Lowering a bike, good?

[ducatilover]

I know what I can do.

Interested in what he thinks he can do.

He is Robert Taylor, if anyone can do it, he can.

The Chuck Norris of the suspension world

[nzspokes]

He is Robert Taylor, if anyone can do it, he can.

The Chuck Norris of the suspension world

Lets see what he can come up with.....

[FROSTY:Me]

Nz spokes. In the case of your "profile" bike lowering the whole bike is going to be an issue.
Unlike rob I won't go into why you should or shouldn't do anything just pure logistics.
WITH YOUR BIKE.
shoving the forks up through the triple clamps say 20mm really isn't a big job.
Put the bike on the main stand. Put a car jack under the front of the motor and undoo the four bolts holding the legs in place. You WILL find you are limited in how far the forks can slide by your handlebars. The fork caps will hit the underside of them.
So mechanically thats fairly easy.
Now the back end. You have dual shocks that are as old as the bike most likely.They are mounted solidly at the top and bottom. No opertunity for "lowering links" etc
SOO how do you lower it. 1) find a set of shocks from a similarish model that are shorter 2) reposition one shock mount so the existing shocks are les vertical -In essence making em shorter.
SOOO--The back end is going to cost a fair bit of money to sort out.
Given that your stated intention is to IMPROVE the bikes handling I must say this would be a total waste of money. I promise you the end result will NOT improve the actual handling. There may be a sensation of better steering because the front wheel is now "tucked" by around 15 mm.
IF you want better handling then my suggestions are as follows.
1) dump the fork oil and even give the unsides a flush out. Have the CORRECT amount of oil of the correct viscosity put in the forks.
2) Get a set of GOOD quality tyres fitted -On a bike of this size good rubber will last forever so its worth spending the loot.
3)Take the swingarm out and ensure all the bushes are lubed and there is NO lateral slop
4)IF the seals on your rear shocks aren't gone and all the oils blown out then see if someone like RT can reoil them for you.-Normally I'd say replace em with weight apropriate shocks but with this vintageand size you are really limited to budget replacement shocks.

Now if the issue in fact is simply that the bike is too tall then I would NOT be touching the suspenders to lower the bike.
I would buy a seat from the local wrecker and then shave the foam down 25mm. You'll buy a seat base for about $60.

Incidently to qualify my comments. YES I have worked on CB250 RS and CBX250's for slightly shorter folk with good effect. But always the seat is the first port of call.

[Robert Taylor]

Nz spokes. In the case of your "profile" bike lowering the whole bike is going to be an issue.
Unlike rob I won't go into why you should or shouldn't do anything just pure logistics.
WITH YOUR BIKE.
shoving the forks up through the triple clamps say 20mm really isn't a big job.
Put the bike on the main stand. Put a car jack under the front of the motor and undoo the four bolts holding the legs in place. You WILL find you are limited in how far the forks can slide by your handlebars. The fork caps will hit the underside of them.
So mechanically thats fairly easy.
Now the back end. You have dual shocks that are as old as the bike most likely.They are mounted solidly at the top and bottom. No opertunity for "lowering links" etc
SOO how do you lower it. 1) find a set of shocks from a similarish model that are shorter 2) reposition one shock mount so the existing shocks are les vertical -In essence making em shorter.
SOOO--The back end is going to cost a fair bit of money to sort out.
Given that your stated intention is to IMPROVE the bikes handling I must say this would be a total waste of money. I promise you the end result will NOT improve the actual handling. There may be a sensation of better steering because the front wheel is now "tucked" by around 15 mm.
IF you want better handling then my suggestions are as follows.
1) dump the fork oil and even give the unsides a flush out. Have the CORRECT amount of oil of the correct viscosity put in the forks.
2) Get a set of GOOD quality tyres fitted -On a bike of this size good rubber will last forever so its worth spending the loot.
3)Take the swingarm out and ensure all the bushes are lubed and there is NO lateral slop
4)IF the seals on your rear shocks aren't gone and all the oils blown out then see if someone like RT can reoil them for you.-Normally I'd say replace em with weight apropriate shocks but with this vintageand size you are really limited to budget replacement shocks.

Now if the issue in fact is simply that the bike is too tall then I would NOT be touching the suspenders to lower the bike.
I would buy a seat from the local wrecker and then shave the foam down 25mm. You'll buy a seat base for about $60.

