CycleKarts GB

Forums => Build journals => Topic started by: ChrisS on 15 January 2019, 09:46:37 am

Title: CK 1 (ERA) build
Post by: ChrisS on 15 January 2019, 09:46:37 am
I decided I wanted to build something British for my first cyclekart so I chose an ERA as my inspiration.

I did some work scaling it into a cyclekart.
I want to keep it simple so I am planning a plywood tub slung in between the chassis rails, probably pit-bike wheels and regular cyclekart style front suspension, solid at the rear with the axle through the centre of the rails.
Progress to date;  steel has been delivered and I've built a mock up tub from hardboard and paper. Predictably, I've had to enlarge the cockpit from my original drawings, and I will need a detachable steering wheel.
Title: Re: CK 1 (ERA) build
Post by: Graham Hill on 15 January 2019, 11:24:20 am
That's a really great start Chris and keep up the build journal for everybody.
It will be good to catch up with you again at Stretton, consider yourself booked for some more drive time in my MG. (if you can stand the pain!).
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 15 January 2019, 12:23:56 pm
Sorry, the pics seem to have come up a bit large, should I have reduced them somehow??
Title: Re: CK 1 (ERA) build
Post by: TheGiantTribble on 15 January 2019, 02:22:58 pm
The pictures seem fine to me.
And great car choice, always liked ERA's myself.
Cockpit size is a compromise but very important to get correct, the first time I tried
to build a CK, an ERA 'E' type, I could get in but not out...opps!
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 20 January 2019, 08:26:20 am
A big day yesterday, as I started building the real thing, no more mock up!  I'm using 12mm ply for the floor and 9mm for the sides although having read Rhys's Kim journal, I think I could have gone lighter. I will probably have to make some relieving cuts to allow the side panels to bend where I want.  I had some 25mm ash left over from a previous project which I am using for the joints. I plan to do the tub first, then construct the chassis round it.

I've bought an axle, carriers, hubs etc for the rear from Gemini, but I'm holding back on the front as I am still unsure about springing and stub axles/bearings and I haven't managed to source my wheels yet.
Title: Re: CK 1 (ERA) build
Post by: RhysN on 20 January 2019, 09:34:41 am
I don't think you need relieving cuts Chris.
Once you have decided on the curve, set up a few pieces of timber on a work table, bits of 3 x 2 at right angles to the side panels, lay your ply on top, then cover with towels (charity shop to save being castigated?) and wet them with hot water. Even better to use a fairly hot iron and get the ply soaked and you will be surprised how supple it becomes. Put some weights on the top and let it settle.  Once it's dry you will have your curved sides. The more effort you put to jigging it, the closer to your required shape. I suggest cutting the sides before curving. In reality the ERA has very little shape until you get to the back axle, which is where the tub on my ERA ended. There is a brief bit on mine, on, then work through "The Cars", mine is in Cars B, but there is a mountain of info there so have a look at the lot. All those cars showing with differentials have removed them.
Don't forget to have a left and a right, guess how I know this!
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 09 February 2019, 02:03:50 pm
Work is going to stop now for a month as I will be away visiting family, so here's a quick progress photo! 

Nothing glued yet or welded, the whole thing is held together with clamps and ratchet straps!  I need to weld up the chassis as a priority when I return, stop it moving around!

I decided to try making the grille surround from mdf, some way to go on that yet, work in progress!
Title: Re: CK 1 (ERA) build
Post by: RhysN on 09 February 2019, 05:01:00 pm
Looks great Chris. Plenty of time to think little details while you are away :)
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 02 April 2019, 01:26:10 pm
I've now got my wheels, I'm using 2 C90 rears and 2 C90 fronts.  I've fitted the driven wheels with 37 x 25 bearings and mated them to Gemini rear hubs.
I pressed out the wheel studs and cut off the Gemini boss to leave a flush surface.[attach=1]
Drilled new 10mm dia holes (100mm PCD)[attach=2]
Filed 4 slots in the Honda hub[attach=3][attach=4]
Made cover plate to fit where the cush drive used to be. (4mm steel)[attach=5]
All bolted up.[attach=6]
Title: Re: CK 1 (ERA) build
Post by: Graham Hill on 02 April 2019, 06:05:34 pm
Keep up the detail of the build posts Chris, it's what this site needs to encourage others. Thanks also for making the trip to Coventry at the weekend it was good to catch up again.
Title: Re: CK 1 (ERA) build
Post by: RhysN on 03 April 2019, 03:21:39 pm
Looking good, I'm curious as to why you have put bearings in the rear wheels.
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 03 April 2019, 07:08:57 pm
Yes, there is no rotation so I could have bushed them but the bearings were available and cheap. I suppose there is a chance that they might start pitting after a while, we'll see.
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 10 April 2019, 09:04:47 am
Here are some pictures re-assembling my rear wheels, it's a first for me but there are plenty of youtube videos to follow.  I bought a spoke spanner, ebay £2, but the hardest part was the dismantling as I wanted to save the spokes. WD40 shifted most of them but the stubborn ones needed a blast with the blow torch.
Title: Re: CK 1 (ERA) build
Post by: Steve Cole on 11 April 2019, 04:56:26 pm
Iíve never done anything like this Chris. How do you get it all balanced and running true?
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 11 April 2019, 08:21:51 pm
You have to mount the wheel so that it can spin freely, see pic above, then fix a batten or similar to use as a gauge ( I used a steel rule). THen by following a process of loosening and tightening you need to first adjust for concentricity and then for side to side. Finally tighten to an even tension all round. Proper wheelbuilders use torque wrenches, but I just keep going until they all ping nicely!  No doubt after 20 mins on a dirt track I'll find out if that was good enough!

Perhaps if anyone is interested I can put a more detailed explanation in the technical section.
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 14 April 2019, 08:12:38 am
Well it's now just 3 weeks till Stretton and I'm determined to bring something that can propel, steer and stop itself, on the shale or in the car park at least.  I guess that means some long days in the workshop, but I have most of the key components, so now all I have to do is make all the bits that hold them together!

Progress pics will follow (I hope)!

Title: Re: CK 1 (ERA) build
Post by: ChrisS on 14 April 2019, 06:55:49 pm
Current progress - Engine mount and caliper mount done and tacked in. Turning my attention to the front end next - springs and hangers.
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 20 April 2019, 10:19:03 pm
Well now it's just two weeks to Stretton! The good news is that I am now on 4 wheels, but it took me much longer than I anticipated.  Just got to sort out steering, braking, throttle, glue up the tub and fix it in, -  easy.
Title: Re: CK 1 (ERA) build
Post by: Graham Hill on 21 April 2019, 06:42:17 am
There's nothing like a deadline Chris. That's good progress since Coventry!
Title: Re: CK 1 (ERA) build
Post by: Steve Cole on 21 April 2019, 08:34:13 pm
Looking great, 14 days to go  8)
Title: Re: CK 1 (ERA) build - how's it going?
Post by: StefanN on 16 May 2019, 01:59:43 pm
How's your build going Chris?
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 17 May 2019, 04:34:35 pm
OK, well I pushed so hard to get it running for Stretton, that I've had to step back and catch up with a few other things, so progress has been slow.  Stretton went well and the only issue I had was with the axle keys becoming loose and working along the keyway.  I just taped them in place on the day, but I'll look at that in due course.

I've started on the bodywork at the front, using MDF for the nose and some left over 0.9mm ali sheeting. I need to fill and sand the nose to it's final shape and then figure out the grille. For the main panels with simple curves, bonnet etc. I've bought some 1.2mm sheet, and I'll put off anything with compound curves until I feel inspired!
Title: Re: CK 1 (ERA) build
Post by: RhysN on 18 May 2019, 10:52:46 am
Common cure for moving keys is a hose clamp, or many karters tape the entire axle with insulation tape.
I have some grille material here I can donate to the cause.
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 18 May 2019, 01:27:22 pm
Thanks for your offer Rhys, I was going to use some left over eml, what do you have?
Title: Re: CK 1 (ERA) build
Post by: RhysN on 18 May 2019, 02:05:44 pm
Expanded mesh which I got for my ERA after looking closely at the real thing.
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 08 June 2019, 10:16:03 am
I've been making my steering wheel, hoping to finish it over the weekend.  I've borrowed the boss design posted by our French friends. Here is an exploded diagram I did on Sketch Up,
Some pics of the rim, I'm using 2 layers of 12mm ply which will be glued and then I'm planning to string wrap it.[attach=2]
Title: Re: CK 1 (ERA) build
Post by: ChrisS on 15 June 2019, 08:01:14 pm
The steering wheel is almost finished and there are a few things I would do differently next time, more slender spokes for starters.  I naively thought the stringwrap would be a doddle and that I would go right round the wheel in one piece of string and just have one join.  After 3 attempts I gave that up and started again accepting that there would need to be a number of joins.  It is a 13 inch wheel and it took over 50 mtrs of string!  I plan to give the string a coat of varnish to help stabilise it and tone it down.
Title: Re: CK 1 (ERA) build
Post by: StefanN on 15 June 2019, 09:38:05 pm
Thatís a lot of string!  Nice result - I like the way youíve worked around the spokes with the string.
Title: Re: CK 1 (ERA) build
Post by: Chris Brown on 16 June 2019, 08:42:33 am
Looks great Chris, I'll have to pinch that method for dealing with the spokes for my next kart. The wheel I'll be using has tapered spokes so it'll be slightly easier to cope with.
Title: Re: CK 1 (ERA) build
Post by: TheGiantTribble on 16 June 2019, 09:02:05 am
Yikes.... there's a hell of a lot of work just in the string
Looks great and well worth the effort.
Title: Steaming Ash
Post by: ChrisS on 04 July 2019, 08:46:59 pm
I was debating how to build my boat tail, I remembered I had some 5mm offcut strips of Ash and I thought I would have a go at making a frame.  I borrowed a wallpaper stripper from a friend and made a steambox from an old pipe. After steaming for an hour I carefully bent it round a jig and clamped it to cool and dry. I made a 2nd one and laminated them together, see pics.

Flushed with success I started on the 2nd frame, but on bending it snapped, perhaps the grain wasn't good. Anyway, I gave up and made the 2nd one in aluminium!
Title: Re: CK 1 (ERA) bending the bonnet
Post by: ChrisS on 07 July 2019, 10:13:11 pm
Here's a couple of pics, bending the bonnet using the 'ratchet strap' method!