Suspension lowering?

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26 Oct 2014 13:35 #651781 by GrumpyBSTRD
Suspension lowering? was created by GrumpyBSTRD
I have just acquired an '81 KZ440D, my wife will be learning on this bike but she is 5'3".

With the OEM seat she doesn't come close to touching the ground so I removed the seat and put a piece of 1" foam on the frame to test it and she barely touches with her toes.

So I will be putting a "low rider" seat on but still need to get it 3" lower.

My question is, what is the easiest/cheapest way to safely do so?

I have seen a number of these bikes with the rear shocks replaced with a solid steel bar but I prefer to keep it a soft tail.

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26 Oct 2014 16:08 #651795 by TexasKZ
Replied by TexasKZ on topic Suspension lowering?
IMO, it would-be bestto startwith a motorcycle that fits her.

You are right about the struts. They will make theride so harsh that shemaynever ride again.

Three inces is a bunch, but you maybe able to getclose by a combination of a thinner seat, shorter shocks and raising the forks. You will want to be absolutely sure that neither tire will hit anything when the suspension is fully compressed.

You should be able to find some shocks that are an inch or inch and a half shorter and may be able to raise the forks an inch. She may haveto settle for tiptoe one one foot at a time.

1982 KZ1000 LTD parts donor
1981 KZ1000 LTD awaiting resurrection
2000 ZRX1100 not ridden enough
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26 Oct 2014 17:21 #651801 by SWest
Replied by SWest on topic Suspension lowering?
You can get lowering blocks. They off set your shocks by a few inches. I bought some on Ebay but I don't think I'll be using them. I'm 6'1". We used to lace 16" rear rims replacing the 18". That would lower it for the short guys. The problem with lowering in this way changed the steering. I didn't like how they handled. I like the tight turning radius of my Z1.
Steve

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26 Oct 2014 17:45 - 26 Oct 2014 17:49 #651806 by SWest
Replied by SWest on topic Suspension lowering?
Somehow I double posted. Sorry. Lowering the center of gravity might be a good thing for her to ride or in case it falls over.
Last edit: 26 Oct 2014 17:49 by SWest. Reason: miss posted

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26 Oct 2014 18:47 - 26 Oct 2014 18:49 #651818 by GrumpyBSTRD
Replied by GrumpyBSTRD on topic Re:Suspension lowering?
I've been warned about the lowering blocks. They change the geometry effecting handling.

I've been looking at the rear shock and noticed the coils are in 2 peices. 1 larger section that seems to have all the travel and a shorter (about 1 1/2") section that is so tight appears to be only there to add length. I may remove it and see if I can bottom it out by jumping on it, then go from there.
Last edit: 26 Oct 2014 18:49 by GrumpyBSTRD.

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26 Oct 2014 19:16 #651821 by SWest
Replied by SWest on topic Re:Suspension lowering?
Those are progressive shocks. The small coils absorb the small bumps. If you take them out, you might bottom them out by sitting on it. If they do on a ride, OH MY BACK! Look for shorter shocks and sell or keep them. They're expensive, don't throw them away.
Steve

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26 Oct 2014 20:14 - 26 Oct 2014 20:15 #651826 by Patton
Replied by Patton on topic Re:Suspension lowering?
Could also consider Honda Rebel and Suzuki Savage, which have very low stock seat heights, and are good reliable bikes that can keep up with traffic.

High heel boots also help.

Good Fortune! :)

1973 Z1
KZ900 LTD
Last edit: 26 Oct 2014 20:15 by Patton.

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27 Oct 2014 03:22 - 27 Oct 2014 03:31 #651842 by Tyrell Corp
Replied by Tyrell Corp on topic Re:Suspension lowering?
I'd look for shorter shocks and drop the forks. if you did the same back and front your frame geometry remains unchanged, save for a touch less trail and wheelbase length. which would probably be an improvement on that anyway. You could go probably go down by 30mm, maybe more if chain run and ground clearance isn't an issue...you will also need a shorter side stand if you lower it by much.

