Down under, an idiot and a 400F

[hillsy]

It still amazes me how they put the pillion pegs on the swingarms on some bikes. Must be a hard ride for the passenger at times.

 

[neevo]

It still amazes me how they put the pillion pegs on the swingarms on some bikes. Must be a hard ride for the passenger at times.

2up riding sucks arse anyway unless you're on an armchair.

 

[o1marc]

Yeah. It's bracing for the mono shock mount.

That's Kevin's swingarm from TTR400 isn't it? Killer bit of kit.

No, It's Rick Denoon's swing arm. I'm making 3 of them right now with bronze bushings if anyone needs one.

 

[neevo]

No, It's Rick Denoon's swing arm. I'm making 3 of them right now with bronze bushings if anyone needs one.

Ah of course. Knew I'd seen it somewhere before.

Maybe I will use the other brace underneath too

How are you fixing the swingarm before welding? Do you have it in a jig?

 

[ronnie]

No, It's Rick Denoon's swing arm. I'm making 3 of them right now with bronze bushings if anyone needs one.

How much you making them for, just curious?

 

[o1marc]

How much you making them for, just curious?

Probably around $250 with your swing arm. $350 with a refundable core charge if I use my arms. $50 extra with Bronze bushings. I may make just the brace for you to weld on yourself for around $200 in either stock muffler mount or one that you need to move the muffler hoop out about 1/2", does that sound fair. Ricks are $375 with $200 core charge.

 

[neevo]

A big day today, not only from a effort stand point but also a significant milestone in the epic journey I've had with this little bike. Without spoiling too much, it's now able to stand on its own two feet, something it's not done since the day I bought it, needless to say I'm quite chuffed

So today the plan was to get the swingarm brace in. Tacked at this stage so I could test it out and check the placement of everything. First up was trimming the brace down to length, I used the old brace as a guide and cut the ends down, leaving them a little longer this time so I could try and finish the ends off nicely once it was welded on the bike. My tolerances on the mockup were too loose so I tightened them up, aiming for a much tighter fit:

Seemed to fit nicely although one side was a little larger than I hoped. Nothing a little extra weld won't fix:

Next up I checked what height I wanted the brace to be, a little fiddling and popping it back on the bike, I settled on 140mm off the swingarm. Funnily enough it changed the stance of the swingarm, much for the better as the sweeping look made it much prettier I thought:

Next up a quick check to make sure the hugger would fit in there. All seems good there:

Before I welded the uprights I wanted to check there was enough clearance for the rear tyre, so it all went back on the bike for another check. Wheel all the way forward, it was close but seemed to be working out well:

So I set about cutting the uprights and lower shock mounts. Had some trouble with the TIG torch and the gas lenses I bought. The electrode kept fizzing like the gas wasn't turned on, tried less gas, more gas, but ultimately couldn't get the bloody thing to work

So I popped the old stuff back in and set to tacking it up oldskool style. Didn't work out too bad and was laying some reasonable welds, all tube edges were heavily chamfered to maximise penetration:

Base is done, however I still need to weld in the middle uprights:

Took it outside for some better pics:

Fitted it up on the bike and set to bolting in the shock, turns out my measurements were pretty tight as there was about 1mm clearance between the shock and the swingarm brace:

So my little bike is back up on its feet:

The rear end is waaaaay to far up in the air and that's because the spring is far to heavy duty. Almost zero static sag, so if I get a lower rated one it should sit 25-30mm lower. The bump stop is in the right place though so the rear wheel does not hit the subframe tray at full compression.

Another problem is my turning circle is appalling!!! Is this normal for USD fork conversions?

 

[MotorbikeBruno]

It is a tad "up in the air" as you say

But very cool, and glad to see this coming together. Love your build man.

 

[neevo]

It is a tad "up in the air" as you say

But very cool, and glad to see this coming together. Love your build man.

Yeah just a touch high, but I'm not overly worried, adding the internals for the motor will add a tonne of weight which will drop it down a bit, if I don't get it to approx 15 degrees below horizontal I will look at another spring rate. The monoshock has way more travel than the stock 400F shocks so that why it starts so low. Should be fine

 

[MotorbikeBruno]

Yeah just a touch high, but I'm not overly worried, adding the internals for the motor will add a tonne of weight which will drop it down a bit, if I don't get it to approx 15 degrees below horizontal I will look at another spring rate. The monoshock has way more travel than the stock 400F shocks so that why it starts so low. Should be fine

Yessir. And just to ask, why 15 degrees. I had read between 0-10 degrees is best, but I suppose that depends on how you want it to handle right?

 

[o1marc]

That is looking nice. I had thought before of how much work making CB400 a monoshock and you have proven it is quite doable. Now I have to go and find another cheap 400 to that to.

 

[neevo]

Yessir. And just to ask, why 15 degrees. I had read between 0-10 degrees is best, but I suppose that depends on how you want it to handle right?

Because with the longer shock I need bit more static sag, so I was thinking if I go 15 degrees that should sit right when there is a bit of weight on it. Static sag on the original shocks is a little less I believe.

 

[stroker crazy]

Looks great neevo!

Crazy

 

[crazypj]

I like the 'nose down' look. 8)
With less offset on forks you'll need steeper steering head angle to maintain trail

 

[neevo]

I like the 'nose down' look. 8)
With less offset on forks you'll need steeper steering head angle to maintain trail

It's a bit too nose down at the moment

What's the alternative for the trail PJ? I assume the lesser offset has decreased trail, and having the arse up a little bit will do the same. Other than cutting the head stem and raking it out, having custom triples made, I'm not sure how to make sure the handling isn't adversely affected.

 

[crazypj]

Less offset increases trail, you may have 5+inches now.
It's why CB350's get so stable when forks are swapped, people thing it's better forks but really it's increased trail
http://www.bikerenews.com/Stories_Archives/Motorcycle_suspension/Rake_trail_1.GIF

 

[neevo]

Ah sorry I got the wrong end of that. USD forks should equal a bit more stability. Good news them

 

[crazypj]

Just edited to put in a link. As offset moves fork legs closer to steering head, the axle also moves 'backwards'
so trail increases.
It's counter intuitive ;D

 

[neevo]

Just edited to put in a link. As offset moves fork legs closer to steering head, the axle also moves 'backwards'
so trail increases.
It's counter intuitive ;D

Yeah that was totally confusing me. Just read an article on it to help get my head around it. That good news as increased trail will help offset a shorter front end. Maybe no negative effects if I'm lucky.

http://bikearama.com/theory/motorcycle-rake-trail-explained/

 

[neevo]

Exciting stuff, my gauge is in:

Tested some positions on the bike to see how it looked.

Attached to the top of the triple clamp (easily done):

It looks great from the bike, but looks too tall from the side.

Next up was a lower mounting point (not easy as I'm going to have to come up with a mount for it somehow):

A much better profile but the lack of mounting point is going to make it a bigger to put in this position. I'm thinking of having the ignition shutoff button mount remade to include a mount for the gauge too by extending the lower part out: