Documenting the rebuild of my Pro Sport 107 - motor, exhaust, etc and some WTFs

[LA_Dog]

Ok so I know I've had a few threads over the past months while I've tried to figure out WTF has been wrong with the bike, most particularly the weird issues after it got warmed up riding for 20 mins (surging, loss of power, running REALLY hot, etc). All with only 3800 miles on the bike..

Here is my rundown of events trying to troubleshoot the issue- which was not too entirely bad at first but got rapidly worse over the course of 200 further miles:

• My initial issue with bike was peeling gas tank liner. fixed that
• Next replaced the carb (XxX Super G) and all fuel lines
• Changed all oils and fluids, plugs- everyhing looked pretty normal.
• Next completely re-wired the bike and consolidated ground points (stunning wiring job if I do say so myself ) No EHC or anything, all direct wire, breakers, relays etc)
• Next replaced the coils plug wires and ignition (dual dyna coils, twin tec ignition, twisted 12mm wires)
• Also replaced tires, brakes etc since I had things apart.

At this point bike ran ok for about 100 miles. but it still felt "tubby" on the power and figured it was probably sub-optimal jetting / new ignition needed final tuning. Took it over to my local dyno shop for proper dynojet tuning. Bike gave me shit on the last few miles on way to shop- running hot, surgy.

From here it was all downhill. short version, took bike back to my usual shop and drained oil. effing metal flakes in oil. fish scale size. steel. a full quart of oil was sitting in the crank case (wet sumping). Great. :angry:

Had to tear apart motor to see what's up since all less invasive options were exhausted. Front piston had started coming apart on the lower skirt. oddly, when the bike was cold it ran ok. after 20 mins, horrible. this was like clockwork. with the piston skirt finally letting go in pieces, oil system getting clogged and wet sumping, finally gave up the ghost.

Here is WHAT I FOUND in this "factory" motor.

Front cylinder - improper honing! the cylinder was scuffing the piston skirt in two locations at the bottom of the clinder. Someone did not use a torque plate obviously. This is probably what messed up the piston skirt causing the eventual failure. also, the clearances were improper for piston to cylinder. So, the motor would get warmed up, tolerances would change, front piston would rub worse = wierd running / heat / eventual failure. Good times..

Rear cylinder was ok- it was pretty much doing all the work, which is why it was running so much hotter than the front cylinder all the time (more than just due to typical air flow blocking)

Both pistons were sitting well below the cylinder tops at TDC

Compression ratio, calculated squish and deck height COMPLETELY WTF :loony:

• The TP 107 cases are a 6" deck height from crank centerline (more than the typical 5.875 on SS cases)
• The 107 SS rods are 7.440 (standard)
• The TP 107 cylinders are TALLER at 4.885 vs typical 4.780.

SO>>>>> The Static CR on this motor was a measly 8.1:1 with the installed 0.040 head gaskets and 0.20 base gaskets (we CCd the heads and pistons)
The squish band / final deck height was a fatty 0.179 :angry:
I cannot even imagine what the corrected / dynamic compression was with the installed Crane 304 600 lift cam. Maybe 7.4 ? Yikes.

So anyway... this was definitely a "beer thirty" motor. I mean, I don't know shit about building big twins and even I would not build it this poorly. Calculator anyone??? :bang:

So- I have all new top end parts, heads are good, bottom end is good, oil pump is still good, getting crank / pistons / flywheel trued and balanced, machine work etc and will hopefully have a rip snorting dragon up and running in a few weeks.

Went with SS flat top pistons, TMan 625 cam, AV&V 650 lift Beehive springs, RB Racing LSR 2-1 pipe, given calculations should end up with a CR of 10.45:1 and squish of 0.030, with a 0.030 head gasket and 0.020 base.
The Edelbrock heads are actually VERY GOOD- they are a special run not sold to general public - 86cc chamber, 2" intake, 1.625 exhaust, CNC ported, raised intake an exhaust ports. Good for up to a 15:1 CR- I'm getting a light valve job on them and some better guides / seals.

