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Nacelle questions:1955 Preunit 6T #146179
08/03/08 3:13 pm
08/03/08 3:13 pm
Joined: Jan 2006
Posts: 343
Ohio
Beljum Offline OP
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Beljum  Offline OP
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Joined: Jan 2006
Posts: 343
Ohio
Triumph 6T nacelle fitment questions.

I recently bought a snipped up and smashed (read cheap!) steel nacelle assembly for my 55 6T and it turns out that it is not exactly the right one, however, I think it will be fine. I also have an aftermarket fiberglass nacelle assembly from many years ago which is the correct assembly; dimensionally it fits OK with stock handlebars and 7” diameter headlight (I’m not using the fiberglass assembly because it is crappy IMHO).

As best as I can tell, each lower fork leg nacelle is secured to the fork assembly by the lower pinch bolt and a screw into the side of the upper fork clamp. The nacelle top is secured to the upper fork clamp with the same screw and attaches to the lower fork nacelles with a few screws (sheet metal?).

Does this sound correct?

Any ideas on what type of bolt secures the assembly to the upper fork triple clamp (This would be a $1000 answer on Triumph Jeopardy)?




Per Hawaiian Tiger in a previous post:
“Pre 60 ones are called "long flash" and 60 up are "short flash" referring to the length of the chrome strip on the side.”

The flash trim that I have is of the long type (bought with the fiberglass nacelle) as opposed to the short type . I’m guessing that the difference in flash trim lengths is because of the handle bar cutout position relative to the head light, and not to the overall length of the nacelle top.
The flash trim has a nice bend to contour to the nacelle at the headlight however it does not fit well at the rear, close to the handlebar cutout.


Should the trim point bend to the contour of the nacelle top?
Or maybe it is clearance for the grommet (that I need to buy yet)?



The nacelles are the same overall length of 9.75”. The contour matches well when placed one on the other. On the steel top, the hole centerline for the damper rod is positioned forward by ¾” as compared to the fiberglass top (2.25” from back for fiberglass and 3” from back for steel). Since the top has been cut up already, I am going to relocate the damper hole to 2.25”.



I also noticed a hole for what appears to be a cable in the steel top. Should I plan on using this or is it best to just go through the handlebar grommet? Now would be a good time to plug it up if the bar grommet route is better.



I’m thinking that the previous owner of the steel nacelle opened up the handlebar cutouts to allow it to fit to an earlier model.


(cleared up some text 8-3-08)


Go for a ride on a preunit laugh

September 2010 Cuyahoga Valley Ride

'55 "The Mighty 6T", '73 Commando in boxes, '01 DR650, '90 CR250

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Re: Nacelle questions:1955 Preunit 6T #146180
08/03/08 7:43 pm
08/03/08 7:43 pm
Joined: Jun 2007
Posts: 5,557
Maui Hawaii
HawaiianTiger Online content

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HawaiianTiger  Online Content

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Joined: Jun 2007
Posts: 5,557
Maui Hawaii
1000$ question. 0BA screw, slotted type. (guess here as I don't have my parts book in front of me.) I would repair the short flash top you have and trade it for the correct one for your bike. Making this one work looks like too much work to me. Do you know if the lowers you have are for short or long flash? They are different enough to cause big problems and are not readily interchangeable. No sheet metal screws were used in Triumph's nacelle, only machine screws. Ace Classice have what you need. By now you realize the difference between the short and long flash types are due to the change in frame design and steering geometries starting in '60. None of this applies to unit 500's or 650' after '63.

The flashes are supplied flat and are gently hand formed to fit the asembled nacelle. Gently in the key word as they are easily creased by overzealous assemblers.

Tip: if you fit taper roller bearing in the headstock you will have significant problems fitting your nacelle.

Tip 2: I assume you will canabalize the lower tubes from the F/glass set for your steel set. Use only two small welds to hold them on just like the factory did. This allows some bending type adjustment when attempting to fit the nacelle leg to the fork. Use something like small wedges of plastic to center the nacelle to the lower leg with the suspension fully compressed. This is not an envious job, so take your time and be a little AR about it. When it all fits right that is its own reward.

The bodgery done to that nacelle top was probably from the DPO's attempt to use something other than Triumph supplied nacelle type handlebars. Shame, really. Cable routing holes in your top were introduced in '58, I believe. Before that the cables were routed through the h'bar grommets.
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: Nacelle questions:1955 Preunit 6T #146181
08/03/08 8:06 pm
08/03/08 8:06 pm
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
RF Whatley Online content
BritBike Forum member
RF Whatley  Online Content
BritBike Forum member
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
Quote:
Originally posted by Beljum:
Does this sound correct?
Going by my 1958 and my 1966 6T, "yes".

