Looking for guidance and wisdom on upgrades
Thread Starter
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2nd Gear
Joined: Aug 2022
Posts: 6
Likes: 1
From: Minnesota
Looking for guidance and wisdom on upgrades
I have a bone stock 98 FLHTC with a hair over 50k on it and I'd like to bump up the power!! I can work on it no problem, but when it comes to mixing and matching and changing things I get a little lost. I was thinking KB 9.5 to 1 pistons, Andrew's ev27 cam, just some slip on pipes for now, and a little more open air filter. Then rejet it. Oh, and replace the cam bearing. Is this a good combo?? Will the engine be reliable? What else will I need? Any and all help would be appreciated!!!!!!
HDF Community Team
Joined: Jun 2006
Posts: 12,776
Likes: 2,607
From: san antonio
Many of us are twin cam guys but there are a few Evo guys here as well. Be patient, they will weigh in. It would have helped get their attention if you had included model year in the subject line.
Road Captain
Joined: Mar 2020
Posts: 659
Likes: 361
From: Sierra foothills
No longer have an Evo powered bike but have owned 3. So...
New ignition module
Dynatek. Dyna 2000i works well
While you have heads off, add compression releases. Never hurts
Before assembly, measure, measure, measure
Too bad the Crane Fireball 310-2 is no longer available. Did a few back in the 90's for myself and a couple friends. That was a good one at 9.2 - 9.5cr, Fxr's and Dyna's
Andrews 3 is also similar to the 27. Was popular back then
New ignition module
Dynatek. Dyna 2000i works well
While you have heads off, add compression releases. Never hurts
Before assembly, measure, measure, measure
Too bad the Crane Fireball 310-2 is no longer available. Did a few back in the 90's for myself and a couple friends. That was a good one at 9.2 - 9.5cr, Fxr's and Dyna's
Andrews 3 is also similar to the 27. Was popular back then
Grand HDF Member
Joined: Aug 2008
Posts: 3,601
Likes: 9,915
From: Florida's gorgeous East coast
Jrwags,
You're on the right track. Frankly, I'm not sure about the piston swap. Noticeable improvement of a bone stock EVO can be found with the EV27 cam, plus the exhaust and air cleaner swap.
It's an "Air Pump"...let it breath..! Rejet the carb and cam bearing too, while you're in there.
If it were mine, I'd do those plus the ignition and see how I liked it before pulling the heads. If you want to pull the heads...have .050" milled off. That was a common modification ( plus the others I mentioned) to really "perk up" the EVO's without affecting reliability, or costing much.
You're on the right track. Frankly, I'm not sure about the piston swap. Noticeable improvement of a bone stock EVO can be found with the EV27 cam, plus the exhaust and air cleaner swap.
It's an "Air Pump"...let it breath..! Rejet the carb and cam bearing too, while you're in there.
If it were mine, I'd do those plus the ignition and see how I liked it before pulling the heads. If you want to pull the heads...have .050" milled off. That was a common modification ( plus the others I mentioned) to really "perk up" the EVO's without affecting reliability, or costing much.
Road Master
Joined: Jun 2019
Posts: 952
Likes: 528
From: Richmond TX
Evo's like compression, but you don't necessarily have to change pistons. I had my heads shaved on my '91, .040" I believe. I ran the stock exhaust header with Cycle Shack side dumps and a stock cam. I spent a great deal of time on setting up the carb, and I indexed the plugs ( install different thickness washers to get the open side of the plugs to face the incoming charge). I got 69 HP on a dyno, can't remember the torque number. I had the heads done at 24k miles. Years later I sold the bike to one of my sons and this year he sold it to one of my grandsons. It's got about 105k miles on it. A hydraulic lifter failed around 90k miles but that's it. It's still running well on the stock pistons and the valve job that was done while the heads were shaved. I'm riding to Maggie Valley in a couple of weeks to meet up and ride with my two sons and my riding grandson. He'll be riding it about 1000 miles to get there.
Just remembered, if you decide to shave the heads, the intake manifold has to be cut a small amount for it to line up properly.
Just remembered, if you decide to shave the heads, the intake manifold has to be cut a small amount for it to line up properly.
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Thread Starter
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2nd Gear
Joined: Aug 2022
Posts: 6
Likes: 1
From: Minnesota
Jrwags,
You're on the right track. Frankly, I'm not sure about the piston swap. Noticeable improvement of a bone stock EVO can be found with the EV27 cam, plus the exhaust and air cleaner swap.
It's an "Air Pump"...let it breath..! Rejet the carb and cam bearing too, while you're in there.
If it were mine, I'd do those plus the ignition and see how I liked it before pulling the heads. If you want to pull the heads...have .050" milled off. That was a common modification ( plus the others I mentioned) to really "perk up" the EVO's without affecting reliability, or costing much.
You're on the right track. Frankly, I'm not sure about the piston swap. Noticeable improvement of a bone stock EVO can be found with the EV27 cam, plus the exhaust and air cleaner swap.
It's an "Air Pump"...let it breath..! Rejet the carb and cam bearing too, while you're in there.
If it were mine, I'd do those plus the ignition and see how I liked it before pulling the heads. If you want to pull the heads...have .050" milled off. That was a common modification ( plus the others I mentioned) to really "perk up" the EVO's without affecting reliability, or costing much.
I have a leak in the front base gasket so I have to dig down to the piston and thought why not up the compression a hair. And a mill job on the heads.
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Grand HDF Member
Joined: Aug 2018
Posts: 4,126
Likes: 2,117
From: W. MI.
When you get all done and its where you want it. Vent to the atmosphere. Before every ride let it warm up. Not doing so is tough on base gaskets. Little things are inexpensive and make a big difference.
Thread Starter
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2nd Gear
Joined: Aug 2022
Posts: 6
Likes: 1
From: Minnesota
When I rode it home my left leg on my chaps was well oiled!!😅😅 I learned about warming them up after replacing the base and head gaskets on my 92 sporty. 5 mins makes a difference!!!! 🤘🤘