Chains and Sprockets

I got mine here: http: http://www.mototraction.com/c/185924/1/wr-250-frx01-08.html

Really happy with their service (They did not leave me in back order hell & they even weighed sprockets for me). Quick ship too. Remember the stock bolts won't work with these.

If you go with the GYTR sprocket, You can get it here. http://www.ronayers.com/

@Clapped - I have a SuperSprox on the R1. Looks cool, very durable, not much lighter than steel. Love it on the R1, but chose not to put one on the little blue.

Yamaha sports Plaza is the cheapest I've found for OE and GYTR parts by far. For example, the GYTR slip on is $345, oil filters are $6.99. Aftermarket stuff is cheap too, a Q4 exhaust is $230 for example.

http://www.yamahasportsplaza.com/pages/home/default.aspx



Ordered a steel 46T rear tonight from Thumpertalk. Did a little browsing through the catalogs, the JT Sprockets series JTR245/2 is the correct rear for our bike (as well as the 01-09 WR250F and 01-09 YZ250F) and they have everything from a 40T to a 53T available in steel. The part number for what I ordered is JTR245/2.46T, should be here early next week and will confirm it fits then (I have an old stock sprocket sitting around).

I just put on a Primary Drive steel 48T to go with the stock 13T front. The chain guard was very close (1/4") to the chain at the top of the sprocket, so I pulled it off. I figure, none of my dirt bikes have had chain guards over the years, so why not?? I ordered the tapered bolts, turns out I don't need them. the P-D has 12 holes, six flat for the WR and six tapered for the YZF.

First impression is fun fun fun, then the rain started. The speedometer error is terrible now. 60 indicated is 50 GPS.

clapped_r6 wrote:

anybody use the supersprox sprockets?

seems like a good compromise between light weight and durability.

i'm not completely sold on the sidewinder stuff yet.

I have the tri-metal 46 rear and it wears like iron and is great quality. I like the sprocket center as there customer service is just fantastic.

Sprocket Center

10Cup wrote:

clapped_r6 wrote:

anybody use the supersprox sprockets?

seems like a good compromise between light weight and durability.

i'm not completely sold on the sidewinder stuff yet.

I have the tri-metal 46 rear and it wears like iron and is great quality. I like the sprocket center as there customer service is just fantastic.

Sprocket Center

For those scoring at home, that is vote #2. My link (earlier in this thread) hooks you up with the same people. Why they have multiple sites? But good people to deal with.

Sprocket came in today, JTR 245/2.xxT is correct. You will need tapered bolts.

give me a week or three and I'll give you my opinion between the two. Had a 47T on the last one for most of its life, and a 46T waiting to go on.

My personal opinion is the 47T is just on the side of too short for lots of highway work. The 46T will have you cruising at 65-70 a few critical hundred rpm lower and should therefore be more comfortable while giving up very little at trail and around town speeds thanks to the gear spread. I'll know for sure once I swap the rear for the MT43 that should be here Monday or Tuesday.

One thing to note, those of you staying with the stock sized rear tire... remember that a 46T or 47T on your bike will be waaay more aggressive than it for those of us running a taller tire. The equivalent ratios on the stock tire is 13/45 if I remember correctly.

MT43's here. :) I'm supposed to do a ride on the 10th of April so long as I have off work so I'll know by then for sure.

Greer, I double checked the gear ratios with the tire sizes over at http://www.gearingcommander.com/

A stock tire with a 45T is in between final ratios obtained with a 120/90/18 and a 46T and 47T. Should be just about perfect.

It's about time I got the gearing sorted out, I'm fed up with the stock stuff. I've always watched my chain tension, but out of the blue the chain stretched a tad and I had that funky skipping thing going on. Weirdest feeling, at first I thought something had gone wrong with the vacuum lines in the tank and that the bike was starving for fuel. I geared down and jarred on it a little and realized it was the chain. Whoever designed that sprocket/rubber ring outfit needs to be hit in the head with it. Thanks again for the note on the sprockets.

Sarah

greer wrote:

Whoever designed that sprocket/rubber ring outfit needs to be hit in the head with it. Thanks again for the note on the sprockets.
Sarah

I am pretty sure the sole purpose of that stupid rubber ring is for noise for the EPA noise cycle......

I can think of no other reason for it's use...

Good thing a normal steel sprocket to replace that sillyness is so cheap...

Too bad more ppl don't replace it and spare themselves the hassle.

vwsandman wrote:

greer wrote:

Whoever designed that sprocket/rubber ring outfit needs to be hit in the head with it. Thanks again for the note on the sprockets.
Sarah

I am pretty sure the sole purpose of that stupid rubber ring is for noise for the EPA noise cycle......

I can think of no other reason for it's use...

Good thing a normal steel sprocket to replace that sillyness is so cheap...

Yeah we were scratching our head over that rubber thing too. Our theory was something to do with assembly method. Would be nice to know what "the rest of the story" really is.

