot, I have no clue how this could be a detriment.
Quote from: turboprop on November 01, 2018, 07:25:33 AM
Quote from: thumper 823 on November 01, 2018, 07:04:45 AM
Ok, continue as I need a reason you don't like a 3 holer.
I am always looking for an education.
On a three hole crank pin the rollers pass over the holes. On a two hole crank pin the rollers straddle the holes.
This. :agree:
The rollers make contact with the oil feed holes on the 3 hole pin. I've seen these wear out prematurely. One mfg. staggered the holes so they wouldn't be on the thrust side of the pin but I didn't see any improvement. The 2 hole pin has the oil feed holes between the rollers. The only thing that is going to touch them is the races & they're just floating in there anyway. When you had 8:1 compression [or lower] you could get away with a lot of things. When you start upping the compression & the horsepower that should follow you start finding the weak links. The 3 hole is one of those. JMO
Great info, thank you
Quote from: wfolarry on November 01, 2018, 06:51:44 AM
Quote from: thumper 823 on October 30, 2018, 06:21:54 PM
What crank pin is recommended?
Thanx
I use the S&S 2 hole pin. Have had very good luck with them. Don't use the 3 hole. Don't like them at all.
Quote from: choseneasy on October 26, 2018, 08:46:50 PM
Why does the pinion race get destroyed?
The thrusting action caused by the tight rods can force the race off the pinion shaft or wreck the bearing. if the race wasn't damaged a little green Loctite & press it back on. Hone the rods & put it back together. Did a lot of those for guys on the cheap.
As a point of interest, my first set of tight rods (98 ultra) came to my attention when a piece of the outer pinion bearing rim broke away and migrated into the oil pump while on a trip to Vancouver Island. A friend (Marv Brimicomb now deceased) ran a Nitro sand drag record holder and had a full machine shop. We tore it down and found just what Larry describes with the side force damaging the race rim. The piece may have been broke off for some time before it found it's way into the pump. I expect by removing the gear cover an inspection could be done to see if there is any indication of pinion brg movement or damage. As for tight rods, there's only one way to check those and that involves cylinder base gaskets. :crook:
Thanks for the education. I appreciate you guys sharing your info.