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  • Writer's pictureMatt Spicer

Tolerance stack up errors and FZ07 Risers.

I took some time to look at the shifter side riser.  I thought this was going to be V3.  When checking apparently this will be V4..

So I wanted to take a look at the OEM riser for clues on the variance Yamaha is expecting with the frames.  I know on one of my bikes the fit perfect...obviously the bike I took measurements from.  The other bike, eh they fit but it's not exactly concentric in one of the holes.

I've also had some feedback that 2-3 customers had issues with bolting them on.  It fit but wasnt perfect and that isn't what I want to hear.  I want people to be excited about the parts I make and not have small issues if I can avoid it.

I originally measured the OE riser using gage pins and triangulating to build the geometry.  Works for simple parts like this and then you can look at the number convert to nominal and most of the time its good.  I do remember I also measured the bike with the mounting bolts to the swingarm pivot and have to compromise to get the original 3d printed risers to fit with the mounting holes concentric.  

Flipping through the versions I made small changes to dimensions, nothing major everything would be forward and backwardly compatible without issue.  I was curious how I originally reference the slot in the OE mount and see where my assumptions failed me.  In the sketch I removed it entirely.  Normally I would take the center of the slot, and add a bit extra clearance .2-.3mm depending on the size of the slot.  Something like this...

With slop in fasteners, etc it would normally work fine and everyone is happy.  The factory slot in the riser can work around 2.1mm of misalignment and allow the fastener to still fit concentrically add in 0.5mm of clearance around fastener you could argue it can deal with a little over 3mm of variance in the lower mount.

My riser not so much.  I was not planning for this kind of variance.  If I hadn't scanned the part I would have just said that is planning ahead for the worse case and at no point would you see that kind of variance out of production for the lower riser mounts.  However, when I reference my riser in the plane I designed it to mount to the bike It's off from the OE plate almost 2mm from ideal centers.  Still fits but the complication is my riser needs slight rotation of .021" to get there and explaining why some bikes have the issue an others do not.

So what's the next move?  Well incorporate the slot in the mounts and I think I'll add height adjustments.  I'm on the shorter side and like my pegs way up and back.  Some of you over 6' might find the position cramped.  I'm currently down to 1 set of risers so now is the time to fix it and over a better part. 

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