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View Full Version : Fitting a rear shock? What's involved?



racefactory
11th March 2010, 07:24
Hi all,

Wondering what is involved in fitting a rear shock (same model) to a bike. Wondering if i can do this myself with some basic tools.

Thanks

Vgygrwr
11th March 2010, 07:50
Maybe depends on the bike. I found it an easy half hour job using a couple of car jacks under the footpeg mounts to take the weight off the shock then the right socket and allan key to undo top and bottom. Easy to lift out in my case the replacement was a bit longer so there was a bit of mucking about lifting/lowering bike and back wheel to get everthing lined up. Good idea to check/grease bearings while apart. Take for granted some comments on ensuring bike will not fall on you and correct torques on suspension parts.

CookMySock
11th March 2010, 07:53
Yes you can.

Crack linkage bolts and shock bolts, and lift the tail of the bike so the rear wheel is just off the ground and the side stand is down, or use the main stand if it has one.

Remove shock bolts and enough linkage bolts to slide the shock out. If linkage or swingarm bits are in the way, lift the rear wheel to provide clearance.

Make sure you torque everything up properly afterwards.

Steve

vifferman
11th March 2010, 07:57
Yeah, depends on the bike. It took me several hours on the VFR800, because the instructions were written based on a 1998 test mule, which doesn't have a catcon under the lower shock mount. Plus the new shock has a remote reservoir, which the factory insisted should be mounted to the right pillion peg (which is where my Satantune is bolted). I wanted it elsewhere, so futzed about for ages trying various options before mounting it under the seat. It has since been moved to the left pillion peg, on a custom-made three-part bracket.
As for doing it yourself - yes, provided by "basic tools" you mean the appropriate spanners/sockets for the bolts you need to remove. If you don't, they should be easy enough to borrow. PM me if you need something you haven't got, or need some help.

racefactory
11th March 2010, 13:51
Hey thanks guys. Is it ok to just stick a car jack under the header pipes of a VFR400 and crank it up? Don't know how people in their garages prop the bike up eh. I did it once by brute strength, lifting it onto my tool box but i have no clue if that is acceptable or not.

I can get hold of a shock in good condition, recently rebuilt... but i want to know if there is a way i can crank up the rear ride height a bit with a simple mod. Is there anything simple ike a spacer you can get to prop it up? I'm not keen on swapping out the shock with another bikes shock unless its a simple direct fit eh.

Thanks heaps eh

CookMySock
11th March 2010, 14:01
Not really safe doing that. If it comes off, the fucker could land on you.

I hang them from the rafters with a rope, mind you thats my solution for everything. A few KBers could do with the same treatment perhaps.
:killingme

Steve

vifferman
11th March 2010, 14:53
Hey thanks guys. Is it ok to just stick a car jack under the header pipes of a VFR400 and crank it up? Don't know how people in their garages prop the bike up eh. I did it once by brute strength, lifting it onto my tool box but i have no clue if that is acceptable or not.
I've done that, with a block of wood to spread the weight a bit, but if it was resting on only the jack/wood and front tyre, it's pretty wobbly. If you need to put any force on a spanner or bar+socket, it's likely to fall off. Find some other places to support it as well.


I can get hold of a shock in good condition, recently rebuilt... but i want to know if there is a way i can crank up the rear ride height a bit with a simple mod. Is there anything simple ike a spacer you can get to prop it up? I'm not keen on swapping out the shock with another bikes shock unless its a simple direct fit eh.
Yes, you can use a spacer - I had one on my VFR800 before I fitted the new shock, but mind you, it was only 6mm.
A common mod for VFR800s/750s is to fit a CBR9xx rear shock, which is shorter, and fit a spacer under the top shock mount.
The big problem with simply spacing another shock like this is often the shock is shorter because the linkages are different, meaning the ratio of wheel movement to shock stroke also varies. Spacing a shock so it fits and has the right ride height isn't adressing this at all. Often another (usually siffer) spring is also needed, plus a revalving.

racefactory
11th March 2010, 15:52
I've done that, with a block of wood to spread the weight a bit, but if it was resting on only the jack/wood and front tyre, it's pretty wobbly. If you need to put any force on a spanner or bar+socket, it's likely to fall off. Find some other places to support it as well.

