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Adjust rear suspension VN800

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42K views 22 replies 8 participants last post by  Demin  
#1 ·
I have an '05 Vulcan 800 stock. I got a used corbin seat to improve the comfort level and it helps but when I hit big bumps in the road It is jarring my back. I found this link on how to adjust the preload on my VN800 but I don't understand if I should increase or decrease the preload. I weigh 185 lbs and mostly ride myself but sometimes my wife 150 lbs rides with me 2 up. Please explain how this works.
-Art
 
#2 ·
Preload adjusts for the sag once you put the expected riding weight of passengers and luggage on the bike.

It does not do anything for the load, really, as as long as it is set from nothing to the correct preload for your weight the spring would have sunk/squished to (or beyond) that level, anyhow once you and your load are sitting on it.

If you are getting a jarring ride, either your preload was set way, way too far (rare), or you have other shock issues going on. How many miles does your bike have? It may be time for a new shock.
 
#3 ·
I doubt that i need a new shock, my bike is an '05 but only has 5000 miles on it. I did a search online about this issue and I am not the only one to feel a jarring ride on the VN800 from the single rear shock. Just trying to understand how preload has anything to do with the ride comfort. My dirt bikes have dampening adjustments on the shock but I dont think this is the case for the vn800.
-Art
 
#4 · (Edited)
No, I don't think 800's have a dampning adjustment either.

Another question for you - if it's harsh for you, does the ride soften out when your wife rides along?

If so, then perhaps your preload is set too high / stiff for a single rider. If that's the case then back off the adjusting ring/nut to lengthen the spring for solo-riding, then try that out.

At 5000 miles your shock should still be OK. On my 800A I was always pretty happy with the rear shock and high-speed highway stuff, but I didn't ride side-roads, dirt roads, or speed bumps with it very often.
 
#5 ·
Mambo Dave,
On the highway when I hit a change in road surface (blacktop to converte on bridges it bumps pretty hard) same thing happens on local roads with bumps going side to side on the roadway. When my wife rides it seems a bit better but not really sure on this because she does not ride with me that much. I read that factory setting is very low preload which lowers the bike. Perhaps it is bottoming out?
-Art
 
#6 · (Edited)
Maybe I'm thinking of it wrong, but more pre-load is a more compressed spring, and that would lower the bike more - less pre-load would raise it... but both won't change the height it once the rider's weight it factored in unless you weigh so little that even on the softest pre-load your weight doesn't compress the spring.

Why not ask your wife to go for a test ride, then hit what you always hit with it and see how it feels? If it improves, then try to reduce the preload a bit for when you ride it.

Two other things that came into play over the course of the last many miles with my Vulcan - the rear tire matters in ride quality in two ways... err... maybe three (unless someone puts on a wider low-profile tire, then all bets are off). You should be airing it up for loaded rides (you and gear, you and your wife), and lowering the pressure a bit for solo light rides. New tires vs. old, with the same amounts of tread, mattered too. I would hope you don't still have the original tires on that bike - 5000 miles or not, seven year old tires (eight if your 2005 was built in 2004) are harder and beginning to dry-rot or crack. New rubber is softer rubber. I noticed a big change when I went to a new rear tire from the new-looking (plenty of tread depth, previous owner stated they had just over 200 miles on them - and the tread depth looked that new), but old Metzler 880's it had on it to the new Dunlop I changed the rear out for. Once the Dunlop wore the ride was harsher, but I didn't realize how harsh it had become until I put the new Kenda Cruz on the rear... wow, much nicer ride!

So I'd suggest you go take a good look at your tire pressure on the rear, and evaluate the rear's age - my VN800A changed dramatically between rears for the nuances of highway bridge joints and such.

Since I noticed ride differences in the rubber compounds, I'd guess that higher-mileage rears would have a harder compound, normally, and thus give a harsher ride. The squish of the air and sidewalls isn't the only thing that matters, the squish of the rubber of the tread counts for a lot on 800's, it seems, where my other bikes aren't so touchy.

Edit: I hope you appreciate this - I set my bowl of ice cream down to type that out, but when I turned to get it I found my cat licking it. One good bowl of Ben & Jerry's down the tube :mad: :rolleyes:
 
#8 ·
I found that with the 800's adjustable rear suspension at the OEM setting of "1" was too "soft" and would sometimes bottom out. This was especially an issue with a passanger on board.

So, at the start of this season (after dealing with this for almost 24,000 miles), I lifted the bike & removed the front sprocket cover, which gave me easy access, with a long screwdriver, to the adjustment collar at the bottom of the adjustable shock.

With the weight off the rear wheel, all it took was a few whacks on the screwdriver with a heavy hammer to get the collar to turn (counter clock-wise, I think, but I'm not certain just this moment - but when you see it, you'll know which way to go). This compresses the shock, making it require more weight/jarring before it bottoms out.

I re-set the suspension to the "4" setting (right in the middle, between the "1" and the "7" settings) and the bottoming out issue disappeared.

