REPRINT FROM OLD HTT: John Rosamond CA Question About EVO Engines

[ClassicRider2002]

DISCLAIMER: THIS IS A REPRINT TOPIC FROM "OLD" HTT

I have saved many great topical discussions as "links" over the years and would hate to see these lost, so I am reprinting this TOPIC here, which may "perhaps" help some.

TOPIC: JohnS_ Rosamond_CA  Question About EVO Engines 08-16-08

  
From: ClassicRider2002  (Original Message) Sent: 8/16/2008 8:00 AM    Message 1 of 19 in Discussion
Hey John.....

I thought I would ask you a few questions.....
I am curious what exactly was done to the EVO engine between 1994-1999:

Were there any specific changes or alterations made to the engine during these years?
Also curious about the transmission as well during these years. what if any changes were occurring during these years?
Also curious about the clutch during these years was the clutch modified in anyway?

I remember you once sharing the following:Umbrella valves were not used for model year 1989, even if the rocker box had a place for the umbrella valve, one would not use it.

So the umbrella valves get their start when?
A) The 1992 and earlier cases breathe out of a hose that comes out of the bottom of the case.

When did this start occurring?
B) Starting with model year 1993, all bikes had the crank case breather that vented out of the cylinder head and into the air filter.  The umbrella valve was supposed to help separate liquid oil from the air stream.

So which one is "better" A or B and why?

Thanks John

Regards,

"Classic"

[ClassicRider2002]

 
From: JohnS_Rosamond_CA Sent: 8/16/2008 10:51 AM   Message 2 of 19 in Discussion
Hey Classic,

Well, I'm sure there's someone out there who can answer better than I but here goes.  I think my sense of chrononlogy is going to be pretty bad.

Engine: From 1991- 1999:  1991 or 1992 the oil flter is moved to the front of the engine case (along with a new oil pump design).  Somewhere around 1994 or 1995 Harley began to use the serrated left side flywheel, with the inductive pickup on the front of the case - for use with the "new" fuel injection system.  Close to that time the stator plug also changed (though I don't remember if the alternator output was higher)- eventually it goes from 32 to 40 for the FI bikes.  Harley switches from paint to powder coating for the black and silver on the crank case and cylinders. Also, at some point in the middle 90's the casting style used for the cylinders was changed (the fins got a little thicker and had a more finished edge).

Transmission / Drive 1994 - 1998:  1995, Softail gets the 32/65 rear pulley system which helps with vibration and fuel economy. Some time around 1996 the tooth count on the Primary changed to alter the final drive for Baggers (with a new rubber mounted frame).  Although there may have been a gear ratio change in the transmission, the case for the 5-speed remained is pretty much the same.  After about 1994, all Big Twins use the electronic speedometer (except the FLHT standard which stuck with cable drive).

Clutch: The clutch was updated in 1990 to the splined clutch basket.  It was updated slightly (I believe) the next year.  I don't believe that the clutch was changed much until about 1998 or so (I'm kinda hazy on that one).  The clutch was changed just before, or just as, the Twin Cam came out.

Rocker boxes.  All evo rocker boxes for big twin fit all Evolution engines.  However, the umbrella valve rockers didn't appear until 1992 (along with the head breather heads), but in the 1992 model they were non functional.  For 1993, the case was changed and allowed the head breather equipment to actually breath out of the cylinder heads.  All Evo 1993-1999 were head breather systems.

Head Breather vs. Bottom breather:  I would say that neither system is superiour to the other in design.  However, I have heard many more reports of head breather systems running "wet."  Generally, the bottom breather bikes tend to run a little drier.  "The Cure" is an excellent fix for head breather engines that seem to run wet.  This is my plug for the bottom breather - The umbrella valve makes the rocker box area a "servicable item."  If that wasn't inside, you wouldn't need to ever get in there.  Head breathers are (probably) less prone to building up internal crank case pressure.  No hoses to bind, no hose ends to get plugged with debris.  For me, I prefer the bottom breather, but that doesn't make it better.