Yes, you can use a spacer - I had one on my VFR800 before I fitted the new shock, but mind you, it was only 6mm.
A common mod for VFR800s/750s is to fit a CBR9xx rear shock, which is shorter, and fit a spacer under the top shock mount.
The big problem with simply spacing another shock like this is often the shock is shorter because the linkages are different, meaning the ratio of wheel movement to shock stroke also varies. Spacing a shock so it fits and has the right ride height isn't adressing this at all. Often another (usually siffer) spring is also needed, plus a revalving.

Hey man, that's an idea. I was originally thinking maybe you can get spacers that you pry back the shock spring and stuff them between the spring and the top of the spring guide where it rests against (shit i don't know what to call it eh) ? Kind of similar to the CBR250 preload mod where you stuff coins and spacers above the springs in the front forks. Don't know if they exist.

Yes i know it's not the absolute proper way but it's not going to be a competitive racer or anything like that. Just want to give it more ground clearance and have it sit a little higher at back.

Robert Taylor
11th March 2010, 18:24
Yeah, depends on the bike. It took me several hours on the VFR800, because the instructions were written based on a 1998 test mule, which doesn't have a catcon under the lower shock mount. Plus the new shock has a remote reservoir, which the factory insisted should be mounted to the right pillion peg (which is where my Satantune is bolted). I wanted it elsewhere, so futzed about for ages trying various options before mounting it under the seat. It has since been moved to the left pillion peg, on a custom-made three-part bracket.
As for doing it yourself - yes, provided by "basic tools" you mean the appropriate spanners/sockets for the bolts you need to remove. If you don't, they should be easy enough to borrow. PM me if you need something you haven't got, or need some help.


The VFR800 is about one of the worst bikes ever to replace a shock on, it seems that the rest of the bike was built around the shock! I empathise as Ive fitted a few to these, not nice, especially as in the case of your Elka where you have found that it did not meet your expectations!! Not a five minute job to withdraw it for a setting or spring change.

A word about fitting twin shocks, especially to Harleys. Very often the top and bottom mounting posts are not in line and can be up to 4mm or so out, requiring very pedantic shimming to ensure the shocks stand vertical when the bike is truly vertical. Otherwise the side thrust on the shafts is extreme creating lots of unwanted friction, a harsh ride and accelerated wear.
Home mechanics beware, nothing is ever as simple as it seems and lack of attention to detail can turn out a bad job.

CookMySock
11th March 2010, 18:37
A word about fitting twin shocks, especially to Harleys. Very often the top and bottom mounting posts are not in line and can be up to 4mm or so out, requiring very pedantic shimming to ensure the shocks stand vertical when the bike is truly vertical. Otherwise the side thrust on the shafts is extreme creating lots of unwanted friction, a harsh ride and accelerated wear. Ugh, what a crock of shit. That's a manufacturing fault that should be recalled.

Steve

Robert Taylor
11th March 2010, 19:36
Ugh, what a crock of shit. That's a manufacturing fault that should be recalled.

Steve

Well that would affect nearly every make and model of twin shock bike made, especially the terrible brands that originate out of mainland China. Its called mass production

howdamnhard
11th March 2010, 19:51
Hi all,

Wondering what is involved in fitting a rear shock (same model) to a bike. Wondering if i can do this myself with some basic tools.

Thanks

Do a search on KB of manuals . If you can find one for your bike then at least you will what is involved and what tools are required. On some bikes removing the pipes is required which means new gaskets,etc. Resting the bikes on the headers may damage them and the bike may be unstable.