Quote:
Originally posted by Beljum:
Any ideas on what type of bolt secures the assembly to the upper fork triple clamp (This would be a $1000 answer on Triumph Jeopardy)?
it seems to be something on the order of a #10 (.190 dia) x 34 TPI x 3/8 long, chrome plated brass, slotted round head.

You can use a cut-down Concentric carb screw for the time being. A lot of people force a common #10-32 UNF into the hole so they can use a stainless steel screw.

Then use #4 screws to secure the front of the "flash" and the rear of the 2 nacelle halves together.


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

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: Nacelle questions:1955 Preunit 6T #146182
08/05/08 1:34 am
08/05/08 1:34 am
Joined: Jan 2006
Posts: 343
Ohio
Beljum Offline OP
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Beljum  Offline OP
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Posts: 343
Ohio
Thanks HT and RF.

You guys pointed me in the right direction (In my “55” parts list, the screws are not shown). I stumbled on this site while searching “0BA”…lotsa good info.

http://www.britishfasteners.com/threads/index.html

HT:
The additional nacelle tips are priceless.

The lowers are short flash and look to be original mates to the top. It is interesting that the lowers were cut off right in line with the bottom of the lower triple clamp. Your mention of two small welds for tube to fork alignment makes perfect sense. I puzzled over this alignment issue with the fiberglass set; there really isn’t a system to align those that I can see. The lower metal tubes are rigidly attached to the glass and aren’t really very round (Caveat emptor). Initially, I thought to cannibalize them, but after inspection, I dismissed that idea. Actually, at first, I planned on using the glass lowers with the metal top but after a night of messing around with it, I’d rather use the cut-up metal lowers.

I would have been real hesitant to bend the flashes (because of the crease) if it weren’t for your suggestion. I went ahead and tried and it works fine.

I can see how to adapt the metal lowers but I’m gonna stop working on the nacelle for now, regroup and consider advice. I will focus on WVK345’s other sheet metal which is real close to paint, and finish the nacelle in a separate paint run (there has to be some bracket somewhere that I forgot too!).

This is no problem..(as Granny use to say “If money can fix it, it ain’t a problem”).


Go for a ride on a preunit laugh

September 2010 Cuyahoga Valley Ride

'55 "The Mighty 6T", '73 Commando in boxes, '01 DR650, '90 CR250

Re: Nacelle questions:1955 Preunit 6T #146183
08/05/08 1:45 am
08/05/08 1:45 am
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
RF Whatley Online content
BritBike Forum member
RF Whatley  Online Content
BritBike Forum member
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
Quote:
Originally posted by Beljum:
The additional nacelle tips are priceless.
For everything else there's MasterCard!

laughing


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

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: Nacelle questions:1955 Preunit 6T #146184
09/07/08 7:10 pm
09/07/08 7:10 pm
Joined: Jan 2006
Posts: 343
Ohio
Beljum Offline OP
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Beljum  Offline OP
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Joined: Jan 2006
Posts: 343
Ohio
Hawaiian Tiger knows of what he speaks….

Quote:
"Making this one work looks like too much work to me. ……They are different enough to cause big problems and are not readily interchangeable.”
The more I looked at this assembly the more I saw how much different the short flash assemblies are from the long flash. Since they were already bodged, I gave it a try hoping that this assembly would be used once again. I’ll save the wordy version for the restore log; here is the quick tour and almost complete result. I’m on holiday this coming week so I might even finish paint the assembly.


I closed up the hacked handlebar holes and cut new ones using my trusty Dremel with a cutoff disc. The damper hole was relocated ¾” back too.





This is a real rough finishing shot of the extension welded to the lower nacelle and the newly rolled tube welded in place (2 places per HT..the forks compress with no interference).




The welds filed down smoother than I thought they would so very little filler was needed. This was a ton of work as HT warned but I have to admit I enjoyed it.

There most certainly is a leak free 6T reserved in heaven for the person that writes a paper on spotting the detailed differences in Triumph nacelle assemblies.


Quote:
RF.. For everything else there's MasterCard!
Whooboy lawdy lawd save me!! Ching swipe ching swipe. At least I never carry over a balance and get 1% credit towards gasoline!!


