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Pre-unit transmission gremlins (or just the user) #83892
09/26/05 2:30 pm
09/26/05 2:30 pm
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
scootermcrad Offline OP
BritBike Forum
scootermcrad  Offline OP
BritBike Forum
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
I have a Pre-unit with a 4-speed slick shift transmission. This weekend I finally got a chance to take out of my neighborhood and get in the wind a little (not registered yet :p ). It's doing some strange things when shifting...

First, I have a hard time getting it in neutral sometimes. Not too bad, but noticable.

Second: When I'm shifting from second to third it doesn't act right. It feels like I'm going back to First??? HUH??? The RPMs spike and the bike slows/lags big time. confused

Is this just lack of understanding the slick shift transmission, or is something going on here? Maybe it's just me, the user, but it doesn't seem right to me.

Any insight would be appreciated!
Thanks!


ScooterMcRad
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Re: Pre-unit transmission gremlins (or just the user) #83893
09/26/05 3:19 pm
09/26/05 3:19 pm
Joined: Oct 2003
Posts: 11,168
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,168
North Georgia, USA
There are no big differences in the 4-speed of a pre-unit and the last 4-speeds of the 1970-1971 models. So we do the same fixes...

We run 90W gear oil (despite what your period manual says), we adjust the clutch correctly, and we run the thinnest lube the primary will accept.

I would never depend upon the slick shift for good shifting. It's just a marketing name, and a bad one at that. Go ahead and use the cluch lever on every shift.

Some of the old shift cam plates had a neutral between each gear and so the usual complaint was "it's too easy to find neutral". So quitcherbellyachin. bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: Pre-unit transmission gremlins (or just the user) #83894
09/26/05 4:00 pm
09/26/05 4:00 pm
Joined: Aug 2001
Posts: 96
Northern Virginia / USA
B
Brent Pinkstaff Offline
BritBike Forum
Brent Pinkstaff  Offline
BritBike Forum
B
Joined: Aug 2001
Posts: 96
Northern Virginia / USA
scooter,

Not being able to find neutral is generally a clutch thing. Make sure you plates are straight, not sticking, and adjusted correctly.

Definately go with the upgrades that redneck suggested. They are well worth the effort.

As far as your third gear issues are concerned, I don't really have a suggestion. It is not possible to mismatch the parts that much and still get the box together.

The 'slickshift' bit of the gearbox won't effect your shifting if you use the clutch. I would be surprised if the mechanism is still active. Most of them were removed (simple to do). As a matter of fact, out of all of the slickshift bikes I have owned, only one still had it in there! (ironically it is the one I currently use as my daily bike)


Brent Pinkstaff - Falls Church, VA
'38 5T
'46 T100
'48 5T
'50 TR5
'50 6T
'58 TR6/A
'59 T120
Re: Pre-unit transmission gremlins (or just the user) #83895
09/26/05 4:35 pm
09/26/05 4:35 pm
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
scootermcrad Offline OP
BritBike Forum
scootermcrad  Offline OP
BritBike Forum
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
Hmmm... thanks for the tips. More info than needed, but things I will definitely think about for the future. I'm thinking of pulling it of the frame this winter and polishing the cases, covers and maybe I can make the upgrade at the same time. What are the part numbers for what I need to order to make the conversion and what should I expect for machining work? Any "how-to" articles I can reference when I do go to do this?

As far as the shifting thing, I think the mechanism is still in there... I will use the clutch anyway though. I know it's not possible to mis-match parts in that tranny, that's why I can't figure out what kind of weird voodoo is going on.... probably just need to mess around with it more. I suspect user error!! laughing :p

Thanks for the tips guys. Any more info available on the "not-so-slick-shift" transmission would be great.


ScooterMcRad
Re: Pre-unit transmission gremlins (or just the user) #83896
09/27/05 1:19 am
09/27/05 1:19 am
Joined: Oct 2003
Posts: 11,168
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,168
North Georgia, USA
I'll lay money on a broken shifter spring. New spring: $2.40. Installation: $10.00. Great shifting: priceless. laughing


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: Pre-unit transmission gremlins (or just the user) #83897
09/27/05 7:49 am
09/27/05 7:49 am
Joined: Sep 2005
Posts: 1,489
South East England
G
Graham Ham Offline
Private sponsor
Graham Ham  Offline
Private sponsor
G
Joined: Sep 2005
Posts: 1,489
South East England
Hi,

I have owned and ridden a number of 'slick-shift' Trumpets, currently have a '55 with one on.

