Just happen to have a stock rear sprocket and a stock chain laying around. Iput them on my Postal scale and...

Stock rear sprocket = 1Lb 13oz

Stock Chain = 5Lb 1oz [img]i/expressions/face-icon-small-shocked.gif[/img]

The stock chain on my 2000 DS was 108 links.

Now if I had a stock front sprocket we would have the whole stock weight...

 

Thanks! Looks like it is a pretty significant savings going to a 520. Almost 2 pounds on the chain, 1.5 pounds turning the hubs, not sure how much lighter an aluminum or ti-moly rear sprocket is. But go with some lighter wheels and paddles and it looks like it would make a differenct... does it?

 

Also Sidewinder claims their kit shaves off 2lb 3oz, but costs ~$300. Looks like if you went with the EK chain and aluminum rear sprocket you would get close to this weight savings for $150 or so.

 

shedding 3 pounds off the mass of the drive by going to 520 width for $150 will give you more real life gains than the tiny bit of horsepower $150 is capable of buying.

personally, I would not bother making the change from a perfectly good 530 stock setup unless building a drag specific bike, but when the stock setup becomes due for replacement, the 520 will be cheaper plus give the gains.
but it will not last as long, the sprockets are thinner and thus will wear faster, and the chain having shorter pins and rollers from the narrower width will wear faster - this is of course comparing the exact same type/brand of sprocket or chain in 520 vs. 530.

its kinda 6 of one, half dozen the other - go thinner and cheaper and replace more often, or stay thick and beafy and replace less often, either way its a wash in the longrun. but you get the gains with the thinner 520, that when combined with lightened wheel hubs makes a difference that is easily felt and noticed.

the DS was designed to win the Dakar and last thousands of miles without service. but for us weekend warriors alot of its massive durability is a bit overkill. I felt the difference turning my hubs and going with an aluminum 530 made, so when I need chain again I will go to 520 and feel even more. I almost can't wait!

 

Good stuff Hightower...

Does my stock setup need replaced? Not really, but since I am selling my other DS I am itching for some mods to do, haha.[img]i/expressions/face-icon-small-smile.gif[/img] My 04 is gonna be loving me this winter, new TCS shocks, new drivetrain and I talked to Jeff Ross today, he is gonna turn my hubs down to a yammy bolt pattern and hook me up with some go fast engine parts. Great guy!

Once I decide on a chain and sprocket, I will weigh everything to de-mystify the 520 conversion on a budget.

 

LOL Yeap Jeff is the BOM!!! as for the 520 kit, My LT500 putting out about 70 HP has been using the 520 DID O ring chain and Aluminum Sprocket for years ( and Im a heavy Weight)its just like any other part of the bike, just adjust it when needed, stay with the DID chains Rocky Mnt has some fair prices.

 

The stock chain for the older DS's is 530x110. I ran the RK X-Ring chain after my stocker and loved the beating it took, i think i tightened it once the whole time i had it, lil over a year. Decided to go with a new chain and sprocket setup and ran the titax sprockets with the HPR lightweight chain, i tightened that like 3 times in 1 year, it ate up my chain roller lol, im going back to the RK X-Ring chain for $64

 

Here is what I have so far,

Stock 530 chain = 5 lbs

DID 520VM chain = 3.35 lbs and tensile strength is 8,050 lbs, it also has the highest wear rating I can find 3220. I can pick one up on the net for $80 or so. It was the lightest chain I could find for a reasonable price.

Weight savings on the sprockets will be 10 oz. or so with the ti-moly, more if I go with the aluminum.

Hubs, Jeff said he can cut mine down to a Yamaha bolt pattern for $150, saving me 1.5 lbs overall.

So it looks like a savings of 1 lb 10.5 oz for the chain, 10 oz. at least for the sprocket, 1 lb 8 oz. for the hubs = at least 3 lb 12.5 oz. of rotating mass!

Now the last question is wheels and tires. Having my hubs turned I have the option to run 8" wheels, but what weighs more? .160 aluminum or rubber? Not sure what would give me the lighter setup 8" wheels with more rubber or less rubber and 10" wheels or even 9"?

And yes I am bored at work, haha.

 

when picking rim size, consider the kind of tire you want, they may not be available in 8" rim size. for us big guys on DS's in the big dunes a 22" tire is best without any doubts. it is a trail bike you're building and you gotta consider what works best for trail riding, and our recreation riding in idaho and utah for us big guys has the DS craving 22's. jmo's mind you, food for thought. but even most of the locals in utah and idaho I hook up with every year run 22's on their yams and hons and suzs, cause they know better.

you might could check with your local machine shop, I had my local shop turn my hubs for me while still maintaining the DS bolt pattern and it cost me $50, the dimensions I had them use are on my pics page in my sig. not as much material removed, but cheaper. this kept me from having to buy new rims too. just a financial option, you'll shed more going the full blown route of course.
the pic says 2.08 lbs. shed, and this is absolutely true of my hubs, yours will not see this much cause the newer models DS's have lighter hubs from the factory than the early models did.

 

Definitely staying with 22's.

On my quest to lower rotating mass I emailed smimotorsports.com to get a price on some bead to beads and some weights.

22x11x8 8 paddle Extremes Bead to Bead on .160's are 2 pounds lighter each tire, so 4 pounds of rotating mass that way. The only thing I am trying to get out of smi is if these will hold up to jumping and the concrete jaunts at silver lake.

This would be about 8 pounds TOTAL of rotating mass lighter than what I am running now. What is the figure that everyone touts, rotating mass equals how much effective horsepower?