Also picked up a Jagg oil cooler

Here are some IMPORTANT numbers for anyone looking to reuild an early 107 TP motor / you'd need these for calculating deck, squish, CR etc (this was not easy to track down):

• S&S 4" bore piston valve pocket relief - total CCs per piston +1.7cc - this is consitent on all of their current series flat top forged pistons for V100, 107, 113.
• Piston deck height 1.200 (measured from centerline of wrist pin to piston deck). This translates to .804 from top of wrist pin to piston deck
• Rod length = 7.440 (typical)
• TP Case deck height to crank centerline = 6.000 (higher than typical S&S 5.875") and oh these cases are THICK! Bomb proof- you typically only see 6" deck heights on big inch motors like 134, 145 and S&S's "SA" motors - There is also plenty of meat on the case to punch out to a 4.25 bore if needed. Way to go TP!
• TP 107 cylinder length = 4.885" (slightly longer than typical)
• The BDM-specific Edelbrock heads have an 86cc chamber

As far as gaskets for the motor- you can use any Cometic MLS kit designed for S&S 4" bore motors from top to bottom. it is all the same spec as S&S V series motors with the offset cam chest and wider stud pattern. The TP cases are patterned exactly after the SS cases / stud patterns. Your only hang up would be if you have the TP rockers and cover, you'd need the specific TP rocker gasket set. Edelbrock website still has complete 4" bore / 4 1/8" bore combo cometic MLS engine kits for $29!!! everything including the rocker covers. comes with 0.045 head gaskets FYI so you'll need to order your correct thickness from Cometic - Google for edelbrock coupon code and get free shipping too!

Good calculators to use:
RB Racing Squish Band and Deck Height Calculator
RSR Static Compression Ratio Calculator





Big Dog Pro Sport Primary information:

• Inner and outer primary case for the 2001 Pro Sport (maybe 2000/2002 as well) is an 84-93 FXR Delkron that BDM chromed, the Delkron replacement part # is D5030. This is a very good inner primary and is made of higher strength aluminum, the offset and fitment is same as regular HD FXR from that era.
• Primary gasket kit is for any 84-93 FXR from James, Cometic, HD etc. You CANNOT use the 94-up kit. The starter shaft gasket is larger on 84-93 and bolt pattern on the primary gasket is different. The large primary-to-engine O ring, main shaft seal, derby, inspection gaskets are all the same though from 84-06.
• You'll want to REPLACE your inner primary mainshaft 2-piece roller bearing with the newer sealed double roller bearing. Less play and slop in the new bearing, espeically with big inch motors. the Drag Specialties kit is like $20 and comes with bearing, seal and clip. PN 1120-0217 for all big twin Evo motors including FXR. BTW the Jim's and Rivera bearing kits are the SAME exact bearing as the DS kit and made by KML. So shop wisely don't pay more for a "name" when it is exactly the same part with a different label.

Here's a photo of the old bearing type and the updated mainshaft bearing kit - Note that installing this REQUIRES removal of your old bearing sleeve from the mainshaft. you'll need a puller to get that off:
OLD on left, NEW on right

 

[Letbigdogintocanada]

Good luck with the build,hopefully you'll be happy with the results.

 

[LA_Dog]

Thanks- it's definitely been an interesting learning experience (with a very high price of admission..lol).

 

[Letbigdogintocanada]

At the end how much is the rebuild gonna run u ??

 

[LA_Dog]

Prolly around $3k-$4k

Not including the cost of the RB Racing pipe... I just sort of fell across that deal so could not pass it up.

 

[Letbigdogintocanada]

Cool ain't cheap that's for sure:bang:

 

[MARV]

sounds like a good build.

but man thats a crazy stupid oem deck height, especially for a bike promoted as they were. understood the larger jugs were to decrease compression to limit warranty claims on the motor. looks like they should have put the extra effort into correct sizing of the pistons.

but hell your better off knowing whats in your motor anyway. i took .040 off the jugs and .060 off the heads to get over 11:1 with a 640 cam. got 5 years of hard riding out of it. she's been waiting a while on me to tear back in. maybe this year.....

 

[pknowles]

Ok so I know I've had a few threads over the past months while I've tried to figure out WTF has been wrong with the bike, most particularly the weird issues after it got warmed up riding for 20 mins (surging, loss of power, running REALLY hot, etc). All with only 3800 miles on the bike..

Here is my rundown of events trying to troubleshoot the issue- which was not too entirely bad at first but got rapidly worse over the course of 200 further miles:

• My initial issue with bike was peeling gas tank liner. fixed that
• Next replaced the carb (XxX Super G) and all fuel lines
• Changed all oils and fluids, plugs- everyhing looked pretty normal.
• Next completely re-wired the bike and consolidated ground points (stunning wiring job if I do say so myself ) No EHC or anything, all direct wire, breakers, relays etc)
• Next replaced the coils plug wires and ignition (dual dyna coils, twin tec ignition, twisted 12mm wires)
• Also replaced tires, brakes etc since I had things apart.

