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Shocks for late model 750 Nighthawk

Started by Bob H, Dec 07, 2022, 11:51 AM

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Bob H


I ordered these YSS shocks from the US distributor, don't have them yet.
Cost $539 delivered.  This photo is from Amazon, listing for $524 but I wanted to talk with a human about rider weight, never carry a passenger, riding style.

My NH has 37,000 miles and the stock shocks were econo to start with, and now there is very little rebound damping (after a large bump the springs shoot you out of the seat).

Previously I tried lower end Progressive 412 shocks for half this price, with no rebound adjustment, no choice of springs (other than "heavy duty" which I avoided as never carry passenger). The Progressive (brand) shocks were so harsh, I sold them on Ebay after 500 miles. The stock used shocks were at least "plush" on gentle roads.

My NH has the same 13" length as Triumph Bonneville, so I searched their forums, etc. for shocks that were not garbage but below $1,000. This video sums up a lot of my research and confirmed that although YSS is not "Ohlins" or Penske, or K-Tech, they are nonetheless a decent shock for the money. (click the link) https://youtu.be/_1TQh2_hA94

https://youtu.be/_1TQh2_hA94
That is the exact shock I ordered, only rebound adjustment. I would have gotten the one with compression adjustment but the plastics are in the way at top on my late model NH. He compares that YSS shock to the factory Triumph, and with Ohlins on the same bike.
If you are considering shocks, watch that video because it really relates to our situation of twin shocks on motorcycle.
Modern bikes are mono shock, and the twin shocks are kind of obsolete.

US distributor https://epmperf.com/yss-motorcycle-and-scooter-shock-absorbers
The manager Mike was very patient, confirmed the shocks would be prepared with exact fit eyelets for my motorcycle. He confirmed my research that these were a sweet spot for price and quality, they do sell other brands. He confirmed there is not a lot out there that fits vintage bikes, for example you put your bike in the search box at Revzilla etc. and find nothing. These should fit. They make them per order, for a specific application.

The US distributor for YSS has a very limited website, but the UK distributor, Brooks, has an amazing site where you can enter a vintage motorcycle and confirm fitment https://www.brooksuspension.co.uk/ On their site, mine are the YSS "RZ" series and my order from US distributor shows part number RZ362-330-TRL-12
These are made in Thailand, interesting that the newer Triumphs are also made in Thailand.
Some years ago there was a guy rebuilding cheap China shocks (under $100) with upgraded valving and confirmed fitment for vintage motorcycles for around $200 but I never ordered from him - did some research - he closed shop 2022 and is no longer offering that service. At any rate, you usually get what you pay for.
And I have paid more than once due to going cheap. Aside from the harsh progressive shocks (that did fit perfectly per order)  I have ordered other shocks in the past that did not fit the lower mount width on late model NH and had to resell the shocks at a loss.
1993 Nighthawk 750

Larry Fine

I put Hagon shock/springs on my '96, bought from Dave Quinn (now retired). We discussed my size and weight, the added fairing and luggage, occasional passenger capability, etc., and he sent me a set that seem to work perfectly.

I also rebuilt my fork with all new parts and seals, original springs match and are about 1/4" longer than minimal spec, and I set fluid level about 1/4" higher than spec. The bike handles and rides as well as my ST1100 does.
'72 CL450
'73 CB750
'82 CB750SC

'96 CB750ST
'01 ST1100
'96 ST1100
'07 ST1300

Bob H

#2
Quote from: Larry Fine on Dec 07, 2022, 01:22 PMI put Hagon shock/springs on my '96
...I also rebuilt my fork with all new parts and seals
Awesome - I was considering those. Hagon is one of the few that still seems to care about bikes with 2 shocks, rather than monoshock.

I reached out to K-Tech because they sell a twin shock that is less expensive than Ohlins and likely a great product. Email back and forth, told them my lower mount was 20mm wide etc. and 13" long - they simply replied they did not list my motorcycle. 
I asked them to just sell me a shock with the correct ends, but they didn't want to mess with it.

My front fork seals were leaking 2 years ago, replaced them and changed fluid - amazed at the difference simply from dumping out old fork oil that was quarter century old. Immediately aware of "some damping".
1993 Nighthawk 750

McG99

definitely keep us posted once you have them installed and broken in and set up to your liking.  Pictures also please
Thanks for sharing and looking forward to the outcome.

Bob H






You have to loosen the black set screw to adjust preload. So that screw needs to be accessible.


I oriented that black set screw forward, so can loosen to adjust preload (which may still be a challenge to access the rotation thing)


1993 Nighthawk 750

Bob H

#5

I moved the rubber bump stops to mid-shaft so I could determine how much of my shock travel I was using.
60 degrees in California but we have had a lot of rain this week. I went for a brief ride, there is a very bumpy section of road within a mile of my house that I have gone over many times on the Nighthawk over the last 10 years.
The first thing that came to my mind when I went over the bumps at 35 MPH was "no drama".
Usually I go over those bumps at that speed, and it is a series of about 6 strong jolts, almost out of seat jolts.

However when I went over it with the new YSS shocks it was a completely different experience. Just "no drama". Of course I felt the transition of pavement (flood control section that drops down 2 or 3 feet, to enable water to flow over the road during biblical downpours). But there was no "jolt". After 10 years of riding that section, it was kind of odd.

