13/52 gearing on a 350 EXC-F

[Horgh]

I decided to try 13/52 gearing with my little 350. The stock 14/52 is decent, but going very slow requires a lot of clutch feathering, and going in second is a bit tall for some of the slower trails I'm trying. So, I want to see how this lower gearing will behave.

I installed a DT sprocket and spring washer, and I reused the stock chain (118 links I believe?). I read in another thread that I'd have to shorten the chain by a link, but I was able to adjust the stock chain. There isn't much left on the adjuster, but I wanted to maximize the amount of space between my tire and the mud guard in the back. Do you guys think this is adjusted too far out and I should, in fact, remove one link? I haven't taken it for a test ride yet, but plan to tomorrow if all this looks fine.

 

 

Edited January 13, 2019 by Horgh

[jrodicus100]

No reason to remove it. I ran mine that way until the chain stretched to the point where I ran out of adjustment, then I had to remove a link.

[Hammy.]

Im assuming when people said you'd need to remove a link, it would be for retaining the stock wheelbase. 

[Horgh]

16 minutes ago, Hammy-56 said:

Im assuming when people said you'd need to remove a link, it would be for retaining the stock wheelbase. 

When I was doing some test fitting, I think removing a link would have actually brought the tire closer to the mud flap that I had originally. And originally I only had 1/2" of clearance there, so I'm not even sure that would work well, but I guess I'll (eventually) find out.

[Spud786]

Id make sure you like the gearing change first, since its already together.  Im up one tooth from stock on the rear, at 2 teeth larger , I didn't like higher speed rpms, that I run a lot, but did like the strength up to that point, it also ate rear tires at a faster rate. I went back to one tooth up.

 

so your 1 teeth on the front (like near 3 teeth on the rear) , should be significant, and really tighten up those ratios

[jrodicus100]

Im assuming when people said you'd need to remove a link, it would be for retaining the stock wheelbase. 

You run out of chain adjustment on the swing arm - that’s why removing a link could be necessary.

[Spud786]

Id really focus on that rear aluminum, those things wear like cht, and throw off metal like crazy.

Never forget this, sunstar steel rears, are the Best longevity sprocket in the industry only like $40 too, stuff like iron man crap need not apply. They skeletonize those iron mans so much for a few ounces of weight, they cant take any kind of hit.  The two piece sprockets, are nice , but you pay double for, and 2 pieces have more potential for flexing that single piece doesn't.

But SUNSTAR rear steel sets the bar, and can not be beat price and or longevity wise

Edited January 13, 2019 by Spud786

[Horgh]

1 hour ago, Spud786 said:

Id really focus on that rear aluminum, those things wear like cht, and throw off metal like crazy.

Never forget this, sunstar steel rears, are the Best longevity sprocket in the industry only like $40 too, stuff like iron man crap need not apply. They skeletonize those iron mans so much for a few ounces of weight, they cant take any kind of hit.  The two piece sprockets, are nice , but you pay double for, and 2 pieces have more potential for flexing that single piece doesn't.

But SUNSTAR rear steel sets the bar, and can not be beat price and or longevity wise

I only have 16 hours of very mild riding on the rear sprocket, neither stock sprocket was showing any wear, which is why I didn't replace the rear. I'll keep an eye on the wear, thanks for the heads up.

[Spud786]

1 hour ago, Horgh said:

I only have 16 hours of very mild riding on the rear sprocket, neither stock sprocket was showing any wear, which is why I didn't replace the rear. I'll keep an eye on the wear, thanks for the heads up.

I ran mine about 3,000 mile, watching it shed metal. Back in the 70's everything was steel, by the 80's everyone was running aluminum, and they did wear alot and can break teeth, I ran sunstar works triple stars back then on mxers, they had pretty good support for an aluminum but still wore out completely within a year. The steels, can litterly go years and years , they just don't wear easily.  If you can keep a lube on the teeth they'll go 50,000 mile easily. Really dang near a life time item , then you only have to replace the fronts and the chain as they wear  , at a more normal rate.  I normally pop on a new front and chain at the same time, or sometimes replace the front sprocket mid life of chain, if it showing wear, but the steel rears are more an after thought. Less labor , and better for the pocket book.

[Doc Brown]

14/52 is the street legal gearing in AT, for sports and race use a 13 teeth sprocket should be installed. I think its the same in the US.

The correct chain length for 13/52 is 116 links. As you already saw 118 works also but brings the rear wheel further back. The OEM chain is delivered with 118 links so that the "legal" 14 teeth sprocket can be installed.

Edited January 13, 2019 by Doc Brown

[KennyMc]

Depending on what type of riding your gonna do you may or may not like it. I tried that gearing and loved it. But I rode all off-road, single track with lots of hillclimbs. Some of the hillclimbs gave me trouble before but with this gearing I was able to start off in a higher gear and work it from there. And the wheelie factor was a side benefit. Just be ready on the clutch as it obviously runs out quicker. But I prefer to be an active clutch rider anyway so it increased the “fun” factor on the 350

[kevvyd]

20 hours ago, Horgh said:

I read in another thread that I'd have to shorten the chain by a link, but I was able to adjust the stock chain. There isn't much left on the adjuster, but I wanted to maximize the amount of space between my tire and the mud guard in the back. Do you guys think this is adjusted too far out and I should, in fact, remove one link? I haven't taken it for a test ride yet, but plan to tomorrow if all this looks fine.