=====================================================

HERE IS A BRIEF CONVERSATION I HAVE PLUGGED IN ABOUT BOTTOM BREATHER EVO'S VS HEAD BREATHER EVO'S WHICH I FEEL FITS IN HERE APPROPRIATELY AS WELL:  

From: reddog74usa  (Original Message) Sent: 12/19/2006 7:22 PM
Can anybody tell me what I have to do to convert a bottom breather EVO to a head breather? Thanks, RD

From: xlfan Sent: 12/23/2006 7:21 AM
The head breathers do use other rocker boxes than the bottom breathers, BUT you can use head breather rocker boxes on bottom breather heads (with the correct gaskets), not the other way around.

The -92 EVO is an oddball in that it looked like a head breather, but was really a bootom breather. The heads were plugged because they used a thread insert from 1/2" down to 5/16" in order to use the -91 A/C box fastener and not the -93 1/2" breather bolt. The -92 were equipped with head breather heads and head breather rocker boxes, and still they were bottom breathers. The -92 also had the early nose cone with the "breather box" inside of it like the rest of the early bottom breathers.  It seems that the early rocker boxes still are available. So, if one has a -92 evo, you can use either type of rocker box sets, you really have a bottom breather.

From: reddog74usa Sent: 12/23/2006 10:37 AM
Ok, So since I have a bottom breather I could run the later heads by using the correct head breather rocker boxes and removing the umbrella valves correct?

From: Traveler_733 Sent: 12/23/2006 12:13 PM
Just use YOUR current rocker boxes. Plug the head breather holes with the threaded adapters. Unless you want to breathe out of both.
I use an S&S steel breather gear and breath out the bottom.    I run the breather hose open ended, no filter, etc. I sometimes run hard at 75 mph, for hours on end, with 337 gearing. which means almost 4,000 rpms. in 95+degree heat. (with oil cooler)  Running 9.5 compression ratio, SE heads, that use the threaded adapters for the air cleaner.And an V-Thunder 5010+3 cam. (.585" lift) No oil misting problem!!

From: JohnS_Rosamond_CA Sent: 12/23/2006 12:47 PM
If you have a 1992 or earlier case (or an aftermarket case set up for those years), then you can never really fully convert to head breather no matter what you do.  The case just isn't designed to relieve all the crank case pressure through the pushrod tubes like a head breather does.  Leave your gear cover and it's gasket alone.

If you want, you can run the 1993 and later heads and rocker covers and you will actually get a little breathing action out of them, but your primary vent will still be the vent in the bottom of the crank case.  Personally, I think a correctly set up bottom breather is a better set up since they had less of a tendency to spit than the 1993 and later bikes did.  John S,

From: reddog74usa Sent: 12/23/2006 2:39 PM
Sounds like I'm set up with already having the bottom breather. As I had previously mentioned, I originally posted this to find out how to be able to run the later heads. Traveller, what do you think of the SE heads? Do you like em or would ya run a set done by a good head porter? I will be runin a Woods W6 cam cv carb and a T-Header or Bassani Road Rage with a Hi4 ignition on 80 inches with 10 to 10.5 CR. 

From: Traveler_733 Sent: 12/23/2006 3:53 PM
I ran professionally ported heads for about a year, They worked well, until a valve guide came loose and wallowed out the head. In the haste to get in more good weather riding, I installed SE heads. Out of the box. The SE heads are a good bang for the buck, and bolt on and then go twist the LOUD handle!!  They worked good too, BUT.. the valve giude seals are JUNK on SE heads, out of the box. I was burning a quart of oil about every 1500 miles. So, the next winter rebuild, I put Cometic valve guide seals on. (you have to call Cometic for these, as they aren't cataloged) The SE heads use .530" guides. The Cometic seals install by hand, so I just used my valve spring compressor and changed them at the same time I installed Cometic .030 MLS head gaskets to get better squish.  These heads are installed on an S&S Stroker bottom end. I'm running the HI4-E ignition, and like the advance slope adjustment to dial out pinging.*
*UPDATE:
Notice that "Traveler's" comment above occurred nearly 2 years ago.....in essence his problem with the heads was only the "valve" seals so if you decide to do the "Screamin Eagle" heads make sure you decide how you feel about the "valve seals".  To take care of them before installing is just a few dollars vs afterwards and if you have a problem.....JUST thought I would take the time to write to you about this......it's your decision of course.....

From: reddog74usa Sent: 1/12/2007 6:31 PM
I ended up picking up a 98 evo top end with rocker boxes so I guess I'll go with them so I'll end up with a little more breathing capability and be able to just swap out the top ends when I get the heads and cylinders back from the machine shop. Thanks for the info as I wasn't shure what would work with the 87 bottom breather evo I have. 

=====================================================


From: JohnS_Rosamond_CA Sent: 8/16/2008 10:54 AM   Message 3 of 19 in Discussion
oops!  Transmission case:  starting in 1994 the touring big twins get the oil Pan transmission case.  Dyna's got it in 1991 or 1992 (with their introduction).  

From: ClassicRider2002 Sent: 8/16/2008 11:02 AM   Message 4 of 19 in Discussion
JohnS.

Thanks for your response.....
quite insightful.....I probably will have a couple of questions...but I am going to absorb this for a little while.....

Regards,

"Classic"

 
From: xlfxfl Sent: 8/16/2008 2:33 PM   Message 5 of 19 in Discussion
Wow John!  lots of info in your head.  i read your stuff here quite often... thank you 

I only know what I have... well sometimes I don't even know that.  anyways
I've got a '97 that has the 'big axle' lifter rollers.  I think it was new that year... from HD anyways.  Found out the hard way when I drilled one out for replacement and my new rollers didn't fit!  And I don't think there is a big axle roller relacement available to this day.  Ended up buying four lifters.Jim's.  wore those rollers out and I have Crane in there now.  They have the origianl size rollers so maybe I can use those replacement rollers afterall.   My left crank is not notched.  My buddy had a '97 or '98 FI and I don't recall it having a crank sensor.  If it didn't, the module got it's timing info from the nose cone module...
      

From: JohnS_Rosamond_CA Sent: 8/16/2008 3:06 PM   Message 6 of 19 in Discussion
Oh yeah, I forgot about that.  Yes, they did switch the size of the roller for the big twin.

On the serrated left hand flywheel, it's my belief that all of the Evo's that had FI did have it.  I have a manual for 1997 FLHT and it shows the crank position sensor - which I think started with the 1995 "Ultra" (but the Big Twins were still using the nose cone ignition pick up as well).    


From: ClassicRider2002 Sent: 8/19/2008 5:13 PM   Message 7 of 19 in Discussion
JohnS......
you of course provided a wealth of information......thank you.....here are some remaining questions....

Engine: From 1991- 1999:  1991 or 1992 the oil flter is moved to the front of the engine case (along with a new oil pump design). 

Ok so is this a good thing or a bad thing....or was it a bad thing when it wasn't in front?

Somewhere around 1994 or 1995 Harley began to use the serrated left side flywheel, with the inductive pickup on the front of the case - for use with the "new" fuel injection system. 

How did this affect the carb engine workings if it did at all....

Close to that time the stator plug also changed (though I don't remember if the alternator output was higher)- eventually it goes from 32 to 40 for the FI bikes.  Harley switches from paint to powder coating for the black and silver on the crank case and cylinders. Also, at some point in the middle 90's the casting style used for the cylinders was changed (the fins got a little thicker and had a more finished edge).

does anyone know when this occurred ie: for the crank cases from paint to powder coating?

when did the casting style used for the cylinders change, does anyone know the actual year?

Transmission / Drive 1994 - 1998:  1995, Softail gets the 32/65 rear pulley system which helps with vibration and fuel economy. Some time around 1996 the tooth count on the Primary changed to alter the final drive for Baggers (with a new rubber mounted frame).  Although there may have been a gear ratio change in the transmission, the case for the 5-speed remained is pretty much the same.  After about 1994, all Big Twins use the electronic speedometer (except the FLHT standard which stuck with cable drive).

This is interesting as the 1999 FXR2's and FXR3's and the 2000 FXR4's were given the 32/65 secondary rear pully drive.....so now I know why....and you are quite correct....when you take the 25/36 comp sprocket and the clutch shell basket of which are the same parts that fit in my 2002 RKC [except for the chain tensior set up, and the friction plates having different part numbers] the entire set up of the primary is exactly the same and the result is 2.925 gearing which is quite friendly for gas and yet offers little in terms of vibration yet allows 5th gear to still primarily work as an over drive while the first 4 gears are quite strong in pulling the bike forward.....so as I said now I know that the 32/65 rear pulley gets its beginnings.....

Clutch: The clutch was updated in 1990 to the splined clutch basket.  It was updated slightly (I believe) the next year.  I don't believe that the clutch was changed much until about 1998 or so (I'm kinda hazy on that one).  The clutch was changed just before, or just as, the Twin Cam came out.  

I guess the clutches were given different amount of friction plates throughout the years....I have read where recommendations for primo clutch would be a good thing for the eariler clutch systems....any opinions on this?  

Is there a particular year of the evo where you say.....hmmmm don't think I will select any bikes from that particular year because of what was done to the engine......and likewise would there be any particular year where you might say.....hmmmm yeah I think I would particularly look at this year because the engine is very good.....?

Finally what do you think about the program HD offers to turn in your engine and get another "freshly" "rebuilt" EVO in return, do you or does anyone know of many that have chosen this program, and if so what do you all think about it?

Regards,

"Classic"


From: JohnS_Rosamond_CA Sent: 8/19/2008 8:07 PM   Message 8 of 19 in Discussion
Oil filter front (good/bad).  There has never been a front mounted oil filter that fell off in service that I know of.  Rear mounted oil filter can do that.  However, having the oil filter right above the front rubber mount (Dyna, Bagger), mean sthat it gets oil soaked quite often.  That's bad.  Yes, I have seen (and used) the plastic guards that they sell, but I have not found one that I like enough to use it consistently.  So, in many cases, I like the rear mounted filter (though it has some drawbacks).

Serrated Flywheels.  If I understand correctly no Carbed Evo (or very few anyway) actually had the serrated flywheels inside.  It was parallel production.  I don't think that all models got them until the switch to TC - though that may be incorrect.

"Good bikes vs. Bad Bikes":  While I don't think that there are any Good or Best Evo's, I would suggest to perspective buyers that they buy a 1990 or later due to the one piece starter and the splined clutch.  I like my '88 just fine, but when it comes to the tapered shaft clutch, I really don't trust hardly anybody to know all the peices or how to reinstall correctly.  There were a few small years where they seem to have some problem or another, but nothing that could make a bike un-buyable.  Generally, I would suggest to a perspective buyer to get the latest model bike that they can afford (one without too much modification).

Harley's Remanufacture Process.  I have not actually done this, and have not ridden a bike with a remanufactured engine.  However, Harley makes you take your bike to a dealer and have them do the job (read: expensive).  I really don't trust dealers (taking too many short cuts), and would suggest that they buy a New Evo and either install it themselves or have me do it for them (I'm cheaper than a dealer).  The problem begins when a person trashes one engine, puts a new one in and then starts it up without cleaning out the oil lines or the oil tank, and 100 crushed needle bearings that c ame outta the old engine go through the brand new engine (then they're mad).
      

From: TarheelFXR Sent: 8/19/2008 8:49 PM   Message 9 of 19 in Discussion
My '99FXR3, as does Classic's FXR2, has a mechanical speedo, the rear mounted oil filter lacked an anti-drain back feature which it did not need.
wink,
T


From: ClassicRider2002 Sent: 8/19/2008 9:27 PM   Message 10 of 19 in Discussion
JohnS....
Great job.....
Thanks, I will mull this over for a few days now....and see what other questions I might have.....
I really like learning about the specifics of the "generational" changes of the EVO.

Regards,

"Classic"


From: baggerrider Sent: 8/24/2008 2:18 PM   Message 11 of 19 in Discussion
I also believe in the 94 and later bikes the MoCo started using the shouldered motor studs as opposed the the cylindrical studs used previously, that and a few gasket changes (at least 3) from 90-93 in an attempt to eliminate base gasket leakage. When my bike was re-done in 97 (it was a 90 FXST/C) I had the barrels machined to accept the new style studs.
 

From: JohnS_Rosamond_CA Sent: 8/24/2008 3:04 PM   Message 12 of 19 in Discussion
Oh yeah, I forgot.  I think that the shouldered cylinder studs began about '93 or '94.


From: Hotham Sent: 8/24/2008 4:45 PM  Message 13 of 19 in Discussion
If you have a 1989 or earlier model, get a 1990 splined trans. mainshaft from Andrews, when you  o/h your transmission.  It is the only year that will work.  This includes 5 speed Shovelheads.  You will need a new clutch and front pulley or sprocket, of course.  A worthwhile change.


From: kenkla Sent: 8/31/2008 10:33 AM   Message 14 of 19 in Discussion
To John S.
I have a 98 fatboy,and after I had about 20000 miles on it I developed a noise in the engine. Sounded like a had an engine full of crickets chirping. The bike went to the dealership and once the problem was found the mechanic said that in 98 the evo engine was running some tighter tolerances than in previous years. The noise was coming from the crankpin. Do you know if the evo had changed tolerances on some of the internals? Thanx, 


From: randallwhitman Sent: 8/31/2008 11:55 AM   Message 15 of 19 in Discussion
Classic asked about the Rivera/Primo Pro clutch.  I have a big inch shovel that I've owned for 23 years.  I put up with the stock clutch for a few years.....they're pretty lousy......then sprung for the pro clutch.  The difference is like night and day.  HIGHLY recommended.  Smooth, doesn't grab, and great holding power.  My shovel is 103" and it holds the big torque with the "stock" spring, no problem.


From: JohnS_Rosamond_CA Sent: 8/31/2008 12:11 PM   Message 16 of 19 in Discussion
Kenkla:  There is nothing that I know of that states the 1998 bikes had a tighter tolerance.  I highly doubt that this is true as the Mo. Co. was busy with the Twin Cam roll out for the next model year and probably was no longer spending any time and energy on the Evolution engine.  Crickets chirping sounds like a heat shield, exhaust, or possibly a gas tank grommet sound.  What did your shop tell you they "fixed?"  

[ClassicRider2002]

From: kenkla Sent: 8/31/2008 12:48 PM   Message 17 of 19 in Discussion
John S.
I have the work order and they changed the flywheel assy, flywheels,replaced cylinders and pistons,sized pinion race to correct size, bearings etc. This was all done on warranty in 2002. Bike had always ran good from new except it always used oil. The first year that I had the bike, I complained about the oil consumption,so they did leak down test and compression test,and all was in spec, but they had said that if something happened down the road they would look after it,so 4 years later they lived up to there word and redid the motor.Bike has since worked very good,uses no oil. Mechanic had mentioned the tighter tolerances,and had a few 98's that had given this problem. As far as the cylinder and piston replacement,he had said the liners had moved inside the cylinder,and this was a common problem,so the new ones were also covered .The flywheel assy was changed to a FLT 23906-93B.Thanx,


From: wingie Sent: 9/8/2008 11:33 PM   Message 18 of 19 in Discussion
Interisting post.  Not that it matters, my 91 flhtp has the oil filter on the bottom. Came loose once, a cleaning and locktite and it's not come loose again.   138 & some thousand miles.
    

From: motardue Sent: 9/14/2008 2:56 PM   Message 19 of 19 in Discussion 
For what I know: 97 new stile oil pump, very similar top the S&S unit; increased flo and more reliable (so I was told).
98, minor changment in the clutch pack wich is similar to the TC88 one.