Incidently to qualify my comments. YES I have worked on CB250 RS and CBX250's for slightly shorter folk with good effect. But always the seat is the first port of call.

Well done Frosty ( if indeed it is the profile bike ) Saved me a lot of typing.

[nzspokes]

Nz spokes. In the case of your "profile" bike lowering the whole bike is going to be an issue.
Unlike rob I won't go into why you should or shouldn't do anything just pure logistics.
WITH YOUR BIKE.
shoving the forks up through the triple clamps say 20mm really isn't a big job.
Put the bike on the main stand. Put a car jack under the front of the motor and undoo the four bolts holding the legs in place. You WILL find you are limited in how far the forks can slide by your handlebars. The fork caps will hit the underside of them.
So mechanically thats fairly easy.
Now the back end. You have dual shocks that are as old as the bike most likely.They are mounted solidly at the top and bottom. No opertunity for "lowering links" etc
SOO how do you lower it. 1) find a set of shocks from a similarish model that are shorter 2) reposition one shock mount so the existing shocks are les vertical -In essence making em shorter.
SOOO--The back end is going to cost a fair bit of money to sort out.
Given that your stated intention is to IMPROVE the bikes handling I must say this would be a total waste of money. I promise you the end result will NOT improve the actual handling. There may be a sensation of better steering because the front wheel is now "tucked" by around 15 mm.
IF you want better handling then my suggestions are as follows.
1) dump the fork oil and even give the unsides a flush out. Have the CORRECT amount of oil of the correct viscosity put in the forks.
2) Get a set of GOOD quality tyres fitted -On a bike of this size good rubber will last forever so its worth spending the loot.
3)Take the swingarm out and ensure all the bushes are lubed and there is NO lateral slop
4)IF the seals on your rear shocks aren't gone and all the oils blown out then see if someone like RT can reoil them for you.-Normally I'd say replace em with weight apropriate shocks but with this vintageand size you are really limited to budget replacement shocks.

Now if the issue in fact is simply that the bike is too tall then I would NOT be touching the suspenders to lower the bike.
I would buy a seat from the local wrecker and then shave the foam down 25mm. You'll buy a seat base for about $60.

Incidently to qualify my comments. YES I have worked on CB250 RS and CBX250's for slightly shorter folk with good effect. But always the seat is the first port of call.

Cheers. But the reason for the original question was that one of my shocks is leaking a bit. replacements seem to all be 20mm shorter. Robert has already told me that my shocks cant be fixed. That I dont believe as they do come apart. I will be having a go at that as Ive done a lot of work on suspension systems before, just not on motorcycles.

Ive since found length adjustable ones on e-bay and found somebody with the same bike wrecking it. So a few options there.

I will be rebuilding the forks, possibly this weekend. I suspect they are orifice dampers so they will be basic. They also have a harsh top out which I will look into. Maybe a shim stack conversion coming? LOL.

Probably hit it with a wheel alignment after that. I may even organise getting some new coil wound for the rear as well, easier than a diet.

Or I could just wait untill I have my full and start on another bike.

[FROSTY:Me]

NZ spokes--okley dokely so "in Theory" any replacement rear shocks are 20mm shorter than whats currently fitted. I'm hearing ya. But what is the current actual useable length of your shocks?
Given you arent overstating your weight its entirely possible that a pair of propperly damped shocks with a more appropriate spring setup for your weight will actually EFFECTIVELY be as long or even longer than the factory shocks.Yes 20 mm is a lot for a road bike but if the factory stuff has 60mm or more sag with you sitting on the bike then any percieved advantage has gone.
When RT and co are setting up his very expensive rears on racebikes one spring certainly doesn't fit every rider and of course the damping gets changed to suit the spring etc (before getting into personal preferences) so within the limitations you have in shock selection you may find a better spring/damping setup that starts out a few MM short

[Robert Taylor]

Cheers. But the reason for the original question was that one of my shocks is leaking a bit. replacements seem to all be 20mm shorter. Robert has already told me that my shocks cant be fixed. That I dont believe as they do come apart. I will be having a go at that as Ive done a lot of work on suspension systems before, just not on motorcycles.

Ive since found length adjustable ones on e-bay and found somebody with the same bike wrecking it. So a few options there.

