My little kz440 project

Venderbroeck

New Member
Thanks for the vote of confidence :) For any other job I would have just done it, but I don't have nearly enough meters on that tig machine to be confident enough to do this kind of structural stuff unfortunately. It's fine though, I have plenty of less critical welding projects to keep myself occupied, and to gain some more experience.
 

doc_rot

Oh the usual... I bowl, I drive around...
DTT BOTM WINNER
Mild steel is very forgiving., the beauty of TIG is it will be VERY obvious if a weld will fail since you are melting the root material, unlike MIG. Do a couple test coupons and then go for it.
 

Venderbroeck

New Member
So it's been a while, but progress has been made nonetheless.
With all the encouragement I was leaning halfway towards welding it myself when someone told me he knew a welder who has been practising the craft for neigh on 40 years who would do it for me in his spare time.
So I chickened out... :p In the end I was happy I did though as the guy said it was tough to weld at places as the metal was spitting at him, probably due to contamination of the steel or something.
At any rate it is now done, and that's a major milestone for me in the build :D

I took some pics of the welds. They look quite good to my laymans eyes. He went through the trouble of researching which method and materials work best for motorcycle frames.
I did specifically tell him to focus on strength rather than aesthetics. Here are some closeup shots:









Quite a bit more pretty than I could have made them.

I didn't have time today to remove the bracket as it involves some cutting, but tomorrow I'll take it off and put the tank on to see if the lines came out as I wanted them.
Some surface rust has started to form on the bare steel, as can be expected of course, so tomorrow I plan to deal with that as well.
I'll probably remove the surface rust with some steel wool, and spray on a clear coat.
The clear coat will be easy enough to remove later, whereas using WD40 or anything greasy would just make handling the frame messy.
Happy days ;D, now I can finally move on to the seat pan.
 

Venderbroeck

New Member
Took a quick picture with the tank on:



The subframe nicely lines up with the tank which is wat I was going for.
I still need to fabricate the mount to which the rear of the tank attaches, as that was cut off along with the old subframe.
I will remove all the superfluous mounting tabs as well of course, which should clean up the rear of the frame even more.
 

Venderbroeck

New Member
I couldn't do much this weekend, as I'm still waiting for some parts and materials to fabricate the seat pan with.
With nothing better to do, I decided to temporarily remount the swingarm, fork, and both wheels to get an idea of the overall lines and shape of the bike.
Here's what it looked like initially:



The bike looked to sit a little high in the front to my eyes, so I slid the forks through the triple trees about an inch worth:



That looked a lot better already.
I was wondering how much the front could be lowered before I would run into interference problems though, so I removed the endcaps of the fork to allow it to bottom out fully.
I then lowered to front a little more until I reached this point:



That's about as low as it can be I reckon. The exhausts run a bit to the sides in the front, so they won't interfere.
After pulling back the fork to their normal length and putting back the caps this is what I ended up with:



I'm happy with that actually. It will probably end up dipping somewhat lower with the engine installed, so the forks probably don't need that much shortening.
I now know how far I can go with it though. Once I know what the final height will be, i will modify the forks internally to shorten them in stead of sliding them through the triple tree.

I might also lower the back a smidge by installing shorter shocks, but I'll have to see how it looks when it has progressed a little more.
Here's how it stands at the moment:



I also took the time to remove the surface rust from the subframe with some steel wool, after which I hit it with some clear coat.
All shiny again:



Hopefully I can start the seat pan process by next weekend.
 

CarbsAndCylinders

Careful With That Axe Eugene
"The exhausts run a bit to the sides in the front, so they won't interfere."

I think you should turn the bars full stop left and right to make sure they don't interfere with the exhaust at those positions.
 

thaBrad

New Member
I am currently doing the same project bike. 1980 kz440. Got the tear down complete over the weekend. Question to ask you, is your hoop an eBay China hoop? I can't find one in US with the long legs included. Everything is the short ones and as you know our OEM seat hoop is not straight so we can't use much of it. I just don't want to wait 3-5 weeks to get it shipped so looking for in the US. Yours looks like a great start. Keep it up so I have a reference! LOL
 

Venderbroeck

New Member
Cool, are you keeping a blog of it somewhere?

