6 Speed for 1988 FLHTC
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Tourer
Joined: May 2006
Posts: 256
Likes: 7
From: Western NC
6 Speed for 1988 FLHTC
I have been looking at the 107 in a bagger thread and I am really considering a six speed for my bike, but all I see are for 1990 and up. What is the difference in a 1988 and 1990? Does anyone know if the Ultima 6 speed gearset can be made to work in my 88?
Road Warrior
Joined: Dec 2007
Posts: 1,854
Likes: 20
From: Eagle River WI
Your clutch is different Your trans main shaft is tapered After 90 HD went to splines Totally different as well as the electric start system I'd keep it 5 speed of course I thought 4 speeds were enough I see if they make a 6 speed cluster for your style
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Tourer
Joined: May 2006
Posts: 256
Likes: 7
From: Western NC
Thanks sqdeal, I just went online and looked at it. Nearly double in price to the Ultima
I have never had any dealing with rev-tech parts, whats opinions on their parts? Makes me think 5 speed ain't so bad, the ol girl seems to be reving pretty good at 75mph it would be nice to have that extra gear on long trips sometimes tho.
I have never had any dealing with rev-tech parts, whats opinions on their parts? Makes me think 5 speed ain't so bad, the ol girl seems to be reving pretty good at 75mph it would be nice to have that extra gear on long trips sometimes tho.
Road Warrior
Joined: Dec 2007
Posts: 1,854
Likes: 20
From: Eagle River WI
I never had a problem on Revtech stuff I did get one recall on one of their early 6 speed tranys 2003 No problem they did the rebuild no charge I run 2 of their 5 speeds in my customs and so far ( knock on wood ) no griefs 5K one one 7K on the other but again do you really need an overdrive??
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
I recently swapped my 1990 motor for an S&S 107, but left everything else as standard (except beefed up clutch spring). First dyno tests are just over 100 each for power and torque, so far bigger numbers than stock. At my 24mph/1,000rpm I would have to ride at around 135mph in fifth gear to reach peak power! Raising gearing with a six speed box would increase that to over 150mph.
Even with a 107 inch engine, these are plainly ridiculous speeds, but help to make the point that the current habit of raising gearing has questionable benefit. If your bike is close to stock or only mildly modified, the times when you will be able to use sixth are going to be few. You are likely to be selecting sixth, then back down soon after, in other words not enjoying the benefit of these lovely lazy engines. Give'em too much work to do and the bike will lose its character.
I believe the current six speed factory bikes are only intended to lower noise levels for passing noise tests, not to provide us with any real improvement.
Tourer
Joined: May 2008
Posts: 442
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From: High Desert of So Cal
My 91 and 05 both have the five speed. The difference between them and the 07 is the newer bike has "longer legs". The advantages of the 6 speed are lower revving motor during freeway speeds, less vibration, better fuel economy. Anything over 60mph and you'll be in 6th...unless of course you're hot rodding. Having said this I would not convert the tranny on any of my bikes, especially the evo. Bigger motor, sure, but not the tranny. I think it would take away some of the evo-ness. Just my 2 cents.
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HDF Community Team
Joined: Dec 2005
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From: NC USA
Before I'd pay for one, I'd want to see it or have a photo of the mainshaft to be CERTAIN it was for the tapered clutch hub, otherwise it'd be BIG BUCKS for the overall swap. The Revtech in JP catalog shows a splined shaft...
A lot of TC-88 riders say they aren't that keen on the factory 6-speed. Even at high speed, they're sluggish in top gear acceleration and running in 5th is noisy (worse than a 5 speed would be in 4th)
I've never ridden an overdrive tranny, but did a 7000 mile ride over Labor Day. At least 1/3 of the trip was at 78mph + and running thousands of high-speed miles, day after day, proved to me that I definitly DO NOT need or want one. My bike was very happy
A lot of TC-88 riders say they aren't that keen on the factory 6-speed. Even at high speed, they're sluggish in top gear acceleration and running in 5th is noisy (worse than a 5 speed would be in 4th)
I've never ridden an overdrive tranny, but did a 7000 mile ride over Labor Day. At least 1/3 of the trip was at 78mph + and running thousands of high-speed miles, day after day, proved to me that I definitly DO NOT need or want one. My bike was very happy
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Cruiser
Joined: Apr 2007
Posts: 181
Likes: 0
From: Chesapeake, VA
FWIW I swapped out everything but the engine on my 87 Heritage last summer in order to put in a 6 speed. I was having starter, clutch and tranny issues. At the time I was able to get a 6 speed for $500 shipped which was cheaper than a 5 speed.
Over a couple of months I picked up everything I needed on ebay for cheap and did the swap over a couple of weekends. Aside from some minor fitment issues it was pretty straight forward. On softails, all primaries to 05 fit all drivetrains at least down to 87 and I've heard even shovels are compatible. I assume there is good compatibility on touring frames too.
I figure I have around $1100 into the swap after I sold my old stuff on ebay.
6 speed rocks on the flats but I downshift to 5th on upgrades (and sometimes fourth as I went to 25/36 primary and 32/65 secondary gearing. Plan to put a 70T rear on this winter). Can cruise comfortably at 75 mph and getting up into the 80's is no problem. With my 5 speed vibes at 70+ were a limiting factor.
Haven't seen better MPG though. I figure my engine is working harder through the gearing so uses same fuel. Hoping the switch to 70T rear will help.
One of these days the evo will need a rebuild and I will stroke it. Clutch and starter now work great too.
Good Luck
Deet
Over a couple of months I picked up everything I needed on ebay for cheap and did the swap over a couple of weekends. Aside from some minor fitment issues it was pretty straight forward. On softails, all primaries to 05 fit all drivetrains at least down to 87 and I've heard even shovels are compatible. I assume there is good compatibility on touring frames too.
I figure I have around $1100 into the swap after I sold my old stuff on ebay.
6 speed rocks on the flats but I downshift to 5th on upgrades (and sometimes fourth as I went to 25/36 primary and 32/65 secondary gearing. Plan to put a 70T rear on this winter). Can cruise comfortably at 75 mph and getting up into the 80's is no problem. With my 5 speed vibes at 70+ were a limiting factor.
Haven't seen better MPG though. I figure my engine is working harder through the gearing so uses same fuel. Hoping the switch to 70T rear will help.
One of these days the evo will need a rebuild and I will stroke it. Clutch and starter now work great too.
Good Luck
Deet
Last edited by IronButt62; Jan 7, 2009 at 12:14 PM. Reason: added stuff
Tourer
Joined: Jul 2007
Posts: 260
Likes: 1
From: Missoula MT
Last spring I put a 2004 gearset in my 89 softail, so it is about the same as what you want to do. Once you are set up for a splined mainshaft, you can put about any gearset in your tranny. I used a 90-93 clutch basket, you will also need for that style clutch: friction plates & steels, pressure plate, release plate, diaphram spring, spring seat, clutch hub & nut and a couple of snap rings. I also replaced my primary chain and motor sprocket, they were about due anyway. I made a tool to compress the clutch spring for assembly, ya gotta have it or buy one. Your clutch pushrod will work fine. I did not have to make any changes in the starter area, that all works fine. I used the 04 shift forks and the 89 shift drum. I also replaced the shifter pawl with a JIMS unit. It is all pretty much a bolt in swap. I got most of my parts off eBay, did it WAY cheaper than buying from the stealer. I still have my old gearset and clutch parts that I am going to sell one of these days. Hope this helps, if I can be any more help let me know. Good luck. JMHO, YMMV, etc.
Bob
Bob
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