This weekend I was finally able to get out on the bike. Obviously this was a very good thing. But as a bonus, I was riding with the new gearing, which was installed during the freeze.

It’s almost tempting to post this in the X Specific section. Admittedly, the bigger issue for determining the right gearing is where & how you ride, not so much because of wheel size. But, how many WRR’s are seeing >90% road time? Since I don’t know that answer & it is bad forum etiquette to start a new thread here are my impressions (yours may differ). My speedometer has been corrected (the Speedo DRD is awesome) & verified via GPS. The new gearing is 13/46.

1)
CRUISING - Lazy cruising @70 mph – Gone. 60 mph is now the lazy spot in 6^th, but that’s not to say 65mph is frantic. According to http://www.gearingcommander.com/,
the RPM at any given MPH in 5^th gear with stock (13/42) gearing is now the RPM in 6^th for that same MPH. That feels right.

2)
ACCELERATION - Doesn’t claw at the sky like a rabid cat each time you crack the throttle. But it exits corners with some authority. I have to hold onto it now. The bike
pulls up hills in 5^th & 6^th gear. Shifting from 5th to 6^th was always a disappointment (especially while accelerating) with the stock gearing. That shift feels right now. The relationship between AMOUNT OF GO : AMOUNT OF THROTTLE feels equal. For passing traffic, the new gearing is reassuring.

3)
TOP SPEED – You might need a different bike if this is a big concern. I did see 80 mph yesterday without having my chin on the tank or looking for flat ground (if anything I was on an incline). Fast enough for this type of bike I’d say.

4)
FUEL MILEAGE – Arrgg. Too many variables. Correct speedo = incorrect tach, as documented on this forum. How far did I actually go? Did I put in a 10^th (or maybe two) more on this fill-up than on the last? That 10^th equates to 5 miles. Here’s what I can tell you. Yesterdays ride clicked 60 miles on the odometer. 1.2 gallons (US) filled up the tank. This equates to 50 mpg. We know that I in fact went farther than 60 miles. My Speedo DRD is loaded with a value of –18% (7% of that assuming speedo optimism from the factory). If the tach was perfect from the factory (big assumption I know), then I retarded it by 7%. In turn, I really traveled 64.2 miles yielding 53.5 mpg. The best mileage I have ever gotten with this bike is 58 mpg & I have gotten mileage this low before the gearing change. I’m not even considering the odd 10^th of a gallon I mentioned earlier because my head is starting to hurt. Yours, too. Sorry. So, to put it simply, CHANGE IN GAS MILEAGE IS NEGLIGIBLE.

Anybody considered a swap to 428? Jager made mention of it sometime back, but that's all I found. Too dinky for the WR? Too hard to source out on the road? Just all around not a good idea?

Sarah

I wouldn't do it.
Myself, I see no advantage, and I'd have to scratch my head a bit to figure out where you'd get the sprockets from.
Would they have to be custom-made, or is there a place that sells them already sitting on the shelf?

I have done the opposite, though:
Take a bike that came with 428-sized stuff and convert it to 520.
XT-350 riders do this as the 520 sprockets from an XT-250 from 1980-1984 will fit right on.

I get the feeling that the reason a few dual-purpose bikes came with 428 chain and sprockets wasn't for performance or because it was stronger or higher quality, but to make less chain and sprocket noise.
That's my guess, anyway. :)

greer wrote:

I hadn't pondered long enough to even consider availability. We get so worked up about weight savings I was thinking the chain may be a place to look. Thanks very much for the speedy reply; I'll go back to sorting my 520 options. Thanks again.

Maybe the question should be: why NOT do the conversion? Especially when you're busily tearing out the AIS and the other mods to find little bits of extra performance here and there.

When chains and sprockets are available, just what is the disadvantage in running a "wimpy" 428 chain of 12,000 or even 16,000 lb tensile strength???? Anyone know if the tensile strength of the stock WRR chain comes anywhere close to 12,000 lbs? My wild assed guess is that the stock chains we're running are probably somewhere around 8,000 lbs tensile strength - but it is just a guess. If the 428 chain has a higher tensile strength than the stocker 520, what makes it "whimpy"?

Bigger does not automatically mean stronger...

There's a fair amount of power sucked up by the chain drive. I don't recall the conversations I had with my master mechanic brother and engineer brother a year ago, so I don't remember the specifics of how much. So once the stocker chains and sprockies are fried, why NOT go down in size at that time? What's the difference in price between buying high end 428 size chain and sprockies and high end 520 size chain sprockies? How much more expensive is the 428 size setup to buy than 520 size?

Reducing the weight of the chain you're driving and the drag and friction within your chain can't hurt.

What would be really interesting would be to run the stock chain setup on a dyno and then swap it out out for a 428 chain setup with the sprockets being the same size. See some specifics on how much of a difference it would make. Sounds like a project HF or Krabill should take on...

... we sit around staring blankly at the wall thinking about gear ratios and "what ifs"... What if I end up liking a bigger tire, etc.