At this point bike ran ok for about 100 miles. but it still felt "tubby" on the power and figured it was probably sub-optimal jetting / new ignition needed final tuning. Took it over to my local dyno shop for proper dynojet tuning. Bike gave me shit on the last few miles on way to shop- running hot, surgy.

From here it was all downhill. short version, took bike back to my usual shop and drained oil. effing metal flakes in oil. fish scale size. steel. a full quart of oil was sitting in the crank case (wet sumping). Great. :angry:

Had to tear apart motor to see what's up since all less invasive options were exhausted. Front piston had started coming apart on the lower skirt. oddly, when the bike was cold it ran ok. after 20 mins, horrible. this was like clockwork. with the piston skirt finally letting go in pieces, oil system getting clogged and wet sumping, finally gave up the ghost.

Here is WHAT I FOUND in this "factory" motor.

Front cylinder - improper honing! the cylinder was scuffing the piston skirt in two locations at the bottom of the clinder. Someone did not use a torque plate obviously. This is probably what messed up the piston skirt causing the eventual failure. also, the clearances were improper for piston to cylinder. So, the motor would get warmed up, tolerances would change, front piston would rub worse = wierd running / heat / eventual failure. Good times..

Rear cylinder was ok- it was pretty much doing all the work, which is why it was running so much hotter than the front cylinder all the time (more than just due to typical air flow blocking)

Both pistons were sitting well below the cylinder tops at TDC

Compression ratio, calculated squish and deck height COMPLETELY WTF :loony:

• The TP 107 cases are a 6" deck height from crank centerline (more than the typical 5.875 on SS cases)
• The 107 SS rods are 7.440 (standard)
• The TP 107 cylinders are TALLER at 4.885 vs typical 4.780.

SO>>>>> The CR on this motor (with Crane 304 600 lift cam) was a measly 8.1:1 with the installed 0.040 head gaskets and 0.20 base gaskets (we CCd the heads and pistons)
The squish band / final deck height was a fatty 0.179 :angry:

So anyway... this was definitely a "beer thirty" motor. I mean, I don't know shit about building big twins and even I would not build it this poorly. Calculator anyone??? :bang:

So- I have all new top end parts, heads are good, bottom end is good, oil pump is still good, getting crank / pistons / flywheel trued and balanced, machine work etc and will hopefully have a rip snorting dragon up and running in a few weeks.

Went with SS flat top pistons, TMan 625 cam, AV&V 650 lift Beehive springs, RB Racing LSR 2-1 pipe, given calculations should end up with a CR of 10.45:1 and squish of 0.030, with a 0.030 head gasket and 0.020 base.
The Edelbrock heads are actually VERY GOOD- they are a special run not sold to general public - 86cc chamber, 2" intake, 1.625 exhaust, CNC ported, raised intake an exhaust ports. Good for up to a 15:1 CR- I'm getting a light valve job on them and some better guides / seals.

Also picked up a Jagg oil cooler

Here are some IMPORTANT numbers for anyone looking to reuild an early 107 TP motor / you'd need these for calculating deck, squish, CR etc (this was not easy to track down):

• S&S 4" bore piston valve pocket relief - total CCs per piston +1.7cc - this is consitent on all of their current series flat top forged pistons for V100, 107, 113.
• Piston deck height 1.200 (measured from centerline of wrist pin to piston deck). This translates to .804 from top of wrist pin to piston deck
• Rod length = 7.440 (typical)
• TP Case deck height to crank centerline = 6.000 (higher than typical S&S 5.875") and oh these cases are THICK! Bomb proof- you typically only see 6" deck heights on big inch motors like 134, 145 and S&S's "SA" motors - There is also plenty of meat on the case to punch out to a 4.25 bore if needed. Way to go TP!
• TP 107 cylinder length = 4.885" (slightly longer than typical)
• The BDM-specific Edelbrock heads have an 86cc chamber

As far as gaskets for the motor- you can use any Cometic MLS kit designed for S&S 4" bore motors from top to bottom. it is all the same spec as S&S V series motors with the offset cam chest and wider stud pattern. The TP cases are patterned exactly after the SS cases / stud patterns. Your only hang up would be if you have the TP rockers and cover, you'd need the specific TP rocker gasket set. Edelbrock website still has complete 4" bore / 4 1/8" bore combo cometic MLS engine kits for $29!!! everything including the rocker covers. comes with 0.045 head gaskets FYI so you'll need to order your correct thickness from Cometic - Google for edelbrock coupon code and get free shipping too!

