rear shock extender

[marp68]

Just wanted to share and tip about raising the rear part of the bike. I did it for the look and for perhaps achieving better handling.

I got the tip about using longer shocks (thanks grizld1!) when discussing tyres heights. Since I like my Koni shocks, a pair of longer good ones would cost a bit. So after googling I found some rear shock extenders used for minibikes and scooters that had the correct measurements and bolted almost right on. For the lower part I had to use two spacers. The extender will lenghten the shock by almost 3 cm, which according to others seem to be max. Other xs owners have pointed out that longer shocks would risk the chain to to touch the swingarm. 3 cm seems to okej, though.

I bought these from www.petrolscooter.co.uk, 2 for £ 5.50. I bought the alloy finish and just sprayed them black with som old paint I had. They can be found in other colours and were sold in other stores as well. Just google on "shock extender/extension".

Has anyone used theese before and know anything about quality and bike handling after mounting them?

Now I'm just wating for some warmer wheather.

 

[CDNTX650]

Thanks for the tip. I want a little more clearance on my xs400. Might have to try those.

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[FLEA]

just ordered a set,mainly to try, should be intresting,,for aust worked out to $16.50 a pair delivered,cheaper than new shocks if they work

 

[Just Plain Bill]

You may need to "lengthen" your side and center stands to make up for the increased height of the frame. The quick and dirty fix is to weld a bit of 1" square tube on the side stand end to get the extra length. However, it contacts the frame and doesn't allow the arm to fully retract. Only an aesthetic problem.

 

[Brassneck]

You may need to "lengthen" your side and center stands to make up for the increased height of the frame. The quick and dirty fix is to weld a bit of 1" square tube on the side stand end to get the extra length. However, it contacts the frame and doesn't allow the arm to fully retract. Only an aesthetic problem.

I don't think that raising the shocks wouldn't raise the frame height...at least it didn't on mine... the tires/frame don't move...just the seat/stance. Or am I missing something?

 

[CDNTX650]

Like the seat being attached to the frame....

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[Brassneck]

Ah...my bad, I stand corrected.

I did notice the frame was raised a bit...but not so much that I needed to adjust the center stand or side stand...but that was a 1" raise...more than that, and I suppose it would need to addressed.

 

[grizld1]

Marp68, that's a fine looking machine. Congrats. Keep an eye on those extenders, though, and make sure they're up to the job! Things could get ugly in a hurry if one failed.

 

[marp68]

Thanks, grizld1

Yes, I've had my concerns. But at least they are made for scooters with single shock and while mounted on the frame, they sort of become one solid unit. But I will keep an eye on them and if I get suspicous about them, I intend to have them made in steel by a local workshop. And of course write about it here...

We've had a few days of early spring, so I went for a short ride. The bike felt okej, especially with the new tires. A little quicker steering, but some of it depends on the new tyres. Will have to try it on smaller and more curvy roads.

FLEA, I didn't have to change my center or side stand.

 

[5twins]

For the added shock length we use, the centerstands are plenty long enough, but the sidestand may need some lengthening. The "fix" is simple enough, just weld some plate to the foot bottom. How much you need will depend on how much longer your shocks are. Usually it's between 1/4" to 1/2" .....

 

[FLEA]

thanks can you do a update after you have used them for a while,good news about not having to exstend sidestand

 

[marp68]

I have to edit my answer about the side stand a bit. Yes, you can use it, but the bike tends to lean to the side more. So be careful if you are ot parking on solid horisontal ground. Or change the side stand like 5twins suggested.

Another way is to just carry with you a little flat piece of plastic with walls that you place under the sidestand. Very handy when parking grass etc, but also for this purpose. See example here http://www.biltema.se/sv/Bil---MC/MC/Depastod-och-transport/Sidostodsplatta-MC-82165/

 

[marp68]

One thing crossed my mind now. As you probably noticed the two extender mounting ends were twisted 90 degrees so that the mounting of the shock had to be turned as well. While searching the net for the extender I couldn't find any that was not twisted.

Since there is a rubber bushing in the mounting holes of the shock, I assume the purpose is that when the shock is pressed/depressed, the mounting will turn slightly around the bolt. Now, when the lower shock mounting is twisted 90 degrees, the bushing can't turn.

Wouldn't it be necessary for it to be able to turn slightly when the shock is pressed/depressed and could it be a danger when riding? Or could one do without the bushing effect?

I'm thinking if I should get my local workshop to have an extender made with no turned mountings and in steel, even though it would cost a bit. Couldn't find any extender to buy that was not twisted 90 degrees.

 

[weekendrider]

If the bolts ran the same way wouldn't it have a tendency to fold like a double knuckle hinge?

 

[5twins]

Yes, it would pivot and fold down under pressure. That would be needed is a triangle shaped extender with the base of the triangle seated along the swingarm. Then it couldn't rotate under pressure.

 

[marp68]

Good point weekendrider.

There is however only one bushing, the one one the shock. The lower part of the extender is mounted tight to the frame mounting. Don't know how big the risk it would be that it could may fold down under heavy pressure, when it's mounted tightly. Turned as now I thought the bigger risk would be that the U-shaped walls of the extender brake under pressure, since it's only alloy.

 

[5twins]

Yes, the extender will stay straight as long as the mounting bolt stays tight, but these are vibrating 650 Yamahas, things don't stay tight, lol. You would need a square base on the extender that sat right down against the swingarm. Then it couldn't rotate even if the mounting bolt did come loose. Look at the rounded bottom of your current extender. That won't do the job on the new one.

 

[arcticXS]

marp68,
I do see the point of raising the rear of the bike at a very low cost, especially as you are happy with your Koni shocks. However, if you got longer shocks, you could get the additional benefit of a longer shock travel, and longer rear wheel travel. I guess most shocks with 320 mm C-C will have 75 to 80 mm stroke, giving around 100 mm rear wheel travel. If going to, say 340 mm C-C, you could get 100 mm shock travel, giving around 120 mm rear wheel travel, which is approaching what a modern bike has.

 

[5twins]

You would want the base on your new extender to look something like this .....

 

[marp68]

lol, yes they do vibrate quite a bit.

Very good point. Funny you mentioned the square bottom. Now I remember when I first talked to my local workshop two month ago about making it, before knowing the price and finding it cheap on the net, we did discuss this possible problem with two point joint. And we came to the conclusion that the square bottom would solve it.

This is my first drawing I made after talking to him about my idea. Sometimes the first idea may be the better one...

When mounting the extender I bought, I however noticed that if I would have mounted the botton of the shock normally, with the holes facing the wheel, the U-shaped wall and nut on the inside would end up very close to the chain guard or chain. If possible at all.