So I'm sitting here staring at the wall wondering why my next sprocky setup shouldn't be 14/49... which is pretty close to 13/46, 12/43. And maybe switch over to 12,000 lb tensile strength 428 chain while I'm at it, seeing as you're buying new sprockets at the same time.

Hmmmm... this really isn't unlike playing with reloading manuals, different bullets from different manufacturers with different ballistic coefficients and wondering what you'll get out of it at various ranges versus what the penalty might be.

There is a point of diminishing returns when gearing down. 12/47

Stock final ratio = 3.31to1 (rounded to 2 digits)

Swapping the front to a 12 gives: 3.58to1 final.

Swapping a 47 in with the stock 13 is very close to the other swap with a 3.62to1.

The proposed 12/47 yields 3.92to1.

At some point you basically render first gear useless for any riding except trials. As you gear down you effectively close up the overal ratio spread from gear to gear too.

No one ratio is going to be right for everyone. I would not go 12/47 on mine because I do want to retain 65+ MPH capacity without wringing its neck all of the time.

Do the math, evaluate the data and decide which one works for your intended purpose. And remember, if you decide that what you go with has a fault, you can change it again later.

To Jäger's point, there are a lot of combination that are very similar in the end result. There are also a lot of 'right' answers to the question of what ratio is excellent.

The ratios you are proposing are far taller than I am aware of folks using. I am not saying not to give it a go though. If you think it will work, then give it a try and let everyone know what shakes out. Just bear in mind that most of us get performance increases from gearing down, not up. In my case I went up five teeth from the stock 43 to a 48 while keeping the 13 in front. I gained a few mph on top end since the engine was free to rev and breath. Remember, these little engines hit a torque peak around 8,000 RPM and make peak HP closer to 11K.

For you tire question I would say to check out the Shinko 705. It is a road oriented DS tire. Here is alinkto a source, there are others to shop from too.

Wayne, perhaps these pictures will be helpful in answering your question. I used a 16 tooth from a different bike. Of course I have to hold it in place since my sprocket and chain are still there, but it is the correct outer diameter as it is a 520 16 tooth.

First with the engine guard in place:



The teeth hit the guard, preventing me from centering the sprocket on the shaft.

Without any guard, stock or aftermarket:



It does clear the bare case. It would work if you choose to run with no cover or case protection.

Hi Ed29:

Thank you!!! If the 16T was seated on the splines, do you think there would there be a clearance issue with the inside of the case and the 520 riding as it normally would? I would be taking some chances if a chain were to break without that case protector!

With spacer standoffs, the stock outer cover should be able to be installed w/out the OEM case protector installed, right?

Thanks again for the pics as it beats the heck out of guessing. I sent a request for a review bike locally plus an event proposal to my friends at Yamaha last week with some of this discussion being presented.

Wayne Gerdes - CleanMPG

There would be plenty of clearance between the chain and the case, and the stock cover could be placed on standoffs as the bolts are nowhere near the low clearance areas. As far as risk of a chain breaking, I suspect that in your effort to squeeze out the most fuel efficient runs you will not be taxing the chain heavy enough to worry. In my decades of abusing bikes I have broken exactly one chain. I had jumped too long on the MX track, landing on the flat after the ramp with the throttle open a bunch. This was on a 50+hp CRF-450R and on a well prepared loamy track. A lot of stress was involved.

As you proceed please start a thread dedicated to your project so we can cheer you on from here!

ps, if you hadn't already thought of it: In your efforts to reduce parasitic losses from friction if you install a plain (no O or X ring) chain a substantial reduction in loss will be had. Sure, it is a pain to maintain compared, but it seems like you are willing to go to great lengths already to attain your MPG goal.

Hi Ed29:

I cannot thank you enough for the terrific advice and for taking the time to snap the pics earlier this morning. I would have never considered a non O-Ring chain and it adds yet another possible addition to my list of minor modifications for a Project bike.

Now that I know a 16 “can” be installed and I am assuming a 38 can be installed in the rear without tearing up the chain guard and swing arm hopefully, I based my latest RPM/MPH around the stock 140/70x17 BW. When I did the calc’s for an upsized 140x80x17 rear tire, the ability of the .25 L to run at just 5K while pulling 66 mph seemed really suspect so I dropped it. Using the stock rear wheel/tire combination, the result yielded 4K at 50 mph and 5K at 63 mph in 6th. I am guessing but the WRX should be able to drive the bike to 55 + mph at approximately 4,500 RPM with a minor head wind from right rear quarter through a straight on head wind to a left rear quartering wind in the flats? And a gear or two drop for any higher speed slab, higher headwinds and inevitable climbs over the Rockies and Sierra Nevada's if I were to take this bike out West of course.

For a standard review I would not change a thing but for a project or event bike, your ideas make for a sound design!

Now all I need is for Yamaha to come through...

Thank you again for your time

Wayne Gerdes – CleanMPG