FT: Frame (Twin) Grade of Stainless Steel

[Monkeypants]

I just checked the Spares Co. and found the F47/3 in ss only.
My 47 Rapide required a new F47/3 as the old steel one was cracked part way through and hanging together by a bit of skin! This was not long after bouncing down the Sulby Straight wot, amongst other silly adventures.
I replaced it and the rear bolt assembly with the club ss versions. Those have been in place for twelve years now.
I removed them last winter in order to do some headwork. Both look as new.
My experience with SS fasteners, going back to Marine work in the 70s, has been very good.



Glen

 

[Herman-Handlebars]

S/less 303 and 304 will eventually rust as some of the fasteners did with ten years of every day commuting use on my Velo in the 1980's (it rains a lot where I live), 316 is much better in this regard. The 300 series are austenitic types and non-magnetic. For load bearing applications, a martensitic type in the 400 series is a better choice - like the front fork and wheel spindles that the club supplies, which I am guessing are likely 420? These will have some attraction to a magnet.

Gerry

Thanks Gerry, I didn't realize 303 was able to rust. So its a trade off against machinability and rust resistance
Thanks for your help

 

[Bill Thomas]

Thanks, they were from Norman. Really pleased with all the parts. Look the part, and like you say they should help with getting it to breathe well! Are they walt phillips fuel injectors? I have read they were all the rage at one point in the 60-70s

They were a copy of Wal Phillips, Only much longer , Brother Ron and I made them,
After I had rebuilt my Twin, I had no money for Carb's, So we thought we would have a bit of Fun !,
We made one for my Goldstar in steel, To see if it worked !,
Then made these in Alloy, They were not perfect, But I went to the Isle Of Man on holiday with them.
Gave us a boost, That they worked !.
I do love to play, Still do.

 

[timetraveller]

The fastest times I ever did were with Wal Phillips fuel injectors, 140 mph at the end of a half mile sprint at Long Marston, bike ridden to and from the meeting with girl friend on the back. However, I would not recommend going down that route again. It was the only way I could afford to get an inch and three eights inlet tract. I bought two, inch and a quarter injectors, bored them out and got one of the chaps at work to make two new butterflies. However, without float chambers they are susceptible to changes in the head height of the fuel. These days there are easier way to get that size inlet tract but there might be restrictions on what you can use depending upon what class you race in. Good luck with it all.

 

[Nigel Spaxman]

I always use Never-seez on stainless nuts. I replaced the FT47/3 and ET154 with a 1/2" grade 5 bolt, and nylock nut. I can't figure out why this system is not better than the original one! Maybe it is a tiny bit heavier. It's pretty much covered by the tank. No one has noticed the lack of originality. I have UNF nuts bolts and studs holding the cylinder heads on to.

 

[Herman-Handlebars]

I just checked the Spares Co. and found the F47/3 in ss only.
My 47 Rapide required a new F47/3 as the old steel one was cracked part way through and hanging together by a bit of skin! This was not long after bouncing down the Sulby Straight wot, amongst other silly adventures.
I replaced it and the rear bolt assembly with the club ss versions. Those have been in place for twelve years now.
I removed them last winter in order to do some headwork. Both look as new.
My experience with SS fasteners, going back to Marine work in the 70s, has been very good.



Glen

Thanks Glen,
There's not much better places for an adventure than Sulby Straight!
Good to hear the stainless studs in your experience have be faultless. They must be of the correct grade for the application as are mine I would hope. I have ordered 303 and en16 to cover all bases
Thanks for you advice

 

[Monkeypants]

I always use Never-seez on stainless nuts. I replaced the FT47/3 and ET154 with a 1/2" grade 5 bolt, and nylock nut. I can't figure out why this system is not better than the original one! Maybe it is a tiny bit heavier. It's pretty much covered by the tank. No one has noticed the lack of originality. I have UNF nuts bolts and studs holding the cylinder heads on to.

There's a tiny bit of motion going on in that connection, especially the rear one if slackened as per Riders Handbook.
If the some threaded portion of the bolt resides inside the lug, that could carve away at it over time.
Just theoretical, in practice it might take 100 years to make things egg shaped!

I like those spigot nuts as that whole connection is a bit of a clever Irving puzzle. It looks entirely inadequate, but it works.

Glen

 

[oexing]

Well, I did not like the spigoted nuts: Once the fits in the steering head lugs and head brackets are not absolutely perfect, more than one thou is not acceptable for me, you get some bending loads on the smaller thread of the bolts inside, onto which the spigot nuts screw . So yes, I reamed all bores in steering head casting and in my homemade alu head brackets for same sizes and made solid bolts,max. one thou undersize, with grease grooves in stainless bolts at 13.15mm dia. , after reaming the lot. So no surprise when someone found a broken bolt combo with spigot nuts. You certainly have the threaded part outside long enough for a solid washer and nut, no lock nuts needed, maybe a mild Loctite for the nervous. Or alternatively antiseize or MoS2 paste as anywhere when having stainless steel for fasteners. Would not see any troubles by various grades of stainless as long as you apply suitable grease on threads for tightening up but certainly no bending loads on threads acceptable in assemblies , stainless or not.
Once a friend had a test ride on a Vincent and was not impressed, said it felt like having a hinge in the middle - no, not the rear suspension in mind. So I was alerted from this to cast an eye on all components critical for road behaviour and would not accept compromises anywhere when seeing scope for improvements.

Vic