I will be rebuilding the forks, possibly this weekend. I suspect they are orifice dampers so they will be basic. They also have a harsh top out which I will look into. Maybe a shim stack conversion coming? LOL.

Probably hit it with a wheel alignment after that. I may even organise getting some new coil wound for the rear as well, easier than a diet.

Or I could just wait untill I have my full and start on another bike.

If there is one thing that irks me it is being misquoted. I get so much e-mail traffic that dredging for copies of correspondence can be time consuming and irksome. I would like you to either remind me of the e-mail address that I replied to you on or publish my full reply here on this thread. I believe I havent been quoted quite correctly

[nzspokes]

If there is one thing that irks me it is being misquoted. I get so much e-mail traffic that dredging for copies of correspondence can be time consuming and irksome. I would like you to either remind me of the e-mail address that I replied to you on or publish my full reply here on this thread. I believe I havent been quoted quite correctly

My apologies if I have misquoted you, I asked via Shaun if It could be done. the response was no it couldnt.

[nzspokes]

NZ spokes--okley dokely so "in Theory" any replacement rear shocks are 20mm shorter than whats currently fitted. I'm hearing ya. But what is the current actual useable length of your shocks?
Given you arent overstating your weight its entirely possible that a pair of propperly damped shocks with a more appropriate spring setup for your weight will actually EFFECTIVELY be as long or even longer than the factory shocks.Yes 20 mm is a lot for a road bike but if the factory stuff has 60mm or more sag with you sitting on the bike then any percieved advantage has gone.
When RT and co are setting up his very expensive rears on racebikes one spring certainly doesn't fit every rider and of course the damping gets changed to suit the spring etc (before getting into personal preferences) so within the limitations you have in shock selection you may find a better spring/damping setup that starts out a few MM short

Agreed and that was part of my thought process also. My sag on the rears is 50%. So a shock that is working correctly with new fluid would be better than one with 25 year old oil in it.

[Gremlin]

I had my factory WP suspension serviced a little over a year into it's life (admittedly past it's service interval of 30k) at 40,000km on my KTM.

Apparently the rear shock oil was sludge and one fork wouldn't move properly. I can't believe people don't just throw suspension into the servicing... some seem to leave it for years and years

[FROSTY:Me]

Agreed and that was part of my thought process also. My sag on the rears is 50%. So a shock that is working correctly with new fluid would be better than one with 25 year old oil in it.

Dude It occurrs to me that the rear shocks from the GB400/500 range would most likely be a good option. OR maybee you could look to a greybeards (classic) mx bike.
Why I'm thinking the MX bike is that theres a bit of money in that area meaning after market quality suspenders may be available.
RT etc know this stuff a truck load better than I do but I'm thinking that yea the MX shocks will be longer but the initial spring rate is VERY soft so the range the shock will be working in with you riding the bike may be perfect for you.
(happy to be proven wrong on that front)

[nzspokes]

Dude It occurrs to me that the rear shocks from the GB400/500 range would most likely be a good option. OR maybee you could look to a greybeards (classic) mx bike.
Why I'm thinking the MX bike is that theres a bit of money in that area meaning after market quality suspenders may be available.
RT etc know this stuff a truck load better than I do but I'm thinking that yea the MX shocks will be longer but the initial spring rate is VERY soft so the range the shock will be working in with you riding the bike may be perfect for you.
(happy to be proven wrong on that front)

VMX ones seem to be 390mm +. But i can get new 315mm ones for $130. Bike spec is 340.

But this weekend will be fork rebuild, maybe flat bars, oil catch bottle, inline fuel filter. Talking to a guy with a bike the same as mine to get the same shocks again, if price is right I will get them and try to rebuild mine. probably will need to make/adapt seals.

need to head out at lunch time to get AFT for the fork. Seems odd to use ATF but thats what the manual says.

[ducatilover]

Have you looked at Hagon shocks? I had some on the CB400 SF and they were really nice, leaps and bounds ahead of the original ones.

I'll probably get a Hagon for my ZZR too.

[nzspokes]

Had a thought today while riding. I could just restrict the travel of the fork by 20mm to match the rear shock. Hmmmmmm

[ducatilover]

What could possibly go wrong?

Why don't you just chop the seat? Cheap and easy.