Tony.OK
11th March 2010, 20:02
Hey man, that's an idea. I was originally thinking maybe you can get spacers that you pry back the shock spring and stuff them between the spring and the top of the spring guide where it rests against (shit i don't know what to call it eh) ? Kind of similar to the CBR250 preload mod where you stuff coins and spacers above the springs in the front forks. Don't know if they exist.

Yes i know it's not the absolute proper way but it's not going to be a competitive racer or anything like that. Just want to give it more ground clearance and have it sit a little higher at back.

Errrrr...............no not a good idea. Packing between the spring and collar would be a bit more than dodgy dude, in a fork a spacer is captive, on a rear shock its not and would be deemed as dangerous by any scrutineer.
If its ride height you're after you need to use a spacer on top of the shock mounting bolt, not sure about your shock though, if it has a vertical bolt going straight up then it it is possible to use washers to "extend" the overall length of the shock.
But if the shock has "eyes" with bolts going horizontally through then your a bit stuck mate, no real way of altering the ride height.

Robert Taylor
11th March 2010, 20:34
Errrrr...............no not a good idea. Packing between the spring and collar would be a bit more than dodgy dude, in a fork a spacer is captive, on a rear shock its not and would be deemed as dangerous by any scrutineer.
If its ride height you're after you need to use a spacer on top of the shock mounting bolt, not sure about your shock though, if it has a vertical bolt going straight up then it it is possible to use washers to "extend" the overall length of the shock.
But if the shock has "eyes" with bolts going horizontally through then your a bit stuck mate, no real way of altering the ride height.

Or buy a proper quality length adjustable shock, that model needs a serious increase in ride height, which in turn needs a well controlled front end

racerhead
11th March 2010, 21:13
but i want to know if there is a way i can crank up the rear ride height a bit with a simple mod. Is there anything simple ike a spacer you can get to prop it up?
Thanks heaps eh

Have a look at this site for a new linkage kit that makes a huge difference. Rick is a top guy and will post worldwide
http://www.rvf.dk/rickoliver/

racefactory
11th March 2010, 23:06
Awesome, I'l have a look at that.

Just found an awesome simple mod to get NC30 ride height up and firm the rear shock in one, thought i'd post in case others come across it.

Robert Taylor, what do you think of this mod? http://www.400greybike.info/newforum/viewtopic.php?f=24&t=5346&st=0&sk=t&sd=a&hilit=ride+height&start=10

vifferman
12th March 2010, 07:33
Hey man, that's an idea. I was originally thinking maybe you can get spacers that you pry back the shock spring and stuff them between the spring and the top of the spring guide where it rests against
You've misinterpreted what I said and meant. I was talking about a spacer between the top of the shock and where it mounts to the frame. This is a length adjustment only, and does nothing to spring rate. When I did it to the VFR, it was only 6mm, and solely for the purpose of raising the rear very slightly to speed up the steering by effectively steepening the front fork angle.
As for that other mod you linked to, if you read through it you'll find out where the original poster suggested drilling a second hole it actually overlaps with the first, effectively making it unusable. The last posts in the thread talk about a special eccentric mount, which would cost a fair bit more than just drilling a hole. Also, it's effectively changing the lower mount geometry so it's changing the whole rate at which the suspension works - another can of worms.
Generally, there's no cheap 'magic' fix. On the VFR800, I had to spend over $2k to sort my suspension to my satisfaction.

Robert Taylor
12th March 2010, 17:30
Awesome, I'l have a look at that.

Just found an awesome simple mod to get NC30 ride height up and firm the rear shock in one, thought i'd post in case others come across it.

Robert Taylor, what do you think of this mod? http://www.400greybike.info/newforum/viewtopic.php?f=24&t=5346&st=0&sk=t&sd=a&hilit=ride+height&start=10

It has merit yes, at least with respect to attaining good geometry. Of course that stock shock is nothing to write home about and given its age the oil etc will be long past its use by date. But improvement is always a term of relativity, it will be better.