This is a very simple operation and did not make the bike ride noticeably more harshly on smooth roads. I am delighted with the results and recommend it if you ever find the rear bottoming out on bumpy roads.

I think the OEM setting of "1" is designed for the slightly smaller folks from the Land of the Rising Sun. We Americans tend to carry a bit more beef.
 
#9 ·
griffjo,
I followed your suggestions. I took off the right cover and the plastic box. I raised the bike and whacked the adjustment collar with a hammer and screw driver about 4 clicks in a counter clockwise direction. I did not notice any numbers on the collar but the light was not great. It is pouring rain out now so I will give it a test run tomorrow. Thanks for the tips. I hope this helps. Only 1 tiny scratch on the upper muffler occurred during the process :(
-Art
 
#10 ·
Art B.

Either side will work, but I found it's a little easier to get at the collar from the left side after front sprocket cover is removed - no pipes in the way.

Also, you didn't see any numbers because there are no numbers. Full clock-wise to the stop is the "1" setting. A close look and you'll note there are 7 possible "nooks"/settings. It's like climbing steps, from one "nook" up to the next. Once weight is back on the rear wheel, it should stay nicely in place.

I've never tired it, but it looks like if you try to turn the collar too far (beyond the "7" [highest] setting), you'll just drop back to "1" and will have to start over.

I'll be surprised it it doesn't help a great deal. If it doesn't completely eliminate the "bottoming out" to your satisfaction, you can just knock it up another nook or two and see it that takes care of it.
 
#12 · (Edited)
At the rate of being the bad man who dispelled myths and made things complex...

http://www.wrrdualsport.com/tech-guide/suspension/106-suspension-201

under "Preload & Sag"

"Adjusting Preload does NOT change the spring rate. Reducing Preload does not make the spring softer, and conversely, adding Preload does not make it stiffer. This is a very common misconception held by many riders. However, adjusting Preload DOES changed how much suspension travel is available to extend the suspension when the bike is unweighted over a bump, the crest of a hill, or anytime it needs to extend to maintain tire contact over a depression. Performance is best when the suspension is normally working within the middle range of its available travel. ... However, adjusting Preload DOES changed how much suspension travel is available to extend the suspension when the bike is unweighted over a bump, the crest of a hill, or anytime it needs to extend to maintain tire contact over a depression."

I know it sucks, but perceptions of bottoming out due to the preload set on "1" seem questionable. What actually can happen is that the suspension may "top out," but I'm not sure this would cause increased discomfort Art is experiencing. I imagine it causes controllability issues when pushing the suspension hard, especially in turns that have rough road surfaces, but Art hasn't stated he has problems with that.

I will agree that many bikes are suspended too soft due to them being made for the Japanese market, however to my knowledge the 800's were assembled / made in the USA. Moreover, few but the loaded cross-country VN800 tourers seem to have ever complained about the rear spring being too soft that I've read here in the VN800 forums. Granted, the preload of "1" is probably too soft for preload, but adjusting it to be correct isn't addressing the problems you guys seem to be chasing.

Art, you may think I'm crazy about the rear tire, or my other comments about your suspension (trust me, though, try the rear tire first if you haven't), but you didn't reply that you're not running the old stock tires. At 5000 miles I'm sure many try it, but you'll gain a lot of road irregularity absorption from tires that have new flexible rubber, and from a tire that has the correct pressure for your bike's load.
 
#18 ·
At the rate of being the bad man who dispelled myths and made things complex...

http://www.wrrdualsport.com/tech-guide/suspension/106-suspension-201

under "Preload & Sag"

"Adjusting Preload does NOT change the spring rate. Reducing Preload does not make the spring softer, and conversely, adding Preload does not make it stiffer. This is a very common misconception held by many riders. However, adjusting Preload DOES changed how much suspension travel is available to extend the suspension when the bike is unweighted over a bump, the crest of a hill, or anytime it needs to extend to maintain tire contact over a depression. Performance is best when the suspension is normally working within the middle range of its available travel. ... However, adjusting Preload DOES changed how much suspension travel is available to extend the suspension when the bike is unweighted over a bump, the crest of a hill, or anytime it needs to extend to maintain tire contact over a depression."...
I don't know where that article came from but it is misleading. I found this article which explains it very well.

http://www.ntnoa.org/suspension_preload.htm
 
#13 · (Edited)
Mambo dave,
I have the original tires on the bike. I will follow your suggestions when the weather clears. I did try to adjust the tire pressure but the gas station I went to had a crummy gauge so I am not sure the exact pressure in there now. I will carry a good one with me and adjust from there. What you say makes sense to me. I really have not figured out if the suspension is really bottoming out or not. Thanks for the suggestions. Control of the bike is not affected by this issue.
-Art
 
#14 ·
Dave,

I KNOW you are very knowledgable (I have personal experience to substanciate that fact), so the last thing I will do is argue with you.

BUT, I was experiencing some genuine jarring when I went over bumps/holes, especially with the wife on the passanger seat. I changed the pre-load setting from the OEM "1" setting up the the "4" mid-point setting - and the problem DISAPPEARED.