I did this and posted in another thread about removing 1 link.  It is not a matter of having the adjuster too far out.  That bolt is longer than it will ever need to be.  The axle or axle block adjuster will mechanically max out before the adjuster bolt.  If you like that gearing and leave it that way....you will need to remove a link in no time flat.  Or ride with a too loose chain.  Also--I am not at all offended by you "second guessing" what I had written in another thread~~LOL

I knew that I would be good with the super low gearing for my terrain and style....and would rather wrench once and be done.  That chain will probably grow enough to be too loose for the adjuster even by the time the chain becomes warmed up....

20 hours ago, jrodicus100 said:

No reason to remove it. I ran mine that way until the chain stretched to the point where I ran out of adjustment, then I had to remove a link.

So, yes

 

6 hours ago, Doc Brown said:

14/52 is the street legal gearing in AT, for sports and race use a 13 teeth sprocket should be installed. I think its the same in the US.

The correct chain length for 13/52 is 116 links. As you already saw 118 works also but brings the rear wheel further back. The OEM chain is delivered with 118 links so that the "legal" 14 teeth sprocket can be installed.

And yes again

Edited January 13, 2019 by kevvyd

[kevvyd]

Also, the sticker on the inside of the airbox door is a "decent" suggestion for chain tension setting.  If you really want to know what you are dealing with:

Put bike on a pit stand.  Remove rear shock (2 screws on your PDS bike) Lift and lower rear wheel through its normal range of travel.  Observe chain tension and adjust the tension based off of what you see and feel.  (not too tight at the point where it will be most tight; aka axle farthest from countershaft)

Put the shock back on and then do your own measurement using the KTM suggested spot/technique from the airbox door.  Record this measurement and use that as your "real world" chain tension setting.

[Doc Brown]

10 hours ago, kevvyd said:

Also, the sticker on the inside of the airbox door is a "decent" suggestion for chain tension setting.  If you really want to know what you are dealing with:

Put bike on a pit stand.  Remove rear shock (2 screws on your PDS bike) Lift and lower rear wheel through its normal range of travel.  Observe chain tension and adjust the tension based off of what you see and feel.  (not too tight at the point where it will be most tight; aka axle farthest from countershaft)

Put the shock back on and then do your own measurement using the KTM suggested spot/technique from the airbox door.  Record this measurement and use that as your "real world" chain tension setting.

This method is good to see where the chain is tightest. That is, most people dont know, when the center of the front sprocket and the center of the rear sprocket are in one line. Though your method is probably the most precise of all methods it needs quite some effort. Another good and quick method is, put the bike on its wheels and ask a fat or heavy friend to lean over the seat until the sprockets are aligned, then check chain tension and adjust if necessary.

Edited January 14, 2019 by Doc Brown

[travertt]

13/52 is stock on my 350 XCF-W....if you`re looking to run technical gnarly stuff and tight single track with minimal 55mph road use...its perfect IMHO.

If your into dual sport and decent length road runs...not so much.

[Horgh]

I rode 13/52 yesterday. It's... different. I may just have to get used to the new gear ratios, it wasn't bad, it just felt a little awkward at first. I do like how short the first gear is for crawling, and the shorter nature of the second gear or trail work.

[Doc Brown]

21 hours ago, Horgh said:

I rode 13/52 yesterday. It's... different. I may just have to get used to the new gear ratios, it wasn't bad, it just felt a little awkward at first. I do like how short the first gear is for crawling, and the shorter nature of the second gear or trail work.

Give it a chance and leave it on for a few rides. you will get used to it. The good part, you probably will never need the first gear, you can do even very steep climbs with second. I never used first after changing to 13/52, not even from stand still or steep climbs without run-up. I bet you will like it ?

[Gflo]

On 1/13/2019 at 11:25 PM, Doc Brown said:

This method is good to see where the chain is tightest. That is, most people dont know, when the center of the front sprocket and the center of the rear sprocket are in one line. 

The center of the front and the center of the rear sprocket are always in line regardless of where the wheel is in its travel.  It’s just two points.  To determine when the chain is at its tightest, you need to align the center of the countershaft with the center of the swingarm bolt and the center of the rear axle.  All three need to be on the same plane.  This will give you the tightest point of the chain through its travel.

[Doc Brown]

9 hours ago, Gflo said:

The center of the front and the center of the rear sprocket are always in line regardless of where the wheel is in its travel.  It’s just two points.  To determine when the chain is at its tightest, you need to align the center of the countershaft with the center of the swingarm bolt and the center of the rear axle.  All three need to be on the same plane.  This will give you the tightest point of the chain through its travel.

Granted. I should have said in line horizontally, the pic below says it all. The center of the rear sprocket and the center of the rear axle are the same in this case.

 

 

[sirthumpalot]

Don't forget to leave a little slack in the chain depending on conditions.  For example, mud will pack up in the chain and tighten it quite a bit.  Ever fall in sand, get up only to find the chain is so tight the rear wheel won't spin?  So you probably won't want to tighten a new or just cleaned chain to the absolute limit, leave a little room.  

In regards to sprocket material; steel is definitely more abrasion resistant than aluminum (longer wear life), the penalty is weight, which may or may not matter to you.  I've used the Ironman sprockets myself for years (used to sell them) and they wear really well.  But for the budget minded, regular old steel from JT, Sunstar, etc.. is definitely the most service life per dollar.  They do wear out, I've worn out plenty of steel rears over the years, but they do outlast aluminum by a good margin.  For entertainment, here's a comparison between sprockets for the same bike from an old ad: