Manky Monkey Motors

Ok here goes, I have allways wanted to build a trike but have allways thought that due to lack of knowledge, funds and space I could never do it, untill I was offered a trike project GT750 with a reliant axle for the right price.
So off i go to pick it all the bits up, load up the van and start the treck home. Unload it all and set it out. Now what i had was a gt750 in bits and an axle, oh well, suppose i was hoping for a little too much for it to be started  :-\
So far i have cut the bits i dont want off of the bike frame, got my hands on a prop shaft and set it all out level and in position.
Hopefully i will pluck up the courage soon to start cutting and tackingthe hardtail rear end onto the original cradle.
I will try to keep this updated as and when i do things

the first 2 pics are me making brum brum noises and my son doing the same  ;D

the next 2 are me and my brother setting it out and my boy again.

I had some erw laying about that i had been using to play with the welder so i thought i would mock up a rear end so I could better see what i had in my mind to do. Not straight, not welded well and not really anygood at all but it helped me visualise what i was trying to do with the back end.
And as the trike is ment to be for my wife it let her see what it would be like.

Jeez, you guys always make it look and sound so easy, I could almost be tempted..........

easy ?  if it was i would have done it by now  ;D  scary is a much better word for it

That's interesting Baldy. Plenty of triangulation in the rear end which is always good to see. You going to use a solid slug between the old & new frame tubes?
Care to write a little bit about the wooden jig you've used to keep it all square? If you could scribble a few words of explanation & add a couple of piccies maybe Mr Yodles will add it to the Trike Tech bit.
Keep adding updates to the build here & when it's done we'll re-edit it & post it in the Motors, 3 Wheels section. Looking good so far.

the wooden frame thingy came with all the bits, I will try to find out more about it but i am sure it was in 100% mag .

the mock-up has no struts or any kind off strentgh to it so it will have more bits than in the pics

hey nice mock up baldyshinehead.
are you welding the upper n lower frame rails directly to the axle or you gonna clamp em round?

clamp them,  cant get it back through the house if its solid  ;D
Not sure on conecting the old and new tubes, my father in-law has loads more knowledge than i do so i will be asking his advice on such things.

the only extras i would consider would be a curved bar between the top n bottom rails, about midpoint but slightly one way or t`other wouldnt be a problem if it looks better.

This is where my odd mind comes into it lol.   I want to keep all the bars on the rear end straight,  partly due to not having a way to bend them but also because most people bend them ( if that makes sense ).  I didnt put any at the back in the mock-up because i didnt have any left  ;)

looks like you have used the old seat rail to mount the top tubes, yes?
if so the easiest way to join them is drill a 10mm hole right through the tube side on, then another one top to bottom, get yourself some solid steel bar that fits inside the tube, cut off six inches n slide 3inches into the tube then hold it in place by welding up 1 of the holes you drilled.drill your new rail the same way, slide it on and weld 1 of those holes too. i only weld 1 hole until i`m completely happy with the frame, its more work if you weld all 4 n then have to rip it apart cos u dont like it.

A few triangular gussets in some of the corners wouldn't go amiss either. No need to over complicate it though. Simple always works best. Yes, the wooden jig was in 100% but if you've still got yours it'd be nice to show it here for those who don't read the mag.
Speedy, it is simple! If I can do it anyone can! Just takes patience & a little common sense. What've you got to lose if it doesn't work out? Well, O.k, your life maybe, but what I mean is, 3 or 4mm wall thickness ERW, (Electrical Resistance Welded), tube is about 2 quid a foot, a 150 amp MIG welder will cost you about 150 - 200 quid, (Desperate Dan sold his on this 'ere forum just recently for 90 quid I think), your local Tech College will do an evening class to teach you how to use it, an old Jap donor bike & away you go. Go on -you know you want to!

you have got it spot on.  that is what i was going to do there, it is the bottom rails i am not so sure on.

i see wot ur thinkin, the reason most are bent is because a bent tube will flex better under the forces actin on it than a staight one. If your set on straight tho, i would consider a triangle rather than just a single tube.

The man knows what he's talking about.
I've been in the garage all day so I'm off for a long soak in a hot bath. Give me a shout when you've finished building it! Back soon.

could you expand on that please. remember im only learning  ;D

bottom rails can be done a few ways. i`ve used 2 methods to date, firstly
lay your new rail up against the old one and mark a line along the rear cradle down tube, cut along this line with mr angle grinder, cut the original bottom rail back and join your new one the same way as the top one. then weld your new lower rail to the down tube.
secondly (n a bit trickier) grind the bottom corners off the rear cradle downtube and insert a longer bar to join your new rails, i would suggest u want at least 6 inches to sleeve over if you do it that way.This involves less welding but its harder to find the centre of the corner without takin too much off with the grinder.

thanks tbone,  ;D
I am being sent the details on that wooden frame thingy, i will post them as soon as i get them.

update on that. I will have to send it to yoda and ask nicelly if he will put it on his site as the file is a little large, 4.3meg  :o

have done a quick sketch, not sure how it will come out tho, u no n pics lol.
Anyway there will be forces acting on the top n bottom rails (am sure some wise guy will no the proper name for them).
a curved tube between the rails will absorb these forces beacuse it will flex ( not that youll ever see it move)
a triangle will allow the rails to flex to sort of, but a staight tube will just push against the opposite rail.
hope that makes sense.

yes tbone that makes perfect sense. that is what i was going to do or something very similar.  thanks again

its wot were all here for, to learn as we go n hopefully help each other out.

lol forgot to mention to bend the bottom slugs before they are welded in place, then you can leave your bottom rails straight, if you use the second method i described earlier. If memory serves me well your gonna need 20mm diameter bar for the slugs ( dont take my word for it tho, please measure the internal tube dia before you buy it ).
anyhows solid bar of that approx dia is a bugga to bend so anyone got any suggestions on that please?

the slugs are sorted so that i can keep the bottom rails straight.

have been thinkin of different ways to try n mount axles so would be interesred to hear your thoughts please mate

another thing that i need to decide on.
the main ways i have seen are
the way MM does it ( seen it somewhere on here ),
using 2 drilled and tapped slugs that weld to the axle and you just bolt into them,
or using a peice of 2 by 3 box section cut and welded to the axle with holes in for the bolts. ( i like the way this one looks )

I will try to find pics of each one

We go for a simple two part clamp made from a 4" long length of 2" diameter tube, sliced in half lengthways, with a piece of 4mm flat plate along each side & an 8mm bolt hole in each corner. Then we add a locating tab that bolts to a similar tab on the axle tube to stop it turning or sliding in the clamp.

thanks MM.
here's the other 2
( sorry stolen pics from somewhere )

ive only ever used 3 x 1" box with a hole cut in it for the axle to recess into and then welded a strip over the front to lock it in place and then weld the whole thing to the axle.
i must admit, i like the look of those clamps tho.

Never seen the 2nd one used before -very tidy but a lot of stress on a very small area. Not sure I'd want to entrust the back end to just 2 bolts. Can't quite make out how the 1st one locates. A flat plate on the end of the frame leg bolting to the flat surface of the box section welded to the axle? Much better but again, personally I'd rather see a clamp that holds the whole axle tube rather than something that bolts to one face of it. Just personal choice.

the second one ( if i got the right one lol ) i was told is a bit of box section, cut one end off and welded to the axle. so it is held top and bottom. then you have a plate on the frame ends that bolts to that.

i`ll go mm on this one, i prefer to have the axle surrounded by something
maybe its the old belt n braces thinkin, but it looks more secure lol

The guy who explained the box method to me just said, look at how the original ones are, its stronger than them.

Glad i came on here MM, all i got on other forums was silly remarks, thanks.
anyway people, its late and i really need my beauty sleep.  night

You'll get silly remarks here too but hopefully some help or inspiration too. I'm certainly no expert but happy to share what little I know -& to learn from others. G'night all.

just out of interest and i know this will cause differing opinions, but what tubeing do you all use on trike rear ends ?
I was adviced to use cfs3

i was told only to use cds but it costs a flippin fortune. BS1387 erw is my choice, it comes in heavy or medium, i use the heavy which has a wall thickness of 3.2mm.
Outside diameter or OD will depend very much on the existing frame OD size, ideally an exact match will give the best look but you can go oversize if you have a particulaly small tubed frame. 28mm OD is my first weapon of choice, with its 3.2mm wall gives an ID of 22mm wich is great for slugging with 20mm solid bar.
Just one more thing, the tube i use is measured in inches n i work in metric, why aint nowt easy lol.

erw is alot cheaper, just wasnt sure on the strength although i think most modern bike frames are made out off it.

have you tried bending it? youll see how strong it is lol.
Joking aside tho, ERW will be fine mate, as i said i opt for the thicker wall stuff, cant remember off hand the wall thickness  of the smaller stuff but its definatly 2mm plus, 2.7mm rings a bell. the thing you have to bear in mind is the power off your welder, can it cope with 3mm+ steel? if not use the 2.7mm instead.

I know how hard erw is to bend, i used to drive a side loader in a steel warehouse.  you can drive up the stuff a long way before it bends  ;D

Lots of "people who know about these things" will tell you you should only use chrome moly or whatever but grade 3 ERW works fine for me. We use 1 inch bore, (pipe is measured on it's internal diameter, tube on the external), which gives a nominal O.D of 1 3/8". Medium weight is around 3mm. Heavy gauge is actually nearer 4mm & is what we use. It'll bend in a standard hydraulic bender, (about 80 quid from "Machine Mart"), but once it's welded into a properly triangulated frame it's as strong as a Sherman tank. We use 1 1/2" bore for our top tubes & off cuts of 2" for the axle clamps. We use a 150 amp MIG by the way.

I have a turbo 130 migmate. havnt had any trouble with it so far but was looking at finding out if the local welding specialist would do me a deal if i just tacked it all and let him finish it off.

Our 150 will weld up to 1/4" plate, (6mm). The 130 will probably be O.K if you chamfer the joints to form a V shape for the weld to run into, but if you're not happy then always go to the professionals, (no, not Bodey & Doyle). Better safe than sorry.

i use a 130amp and it will cope with 4mm. thats a good tip from MM about the edges, and it also means you can dress the weld almost flush to the rails, if your so inclined.

more good advice, thanks.
how do you you cut the ends to match up with tubing ?  a tool in a drill or just a grinder

"fish mouthing"? Profiling the tube ends to butt against the side of another tube? Angle grinder for me I'm afraid. Laborious but I can't afford a proper bench mounted cutter. My brother had some success with a hole saw in a pillar drill but it didn't really work for me. When I've been working in lock-ups with no electricity getting stuff ready for welding elsewhere, it's been a hacksaw & handfile but that really is laborious!

glad you use a grinder, i wont feel so bad doing that way myself now  ;D
oh right thats what its called, fish mouthing

and while i think of it, i sent the wooden frame jig page to mr yoda today so hopefully it will be up soon

Well that's what my brother's always referred to it as & he's dead clever so it must be! Qualified engineer he is.

Great. Thanks for that. Yodie's getting seriously busy these days so it may take a little while to appear. Give 'im a week then gently remind him! I'm slowly learning this website stuff but it's taking an awful long time to sink in!

thats ok, im in no rush i have the designs  ;D  I very nearly re-typed it all out and copied the pics to save him messing about with it because it was sent to me as one big picture. If he has trouble with it i can still do that.

Fank U! ;)

back to an old question  ;D
I have called 3 local steel suppliers today and not one of them knew if the ERW they can get is grade 3.
is grade 3 the normal stuff or a special order

Welcome back mate. Thanks for sticking with us while the forum was down.
Yes, grade 3 is the most common one, so if your guys stock ERW it's almost certainly that.

Would we be talking about Sched 40 or 80?

 ;D Now you've confused me!
Whatever you want to call it, it's simply heavyweight, (just under 4mm wall thickness), ERW.

Sorry mate. There are loads of grades but I think sched 80 is near the top in quality.
When I started on my first frame I asked an engineer I was working with for some advice, and thats what he said to use.
Up till recently I have had 3/4 and 1 inch I.D. 4mm wall stuff, but the price has gone ballistic since christmas.

well i got the frame done ( should have been looking for work  ;) )
hopefully will get the welds looking good this week.

(http://i51.photobucket.com/albums/f363/baldyshinehead/HPIM0891.jpg)

(http://i51.photobucket.com/albums/f363/baldyshinehead/HPIM0890.jpg)

Looks ok. Watchout for that cat. Ours are always stealing my tools.

You're right Reliantman, the 1" bore 4mm wall stuff that we use has doubled in price in the last year.
Frame's lookin' good Baldy! I see you've got a garage cat to give you a hand -what's he like at welding?

 ;D the daft one in the second pic chases the sparks while i grind,  have to lock it indoors


and its welding is better than mine  :o

 ;D

before i go in all guns blazing and screw it up  ;D

how do i remove the bit what the wheel goes onto ? ( i love that description )

(http://i51.photobucket.com/albums/f363/baldyshinehead/HPIM0904.jpg)

That'll be the "hub" then!
That's a Reliant drum by the way for those of you lucky enough not to have worked on one. And a seriously rusty one too! Suggest you soak it in WD40 or Plusgas for a day or so first. The hub's on a tapered shaft with a woodroffe keyway to stop it rotating around the shaft. Some careful heating with a blow lamp then lumping it with the biggest mallet you can find sometimes works but you run the risk of weakening or bending the end of the shaft in the process. Easiest way -the way I do it! -is to take it to a local garage & give 'em a fiver to press it off for you with a hydraulic bench press. Any competent repair shop will have one. I actually go to the local Tech College & use the one in their mechanics bit.

my way of saying is much more flamboyant than hub  ;D
so basically it just pulls off then.

 ;D Yup, but it'll be wedged super tight onto the taper cos it's torqued up to quite a high pressure. When they're pressed off hydraulically, nothing seems to happen for a few seconds then there's an almighty bang as it frees itself from the taper.