My 70 frame snapped in half a while back so I've rounded up most of the parts now to build my suspension frame. I'll post more pictures here as the build progresses.

I'm using a pit bike frame, making my own swingarm and triples.



Today I've been sizing everything up on the bench, trying to work out what wheelbase length I want to go for. I don't know how the extra length, width and rake affects the ride so it's really hard to decide. Maybe some of you guys can help me out here; The A+ frame looks about right to me - it obviously has a longer wheelbase than stock, can anyone tell me exactly what it is (or the length of the A+ swinger) and did the A+ use wheel spacers to increase the width to keep the overall geometry the same?

Thanks for all your comments...

Made a bit of progress on the swing arm today:











All I need to know now is the what length it needs to be - anyone???

depends / The stock A Plus was a bit short / Kasey extended his 5 inches. I am doing 3 inches with their stock A plus wheel spacers!

I will try and get you measurements....the bike is tucked away in my trailer at the moment.

Thanks POULE43, I'd really appreciate that, I'm held up now until I decide the length. I'm leaning towards a 4 inch over stock swingarm. What width were the A+ spacers?

Got a bit more work done on the swingarm and frame this afternoon - swingarm is 13 inch / 330mm





I'll be making the yokes this weekend from these slabs of billet ali:



Front forks and rear mono shock are new pit bike parts:



Should hopefully be a roller by the end of the weekend.

Got the swingarm spot welded together, didn't want to weld it all in case I need to make changes. Also lowered the rear shock mount on the frame because it was in the way of the seat. Feels good - seat height is about right. Going to have to make a hinged seat so I can use the kick start.



Marked out the bottom clamp ready for drilling and cutting.

In my haste to get the triples done I made a stupid mistake on the setting out, luckily I spotted it before I messed up the 2nd one. Managed to make a couple of 1 inch wheel spacers out of the centre part of the 1st but it meant I had to drive all the way out to the metal supplier today to get a replacement. Hopefully I'll get her rolling later this week.

Bummer sorry too hear that, at least you where able to use the aluminum for spacers. Keep the progress pics coming

Yeah sure, will do.

Aluminium is strange stuff to work if you're used to steel, it's taken me a while to get the hang of it. Making something else first, like wheel spacers is a good idea, as it's not such a loss if you mess up and it gives you a chance to get used to working thick aluminium.





I've been re-drawing my the plans for the triples and getting them checked over. I hope to mark them out ready for cutting later this evening.

What grade aluminum are you using? 7075?

No idea, I was lucky to find anything, it was the only piece of billet ali in the whole shop and we had to dig it out from the bottom of a huge pile of steel.

Got all the holes drilled out on the yokes today, if all goes well I'll hopefully get them shaped up tomorrow and then I can finally start getting her up and rolling.

Took me the whole day to get the bottom clamp shaped up, I'm not looking forward to another day of it doing the top. I'm really starting to hate aluminium...

Are you doing all that by hand, via Power tools? If so, I tip my hat!! That is alot of work on material that thick. I do small/thinner items like that but I would be bribing my machinist buddy for that work.

Great Job! Keep the pics coming!!!

Yeah, I using a mix of drill, grinder and jigsaw - painfully slow on ali this thick - need a bandsaw for this kind of work really.
Still got to cut the tightening slots in it so it'll clamp the forks.

Great work. Coming together nicely. Good avatar too!
tmas

I had to go to an engineers workshop yesterday to get a wider front axle turned, so while I was there I asked them to rough out the 2nd Ali triple for me - wont be ready till next Friday, so today I decided to have a go at knocking up a set of steel ones - a few hours later and they were almost done, just need welding in the morning.

Great work. Seeing to as you make it look so easy, why dont you widdle me up a set? what say?

LOL, There's a lot of hard work that goes into making it look easy.

Got the steel triples welded up - can finally start putting something together now.



Another piece of the jigsaw arrived in the mail today - should look good on her.

^^^^^^^^^Very Nice work... very interesting thread to follow.. thx
tmas

looking good!!

looks good bro considering your working with all hand tools!
can't wait to get some suspension on my atc70, i just finished up my motor and wheels on mine.

My first welding in nearly 25 years so not as good as I'd like. Post a thread on the forum when you do your 70 suspension.

Starting to shape up today.

Today I got the new wider front axle back from the engineers and installed, along with the handlebars and risers.
Hope to get her running tomorrow.

Was it too choppered out with the fork legs facing the other way?

It did look a bit long with the leading axle, and after reading up on the differences between leading and trailing front axles I prefer the sound of trailing. It's easy enough to change it round, you just take out the front axle and rotate the bottom of each fork and reassemble.

Hoped to get her running today but hit a few snags... The atc70 foot rest clashed with the pit bike frame which has a built in mounting for the 2 rear foot rest bolt holes, so I had to work something out without weakening anything - eventually by cutting a couple of slots and lots of wiggling I got them to go together.





Neither the atc70 or atc110 manifolds I have, fit with the new frame - can anyone suggest one that might fit this or a work around?



Also I was hoping my spare 110 chain would fit with the extra length but its 3 or 4 links short, so I might have to borrow a few link from my 110 for a while...