Go for a ride on a preunit laugh

September 2010 Cuyahoga Valley Ride

'55 "The Mighty 6T", '73 Commando in boxes, '01 DR650, '90 CR250

Re: Nacelle questions:1955 Preunit 6T #146185
09/07/08 9:23 pm
09/07/08 9:23 pm
Joined: Jun 2007
Posts: 5,557
Maui Hawaii
HawaiianTiger Online content

BritBike Forum member
HawaiianTiger  Online Content

BritBike Forum member
Joined: Jun 2007
Posts: 5,557
Maui Hawaii
Hat's off to you. This should be one sweet bike when you are done. As for that free 6T, that would go to Cliff Rushworth who actually did the work in reproducing the nacelle. I believe it took him several years to discover the secret to how Triumph formed them without ripping the metal to shreds. I hope he made his money back, but knowing Cliff I think he probably would have done it for free. Oh, and I think he prefers TR6's
Bill


Bikes
1974 Commando
1985 Honda Nighthawk 650
1957 Thunderbird/T110 "Flying Tiger"
Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Re: Nacelle questions:1955 Preunit 6T [Re: HawaiianTiger] #213573
09/14/08 12:35 am
09/14/08 12:35 am
Joined: Jan 2006
Posts: 343
Ohio
Beljum Offline OP
BritBike Forum member
Beljum  Offline OP
BritBike Forum member
Joined: Jan 2006
Posts: 343
Ohio
Quote:
Cliff Rushworth who actually did the work in reproducing the nacelle. I believe it took him several years to discover the secret to how Triumph formed them without ripping the metal to shreds.


Yeah…I imagine he had some head scratchin’ over that puzzle. I never met him but I would bet that he enjoyed the challenge.

One thing I noticed while hammering out the millions of dents is how malleable the steel is; much more so than the fenders or tank. I think the grade of steel that the nacelle is made from is much lower which also may explain the rust issues as well.

PS:Thanks for the compliment..It's like its all coming together at once. My goal is to paint it this month while we still have warm weather here in Ohio and bolt all the bits back together during the fall and winter.


Go for a ride on a preunit laugh

September 2010 Cuyahoga Valley Ride

'55 "The Mighty 6T", '73 Commando in boxes, '01 DR650, '90 CR250

Re: Nacelle questions:1955 Preunit 6T [Re: Beljum] #213637
09/14/08 2:06 pm
09/14/08 2:06 pm
Joined: May 2004
Posts: 181
Portland OR
Z
zgears Offline
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zgears  Offline
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Z
Joined: May 2004
Posts: 181
Portland OR
Any ideas on what type of bolt secures the assembly to the upper fork triple clamp (This would be a $1000 answer on Triumph Jeopardy)?


I got a correct nacelle screw kit from Triumph Twin Spares Ltd on eBay


53 thunderbird
Re: Nacelle questions:1955 Preunit 6T [Re: zgears] #213639
09/14/08 2:21 pm
09/14/08 2:21 pm
Joined: May 2004
Posts: 181
Portland OR
Z
zgears Offline
BritBike Forum member
zgears  Offline
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Z
Joined: May 2004
Posts: 181
Portland OR
I have a 53 6t with a smaller 6 1/2" 1956 nacelle. here are some reference pics.







53 thunderbird
Re: Nacelle questions:1955 Preunit 6T [Re: zgears] #213803
09/15/08 5:54 pm
09/15/08 5:54 pm
Joined: Aug 2001
Posts: 3,348
Michigan, USA
BONZO R.I.P. Offline
In Remembrance
BONZO R.I.P.  Offline
In Remembrance
Joined: Aug 2001
Posts: 3,348
Michigan, USA
It sounds like you have an answer to your original question , but I was stumbling through this and the thread caught my eye as I am back at dabbling with a pre unit Triumph back backburner project for a minute . thought I'd post a few observations on nacelles that I have noted while playing with this current bitsa and restoring a '56 a while back . Just from memory I recall there were at least two different sets of sheetmetal lowers for the swingarm nacelles , the big difference being the front brake cable attachment , another difference would be for the alt/gen models , alt would have a grill under the lamp and genny models had a pilot lamp , the nacelle tops were also different for these models with different switchgear layouts , some had seperate holes for cable routing , others routed with handlebars. the rigid frame models had a smaller headlamp and different angle and width , I havent seen enough of those to spot differences other than that .The later pre unit duplex models also had a different angle if I am not mistaken , so they may "fit" the earlier swingarm models but wouldnt be correct , also , tops woul not interchange . the early unit twins also had a different angle as well as using a 5 piece sheetmetal set rather than the 3 pieces , the lower spring covers changed length at least once before the bacelle was dropped from the line . The unit twin 350 and 500cc range probably had their own variations?? I have never dealt with them , and the lil' singles had yet another world of variations , looked the same but smaller . SO , if you are hunting eBay , be very very careful , most sellers probably have no idea what the parts fit, this particular styling piece could probably make a large chapter in a resto book but it is rarely covered in detail. To make things even more interesting , you might wanna look at a a vintage Jawa or CZ, they were sportin a very familiar nacelle in cast alloy???