I looked at my "rubber bump stops" and they had been pushed down into their factory position (at the bottom of the shock). So obviously I had used 100% of the travel, and bottomed out. But it didn't feel like it bottomed out, everything was more gradual than before with the stock shocks.

In hindsight, I think the quarter century old (and econo) stock shocks had insufficient damping, allowed the shock to compress quickly. The new YSS shocks CONTROLLED the compression stroke better, so that I still had at least some travel left for most of the stroke because I didn't really notice that it had hit the bump stop.

When I get a chance to put more miles on these new shocks I may do an update, but for now I do agree with the similar experience the Triumph guy had in the video link I posted earlier - that it is a big improvement over stock.

With the rain starting as I was wrapping the install I have not checked sag on these YSS yet, I just bolted them on and hit the road before the big downpour.

The guidance from YSS is to leave the rebound setting in the middle (15 of 30 clicks). I will play with it as time permits, but for now it is a nice improvement.

My impression before hitting the really bumpy section was that the newer YSS shocks felt a bit more firm, less plush than the worn out stock ones.

But then the big bumps made me a believer that they were doing their job and relieving the pressure when the demand came. They soaked up the bigger hits. Like the shim stack - valving was relieving hydraulic pressure. That is something the econo stock shocks were not doing, they were just blowing through the stroke (insufficient damping)
1993 Nighthawk 750

Bob H


With sag set for my weight with gear, the adjuster is easily accessible below the plastics. Each turn of the ring is 1mm. Out of the box the preload was not tightened down very far, with about 1/2 inch of threaded area above the ring.


This is my "test area" within a mile of my house. The road sections go low, so water can flow over the road if extreme rainfall. After adjusting sag, I raised the rubber bump stop again (acts like "zip tie" on forks to determine how much travel you are using). I went over this section of road at 35 mph and had 1/2 inch of travel left, did not bottom out.

Then I went over it at 45 mph, didn't feel much different but the rubber stop was pushed all the way down. During both runs the back end felt "controlled" and no drama. The stock shocks felt like a bucking bronco.

I watched 3 cars go over this section while I was taking photos, all of them had their front ends banging up and down as they went over the uneven pavement.

Living with the stock shocks for 10 years, I didn't realize how bad they were - as the "bounce back" didn't repeat (and you could test that shoving down on the bike, it came up quickly and not repeat). However something was lacking in the damping, maybe coming up too fast, as it bucked a lot more than it does with the YSS shocks.

Dave Moss says that suspension set up for high speed at the track will "feel like a brick" on the street. So there are compromises with plush feel on smooth streets vs higher speeds which I don't get into that much anymore. I would say the YSS are not as plush (mushy) on easy roads, but maintain much more control at higher speeds.

I would not describe them as stiff, or harsh (like the Progressive 412's that I bought new and sold). They are good for the street legal speeds I ride. Initially I wanted to get something with "full" adjustability (compression, as well as rebound) but honestly I don't know what I would want to change on the compression (it feels right).

Rebound remains set in the middle at 15 clicks out of a range of 30. It is very easy to adjust (bottom of shock) so I will fiddle with that as time goes on, but it also feels good out of the box.
1993 Nighthawk 750

Bob H

1993 Nighthawk 750

Pete in PA

Im more critical of the forks then the rear on my bikes.

I'll have to do more testing come spring.
92 Honda 750 Nighthawk
Previously: 250 Nighthawk, FJ-09, ST1300, FZ-07, CBR1100XX, V65 Sabre, 83 650 Nighthawk.  Two XR650L's, KLX650C.

Bob H

Quote from: Bob H on Dec 31, 2022, 06:08 PMWhen I get a chance to put more miles on these new shocks I may do an update, but for now I do agree with the similar experience the Triumph guy had in the video link I posted earlier - that it is a big improvement over stock.
8 months later and still happy with the shocks.
1993 Nighthawk 750

Bob H

This is a copy of Cycle World 1991 review mention of the late model NH rear shocks.
They were considered bad back then, when the suspension standards where no where near what they are now.

They considered the antique "damper rod" front forks excellent compared to the rear shocks.
My main complaint was the lack of rebound adjustment and they just "pogo" bounce right back rather than soak up bumps. The YSS shocks are doing a lot better for me.

1993 Nighthawk 750

Bob H

Quote from: Pete in PA on Jan 06, 2023, 08:11 AMIm more critical of the forks then the rear on my bikes.
If you ever have the front end off to do steering bearings, seals, or even a tire change you may want to ask Traxxion Dynamics if they can set this up for your Nighthawk.

At about 10:30 into this video he shows that they make a variety of sizes and can fit any damper rod fork 41mm or larger.


That video is 5 years old, he describes them as "a new product" but at this point there are some favorable reviews.
There is a favorable thread on the FZ-07 forum and one of the racers on that thread has the Traxxion kit on an SV-650. The FZ07 rider asked for it to be configured for street (not race) and says it is plush, likes it.
1993 Nighthawk 750

Hend238

Wow that's a very informative video.
1984 Honda Nighthawk S 750
2023 Triumph Tiger 1200 GT Explorer
Dreaming of a mid 80's Honda CBX750F

Hend238

I'm going to check out those YSS shocks for my 84 750S. In the next year or so I'll be doing some maintenance on the front end and will consider that Traxxion kit. How interesting.
1984 Honda Nighthawk S 750
2023 Triumph Tiger 1200 GT Explorer
Dreaming of a mid 80's Honda CBX750F