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Kimjon

Kimjon's Harley bobber project

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Got the sheetmetal hidy-hole seat pan thingy finished off and painted.

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I hammered a recess in it to allow the cord to go through.

The seat needs to hinge forward so I can access the oil tank, so bringing the wires out the front by the pivot point will allow for this to happen.

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And finished the LED rear lights hidden in the seat.

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And from a few paces back you'd hardly even notice it when it's not turned on.

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This performs a heap of functions like:

• Dim red when lights are on

• Bright red when brakes are used

• Left and right turn signals 

• Hazard lights.

My certifier will have the final say: if it's okay...its staying - If it's not enough, then I'll go to plan B.

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4 hours ago, Kimjon said:

My certifier will have the final say: if it's okay...its staying - If it's not enough, then I'll go to plan B.

My woffer didn't mind the brake and tail light but wasn't okay with the integrated indicators so went for some really small LED ones on the side..
Might be an option if you run into this. Looking goood man!

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Got sick of working in the shed, so fucked around on this for 20 minutes. Its amazing how you don't think of much else - just live in the moment when there's a slight element of risk associated with an activity...love it!

 

 

Will get back on track with the harley build soon. But nice to have a distraction for a while.

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Arghhhh my eyes...my eyes...it hurts so much!

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Ugly as fuck front fender. I paid $30 for it at a swap meet, possibly around $28 too much? God its ugly. But some dumb law in NZ about needing one apparently exist? I'll give it some time to grow on me, but yeah/nah I'm not a fan.

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Here's the problem.

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Without actually measuring it, it looks like a 2/3rds ratio. The rocker is attached to the fork legs on a fixed pivot. The wheel axle is right on the end. The spring forks are about 2/3 the way on the rocker.

So example:

Say the front tyre hits a huge 100mm bump in the road, the front axle goes up 100mm.

The fork tubes go up 0mm

The springer tubes go up 2/3 of 100mm = 66mm.

 

Problem:

The fender mounts to the Springer tubes. So if you have a nice tidy 15mm gap set between the fender and tyre at normal ride hight, then you hit this hypothetical 100mm giant bump in the road, the fender only moves up 66mm, but the tyre moves up 100mm.

Maths is fun:

100mm tyre movement - 66mm fender movement - 15mm true fender gap = 19mm of interference between tyre and fender resulting in killing the rider (me). Sad face!!!

 

Solutions:

1) mount the fender a mile higher than the tyre and look like a total cunt.

2) create a pivot point off the axle, so the fender moves with the axle and maintains constant gap between the tyre and fender irrespective of travel.

 

I like solution No2. But that means heaps of work. Hmmm???? Balls!!!!....

 

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Google searching and I found my theory confirmed.

846722011_OlSkooldamage001.jpg.4961b8d73437cf7d773bedbe0d72b33c.jpg

This is what happens when the fender is mounted on the springer arms and set to low. 

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Just now, Beaver said:

Mount off the caliper mount/arm thingy?

Yeah, something like that looks like the answer.

It's fine line at this point. The risk of ending up here is only a few bad styling decisions away from happening.

 

  • Haha 2

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Just realized anyone younger than 40 probably doesn't get jokes from 1980's movies.

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  • Haha 1

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Righto, did the real maths.

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So, ruler is back to front...but imagine it's the other way around and zero is where 3.5" is, then:

2" ÷ 3.5" = 0.57 ratio.

What this means is for every 100mm the tyre moves, the guard only moves 57mm.

Now looking at the springs, the average gap is 5mm. It ranged from 4 to 5.5mm but 5mm is good enough to use. There's 10 gaps, so:

10x 5mm = 50mm 

So maximum tyre movement is:

50mm ÷ 0.57ratio = 87mm suspension travel.

 

Now...This is the fender mounted 30mm above the tyre. Looks okay, but not great.

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However 50mm, which is what's actually required for it not to contact the tyre will just look dumb! So that means doing what Beaver describes above, radius off the axle. Now I've confirmed that...just gotta make it look good???

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Next up, a problem I could solve. My mailbox had the correct banjo bolts in it this morning. Supplied free of charge because the dumb fucks sent the wrong ones a few weeks ago.

Should just bolt straight on eh...

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WTF!!!

That's the forward control, the rear was even worse. So I need to machine at least 1mm off the front banjo bolt, and 4mm off the rear one just to get them to fit. 

So:

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I made this collet to hold the bolts without fucking the fine thread.

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Mounted in the chuck.

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Machined down and a new countersink cut in, just like they came from the factory...but now shortened the required amount/s to fit.

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Front finished 

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And the rear.

So that's one less thing to do. Makes me wonder how people get on building this stuff if they don't have a lathe? Pretty much everything I buy online doesn't work first time, nothing just "bolts on" like its sold to you as.

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V1.0

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Still sucks cock... but I'm stuck with either terrible high boy fender or persevering with this concept.

I'll walk away from it and come back to it again later. Sometimes that's enough to allow for:

A ) to accept this is an okay solution 

Or 

B ) a better idea comes to mind.

 

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How sure are you of those calcs? I'm just picturing the lever action in my head and I can't make the numbers work (i.e. it doesn't look right that the difference between the wheel path and the spring link is that much). Obviously you have the bike in front of you so I'm not doubting you, just want to make sure that you're sure....hahaha. Is it possible to do move the linkage through it's travel without the spring or whatever?

Feel free to tell me to go away haha

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1 hour ago, Beaver said:

How sure are you of those calcs? I'm just picturing the lever action in my head and I can't make the numbers work (i.e. it doesn't look right that the difference between the wheel path and the spring link is that much). Obviously you have the bike in front of you so I'm not doubting you, just want to make sure that you're sure....hahaha. Is it possible to do move the linkage through it's travel without the spring or whatever?

Feel free to tell me to go away haha

Any input is always welcome. We all see things through a different lens and sometimes the answer is obvious to anyone but the person who is looking for answers.

Calc wise, I'm 95% confident. It's never going to fully compress those springs, just like your car never will either. But theoretically if it did, then theres approx 50mm of compression there to be had where the fender is mounted (87mm of tyre movement at the axle). So the fender has to be mounted bare minimum 50mm above the tyre if using those factory tabs on the front end.

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Which would look like this (or worse). Ugly!!!

May as well be a MX bike with a fender that high...

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So I've mocked this up today, which takes the geometry out of the equation as it moves the fender over from the springs to the axle. Then its just 1:1 ratio. As in the fender moves with the tyre, the gap never changes.

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It's not finished, needs a tweak or two, but it will work. I just wish our laws were as relaxed as the US fucken A. Then I wouldn't run a front fender at all.

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Have you got something you can mount it to on the other non caliper side? 

Another idea, what about limiting the front travel with some sort of bump stop setup? If you got the front travel down to say 40- 50 mm max then your guard could be mounted at your original 30mm height?

 

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What colour you going On the fender , obviously the current colour isn’t doing it any favours Sticks out like dogs balls etc 

 

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Just now, cletus said:

Have you got something you can mount it to on the other non caliper side? 

Another idea, what about limiting the front travel with some sort of bump stop setup? If you got the front travel down to say 40- 50 mm max then your guard could be mounted at your original 30mm height?

 

I was going to see how rigid the cantilever was. If needed I'll machine a plain oil life (sintered bronze plain bearing) into the spacer on the other side and mount off that with a connecting rod.

I like the idea of a bump stop though. Will have to think on that one...thanks! 

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