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TY 175 Rear Shock Top Mount Mod


rock hopper
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Very common mod to increase rear wheel travel and if you use the same shocks, raise the rear.

Was standard on Yamaha frame Majesty 175/200.

Lots of TY175s modified that way by owners in the 1970s and still commonly seen being done.

There was a kit available for it a few years ago.

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  • 7 months later...

I designed aluminum brackets to lay the standard TY175 shock forward as much as they could go, brackets could be taken back off to return the frame to stock and the only modification that altered the rest of the bike significantly was that the chain guard needed to be modified to give the shock clearance, otherwise they connected to the existing shock mounts.  I ran the springs off a TY250 at the time and that was sufficient for my lightweight, many would need to upgrade the spring rate even more.  The modification for my weight and spring rate didn't alter the static ride height much from stock, but the rear wheel drops way further down and improves traction going over big logs and the such.  I could share the pattern here if you still have interest.

Edited by lemur
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2 hours ago, mcman56 said:

I would like to see.

Might take a while, it's not stored where I expected and I think my only computer copy is on a floppy disc lol

 I'll post it up here as soon as I can locate.

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Super rough not to scale mockup on a completely different bike model just to show how it works:

rail.jpeg.d0ec634fb8620ab171901b2b32b05740.jpeg

1.25" x .5" by roughly 7 inch long piece of aluminum bar stock cut something like the photo, the top 2 round circles represent threaded holes, the large black circle indicates where a larger threaded hole will be the new top shock mount post or bolt.  The yellow tape represents a stainless steel strap or plumbing clamp to prevent the bracket from pivoting on the original shock post when the shock tops out and needs to carry the rear wheel.

 

topmount.jpeg.38f015311c9a905c7917fe6b3dff3916.jpeg

Top bracket is 1.25" x .75" thick aluminum bar stock about 3 or 4 " long, bar is rounded at the top where the .5" clearance hole is drilled and affixed to the original top shock post.  the 2 big black dots represent where you drill countersink clearance holes to solidly connect the 2 aluminum bars together.

shockposition.jpeg.716aed636a0a32a930b5b6495e299190.jpeg

Next you attach the shock to the lower bar and for a twin shock TY175 or TY250 you are looking at moving the shock 2.75" or to where the distance from the swingers pivot to the lower shock mount is the same as the distance from the lower shock mount to the new shock top mount position.

Remove the springs from the shocks and remove the chain guard, move the rear wheel through it's entire travel to make sure the position is correct and nothing binds and that the  rear brake does not activate when the wheel is traveling further than before, if the brake does activate or pulses at the lever you might need to loosen off the brake setting or convert the solid brake rod to cable which is way better anyway.

For tools you are going to need a bandsaw or hacksaw, drills and taps to cut and thread holes in the aluminum and a couple of cheap stainless pipe clamps from a plumbing store.  You will have no problem making it look way better pretty then these 5 minute mockup, if you drill the holes right the two aluminum bars should end up inline with one another.

 

Edited by lemur
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Spell check messed one part up; distance between the swing-arm pivot point and the lower shock mount bolt, should be the same as measured from the swing-arm pivot point to the new upper shock mount bolt, so basically the shock won't need to rotate on their mounting brackets very much.

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8 minutes ago, mcman56 said:

  How much did it raise the seat height?

With the spring rate I was running, once I was riding, pegs the seat height was the same as stock but the wheel moves 2 or 3" more overall.

 lol I can do it cheaper then 30$

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