I cut and shut my manifold using this stuff but it was still a tight fit between the tank and frame

For a chain i added a few links to a stock chain i had lying round

Your build is looking good, looking forward to hear how it rides

I'll have to get myself some of those ali brazing rods, they look like they'd be useful to have around.

I was desperate to have a ride on it today, so I modified the old 110 manifold and managed to get it to fit with a slight rise in the rear end of the tank. Threw on the exhaust, wiring, and chain - she fired up first time, I set off and... bang! the chain snapped
The way the rear suspension is at the moment, means when swing arm goes up the chain gets gradually tighter. I guess that's another reason to move the shock mount farther down the arm?

I've even fixed holes in th bottom of my dads tinny with those rods!

Did your frame come with a tensioner? You may have to sort something out so the chain can be long enough to allow full suspension travel.

Carefull with lowering the rear end as the tires may hit the rear fender on full compression

Sorry to hijack you build thread vortex......., MuckUte, how did you go with your triple clamps? I sent you a message, but you musnt have got it.

LOL! Did you drill holes in the bottoms of his tinnies - drink the contents - refill with water and weld the holes up?

No tensioner on the frame but the mount is there, I found a roller but need to make up an arm and spring to tension it.

Today I moved the bottom shock mount a couple of inches down the swing arm and raised the subframe up a bit to compensate. It's now got that V shape back that pit bike frames always have, and now when I put the seat back on, its too high at the back, now I see why everyone else's is like a bar stool... Think I might have to lower the swingarm pivot mount instead....

Drove all the way out to the nearest motorbike shop to buy a new longer chain today, only to find when I got back that it's the wrong size, so I still haven't got to ride this thing

so just knock a couple of links out and ride that sucker!!!

Vortex, muckute is from Australia, like me. Over here we call small aluminium boats 'tinnies'. But yes, we call cans of beer 'tinnie's too.....I do think he was talking about a boat though....

Bummer about the chain size.

I did mean the boat sort if tinnie

I did, the chain hits the side of the engine casing, jams, and snaps. Need a 420 X 96 I think. It'll be Wednesday before I can get back to the shop now. Ohhh the frustration....





Ah, that explains it - knew about the beer can expression but not the boat.

Got the right chain this morning, threw together a rough chain tensioner and finally got to ride it Hasn't lost any of the fun, the suspension's just made it much better. Couldn't really go for it though as the brake is hardly working - looks like the cable isn't long enough now that the wheelbase is longer.
Need to spend some time now working out all the little niggles and decide what changes need to be made before tearing it down for finishing and paint, then the final build up. Will post some pictures when it's all done.

The last couple of days I've been working out all the little faults and finishing off;
Shortened the swing arm by quarter inch and now it's the perfect length for the chain.
Bolted the rear sprocket directly to the drive hub, makes it a lot more responsive - wheelies galore.



Made up a sliding seat mount so I can use the kick start, works really well



Still need to make a catch but the bit of rope did OK for today.



Gave her a real hard test drive around the fields, and WOW is it fun! :p

Looks like a mini 250r

NICE JOB!!!! You will have a ball!!!!

A sliding seat mount? Awesome idea!!!

I first made a hinged seat but wasn't happy with it - you had to get off to lift it up and then try to hold it up while kick starting. This one you dont even have to get off. Quite easy to make on a pit bike sub frame because of the parallel bars, surprised no one hasn't done it before.

OMG! Sliding seat!!! What a wicked idea!

I used 20mm x 3mm angle, hardest part was getting the angle of the mountings right. Found the easiest way was to make it up with the seat upside down on the bench and the subframe off the bike.

Did a few more bits on the bike today. Took off the foot rest and cut out the middle section turned it and re-welded it so the foot pegs are about 2 inches lower. Feels much better - no more knees under the armpits.



Also made up a new chain tensioner, the pit bike one just pushed the chain up against the bottom of the swingarm. This way it lifts it slightly and stops any chain drag on top.



Working on an adjustable silencer baffle now, so I can turn the volume up and down

It all seems to be coming together nicely. How are the alloy triples coming along

Only done a few little jobs on it recently.

Got the sliding seat catch figured out:





Temporary extension for the brake cable until I get a hydraulic disk setup made.



Haven't got around to finishing the ali triples yet - did you get yours back from the engineers?

That's going to be a blast when its all finished up. Looking good.

It's a blast already

Got a perfect NOS 90 headlight for her today.

Got a few more bits done on the 70 recently so must be time for an update.

Headlight brackets made and the headlight on. New Maier rear plastics, (on but need to rebuild the sliding seat catch as it's a different shape underneath). Complete new hydraulic hand operated rear quad disc brake system on and working

Looking good!!! but.....
Paint those triple clamps..... (yes, I'm a stalker)...lol
Kidding buddy, its coming together well. So is it almost done?

Summers over and it's gettin muddy out there, so I'm looking to put some mud guards on the bike - did they ever make them for the 70?
I have a set on my 110 so I took one off to size it up to see if they would fit - not bad, anyone got a set they want to sell?

There was an optional rear mud flap kit, it is nwt discontinued, but they show up every now and then, best thing would to modify the 110's.

http://www.cmsnl.com/honda-atc70-83-us_mod...list/FOP01.html