Have never managed to get ANY of them working satisfactorily, and tend to agree with the consensus here - stick to clutch !

:0)


Good judgment comes from experience, but the most memorable experiences tend to come from bad judgment!


http://www.panther-publishing.co.uk/default.asp?contentID=18

Re: Pre-unit transmission gremlins (or just the user) #83898
09/27/05 9:43 am
09/27/05 9:43 am
Joined: May 2003
Posts: 48
coventry
M
mike750triton Offline
BritBike Forum
mike750triton  Offline
BritBike Forum
M
Joined: May 2003
Posts: 48
coventry
info so far i can't add to but the slick shift does work great if the clutch is set up right and the push rod is correct length. i've used one for years and fool people at traffic lights into thinking i'm not ready for the off when they change as i still have just one hand on the bars (at the throttle end). gently open throttle and lower gear lever and we're off. it's great for short shifting too. people found it weird when changing gear when the lever operated by itself, a lot more couldn't be arsed setting the clutch up, so it was discontinued


my 2 bobs worth
Re: Pre-unit transmission gremlins (or just the user) #83899
09/27/05 2:55 pm
09/27/05 2:55 pm
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
scootermcrad Offline OP
BritBike Forum
scootermcrad  Offline OP
BritBike Forum
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
I went for a ride last night and messed around with shifting a little more. I used the clutch going into 3rd and everything seemed fine. User error is the hardest thing to diagnose!! :p

I got to thinking more about my clutch though... I have a feeling it's slipping just a little bit. I got to talking with a buddy last night and he made a comment that after he got his clutch all installed someone told him that he should have soaked each of his plates in oil for 10-minutes before installing. Is this true? I didn't do this either. I put the new plates right in out of the box. I have to pull the primary cover again because I have a little leak, maybe I can check this out when I have it off. What do you guys think?


ScooterMcRad
Re: Pre-unit transmission gremlins (or just the user) #83900
10/02/05 3:16 am
10/02/05 3:16 am
Joined: Aug 2001
Posts: 6,892
Vermont
Jon W. Whitley Online content

BritBike Forum member
Jon W. Whitley  Online Content

BritBike Forum member
Joined: Aug 2001
Posts: 6,892
Vermont
Scoot,

I just installed brand new clutch plates in the '57 Thunderbird,and I soaked them in 20wt fork oil for a few minutes each plate.Then I drained and dabbed the excess off and installed them as well as scuffing up the steel plates with 220 grit.I also checked the plates on a flat glass surface to make sure they weren't warped, everything checked out.We'll see how it works! beerchug


Jon W.


1957 6T Thunderbird 650
1968 T100R Daytona 500
1971 TR6R Tiger 650
1970 BSA A65F 650
1955 Tiger 100 - Project

Re: Pre-unit transmission gremlins (or just the user) #83901
10/03/05 3:57 pm
10/03/05 3:57 pm
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
scootermcrad Offline OP
BritBike Forum
scootermcrad  Offline OP
BritBike Forum
Joined: Apr 2005
Posts: 441
Huntington Beach, CA
Thanks Jon! When I take the primary cover off again I'll do all that. Sounds like a good plan!
bigt


ScooterMcRad
Re: Pre-unit transmission gremlins (or just the user) #83902
10/03/05 11:16 pm
10/03/05 11:16 pm
Joined: Oct 2003
Posts: 11,168
North Georgia, USA
RF Whatley Offline
BritBike Forum member
RF Whatley  Offline
BritBike Forum member
Joined: Oct 2003
Posts: 11,168
North Georgia, USA
Put as much oil on as you like. The spinning clutch slings out all the excess in the first minute. The light weight oil in the primary should just barely have the chain dipping into it. Check it with a flash light. Twice.

bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes

Moderated by  John Healy 


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