Good calculators to use:
RB Racing Squish Band and Deck Height Calculator
RSR Static Compression Ratio Calculator

I have read this post twice now, guess I need to read it one more time

 

[LA_Dog]

Cool ain't cheap that's for sure:bang:

Yup never is...

 

[LA_Dog]

sounds like a good build.

but man thats a crazy stupid oem deck height, especially for a bike promoted as they were. understood the larger jugs were to decrease compression to limit warranty claims on the motor. looks like they should have put the extra effort into correct sizing of the pistons.

but hell your better off knowing whats in your motor anyway. i took .040 off the jugs and .060 off the heads to get over 11:1 with a 640 cam. got 5 years of hard riding out of it. she's been waiting a while on me to tear back in. maybe this year.....

Yeh I was quite shocked with seeing this in the top end- particularly the bad honing job. Glad to hear your engine upgrade is treating you well :up:

 

[liferider]

What I did when I rebuilt my EVO motor on my Ultra was, get on the phone and call Wiston Salem and talked to Kendall Johnson. He was extremely nice, explained very simply why to do this and not that. What was I looking for on the final product and then gave me a price to do the work. I bought my cam, pushrods, pistons and power commander from him and he decked my heads, did a polish on the exhaust and intake air and redid the valve guides. It was his recommendations to leave the smaller valves to increase torque. Phone calls are usually free. And Kendall is the King of motors hands down! End result was a bad ass 98hp Evo motor that was done correctly and is very dependable!

 

[LA_Dog]

What I did when I rebuilt my EVO motor on my Ultra was, get on the phone and call Wiston Salem and talked to Kendall Johnson. He was extremely nice, explained very simply why to do this and not that. What was I looking for on the final product and then gave me a price to do the work. I bought my cam, pushrods, pistons and power commander from him and he decked my heads, did a polish on the exhaust and intake air and redid the valve guides. It was his recommendations to leave the smaller valves to increase torque. Phone calls are usually free. And Kendall is the King of motors hands down! End result was a bad ass 98hp Evo motor that was done correctly and is very dependable!

Thanks bud- much appreciated. Yeh it is always nice when the "masters" are willing to share their hard earned knowledge and guidance. I ended up in a similar path- My biggest snag was with the BD edelbrck heads. No one really knew much about them or what to do with them, and there are ZERO specs on the internet. Not even Edelbrock knows about them anymore. Talked with Branch, Mackie, Revolution, TP, S&S, Bob Wood, AV&V, T-Man, exchanged a few messages here with John S, and other members here throughout my various threads / posts. Everyone has been REALLY helpful and I am sincerely appreciative for the knowledge shared.

I received the most valuable insight from Wink Eller in regards to the BD edelbrock heads. That is one cool dude, and really knows his stuff. :2thumbs: I was about to toss the heads for a set of S&S and he talked me out of it. told me exactly what I needed to do, what not to do, and what to expect with these specially designed heads.

So where I'm at now is with all parts needed, waiting for machine work to get done and also polishing up some of the parts. Hopefully will start on re-assembly next week. I'm also getting the tins re-painted - I kinda got over the flat satin black thing and the last place that recently re-painted them did a damn horrible job anyway. Going with a metallic gloss black with slight color-shifting clear coat.

 

[Letbigdogintocanada]

Keep us posted and iam curious on how that set up is going to work.

 

[LA_Dog]

^^ Definitely. I just had all the motor parts cryo treated (along with my favorite pocket knife - they threw it in the cryo batch w/ my parts). that is some bad ass shit, I just re-sharpened it and the thing holds an edge like a scalpel.

 

[chacha]

Great write up. Thanks!

 

[Five Five]

Good write up LA DOG... love the tech language, and learned a few things ....

 

[liferider]

^^ Definitely. I just had all the motor parts cryo treated (along with my favorite pocket knife - they threw it in the cryo batch w/ my parts). that is some bad ass shit, I just re-sharpened it and the thing holds an edge like a scalpel.

I cryo'ed my rifle barrel a few yrs back to releave stress points

 

[LA_Dog]

Good write up LA DOG... love the tech language, and learned a few things ....

Thanks brother- Just trying to give back to the forum!

 

[LA_Dog]

I cryo'ed my rifle barrel a few yrs back to releave stress points

Yep I'm going to bring in all my stuff and have it done - barrels, slides, knives etc. The more stuff you bring in for the batch the cheaper it is per piece, since they charge by the pound of nitrogen used. And it really isn't that expensive anyway.

 

[LA_Dog]

Updated my first post to include identification and part numbers for the 2001 Pro Sport primary case, gasket set, bearings. Really hard to find this info so well worth documenting.