Lifting the rear end sharpens the steering, and vice cersa. ..hence my suggestion doing back and front together by the same amount, then dropping the front gradually and seeing how it feels.

Custom style bikes have wide frame castor angles for straight line stability, a modern sports bike runs much tighter castor angle for quick steering. You probably have plenty of range of adjustment here on that bike.

Lowering the front more than the back would give lighter and quicker steering which might also be an improvement, if not overdone. If you put an inch thick plank of wood under the rear tyre you can actually feel the difference by just turning the bars whilst sitting on it: although it brings the weight distribution further forward so there is more weigh on the front, the sharper castor angle makes it feel slightly lighter to turn the bars.

I'm 6'4 tall so generally go for longer rear shocks where I can.

1980 Gpz550 D1, 1981 GPz550 D1. 1982 GPz750R1. 1983 z1000R R2. all four aces
Last edit: 27 Oct 2014 03:31 by Tyrell Corp.

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27 Oct 2014 13:14 #651890 by GrumpyBSTRD
Replied by GrumpyBSTRD on topic Re:Re: Re:Suspension lowering?

Patton wrote: Could also consider Honda Rebel and Suzuki Savage, which have very low stock seat heights, and are good reliable bikes that can keep up with traffic.


The Rebel 450 was my first choice but couldn't find one within budget. I picked up the KZ for next to nothing due to engine issues (but that's for another forum :rolleyes: )

I just removed the smaller of the coils on both sides and by the time I cut the seat down should be about right. Even with my fat 225lb rear jumping on it still only squatted a couple inches.

But will definitely need shorter shocks though, when these shocks extend to top out they exceed the length of the coils and risk loosing the keepers.

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27 Oct 2014 15:31 - 28 Oct 2014 06:20 #651904 by martin_csr
Replied by martin_csr on topic Re:Re: Re:Suspension lowering?
No eBay APP ID and/or Cert ID defined in Kunena configurationNo eBay APP ID and/or Cert ID defined in Kunena configurationIf the KZ440 has 13" shocks. You might be able to install Harley-Davidson Sportster Hugger or lowering shocks. I wouldn't get them too short, though (rear tire fender clearance). I guess they would fit the 440 about the same as the bigger KZs. You'll have to swap bushings (easy) & spread open the lower mounts on the swing arm (or grind down the shocks 2-4mm). The chain guard may rub the Sportys a tad.

Edit: eebbaayy item links are not visible on my Mac computer using Apple Safari. doh.
Item # 221585175841


Item # 380470596619 (these may be too short - rear tire fender clearance - see Patton's reply below)
Last edit: 28 Oct 2014 06:20 by martin_csr.

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27 Oct 2014 16:13 #651909 by Tyrell Corp
Replied by Tyrell Corp on topic Re:Re: Re:Suspension lowering?
Grumpy, losing a spring coil is altering the preload to reduce the ride height - not really the way to do it. It'll work , just about, but there are much better ways of doing it.

Maybe make a pair of struts to temporarily hardtail it and experiment with ride height and see howthe steering and clearance feels.

1980 Gpz550 D1, 1981 GPz550 D1. 1982 GPz750R1. 1983 z1000R R2. all four aces

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27 Oct 2014 19:54 #651947 by Patton
Replied by Patton on topic Re:Re: Re:Suspension lowering?
Would assure that the top of rear tire doesn't hit the underside of the rear fender upon maximum compression of the rear shocks.

One way to measure is to test clearance with only one of the two rear shocks attached, which helps assure being able to achieve maximum collapse of the rear end.

Can also put a ball of modeling clay on top of the rear tire when compressing the rear suspension to measure the clearance at full compression.

Besides the specter of ripping out under-fender wiring, hitting a large bump or pothole that unexpectedly bottoms out the rear suspension might cause loss of control, especially by a novice rider.

Good Fortune! :)

1973 Z1
KZ900 LTD

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