V star 650 hardtail

[Skjoll]

... yeah kinda like the idea of fibreglass but at the mo , not sure bouts it’s legality for a petrol tank in the uk . Plus minor concerns about ethanol Proofing it , which I know can be done...

Of course I have no idea about the legalities of using fiberglass as a fuel reservoir in the UK but I know from first hand experience that it's alcohol safe which is verified by fuel industry related technical documents.

[dowood1]

I don’t have any idea either ,lol
Thanks for the doc it looks interesting , will have to read it when I get a chance . What
I do know is historic f/glass fuel tanks on Brit bikes in the late sixties / early seventies where made illegal to fit , and that they do not like fuel with ethanol in it as have been known to go soft then become porous . Although this can be prevented with a modern tank sealant application . But I know that is nearly all in the past and a lot has changed in the last 45 to 50 years !
It will be interesting to look into . As it is an easy medium to work with and to shape as you quite rightly said

[dowood1]

The adjusted and restyled seat frame , still gotta drill it for the springs and make the mountings , when I know how much space I’ve got .
( Thinking of some led lights between the sides of the seat and the m/ guard/ fender at the rear of the seat )

[farmall]

Fiberglass is delicate trash and motorbikes people ride lead harder lives (especially when hardtailed) than one might imagine. It's not approved for road use for good reason. Tank sealant fails often. I wouldn't run a 'glass tank if it were free.

Consider practicing enough to weld what you need welded, as welding skill is worth far more than one motorcycle. An acetylene torch is outstanding for light sheet metal work, more versatile than a TIG welder (I have both aplenty), and can heat and bend besides welding. You can also gas weld aluminum. Avoid looking for shortcuts which are usually the LONG way round.

Nearly anyone can weld. Most refuse to systematically practice (though steel is cheap!) and only weld when they need something welded which is not a way to build experience. The Ron Covell videos are excellent. Visit the Weldingweb forums, and the migwelding.uk forums which cover all processes. Practice on scrap and run long weld beads to build muscle memory.

https://www.mig-welding.co.uk/ https://weldingweb.com/

If you have a wire welding machine, ensure it is gas capable (cheap FCAW is not MIG) and use appropriately thin wire, not the usual .035".

[dowood1]

Thanks farmall , I hear what you say about fibreglass tanks .
Not sure steel is cheap this side of the Atlantic , and I do have a very limited budget budget .
The only welder I can afford is an arc welder . I wish I could afford a mig and an Oxy acetylene welder , that would be a dream come true, but hey ho , I will have to manage with what Ive got . I admit it’s not always pretty welding but it is solid !
I try to practice when I can and have seen quite a few web tutorials on it .
I am also ham strung by having to work outside in the cold and damp which make it far from easy .
But thanks for your thoughts on the welding .

[Luky]

Fiberglass is delicate trash and motorbikes people ride lead harder lives (especially when hardtailed) than one might imagine. It's not approved for road use for good reason. Tank sealant fails often. I wouldn't run a 'glass tank if it were free.

Consider practicing enough to weld what you need welded, as welding skill is worth far more than one motorcycle. An acetylene torch is outstanding for light sheet metal work, more versatile than a TIG welder (I have both aplenty), and can heat and bend besides welding. You can also gas weld aluminum. Avoid looking for shortcuts which are usually the LONG way round.

Nearly anyone can weld. Most refuse to systematically practice (though steel is cheap!) and only weld when they need something welded which is not a way to build experience. The Ron Covell videos are excellent. Visit the Weldingweb forums, and the migwelding.uk forums which cover all processes. Practice on scrap and run long weld beads to build muscle memory.

https://www.mig-welding.co.uk/ https://weldingweb.com/

If you have a wire welding machine, ensure it is gas capable (cheap FCAW is not MIG) and use appropriately thin wire, not the usual .035".

There is nothing wrong with the FCAW process. (Flux Core Arc Welding)
It is used on structural steel for buildings. Use Lincoln NR211 MP wire.
It is multiple Pass (MP) and is structurally rated.

[Skjoll]

Like I've said, I have experience running fiberglass tanks and I haven't had any issues with them. Maybe it's because I made them stout with thick walls (8-10mm) and rubber mounted them but they're nothing new and have been a staple in the cafe and race crowds for decades.
http://gftpstore.com/Cafe-and-Roadrace-Fuel-Tanks_c5.htm
https://www.airtech-streamlining.com/vintage-fairings-seats-fenders-parts/vintagetanks.htm


As for welding I've gotten by since the 80s with FCAW, not the prettiest and there's a lot of spatter to clean but it does the job in capable hands. The only time I reach for my cheap ss TIG rig is when making exhausts, oil tanks or wherever thin walled steel is used.

[dowood1]

Thanks Skjoll . Interesting to see so many fibreglass tanks are still being made .
Iit would never have Occurred to me to make them so thick ! And if one used rubber mountings as well That would certainly solve a lot of the issues an interesting idea. Re the welding I use an arc welder ( all I could afford ) which is not the “preferred” method . But it does adequate and solid Welding

[hillcat]

Like I've said, I have experience running fiberglass tanks and I haven't had any issues with them. Maybe it's because I made them stout with thick walls (8-10mm) and rubber mounted them but they're nothing new and have been a staple in the cafe and race crowds for decades.

