oldfatguy

Member
Jul 15, 2002
21
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When you're as slow as I am, the stock gearing on the 300MXC can seem a little tall. I'm thinking of going to a 13 front / 54 rear combo (stock = 14/52). Any counsel from you experienced folks? No need for the "it'll reduce your top speed" comments - I'm too slow right now to worry about that.

Chain clearance problems? Too much pressure on the crankshaft? Will the chain prematurely wear the plastic guard on top of the swingarm?

I'm guessing that I'd be better off with a 14 front and an even bigger rear (that sounds bad, doesn't it). Does anyone know the max rear size before trouble starts? 54? 56? Bigger? Would an aftermarket chain guide and/or chain guard allow me to go to a bigger rear?

Thank you in advance for your counsel.
 

KaTooMer

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Jul 28, 1999
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I've been using a 13-tooth front on my '99 300 EXC and haven't had any chain issues. On the rear, I've never gone higher than 52 teeth, so I don't know how a larger sprocket might affect the chain guide. You might want to try a 13-52 combo and see how that works for you (I'm using 13-50; a bit lower than stock). If nothing else, it's the cheapest way to start out.

Now that I have a '02 300 MXC, I'll be playing with various sprocket combinations to get a little more top speed for the more open hare scrambles in Missouri. The MXC gearing would be fine as-is, except it could use a 6th gear to match the speed of the EXC's. Maybe I'm the only person who thinks this, but I would take the MXC tranny for enduros, and the EXC tranny for GNCC-style hare scrambles. Call me crazy.
 

oldfatguy

Member
Jul 15, 2002
21
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Thanks KaTooMer. I was more worried about the 13 front than I was about the rear. It's good to hear that there are no "tight wear" issues with a 13 front.

MXC/EXC -- if I had known then what I know now, I would have bought an EXC. What I really need is a tractor-like first gear without losing too much top end. The taller 3rd, 4th and 5th gears in the EXC would have allowed me to really bring down the overall gearing and still give me the top end I have on my MXC. Oh well, maybe I'll get it right on my next bike...
 

djr

Member
Apr 22, 2002
45
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Hey Old Fat Guy,
You sound exactly like me. I ride a too fast 2000 KX 250 in the tight, slick woods of Southern Ohio. I need a granny 1st and could not care less about top speed. I have tried to find a way to replace 1st gear with a lower gear set but no luck so far. What I really want to know is what is the difference between 1st -3rd on a KTM 300 MXC and an EXC. I have considered these two bikes for my next purchase and I thought these first 3 gears were the same. My KX has a 13-48 tooth sprocket set and no problem with the 13. I am going to try a 50 tooth this week
 

oldfatguy

Member
Jul 15, 2002
21
0
I don't have my manual handy but if I REMEMBER correctly, 1st and 2nd are the same between the two models. I THINK that 3rd is the same (or darn close). Then the EXC starts to spread things out (4th and 5th are much taller). I ended up going to a 13 tooth front and it helped a bit (but I would still like a lower 1st for the really snotty stuff). I don't miss the top end as WFO 5th stills scares the crap out of me.

I think that I'm going to quit changing gears now. I could go slightly larger in the back but probably only a couple teeth (clearance problems) and I believe that a 12 front would cause excessive wear on the chain guide and probably a lot of stress on the crank.

It would seem to me that a granny 1st would be a good thing on a trails bike (yes, I know NOW that the MXC isn't really a trails bike - I wish I had figured that out before I bought it) but I haven't seen anyone offering that option.
 

KaTooMer

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Jul 28, 1999
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That's correct, 1st and 2nd are identical on the EXC and MXC. Third gear is when things start to change. The 3rd gear on the MXC is spaced very close to 2nd, so there's not a whole lot of difference when you shift. In 4th gear on the MXC, it feels like 3rd gear on the EXC. Same goes for 5th gear on the MXC - feels a gear lower. I have tried a 14/48 combo, and that seems to get top speed back to a 13/50 EXC combo. With 14/48, I like the higher first gear (I don't really need a granny gear) but 2nd is too high for tight trails. There are certain hare scambles courses where I will use 14/48, but on others I'll either go 13/50 or 14/50.
 

Shaw520

Damn Yankees
LIFETIME SPONSOR
May 14, 2000
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I'm not sure about the two stroke trannies. But the four strokes,..the MXC and the SX share the same tranny, whereas the EXC tranny is completly different; 1st, 2nd, and 3rd are much lower on the EXC, 4th is the same, and 5th and 6th are much higher on the EXC.