FWIW-BONZO

Re: Nacelle questions:1955 Preunit 6T [Re: BONZO R.I.P.] #213847
09/15/08 10:26 pm
09/15/08 10:26 pm
Joined: Jan 2006
Posts: 343
Ohio
Beljum Offline OP
BritBike Forum member
Beljum  Offline OP
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Joined: Jan 2006
Posts: 343
Ohio
zgears
Thanks for the info and pics. Did you end up converting from 6 ½” to 7”? That is a great looking bike, did you figure out the front tire offset problem? If I remember, a knowledgeable guy, Paddy from the MFMCC, had a nice “how to” on setting up the front wheel.


Bonzo
Yeah..I think a whole book could be written on Triumph nacelles. The more I dig into the subject, the more I find out I don’t know. It would take the patience of a saint to research all the parts books and couple that with sales photos to come up with just a hint of what to look for. As you mentioned, there are subtle differences that can only be identified with direct measurements; photos just aren’t enough. I ran across a lot of folks that just roll the dice (me included!). I remember one poor guy that bought three nacelle assemblies on the word of the sellers “Gee…you mean they are not all the same? They sure do look it!!”


Go for a ride on a preunit laugh

September 2010 Cuyahoga Valley Ride

'55 "The Mighty 6T", '73 Commando in boxes, '01 DR650, '90 CR250

Re: Nacelle questions:1955 Preunit 6T [Re: zgears] #213906
09/16/08 5:26 am
09/16/08 5:26 am
Joined: Jan 2007
Posts: 6
Gettysburg, Pa.
Retro Rob Offline
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Retro Rob  Offline
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Posts: 6
Gettysburg, Pa.
Here's another tip. If you can't Find the obscure Triumph washer spacer thing for the nacelle tube for the fork leg, I used black foam pipe insulation from a Home DIY store (Lowes) plumbing supply. It was only a couple of bucks for an 8' piece. Just cut to size and its almost a perfect fit.


Rob G.
1955 Triumph T110
Re: Nacelle questions:1955 Preunit 6T [Re: zgears] #215529
09/26/08 2:36 pm
09/26/08 2:36 pm
Joined: Jan 2006
Posts: 343
Ohio
Beljum Offline OP
BritBike Forum member
Beljum  Offline OP
BritBike Forum member
Joined: Jan 2006
Posts: 343
Ohio
I pulled this thread back into activity just to show an example of why inexperienced restorers have to be careful.....(eBay screengrab),





This is a nacelle for a preunit 6T 5T T110 TBird...or so bobdog says. If somebody trusts the description, they sure will be surprised when they try to install this on their 6T.


Go for a ride on a preunit laugh

September 2010 Cuyahoga Valley Ride

'55 "The Mighty 6T", '73 Commando in boxes, '01 DR650, '90 CR250

Re: Nacelle questions:1955 Preunit 6T [Re: Beljum] #215541
09/26/08 4:06 pm
09/26/08 4:06 pm
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
RF Whatley Online content
BritBike Forum member
RF Whatley  Online Content
BritBike Forum member
Joined: Oct 2003
Posts: 11,138
North Georgia, USA
Correct! One has to remember that Terriers and Cubs had nacelles too!


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

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
Re: Nacelle questions:1955 Preunit 6T [Re: Retro Rob] #218608
10/13/08 9:19 pm
10/13/08 9:19 pm
Joined: Jan 2006
Posts: 343
Ohio
Beljum Offline OP
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Beljum  Offline OP
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Joined: Jan 2006
Posts: 343
Ohio
Originally Posted By: Retro Rob
Here's another tip. If you can't Find the obscure Triumph washer spacer thing for the nacelle tube for the fork leg, I used black foam pipe insulation from a Home DIY store (Lowes) plumbing supply. It was only a couple of bucks for an 8' piece. Just cut to size and its almost a perfect fit.


I just looked in my parts list..is this part the "washer, cover tube felt H420"? Does this fit onto the "Sleeve, cover tube dust collector H390"? Is the function of this washer to act as sort of a bushing between the lower fork and nacelle lower? Nice find RetroRob.


Go for a ride on a preunit laugh

September 2010 Cuyahoga Valley Ride

'55 "The Mighty 6T", '73 Commando in boxes, '01 DR650, '90 CR250


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