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Tire centered in frame??


NotStock

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On Thu Jan 25 2018 at 12:11 AM, NotStock said:

Well that was absolutely terrifying. Stress level is at 11 when twisting your frame up like a pretzel. I tried some really questionable setups with ratchet straps before resulting to the mess shown below. End of the day, it all worked out, just had to jam a floor jack in there...

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3/4" doesn't sound like much, but it was well worth the effort. 

 

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Big thanks, yet again, to No Class for the instructions. 

 

Just curious and maybe missing something but how did you make sure the spread was even ?

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16 minutes ago, gsx said:

Just curious and maybe missing something but how did you make sure the spread was even ?

Thats a good question, and I had the same thought before shoving the jack in there. First thing (in my case only) was to finish weld the repaired side to make 100% sure both sides were equally stiff. After that, you don't really get any guarantees. Aside from making a serious jig, or putting it on a straightener, I don't see any way to ensure both sides are perfectly offset from the centre.

The good news is there is no reason for it to want to spread one side more than the other assuming your frame is in OK condition. Pushing against both sides when spreading the rails should keep everything even, both sides see the exact same force. When I squared everything back up and welded the last brace in, the pivot bolt didn't bind in the the existing bushings, which is a good indicator that everything stayed pretty parallel. 

If you had something go south and one side spread more than the other, you could make adjustments in the motor mount spacers I suppose. It might even be beneficial to spread the chain side a bit more? In my experience messing around with a bent frame, it is REALLY difficult to find tiny misalignments in your frame in your home shop, so I doubt you'd be able to notice if one side spread a 1/16th of an inch more than the other. At the end f the day, we are only talking about 3/8" per side.

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7 hours ago, SiBag said:

I was putting a XJR 1200 swingarm in my GS1000. Pivot point needs machining down but its doable.

Quite chunky looking.

I really like the xjr swingarm, and I have pivot room for it, but I'm worried it's too long for what I'm after. How long is that swinger from pivot to axle?

I bought the cheapest b12 swinger on Eblag and I think I might even take an inch out of it. Looks easy enough. Maybe not. I may just put it in the corner for my Z and buy something else for this project.

Check out the before and after on this greasy mess.

 

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 This guy didn't mess around when it came to chain lubrication. That thing spent a long time in my home brew parts washer.

Edited by NotStock
ugly
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23 hours ago, SiBag said:

This was a quick mockup with the XJR swinger in a GS1000 frame.

(Yes I know the shocks are the wrong was round)... :$

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I like that swinger a lot. Looks like the bandit one, but has dual shock mounts already welded on. I have a real fear of structural aluminum welding so it is a big point in favour of that arm. The chain adjusters on that arm are also cool looking.

I have a lot of good options now thanks to this thread and some conversations with members here. I find half the problem is knowing what is out there! I'm going to get the bike on its feet, set the rake, ground clearance to see what the shock mounts, swinger angle, and chain run look like before buying more stuff! 

Also, good call on the shock disclaimer. The internet is full of people who are easily triggered, so its always good practice to disarm them right off the start lol. Bike looks cool! I was always a Z1 and H2 guy, but this Kat (and OSS in general) have me wanting a GS1000 now!

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On 2018-02-05 at 6:29 PM, no class said:

Yam thunderace has a beefy looking short swinger.... can't give ya the actual measurent though ..... btw.... good response on the frame spreding.... could not have said it any better myself .

 

No Class, any thoughts on lowering the swingarm pivot point while I'm in the process of making new bushings?? I was thinking of boring the bushings eccentric by a bit to move the pivot point down. Know what I mean? My thinking was to provide a bit more chain clearance on top of the pivot point when raising the back of the bike up. I would have to completely reassemble the bike and check the chain run to know if this is a good idea, so I'm just feeling it out right now. Maybe I would just be better off to make a slider for the top of the arm and not worry about it. 

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What motor are you using .... air... oil ?  I ask this because depending on where the motor is placed ..... oil cooled for example ... if central or forward , the output shaft is now further away from the pivot point which will slightly change the chain height (lower)..... this can be compensated by using larger F/R sprockets . The other problem is chain tension..... moving things around changes how the chain reacts to up and down movement of the suspension via the swingarm / pivot..... the last thing you need is your chain tightening when the suspension is compressed . I guess you can get away with subtle changes at the pivot as long as the arc  remains within a measured amount of suspension travel .

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12 hours ago, NotStock said:

No Class, any thoughts on lowering the swingarm pivot point while I'm in the process of making new bushings?? I was thinking of boring the bushings eccentric by a bit to move the pivot point down. Know what I mean? My thinking was to provide a bit more chain clearance on top of the pivot point when raising the back of the bike up. I would have to completely reassemble the bike and check the chain run to know if this is a good idea, so I'm just feeling it out right now. Maybe I would just be better off to make a slider for the top of the arm and not worry about it. 

When (if?) I pull my bike back to the bare frame at some point, along with knocking some head angle out of it, I'm going to either lift the back of the motor, or mess with the swinger pivot - a bit of extra height over the swinger pivot would make life a lot easier.

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6 hours ago, no class said:

Yes..... how could that possibly be when I have the fastest Kat on the planet ?

Im talking about around a race track, not at the drags. And it has a sister now. Well two weeks ago the only bikes that finished in front of them where harris/xr69 type specials im sure.    http://bikereview.com.au/shawn-giles-19-tbr-katana/

 

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Edited by sharpy
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Those bikes are the reason I'm all stressed out about swingarm length. They are running (from my measurements) 20" long swingarms. Looks like the b12 is 21" at its shortest. A bit long, but certainly better and lighter than the 22" arm I was planning to use.

Since I didn't get a stock kat swingarm with my bike, anyone know the approximate length from pivot point to axle? I believe the bikes you posted pictures of are running braced stock swingarms.

Since I have no idea how to make decisions on wheelbase and rake I decided to just copy track bikes. After measuring up pictures of old race bikes and the 1135r (from pictures in cad), they all seem to share some dimensions. Makes me think I'm on the right track.

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  • 1 month later...

The quest continues...

Before anyone says "this is an exact copy of what no class did on his bike". Yes. Yes it is. There is not one original thought here, right down to the zrx pivot bolt! Thanks again, no class.

Built a bushing to cut the pivot out of the frame. 

 

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Naturally, after buying what I thought was the best hole saw I could get my hands on, and a fancy 3/8 arbor....

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its super effing crooked and crappy looking. I ended up messing with it and getting some of the runout out of the whole setup, but it still had a good wobble. Note to self, order Lenox next time...

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Metal chips and PB Blaster in my coffee, but the holes are cut. Get a 1/2" hole saw and a 12" extension. No class mentions this in his build. An 18" extension won't fit!

whipped up some bushings in the lathe and...

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Ready for measurements and welding. Next up, swingarm install and spacers to finally get around to that problem of squaring the ass end up. God, did that ever snowball out of control.

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