Longer chain makes a difference?

[zunkus]

I converted my SV from a naked to SVS.
Changed handlebar to clip-0ns.
Changed top yoke to svs.
Changed rear sprocket to one tooth less like SVS.
Changed to higher and more rearward footrests.

I did all this 'cause I liked the way my brother's SVS handled, but still it doesn't steer that quick as his. Cranking the rear adjuster all the way up to rise the rear doesn't help. In fact it feels worse. I feel the best setting there is two notches up from fully down when riding solo. I'm 74Kg. When the wife's riding pillion, the bike feels great! Very planted if somewhat a little harder to steer. For some reason I'd trade the slow steering for more stability which is how it feels two up. What wrong you think? The only difference between my bike and brother's is that I'm still on stock chain which is longer than SVS stock one. So the wheel base is a tad longer. Is this making all the difference? When I ride his bike everything seems great, my bike on the otherhand is hard work.

[MavUK]

Not sure if this is correct or not,but I thought that the naked also had different foot pegs, which may also throw off your centre of balance. But I can imagine that having a longer chain is also not helping (Both points guesswork though)

[northwind]

As you say, the longer chain will give you alonger wheelbase, not a huge amount but enough to be noticable I'd imagine (never done it myself, I mucked up the timing when I tried) It'll also slightly increase ride height, and I suppose change the leverage on the shock a bit. I'm not even going to pretend that I can predict the impact that'd all have.

Is it a standard shock? You mentioned using the adjuster to raise the rear...

[zunkus]

Well MavUK, I did change to SVS rearset footpegs so that's ruled out.

Northwind, Yes I'm on standard shock but the stock item does increase ride height effectively when you compress the spring as it 'gives' less under weight so keeps the rear higher. The comment about the rear wheel being more back increasing leverage does make sense. I'll change the chain next making it the same length as stock SVS and see how it goes. Was going to change it anyway.

[yorkie_chris]

The naked steers faster than the S as standard...

Anyway, try drop the forks in the yokes a little to speed up the steering.
Also tyres can make a difference to the ease of turning.

[dirtydog]

aren't the swingarms different lengths as well? could be a contributing factor?

[zunkus]

As I said before, the steering is not much the issue, I can't explain this too well but it seems there's not much weight on the rear wheel. I enjoy the ride better when having someone riding pillion. I'm thinking that reducing the wheelbase to stock SVS dimensions is the next step. I failed to mention that I did drop the forks to experiment. The bike started to turn much quicker but did not keep a good line in a fast corner and it got unstable pretty quick when the road was bumpy. I also tried making the front higher by pushing down the tubes flush to upper yoke, as far down as they would go. This has the effect of harder steering but a more comfy riding position with a more balanced bike front to rear making it hold a line better. I ended putting them back to their original SVS position taking reference from my brother's bike. I must point out that I do ride with my upper body weight more on the front. The rear part of the seat is never used.

[yorkie_chris]

I think it's your rear shock, maybe stick a ninja one on it with the sag set close to correct?

[zunkus]

aren't the swingarms different lengths as well? could be a contributing factor?

Swingarms on a curvy are the same as far as I know.
Could check part numbers on a parts fish to confirm...

...you are in fact quite right. The swingarms are different part numbers.
I found a partsfish here... http://www.alpha-sports.com/suzuki_parts.htm?gclid=CJutp7_YtZICFQJYZwodryxbFw
Rear swingarm SV650X/Y/K1/K2 61000-19F11 (http://www.alpha-sports.com/spart.php?part_number=61000-19F11)

Rear swingarm SV650SX/SY/SK1/SK2 61000-19F01 (http://www.alpha-sports.com/spart.php?part_number=61000-19F01)

http://alpha-sports.com/spst/2000%20SV650,S/52.gif

[zunkus]

So the fact that there are two different swingarms I have to conclude that there is a significant difference in length between the two models. That must be a significant factor to the difference I'm experiencing between the two bikes. I'll take my inch tape to my brother's tomorrow. The only problem is that now if I put in the same chain on my bike most probably I won't have enough adjustment play. I'm not thinking that Suzuki would have gone to the trouble of making two different swingarms for nothing.

[yorkie_chris]

Change the wheelbase mebbe?

IIRC there's a 10mm difference.

[zunkus]

Quite right Yorkie_Chris.

In fact I've done some research in the old posts section and found this...

02/03/2000 - MORE WHEELBASE MATHEMATICS - you just knew this subject wasn't dead yet.....thank you Bruce (bdickson@start.com.au) for taking the time.. Thanks for all the work you put in to this excellent site. All of the SV owners and other interested parties of the world are in your debt. Unfortunately I'm still only in
the interested parties category as my budget can't quite stretch to an SV yet but I will definitely be looking for one in a few years when something new and better comes out and everyone forgets how great SV's are and they are available cheaper used. I currently ride a GS450.