The hoop came from caferacerwebshop: https://www.caferacerwebshop.com/en/1-upswept-15-degrees-loop-extra-long.html
They have different styles of long hoops: https://www.caferacerwebshop.com/en/the-workshop/diy-material/frame-parts/?mode=grid&limit=24&sort=popular&max=250&min=0&sort=popular&brand=0&filter[]=245258&limit=100
I'm not sure if they have us based stock as it seems to be a dutch company? But shipping should be faster than 3-5 weeks.
Also, I don't kknow if I'm allowed to post links in this way. I will remove them if they offend any rules.

I have started working on the seat pan, and currently have laid6 layers of quite dense fiberglass. It was still a little tacky when I left it, so when I come back this weekend I'll have to see if it is rigid enough. Yesterday I also met someone who does upholstery... specifically for saddles (well imagine that!). Quite a coïncidence. We talked a little and unsurprisingly he had some good info. He also knew what kind of foam I should use, and he could supply it so that helps things along a bit. Once I do a bit more work on the seat pan I will post another update.
 

NoRiders

Member
Cool, are you keeping a blog of it somewhere?

The hoop came from caferacerwebshop: https://www.caferacerwebshop.com/en/1-upswept-15-degrees-loop-extra-long.html
They have different styles of long hoops: https://www.caferacerwebshop.com/en/the-workshop/diy-material/frame-parts/?mode=grid&limit=24&sort=popular&max=250&min=0&sort=popular&brand=0&filter[]=245258&limit=100
I'm not sure if they have us based stock as it seems to be a dutch company? But shipping should be faster than 3-5 weeks.
Also, I don't kknow if I'm allowed to post links in this way. I will remove them if they offend any rules.

I have started working on the seat pan, and currently have laid6 layers of quite dense fiberglass. It was still a little tacky when I left it, so when I come back this weekend I'll have to see if it is rigid enough. Yesterday I also met someone who does upholstery... specifically for saddles (well imagine that!). Quite a coïncidence. We talked a little and unsurprisingly he had some good info. He also knew what kind of foam I should use, and he could supply it so that helps things along a bit. Once I do a bit more work on the seat pan I will post another update.
Just read the whole thread....some nice, considered work going on there fella, good.

I think the pro upholsterer is an investment, a crappy best effort diy seat can spoil the entire bike...for me anyway.

I think the slight nose down stance looks nicely aggressive, but not too much to be silly. :)

I've just picked up on my Suzonda project after a little lay off as life got in the way....back in the garage :)
 

thaBrad

New Member
No I'm not blogging it really....its my first good try (last one was literally in a box and I couldn't finish it) so I'm not sure I have anything I could teach people. I have been taking pictures in case I change my mind. Or maybe start one on KZrider? Thank you for your helpful info of the websites. Good luck on yours....I'll keep watching this for sure.
 

Venderbroeck

New Member
Thx NoRiders, yeah actual upholstery is not one of my strong suits, so I'm getting that done for sure.
Gotta save up a bit for it though :)

Thabrad, this is also my first try at building a bike. It's always nice to see what other people come up with.

The last weekends I had just little bits of time to work on the bike, so while I did get stuff done I didn't have much time to sit down and write a post about it. As said before I was planning to build my seat pan with fiberglass and epoxy. To start off I wrapped part of the bike in plastic wrap:



I am using these of 220g/m2 fiberglass sheets, and epoxy from mr. Boat:



Then after mixing the epoxy and the hardener in the correct proportions the exciting part commenced.
I didn't take any pictures during the process, as I was stacking the fiberglass sheets and frantically applying epoxy on them, but after 6 layers of fiberglass sheets the result looked like this:



I left it to dry for a few hours, after which it looked like this:



I left it to dry more, as it was still tacky. One week later I got back to it and marked it up for the first rough cut:



Here's a view of the tank area after the first rough cut:



I put some extra fiberglass pieces in this area to build it up a little more so I had ample space to shape it the way I wanted.
I then marked it up for a second rough cut:



Here's what it looked like after cutting it:



It's getting pretty close to the look I want. The fabric will lift it slightly more off the framerails exposing them a little more which should look pretty good I think. I still need to clean up the pan further, which I will do using hand tools I think. The angle grinder is a bit too rough for that.

Lastly I welded in another crossbar to support the seat:



It's a bit out of square, which is something I'm not really happy about, but fortunately it will be hidden by the seat. I don't think I will be grinding the welds to get it out again, so I will have to live with it I guess.
If you look closely you can also see the seat latch mounted in the rear of the hoop. There will be a pin mounted on the seat pan that will fit through the hole, where it will be constrained by a catch. The catch can be actuated with the cable. Nice and simple. The latch came off of a KTM, if anyone's interested.

That's all the progress up to now. Next I plan to finalise the seat pan mountings and supports. I may also add some layers of fiberglass in some places to try and strengthen it a little more. With the 6 layers it may still have just a bit too much flex in it, even with the extra support. After that I can start to put on a few layers of foam, and shaping the seat.

I will leave you with a pic of the seat pan as it sits now after all that:
 

Venderbroeck

New Member
Thx :)

I finally had some more time to spend in the garage.
As mentioned before, life does seem to be very good at keeping one out of ones garage unfortunately. Of course I try to spend some quality time perusing the webshops for parts. I found some good quality aluminium clipons that I liked, so finally I have something to hold on to when I'm moving the thing around:



I always liked the look of clipons, so it was cool to finally see them on there. I still need to play with the position though to prevent interference with the tank.

The seat pan also got some attention, as I really wanted to finish it so I can start to put foam on next time. I started with creating and attaching the mounting hardware for it.In the front the pan will be held on by a aluminium bracket which hooks behind a crossbaron the frame.



For the back I created a bracket with a pin which will fit into the aforementioned latch. I made the pin from a piece of round stock that I mounted in the drillpress. Using a file I could round off the end of it. Once the seat is finished and upholstered I will make a cutout at the right position for the latch.

The whole thing then looks like this:



The aluminium bracket will get a better finish, and all the fasteners will be replaced with stainless steel hardware, but otherwise the mounting stuff is pretty much done.

After that I put on 3 additional layers of fiberglass matting and epoxy to add some stiffness. I also reinforced the mounting points for the hardware with 2 additional layers of smaller pieces of fiberglass matting. This really improved the sturdyness a lot. I finished it off using files and sand paper, achieving a satisfactory result I think:





I then finalized the fitment of the seat latch, which works pretty well.


If you look closely to this pic you can see the pin protruding through the hole between the two nuts ;D.

Next up will be seat foam.. Finally! :)
 
Last edited:

doc_rot

Oh the usual... I bowl, I drive around...
DTT BOTM WINNER
Becuase your seat is so flat i'm worried it might bow when you stretch the vinyl over it. Happened to me, and I had more structure than what you have now. it was all good until the first time I parked in the sun and the vinyl shrunk and bowed the whole seat resulting in some decent sized gaps, i eventually got it professionally recovered 5 years later but I made the seat pan a second time. If you add a bit of structure you will be better off, I would lay two or three 12mm x 12mm strips of foam or balsa wood length wise across the seat and glass them in (if possible do both sides as the resin can shrink and bow it as well). No worries after that.
 
Last edited:

Venderbroeck

New Member
Noes, still no foam attaching next time then. It makes sense though, so I will acquire some balsa wood to laminate in there. I think I can still fit something on the bottom side. Thanks for the tip, it would have been a shame to have it ruined by that after all the effort.
 

Venderbroeck

New Member
Becuase your seat is so flat i'm worried it might bow when you stretch the vinyl over it. Happened to me, and I had more structure than what you have now. it was all good until the first time I parked in the sun and the vinyl shrunk and bowed the whole seat resulting in some decent sized gaps, i eventually got it professionally recovered 5 years later but I made the seat pan a second time. If you add a bit of structure you will be better off, I would lay two or three 12mm x 12mm strips of foam or balsa wood length wise across the seat and glass them in (if possible do both sides as the resin can shrink and bow it as well). No worries after that.

How about this then?

In the end I used the same foam as I'm using for the seat itself, as I couldn't get balsawood in time. The pan is also slightly curved length wise, so it would have been hard to get balsa wood to stay flat against the seat pan. It certainly worked well though, as it is now super rigid. It also became a bit heavier, but it's probably worth it to have a seat that won't ruin itself.
 

doc_rot

Oh the usual... I bowl, I drive around...
DTT BOTM WINNER
nice work. it sucks to have to do things twice so i always error on the side of caution. still screw up sometimes though.
 

Venderbroeck

New Member
Yeah, again thx for the headsup. I have a lot more confidence in the seat pan now. I can now easily sit on it without bending it. And I didn't even install the supports yet so it's only resting on the framerails. Good times. Now for that foam..
 
Top Bottom