It is a fact that ethanol gas degrades fiberglass, it doesn't matter how thick the walls are. They are sometimes used with pour-in tank liners that also tend to degrade with time. A fiberglass tank is a bad idea these days.

[Skjoll]

... it doesn't matter how thick the walls are...

It does with concerns to fragility (I believe the comment was "delicate trash") which is what my response was directed towards. I understand that this a debatable topic but so far from what I've read the complaints about fiberglass tanks going bad seemed to involve pre-1980s fiberglass boat fuel tanks that may have had a different resin formulation than what is/was used more recently. I'm not denying that there may be legit concerns however I'd like to see more evidence than people merely posting on forums. Seriously, I genuinely welcome it. Generations of builders/racers have had favorable experiences and we regularly used 'oxygenated' race fuels... the ones we had available at the time with 100+ octane rating employed a combination of methanol and ethanol. Tank liners such as Kreem were also seemingly unaffected.

So if I were to base a decision of whether or not to use a fiberglass tank on a future build on either experience or internet/forum heresay, guess which one I choose? However if someone here were to share evidence of fiberglass tank failure, I would certainly take that into consideration. After all, modern fuel formulations that contain alcohol may also contain ethers with the latter being the real cause of fiberglass degradation... we don't know and making general assumptions based on forum comments without knowing specifics would be foolhardy.



***Addendum***
Incidentally, I try to avoid modern fuels that are stated to contain alcohol because it has wreaked havoc on rubber o-rings and fuel lines, something that I didn't experience back in the late 70s when 'Gasohol' was such a hot new thing at the time in New England or during the 90s and into the early 2000s.

[dowood1]

Another mock up , wrapped the seat in wallpaper to get an idea of how it hangs together .
Not the usual fayre ! but it kinda works for me , even with the seats in odd colours .
Tried welding the ex tank back together today , but it wasn’t gonna happen . So I’llhave a go at brazing it when I get a chance

[dowood1]

Gonna have to modify / simplify this build a bit , it’s beyond my “working space” and the tools / facilities I have available .
For a start I am gonna try a more conventional petrol tank arrangement .

[dowood1]

Have also decided I need to get another mig welder , I can get on with them . I’m not getting on with the arc welder There’s to many jobs where it’s not working out for me , but it was fun trying , lol .

[dowood1]

Gonna have to believe I can sort the single carb conversion ok . As I have just put the original carbs on e bay to help fund the new welder I’ve just ordered . Lol , patience is not my strong point either

[dowood1]

Think I’ve found the right tank to do what I want , and it holds 3 UK gals . Needs a couple of mods and I have a couple of ideas to style it into the two top tubes .

[dowood1]

Ok looks like the ideas to blend the tank in are going to end up with a single top tube conversion . Should to be a fairly easy job . Reckon I Can fit the top tube . Without completely removing the twin rails .
Therefore not needing to have a jig , maybe a couple of supports tacked on to make sure it all stays square

[dowood1]

OK , here I go again lol
Just realised Ive been drifting and trying to find the easy way out . But that means I’m loosing out on what I wanted to do with this build .
So it’s back to the original plan tank under the seat , electrics under a faux tank along with the remote front master cylinder. A hard tailed frame . Plus single side draught su carb
. Took a pic today and it looks so right to me , so I need to build it like I had decided . Otherwise I will just end up beImg disappointed !
Today’s pic
.
Also decided that I’m aiming to build the petrol tank under the seat as part of the frame , think will look cool like that if it’s flush with the frame and moulded in .

[dowood1]

Ok gonna take my reverting to what I originally / really wanted a step further .
Am gonna stretch the frame behind the rear down tube appx 4” . To allow more space for the seat and also a bigger fuel tank under the seat . Also if I can get the right parts made gonna goose neck it as well .
Lastly I am reverting to the sporty tank and using the virago seat either with a new base or as a pattern for a spring seat , with the extra space I’ll have .
Have a plan for and have just ordered some steel to make a jig for the rear end stretch .
Gonna keep the same geometry tho , just stretching it .

[dowood1]

I think that the easiest way to goose neck it is to stretch the top tubes then fab the down tubes to suit .
If I do that and goose neck it 4” that will drop the front of the bike appx 1” and if I do 6” that will drop it appx 1.6” . I would balance that by dropping the rear end ( when I hardtail it ) the same amount to keep the same geometry .
Is that gonna cause any ground clearance / handling issues / probs .
I was surprised that the ground clearance as std is 5.5” and the fork travel (was) on the original soggy springs the same . But I guess it normally only bounces one end at a time, lol

[dowood1]

Ok no worries with that last question , have checked the ground clearance I have at the mo ( with no seat and tank but that shouldn’t make any odds ) with the heavier fork springs , where it was with the firmed up rear shock ( now a strut ) and without me on it . .
And I seem to have about 7.25” so I don’t think there’s gonna be any probs with lowering it a couple of inches , it handling ok and still being practical to ride