I've been occasionally looking at your site and have been following with interest the wheelbase discussion so thought I'd throw in some of my own maths to try and clear a few things up.

SV650 (unfaired)
Front sprocket 15t
Circumference = 200.025 mm (=15*13.335mm (chain pitch))
Diameter = 63.66993 mm (=C/pi)
Radius = 31.83497 mm (=D/2)

Rear Sprocket 45t
Circumference = 600.075 mm
Diameter = 191.0098 mm
Radius = 95.5049 mm

Chain length = 1466.85 mm (110(links)*13.335mm)

Now the length of chain covers the distance around the outside of the two sprockets and the two lengths at the top and bottom. So the length of the top and bottom bits between the sprockets is
533.4 mm = (1466.85 - 100.013(front sprocket C/2) - 300.0375 (rear sprocket C/2))/2

So the distance between the centre of the two sprockets is worked out using the pythagoras theorem
sqrt(533.4^2 - 63.67^2) = 529.5863 mm (63.67 is the difference in radius of the two sprockets)


Now similarly for the SV650s
Front sprocket 15t as above
Rear Sprocket 44t
Circumference = 586.74 mm
Diameter = 186.7651 mm
Radius = 93.38257 mm

Chain length = 1440.18 mm (108(links)*13.335mm)

The length of the top and bottom bits between the sprockets is
523.3988 mm = (1440.18 - 100.013 - 293.37)/2

The distance between the centre of the two sprockets
sqrt(523.4^2 - 61.55^2) = 519.7674 mm

So the difference in wheelbase between the two bikes is 9.818953 mm and since the front sprocket is in the same place on the two bikes the rear wheel will have to be this much further back on the unfaired model which is close enough to the 10 mm stated in the specs I think.

Incidentally if the chain on the S was the same as the unfaired model and the only difference was the smaller rear sprocket the wheelbase would be 3.60687 mm longer not as Colin Winslett stated 2.11 mm. He also stated in a previous posting that Suzuki could adjust the chain length to make the wheelbases of the two bikes the same,
but in reality a chain must have an whole and even number of links. You would need a chain with 109.463 links on the S model to give it the same wheelbase as the unfaired model. Now if the sprockets were the same and the only difference was the shorter chain length then the S wheelbase would be 13.43352 mm shorter.

The above calculations are approximate and assume that the chain is completely tight and don't take into account that the chain wraps slightly more around the rear sprocket and slightly less around the front one but are a lot more accurate than assuming that the difference in rear sprocket radius is the same as the difference in wheelbase. I did all of these calculation in a simple spreadsheet if anyone is curious.

[northwind]

The swingarm doesn't control the wheelbase though, the chain does- the longer chain will put the wheel in the same place for either swingarm, just that the range of adjustment is different (the S model chain puts the wheel right at the front of the adjusters on the N swingarm)

I'd say you should go back to the rear shock and get it set up right for sag, trying to do anything else with it will tend to give a bit of an iffy ride... Not that this is definately the cause but it's an easy one to eliminate.

[Rhiwbina_Squirrel]

Excuse the completely, almost beyond, amatuer comment but are both the tyres correctly inflated? I read on here how many people had done it before and I know I have, just an idea.

[BanannaMan]

The naked model has a sharper steering head angle than the S model.
Also the naked model has a longer swingarm and lower gearing (standard) than the S.

Don't know that the shorter chain will work on the longer swingarm....however...
I run the longer chain and "N" gearing on my "S" model.
It improves the way the bike handles... for me.
It also leaves part of the adjustment slot showing in front of the side plates.

Also tyres can play a big part of how quickly the bike steers.
What brand of tyres are on the "S" bike vs. what's on your bike???

[zunkus]

Northwind
You're right of course, the wheelbase is not controlled by the swingarm, the chain length does, my only concern was the adjustment for the smaller chain. Thanks for your suggestion; ie(the S model chain puts the wheel right at the front of the adjusters on the N swingarm).

R Squirrel
Yes, I'm almost religious on tyre pressure checks. The climate here in Malta, hot, does cause the tyres to deflate more so bestto keep an eye there.

BananaMan
Naked model having a steeper steering head angle then S model? I never really understood this theory, maybe I'm missing something here but I don't agree. I converted the top yoke to the S model to fit the clipons better right? The fork legs went up properly using the old lower yoke so there is no offset or any difference there is there? The only thing I've noticed between the N and S curvies is that the S models have their ubes dropped less than the N. I'm guessing now after gathering a bit of knowledge that they did this due to the N having a longer swingarm/chainlength resulting in approx 3mm difference in wheelbase between them. The point noted by Northwind of having the wheel further back creating more leverage is justified and the drop in forks is there to compensate to put the bike balance to where they wanted. Do you agree with this?
Oh almost forgot, I've got Metzeler Sportec M3's which are a huge improvement on the old MEZ4's.

[petevtwin650]

Reading this thread with interest. I've got a curvy S with a N chain and sprockets fitted. Firstly it doesn't allow much chain adjustment as the adjusters are nearly at full stretch, plus it shows the slot which the plates are supposed to hide. Also I reckon it slows the steering up slightly as the wheelbase is longer. More stable in a straight line but less inclined to drop in IMO. I've got a 46 tooth sprocket to drop in to see if that takes up some of the excess and helps with the steering.

[Dangerous Dave]

The naked model has a sharper steering head angle than the S model.
Incorrect, the only rolling chassis difference between the 'S' and 'N' is the different sized rear sprocket and the 'N' has a slightly longer swingarm.

[yorkie_chris]

Well no he's not incorrect, as the naked has the forks dropped in the yokes by 6mm as standard whereas the S is flush. Which gives a slight difference in rake.

[21QUEST]

The difference in the amount of fork stanchion protruding, is due to height difference at the hole which the stem goes through..... stick an 'N' top yoke on an 'S'(which has forks flush) and forks will protrude 6mm ;)


Ben

[Dangerous Dave]

The difference in the amount of fork stanchion protruding, is due to height difference at the hole which the stem goes through..... stick an 'N' top yoke on an 'S'(which has forks flush) and forks will protrude 6mm ;)


Ben
Agreed, the rake is the same. This is what makes me laugh when 'N' riders start to compare there bikes to S's. Plus dropping forks through the yokes isn't a rolling chassis change!

[zunkus]

The difference in the amount of fork stanchion protruding, is due to height difference at the hole which the stem goes through..... stick an 'N' top yoke on an 'S'(which has forks flush) and forks will protrude 6mm ;)
Ben

Now this is something I never actually realised.
Well done 21Quest for illuminating me.

[zunkus]

... Plus dropping forks through the yokes isn't a rolling chassis change!

Sorry, I'm lost here, can you kindly explain the rolling chassis change thing?
Truely, I'm interested.

[Dangerous Dave]

Rolling Chassis - Frame, Swingarm, Suspension, Wheels.

There is no difference between the 'S' and 'N' other than the slightly longer swingarm of the 'N', everything else is the same. The so called rake difference between the two bikes is actually an optical illusion created by the difference in top yokes!

[northwind]

AH, but if all other things are equal and you lengthen the chain by 2 links, then you make the rear ever so slightly higher (what, 1mm?) which will decrease head angle and trail by... Practically nothing, but still :D

[zunkus]

AH, but if all other things are equal and you lengthen the chain by 2 links, then you make the rear ever so slightly higher (what, 1mm?) which will decrease head angle and trail by... Practically nothing, but still :D

This I can confirm, my bike's rear is measured slightly higher than my brothers, mine a converted N but still with two extra links and Simon's a standard S.

[sinbad]

Assuming the tyres of each bike are identical in brand, wear and pressure, and both have properly working parts, which are set identically (preload), and they still handle differently in an obvious way with the same rider atop, then perhaps it could something as minor as the wheelbase being lengthened minimally. I wouldn't bet on it, though. I reckon it's one of the other things.

Ignoring the difference between it and your bro's S, how does it compare to when it was in N form?

[zunkus]

Well to say the truth I rode around 2000 miles in 12 days last summer on an N and felt no back pains while my younger brother (by 12yrs) riding an S was not feeling all that great and had all sorts of aches and pains. We rented a pair of pointies to tour back then. I'm not sure if I would have felt so great on an S. I use my SV mostly for short blasts on Sundays and that was the main reason for the mod. The riding position is not as comfy as it was but it's more fun and the bike looks much nicer IMO. Its my toy primarily and love to modify it. I've also got a supermoto bike for everyday use which I find much more suited for all weather, traffic filtering and instant handling. I love both bikes for different reasons. I'm actually quicker on an SM, but that's because our roads here are always filled with traffic and there are junctions and obstacles everywhere. So its more of a romantic feeling with me and my SV. I've always loved the look of cafe racers with their clipons and exposed engines and I modified mine to a modern version of that expression.
SO, for Malta, the N is more practical and the S just makes you feel better in my opinion.
It may be different in the UK.