...can i expect from a cam swap, EV13, into my evo. im running cycle shack slip ons, hi flow AC, re-jetted carb with andrews accelerator pump kit. this is in an 89 FLHTC. from what ive gathered stock should be close to 56HP/77TQ?? im not really a numbers guy, prefer the "seat of the pants" test, but i am curious.
thank you in advance

 

I would say you will be more in the 60/68 range with the mods you are working with, if you base what it takes to get to 80/80, you are going to be short of your estimate goal

 

I put a 13 into my bagger to give me more grunt outa the hole & it works really good! Off the line once the clutch is engaged, I'm shifting as fast as I can when I'm twisting the wick because the power build is instant. Same fuel mileage +/-
88 FLHTC 80 ci with stock bore, new rings & gaskets. Compression is 180 both barrels.
Hatch.

 

Hatch,
I'm wrestling with my understanding of compression ratio's, maybe you can help. I always believed that a rough estimate of expected cylinder readings could be made by multiplying the "standard" value of Atmospheric pressure (14.7 psi in the states.) x the compression ratio. For an Evo with 8.5:1 I would expect about 125 psi, which of course is somewhat dependent on temperature, altitude , carbon build up and probably a ton of other "stuff".
That said "180, both barrels" is completely unexpected, though it's not the first time that I've read of numbers above 125 psi, but this certainly is at the higher end. I'd like to better understand what is reported.

Please help me out here, what am I missing? Are you running High compression pistons/heads? Or????????
Thanks.

 

No, I had my heads milled just enough to take out warpage & the same with my deck surfaces. I went with a slightly thinner head gasket as well. My pistons & bore are stock but & went with over sized rings so I could adjust them perfectly to the bore.
Add that to the larger cam & the Mikuni carb (40mm), and your compression begins to rise. I ran the bike for 1000 miles & than did the compression test while the bike was hot. Throttle wide open while doing the test is mandatory for max air flow to the cylinders.
Hatch.

 

Re-compression; My Pistons where 10:1 out of the box, I milled them down a bit to bring them closer to 9.5:1, my compression is now 220psi with stock heads and an EV-27 cam.

 

HMMMMMMMMMM........My FLHS has almost 54K on it, starts and runs well but my stock bike puts out 125 psi both barrels, tested on a hot/warm engine.

I thought that this was good, but it's starting to appear to be too low.

I may have to rethink my timetable between Freshening up the paint and accessories, and freshening up the mechanicals. I thought another season of riding it as is would provide time to really be sure of what I wanted with the engine.

When I bought the bike I had my 3-year plan:
Last year was new rubber, battery (AGM Type), battery tender cables, Spark stuff, complete flush all 3 "holes", screen clean, gas tank flush & filter, brakes, light upgrades (front and rear.), etc, all done by myself, with a thourough 50k checkup by a well regarded local Indy to get it road ready. Lot's of small things fixed up, cleaned out, and adjusted which gave me a great riding season.

My baby is old and a bit shabby looking, but I believed her to be solid.

Year 2 (Now) was planned for spruce up. I've started sanding in prep for paint touch up on some items. New wind screen, general grime clean-up and starting on parts acquisition. I just picked up a 40mm CV carb, (need a manifold, and Air cleaner) have replacment crash bars (still looking for a right rear/battery box.), mirrors, passing light bezels, highway pegs, picked up a rear rack and backrest, a matching pad for my Mustang seat, am making arrangements to get some slight seat damage repaired, etc.

And year three (next winter) was planned for performance upgrades, along with a "probably due" top end freshen up.

The plan was for the top end rebuild, with a better cam, Port-Polish for the heads, convert to a free flow CV carb set-up, with a performance dual exhaust (Yeah I know, 2 into 1 is better, but it's a bagger, and it needs duals.) These, along with some frame stiffening mods would give me the bike that I want without going stupid with the money.

Now I'm wondering if next years plans need to be moved up? Like I said, it's been reliable, and my indy is not yet concerned. He was satisfied with the leak down test, only saying that I was getting close to needing some head rework, and that my bike " Would really come alive if I did a top end rebuild that boosted compression, along with Port-Polish work at some point. But you've got time before we need to do this."

I'd like to stick to my plan, but my "numbers" now appear to be a concern.
What do experienced riders think?

 

Dont sweat the lower compression numbers. If both cylinders are close than you can rip for another season, I did. keep the oil clean & ride it!
I wanted more battery power & didn't want to pay through the nose for a bike battery so I bought a lawn tractor battery, slid it down into my left saddle bag & extended the wiring. Got way more reserve power, I can run lots of lights & I only paid $50 for the battery with a 2 year warranty!
Stick to your plan & when you finally do re build the top end, You will be shocked at the difference!
Hatch.

 

After thinking about this all night I concede, I'm sticking to my original plan. It ran fine last season, another season to get more familiar while gathering parts is probably the best approach. Thanks for the input.

Hatch, Bagger if you are willing to share, how much have you done to your bikes? Any negatives? Any handling improvements? Pulley changes?
Thanks.

irydasteelhorse, just so I don't totally steal your post, I dug up a comment made by Scott at Hillside that essentially restate's what my indy advised.

straightforward approach to increasing the output of that Evo is this;
Either re-ring, or bore to next oversize.
Valve job, along with removal of .065" from cylinder head gasket surface.
Install either a Wood 6, or an Andrews 27.
75 hp, 85 ft/lbs within easy reach.
Must've done 80-100 of these combinations, in our almost 30 years in business.
Scott

I was told 10:1 pistons, but with gas quality the way it is and will no doubt continue to deteriorate, I'm opting for less compression, and the above advice is said to yield about a 9.6:1 compression ratio.
However one other piece of advice given to me was that since I have a 1989 bike I have the older style carb, and I was also advised to go to the newer CV style. I suspect that I will also do some work on that piece to better match it up to it's intended use. But following my schedule I have "a ways to go" before getting there.

 

All good ideas. That's essentially what I have done to mine, with some minor differences. The very first upgrade was to replace that old butterfly carb with a later CV. That was a world of difference right there. I can highly recommend the CV carb/manifold swap as a great place to start on your '89.

In the years since I have added the Wood 6, heads ported and shaved .060" (stock pistons), valve job with upgraded S&S springs, Harley B lifters with adjustable pushrods, true dual exhaust and a Spyke ignition replacing the entire stock system.

In the chassis area I got the True Track kit (which includes all new motor mounts and swing arm bushings), another upgrade I can highly recommend. Also replaced the stock air shocks with Progressive 440s and put Progressive springs in the forks. This really tightened up the handling; no more of that wallowing feel when taking curves at speed.

My latest indulgence was to replace that CV that I bought used five years ago. It was still doing OK, but was starting to show signs of emerging problems. So I sent my now well-used CV carb off to Bobby Wood for some R&R, but he judged the body to be unsound. I took the plunge ($) and got a Wood CV with a new core. He took all my specs about the bike and the mods already done to it and built the carb with that in mind. The thing was like a work of art when it came out of the box, and installed it was a revelation. The day I fired it up (just a few weeks ago) was only 26 F outside, but I took it for a ride and it was just running so good that I just kept on going until my fingers were about frozen.

All of this took place over a five year stretch; the bike slowly got running better and stronger and handling better with each successive mod.