TC88 engine upgrades
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Novice
Joined: Aug 2014
Posts: 16
Likes: 4
From: UK
TC88 engine upgrades
Hi guys, I'm planning on making an upgrade to my engine and wanted to sanity check first.
I have a Road King TC88 with:
Hi Flow Filter
2:1 pipe
Thundermax Autotuner.
Andrews TW26a Cams
I am intending to add a set of ported heads (S&S), it has to be these due to reasons too boring to go into.
I don't really want to go for a big bore kit as I believe that there is enough 'potential' in the stock displacement with these additions.
So, am I on the right track, or is this build not going to work?
Comments please!
I have a Road King TC88 with:
Hi Flow Filter
2:1 pipe
Thundermax Autotuner.
Andrews TW26a Cams
I am intending to add a set of ported heads (S&S), it has to be these due to reasons too boring to go into.
I don't really want to go for a big bore kit as I believe that there is enough 'potential' in the stock displacement with these additions.
So, am I on the right track, or is this build not going to work?
Comments please!
Last edited by TikTok; Nov 22, 2014 at 10:53 AM.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
Hello old chap, UK S&S owner here! To make your ported heads work well and give you a decent return on your investment will require a boost in compression ratio, over stock. To be blunt it would be a waste of money buying heads and not increasing CR, the easy and economical way of doing that being to also bore out to 95". You will also need a change of cam IMHO.
Whereabouts are you based? If you are buying heads from an S&S dealer you should be able to get advice on a complete package that will all work together.
Whereabouts are you based? If you are buying heads from an S&S dealer you should be able to get advice on a complete package that will all work together.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
heads are coming off- changing cylinders and pistons is a marginal cost at this point.
you could increase displacement and/or compression
best to look at a package in which all the parts work with your heads- spell that "S&S"
mike
you could increase displacement and/or compression
best to look at a package in which all the parts work with your heads- spell that "S&S"
mike
Last edited by mkguitar; Nov 21, 2014 at 01:03 PM.
Seasoned HDF Member
Joined: Jun 2012
Posts: 6,154
Likes: 2,561
From: CT/FL
Do S&S heads have the same chamber volume as stock TC88 heads?
Here's what you have to think thru: ported heads can flow more air than stock heads, but port velocity suffers at low air flow (low RPM). This means you can and should be running at higher RPMs or bigger displacement. Keeping stock displacement, the camshafts should be chosen to make power in that higher RPM range. CR should be chosen to support those camshafts. That will require either shaving the heads or cylinders or new pistons. If new pistons you might as well get new bigger bore cylinders. Now you need to re-look at your camshaft and CR... and so we go down the high performance rabbit hole...
ps Gearing changes may also be required on a heavy bike to be happy with a high RPM camshaft.
Here's what you have to think thru: ported heads can flow more air than stock heads, but port velocity suffers at low air flow (low RPM). This means you can and should be running at higher RPMs or bigger displacement. Keeping stock displacement, the camshafts should be chosen to make power in that higher RPM range. CR should be chosen to support those camshafts. That will require either shaving the heads or cylinders or new pistons. If new pistons you might as well get new bigger bore cylinders. Now you need to re-look at your camshaft and CR... and so we go down the high performance rabbit hole...
ps Gearing changes may also be required on a heavy bike to be happy with a high RPM camshaft.
Tourer
Joined: Apr 2012
Posts: 344
Likes: 4
From: California
Sounds like you have answered your own question. Do you have an idea of what you want from the upgrades? Horsepower, torque? Dependability? I wasn't sure what I wanted and got tired of reading on the Internet so I went and talked to an independent who came highly recommended. I basically let him make the decisions told him I wanted 95 hp and over 100 torque. I wanted a motor that thumped but wasn't an over cammed pos that wouldn't idle.
He built me a clean dependable motor with great torque.
He built me a clean dependable motor with great torque.
Road Warrior
Joined: Mar 2010
Posts: 1,290
Likes: 7
From: D/FW Texas
if you're gonna invest in S&S heads, spend the small extra and get their 97" big bore kit. And perhaps look at their gear drive EasyStart cams. My 06 TC88 runs strong thanks to S&S parts.
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Outstanding HDF Member
Joined: Jan 2008
Posts: 3,328
Likes: 15
From: Pacific Northwest
If you don't go with a 95" you'll always wish you had. After all the heads are already off and it's a matter of buying pistons and some machine work.
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Road Warrior
Joined: Jul 2012
Posts: 1,521
Likes: 185
From: Ft Myers FL
'05 RK.....did the following and very happy...
Upgraded to the '95
Ported S&S heads with the S&S 585 Cam
New heavier springs/ lifters
New hydraulic lifters
this was done after stage 1.....
I wanted to keep up with my fellow riders on those long stretches of highway.
Attached is my map.
Upgraded to the '95
Ported S&S heads with the S&S 585 Cam
New heavier springs/ lifters
New hydraulic lifters
this was done after stage 1.....
I wanted to keep up with my fellow riders on those long stretches of highway.
Attached is my map.
Last edited by giacomo56; Nov 21, 2014 at 09:00 PM.
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