I have an 02' SX400 with 12/54 sprockets, the 54t rear will fit the stock guard with the wheel pulled back a bit, (longer chain). I got nearly a whole season out of the slider with this sprocket combo. The slider is only $16. small price to pay to have the correct gearing for your needs.
 

oldfatguy

Member
Jul 15, 2002
21
0
It's always better to have the facts than to rely on memory so I pulled my manual. This info relates to the USA versions of the 300MXC and 300EXC models.

300MXC:
Primary Drive = 25/72
1st = 15:29
2nd = 18:26
3rd = 19:24
4th = 21:23
5th = 23:21
Sprockets = 14/52
Rear Tire = 100/100 x 18"

300EXC:
Primary Drive = 25/72
1st = 15:29
2nd = 18:26
3rd = 19:22
4th = 21:20
5th = 23:18
Sprockets = 14/52
Rear Tire = 100/100 x 18"

It looks like the Euro EXC gets a 140/80 x 18" rear tire (lot of tread on the ground) with 15/48 or 14/50 sprockets.
 

KTM Mike

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Mi. Trail Riders
Apr 9, 2001
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I have ran 14/52 and 13/52 on my 00 300 EXC. I was hoping to address gearing particularily in tight slow stuff with the stock 14/52. with the 13/52 i found it was great for real slow tight stuff. I could run a gear higher, say a tight section that was 2nd gear with 14/52, and 2nd was a bit to low yet 3rd to high...with the 13/52 i found 3rd could be just almost perfect, maybe a hair to low 2nd now way to low. I lost tons of top end and in general I felt that combo was a touch low. BUT i would still say overall i still preferred the 13/52.

I recently went back to the 14/52 for grins and giggles and found myself needing the clutch much more, and always in just the wrong gear - just a tad to high, always needing to drop it down a cog at just the wrong moment.

So i calculated the actual ratios for each and a few other combos. end result by going to a 14/54 put gearing right between the 13/52 and 14/52. that will be my next experiment. your mileage may vary! So calculate the ratios of the gearing combos you are considering 13/14 50/52/54/56 etc and see what makes sense vs your objective.
 

trailmeister

Member
Nov 13, 2001
18
0
How about the 14/53 combo i just put on the other day. i haven't taken it out yet ( 300mxc),. but i thought this would be the perfect option.,...by the way, the 118 link 520 chain looks awfully loose, and i hardly have any room to move the axle back more (brand new x chain too)...can i easily remove 1-2 links? and how is it done best?
 

Jaybird

Apprentice Goon
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Mar 16, 2001
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Trailmeister,
Are you out of axle slide or out of adjuster bolt? Does you ride have the changeable blocks around the axles? This would be the block that has a flat out one side longer than the other. You may be able to turn it around to gain some more adjuster bolt.
If it were my new chain, I would make sure my short side of block was to the front (it would be the end making contact with the adjuster bolt), then I would wrap my chain around the sprockets to get an idea of how many links long I was. You want to be certain you don't cut a link short, but use a chain breaker and take the extra out. You can also use a small angle grider or a dremel to gring the post heads off, but I highly discourage the use of these, especially when using any sort of ring chain.

old-n-fat,
I'd try the 13/52(4:1) if I were you.
 

lawman

LIFETIME SPONSOR
Sep 20, 1999
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i have a new leftover '01 300 exc. the 14/52 seemed a little tall so i tried the 13/52, it seems a little too low (call me goldilocks). i just got a 51 for the rear to try, or may end up with a 50. of course the real answer would be the mxc with a 6-speed but that isn't likely to happen, with all of the r & d $ going to the 4-strokes.
 

trailmeister

Member
Nov 13, 2001
18
0
jaybird...it appears that i'm out of axle slide, and with a brand new 118 link chain? is a chain breaker easy to use? do i go 1 link or 2 to remove first?
 

Jaybird

Apprentice Goon
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Mar 16, 2001
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Charlestown, IN
A chain breaker is a very simple to use tool. It actually is a clamp that drives the pins out. You will be taking a male out with any removal. (the male part will have the pins attached to the outside plate) Drive each pin of the part a little bit at a time until they both break through the plate they are held by. Once the heads are shoved past the plate, it will come the rest of the way out by hand. What you will have left is two female ends of the chain and you will need a master link that replaces the link you just took out.
To shorten the chain overlap one chain over another on top of the sprockets to get an idea of just what link you will need to cut. This should be done while your axle is in the forward position. You will be ale to see just what link will need to be removed so you can get a master in it's place and be able to connect the other female end. Take up the slack according to your manual from there.

You should be able to get a chain breaker at any NAPA or AutoZone.
 
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