Winter project: upgrading time! (R6 forks and more...)

Question for the community: one of the things I want to make now is the new seatpan. It needs to have more space to accommodate the ignition and the battery that will be located underneath the seat. Here is a picture of the situation
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Since the seatpan will need to have a lot of 3d shapes (cutout for the tank, hollow for the battery, hollow for the ignition and new seatlatch) I'm trying to decide whether to go with metal or composite like fiberglass.

I can't make it out of alu because I don't have an AC welder. Steel is an option for sure. The old pan i made was steel. I know I need to incorporate stiffening like beads to prevent warping. And it going to be a lot of pieces. Here's a mock-up
IMG_20210124_111741249_HDR.jpg


Then I thought fiberglass might be an option. I have never worked with it but I see people using it to make seat pans. The up side seems to be more freedom to make 3d curves. It doesn't need to me super pretty because you won't see it. Possibly lighter ?

Anybody with some experience?
 

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Fiberglass is pretty easy to work with... I've made and repaired a few things with it, and have been pretty happy with the results. Get some rubber gloves, mixing cups, stirring sticks, and paint brushes that you won't care to ruin...and a little roller helps push everything together. It gets a bit messy...and sticky.

There are some great youtube videos on how to do it. This is one that gives you a general idea on how it's made (The last part of part 1 begins the prep, and part 2 shows the meat of how it's done):

If you're going to reproduce the seat, then making a mold (aka a "plug") first is important with various additional things to consider (like adding a few mm's around the base for the layers of fiberglass to sit flush onto the frame, gel goat and releasing agents, etc...but if it's a one-off seat, then you can skip that and just get to layering on the fiberglass. (Wear a respirator when cutting the fiberglass, you don't want to breath in the dust.)

I made one with 4 layers, and it was just a bit thin and a little flexible (not unusable, but I would do 5-6 layers at min.) I also used fiber cloth (woven pattern) vs. chopped mat fibers. Not sure which is better.

Good luck!
 
Oh...and you should consider how you're going to attach the seat to the bike...you may want to add supporting tabs, or mounting points, etc. in your fiberglass layers.

ALSO, how the seat cover will attach. If you're wrapping it around the edges/staples/rivets, etc...you will need to make sure the seat pan has room around the edges to account for the extra material or you'll never get it to sit flat.
 
Haha I watched that video yesterday! It's going to be a one off. But I do need to fill all the open spaces with something to prevent the fiberglass falling through.

I also read glass fiber with polyester resin or epoxy resin. Can't really figure out which one would be more suitable .

I could make Alu brackets for the mounting and rivet them on. The edge will face down and the fabric goes around and gets riveted.

O it's winter here, not mega cold but the heater can't make it to room temp, would that be an issue?
 
Epoxy resin is all I've ever used. I did find a fuel resistant epoxy resin for a gas tank I built, but it's way expensive and not needed on a seat pan. Temp will just determine the curing time. I think the colder, the longer it takes to cure, but otherwise, shouldn't be too much of an issue from my experience.

I would just use heavy cardboard...cut it into the voids, and then tape the whole thing up over every angle, etc. You want smooth transitions so the mold can pull off easier.
 
Any particular reason for wanting to locate the battery under the passenger seat? At least with a lead/acid battery, that would just put more weight on the rear wheel. And the XS is tail heavy enough as stock.
 
Yes there is a very good reason haha. I have always had the battery box underneath the swingarm. Best sport regarding looks. You can't see it.

However after 12 years of owning the bike, I've had my share of electrical problems. And i don't like laying on the ground next to the road when I'm troubleshooting.

So I've decided the battery will go underneath the seat. Easily accessible and less wiring throughout the bike.

The battery is a glass Mat lead type. But because I don't run the electronic starter its a very small one. I think it's 500-600 grams.

Thought about a lithium one. But I realize they need a different regulator (just got a new stock one). And just seem to be quite sensitive.
 
Thought about a lithium one. But I realize they need a different regulator (just got a new stock one). And just seem to be quite sensitive.

That is not my experience with LiPoFe batteries. I have been using 2 different sizes from Super-B, 2600 and 5200. The smaller size 2600 on my RD350 with Powerdynamo CDI/ PMA, and the larger 5200 on my 1995 Ducati Monster and my 1977 XS650. The same battery has been swapped back and forth, both bikes had totally stock charging systems. No problems of any kind whatsoever.
I believe Super-B is a Dutch or Belgian company, so local to you as well. They do have a disclaimer regarding the batteries, but I believe that is just a precaution against being sued, and not really something to worry about. They say the charging voltage should be between 14 and 15 V, which is pretty much what a lead battery needs anyway.
So I would not even consider going back to lead- acid batteries anymore. Weight wise it is day and night. The original Monster battery is 16Ah, and weighs 5.2 kg. The Super B5200 weighs 0.9 kg, and has no problem at all, cranking the 680 cc 10:1 CR V-twin on a cold morning.
 
Sounds interesting! Just checked the website from Super-B, seems to be a dutch company indeed.
I got the stock alternator, so far its not been super reliable. Mabye the powerdynamo is more consistent?

Just checked the datasheet of the lightest super B battery. The charging rating is quite tight.... (its the ''laadspanning''
super b accu.JPG
 
No major update, but I've been working on the new front fender! Got one from a Ducati Desert sled. Thought it would be ''pretty easy'' to make it fit. It wasn't hard but jeez why does making brackets take so much time:whistle:

I like the looks of it! looks totally different than before. Also managed to get rid of some grams.

OEM fender: 1550 gram of unsprung weight
New fender incl bracket: 700 gram of sprung weight

Time will tell if its capable of dealing with the vibrations:D

Fender 5.jpg

Fender 4.jpg

fender 3.jpg

fender 1.jpg

fender 2.jpg
 
Reducing unsprung weight, especially at the front, will improve the suspension noticeably. I guess your discs and calipers saved at least 2 kg from stock twin discs, maybe more. When I went from the OEM twin disc setup, to a single 320, and a Brembo caliper, and used an alloy fender (conventionally mounted), I lost around 5 kg of unsprung weight. This made the stock 35 mm fork perform a lot better. Surely, your R6 fork is way better again.
 
Yeah a single disk also saves a bunch. I still got two. Do kinda like them. The disks I sourced second hand. The carrier are still from steel, I believe you talked about this before?
Might swap those... some day. Its easy to fall in the trap of spending tons of money on some lightweight parts.

Right now im a woodworker..... the dust of the dead tree carcasses...blegh
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Its for a good reason, making the plug/mould for the fiberglass seatpan.
IMG_20210209_213446603.jpg


hopefully the temperature goes up a bit, its really cold in the Netherlands right now. Too cold for the epoxy.
 
I've learned alot about composites in the last couple weeks. Making the seatpan was a slow process, but i kinda like working with fiber glass. It opens up a whole other can of design possibilities. And its nice that you can do this without expensive machines.

looking back I probably could have dug up some iron ore, cast it, machine it and still be done quicker but hey:laugh2:

seat 1.jpg
seat 2.jpg
So I made the mould out of wood. used some car bondo for the fillets and rough shapes and covered the whole thing in PE packing tape. Since I dont care to much about surface finish, the tape lines dont really matter. After that I put a couple of layers of release wax on it, dont know if it was really necessary.
seat 3.jpg

Before starting on this i made a test piece. I realized that forming the fiberglass over the edges was going to be a challenge. I got two types of twill fiber glass. 220gram/m² and 320gram/m². I started with the thinner of the two and used some reinforcements parts of the heavier stuff. After doing 3-4 layers I covered it in peel ply and put the whole thing in a cloths vacuum bag.
seat 8.jpg


The vacuum bag really helped to press the fiberglass into all the corners. However not all was perfect. I used to much resin and got some air pockets. I reckon some of it is due to the shape of the mould (not ideal) and the vacuum was being blocked due to the excessive resin.

seat 4.jpg


Here you can see a piece where there is no adhesion between the layers. The front of the part was the most problematic due to the shape.

seat 5.jpg

I repeated the laminating process 3 times. Using a total layer of around 7. For the last run I used breather cloth over the peel ply so the air could flow out instead of being blocked, this really helped!

seat 6.jpg
seat 7.jpg


In the end the part cam out really nice! way better than i expected for my first part. The strength seems to be good. Everything needs to be finished but its looking great! Did forget to make a 'pocket' for the tank bolt. Now i need to think about some sort of hook, to hook it under the tank.

O and the weight has been reduced! quite happy with that to.

Previous steel seat pan : 1900 grams
Fiberglass seat pan: 700 grams
 
O in hindsight, what would I have done differently. (maybe someone else wants to try this process):

  • use thinner fiberglass, even the 220grams was hard to conform to the mould. would try around 160 the next time
  • use bigger radii on the mould
  • try to find a resin that is more ''tacky'' so the fiberglass sticks better during laminating.
  • use less resin
  • always use a breather over the peel ply
 
I also geeked out on the bracket for the horn. I wanted to stiffen the steel bracket, so I experimented with pressing a rib into it. Made two V-blocks and using a press it worked pretty good.
horn bracket.jpg

I made a new tray for the battery and the rest of the electronics. Made it out of Almg3 aluminium. I did the fabrication and a coworker welded it. Would be nice to have an AC machine at home...o well cant have it all.
batt tray.jpg

batt tray 2.jpg

used four rubber grommets to mount it to the frame. I welded some threaded bungs into the frame (no pics from that). Its a snug fit but I like it, its not that much bigger than the old tray. Especially because I made the cut out on the seatpan.
 
Almost forgot! Im now working on the new and lighter sidestand
sidestand 1.jpg
The head is mild steel and the tube is Chromoly (24CrMo4)

sidestand 3.jpg

some preheating before welding

sidestand 4.jpg

All welded up. According to the datasheets the thin walled stuff should not need a heating treatment. Lets hope it wont snap haha
 
Very nice! Do you realize how bad you make some of us others look ? ;)
And you may already have thought about it, but a small drain hole in the battery box may be a good idea.
 
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