Same tires, same tire pressure, same chain, same chain slack, same chain lube frequency - SAME EVERYTHING.

I don't pretend to know exactly how the rear suspension works or is supposed to work or what adjusting the pre-load setting is supposed to do or is not supposed to do. Perhaps "bottoming out" is not technically what I was experiencing - I just know that is what it "felt" like. Nearly 40 years ago I rode a HD Sportster and that's EXACTLY what riding that thing felt like most of the time.

However, I do know that I had a problem with some fairly serious jarring over bumps/holes. And I do know that the problem virtually disappeared after I made the setting change - and this was the ONLY remotely related change made.

Why it helped, I suppose I really can't say - BUT IT DID.

Also, although the 800 was indeed assembled/made in the USA (Omaha, NB, if I recall correctly), it would not surprise me to discover that it was at least partially designed by Japanese engineers who's "normal" size perception could very easily be culturally colored.
 
#15 ·
I believe ya. I'm not sure how it affected your bike, but preload - up to the point of being way too much for a given load - does not change spring rate, nor stiffness, as a rider and load would already have any spring compressed beyond the preload setting anyway by just sitting on the bike. Thus the correct preload is negated by normal sitting and riding up to the point at which, over some really rough terrain, the rear suspension actually becomes unloaded. At that point the preload keeps some tension on the spring.

This is just conjecture, but what could be happening is that preloading a spring down may keep the not so great shock from extending too far... that is if extending too far for some reason screws up the valving and allows a VN800 shock to bottom out easier.
 
#16 ·
Does the jarring occur only in the rear suspension and not the front? Just a thought if your adjustment does not help.

Pre-load it the pressure the spring provides to keep the shock from moving. The shock does not begin to dampen until the pre-load is overcome. The more pre-load, the stiffer the ride. Adding pre-load will raise the bike and less chance of bottoming out. Less pre-load and the bike lowers and you get a mushier ride.
If it bottoms out, you get a thump, and an unpleasant jar like you said. So I would say that if it's not a bottoming out, decrease the pre-load. If it is bottoming out and your preload is already high, then is a dampening problem, in which case you need a new/different shock.
 
#17 ·
Well the rain finally stopped, i took my 800 for a test ride with the preload increased a few clicks. It does seem to be a bit better. I will try to go 1 or 2 more clicks and see how that works. I also need to get to the gas station and check the rear tire pressure. What pressure would you recommend? The front end is not an issue with the ride, just the rear over bumps in the road and I weigh 180 lbs.
-Art
 
#19 ·
I have recently encountered this back Jarring problem.

I have just put a solo seat on my VN800b and started getting a real pain in my back whilst riding and a feel like the bigger bumps are Jarring right through my body!

I took the cover off to find that the Shock was still in position 1.
Considering the bike has done 26000km this suprised me!

I knocked it round to 6 but I am still getting Jarring and can really feel the bumps on the road.

I am fairly certain that the mildly padded factory seat couldnt be taking away all the bumps.
My new theory is that the solo seat and new bars have put my body on a different angle on the bike, which may be the cause?

Any thoughts...? is really affecting my enjoyment of my motorcycle!:mad:
 
#20 ·
I know this is wrong but I've always used the contact patch on the tire to adjust my air to.

Start at factory recommended, take a short ride, stop and look at the stripe the pavement is leaving on the tire. Adjust a pound or two if you think the patch needs to be wider let some out if it needs to be narrower put some in. Ride and recheck. I just eyeball it to get the most rubber on the ground without being on the side wall this helps to get even wear and usually ends up being less than the mfg recommended setting. Less air gives a little softer ride too. Works for front and rear I've been doing it for years on all my bikes. Especially when using different sized tires than stock, it's the only way to figure out what you need and as each person and load is different it is custom for you only.
 
#21 ·
I adjusted the preload to it's max setting and still feel the same jarring on my back (possible small improvement). I also set the rear tire pressure to 30 lbs and that is about the same as well. I guess I will try to drop the pressure a bit more and see how it feels. How low can the stock tire pressure go and still be safe?
-Art
 
#22 ·
I need to figure this issue out too. With my younger daughter the motorcycle never bottoms out but my older daughter is about 30lbs heavier and we bottom out on bumps. I am looking for advice if I need a stronger spring or perhaps it's time to buy the Nomad for 2-up riding.

I hate to spend a lot to redo the suspension as I do plan to add a Nomad soon.


Sent from Motorcycle.com App
 
#23 ·
I have a Works shock on my bike,so it's a little different.But the concept is the same.If you're a solo rider and normal weight you want less preload.On seems like these bikes number scale,might be a 1 or 2.If you're a big guy maybe 3 or 4.And an old lady or some gear 4 up.
Preload is loading the spring.The more weight,the more it compresses.When you go up in the numbers it is compressing the spring.
Here is one similar to mine.To add preload you thread the nut tighter against the spring.
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