DR650 FAQ - Drive Train

Q:

Will a 14 tooth countershaft sprocket wear my chain faster?

I am about to place a order which will include a 525 chain and sprocket set. Is the chain in the kit an "O"-ring, "X"-ring or something else all together? Also, does it have an old style clip master link or a newer rivet style? I would prefer an old style clip master link and was wondering if I can specify what kind of master link I want in my order.

I have another question before I place the order. I wanted to test a 14 tooth CS sprocket and mounted it up using a well used stock 525 chain with a 42 tooth rear sprocket. That used chain stretched to the limits of the adjustments in a matter of 1,500 miles. While mounting the 14 CS I noted that the radius seemed a bit snug. My question is, does the 14 CS tend to wear chains faster than a 15 CS?

Last but not least, which of the following two ratios, 44/15 and 47/16, would give me the same ratio as the 42/14? I would like to keep the low end grunt with 70-75 mph still obtainable without trashing the motor?

A:

First of all, the 525 chains we sell are EK brand "O"-ring chains. They come boxed with a rivet type master link which is pretty normal for a 525 chain. If you like, we can add a clip type master link to your order for $5.95. As a side note, the 520 chains we sell come boxed with a clip type master link.

If you stay with a 525 chain, your sprocket choices will be limited to 14 or 15 tooth CS and a 42 rear. This is one of several reasons why so many DR owners switch to a 520 chain. In the 520 size, you can choose from 13 through 17 CS and 41 through 52 rear. You are also much more likely to find a 520 chain at a motorcycle shop on the road should you ever need one. Most shops don’t stock a 525 chain.

All things being equal, wear on a 14 CS sprocket will be about 7% faster than with a 15 CS. Chain maintenance has a MUCH bigger influence on chain life than sprocket sizes. Also, chain wear accelerates. It's the nature of how chains wear. The last 1000 mines in a chain goes away much faster than the first 1000 miles. When you put the new sprocket on the worn chain you created a mismatch which contributed even more to the faster chain wear.

Your question about gear ratios requires two answers. First of all, in the 525 chain, you cannot get a 44/15 (2.933 ratio). You can only get a 42/15 combo (2.800) and the 42/14 (3.000) set-up. If you go with the 520 size, there are a lot more options available: 13, 14, 15, 16 and 17 tooth front sprockets as well as 41 thru 52 rear. To compare gear ratios just divide the number of teeth on the rear by the teeth on the CS.

Q:

Where is sixth gear? (or how do I live without one?)

It seems to me the biggest shortcoming of the DR is the lack of a six speed transmission. I don't have much off-road experience but 1st gear just seems too tall off-road and 6th could be a little taller for highway speeds. I'm thinking of changing the gearing to 13/43 for off-road and 16/43 on-road.

A:

I've run gearing from 13/42 to 17/42. The 13/42 works well for trails but starts to feel pretty busy at speeds over 60 mph. Half of the perceived gearing problem is related to the stock carburetor working poor at low RPMs. We carry a complete selection of gearing and chain sizes. From pre-packaged kits, to build it yourself packages.

Though it has nothing to do with the gearing and it is a lot more costly than changing the gearing, installing our TM40 carburetor kit will make the 5-speed transmission you've got seem just fine. The improved performance in the lower RPM range allows you to run taller gearing while also giving you improved top-end performance. Click here to read more about the TM40 installation.

Q:

TM40 equipped DR650 able to use 17/42 gearing?

With the TM40 kit installed, will the DR650 pull the 17/42 gearing? Question #2; Can you go from the 13 to 17 countershaft sprocket using the same chain length? Question #3; How does the TM40 handle large altitude changes? In a regular day’s riding for me it is possible to have 5,000 to 6,000 feet of elevation change and the CV carb seems to handle that pretty well.

A:

Answer to Question #1; 17/42 gearing works much better with the flatslide but the stock carb will pull it just fine as long as you don't let the revs drop too low. It puts 5th gear right where my imaginary 6th gear would be. With the TM40, you don't have to worry about the revs dropping too low, within reason of course! Answer to Question #2; Yes, you can go from 13 to 17 on the countershaft sprocket with the stock length chain. Question #3; The TM40 isn't bothered by altitude changes. I've run mine from sea level to 9,500 feet in a single day without a hitch. Click here if you have more questions about the TM40 carburetor swap.

Q:

Countershaft sprockets - retainer vs. circlip

I know that you sell the retainer plates for the small countershaft sprockets, but I see that some other companies sell just a circlip to hold that on. Is it OK to just use the circlip? Also, if I use the retainer plate, do I need to use Loctite© on the bolts every time I remove them?

A:

I never was sold on just using a circlip. I don't necessarily think it would cause a problem, its just that the clip just leaves the sprocket 'wobbly' which doesn't seem right. There are plenty of other bikes that only use a clip (KTMs for example) but on those bikes the clip holds the sprocket firmly against a shoulder on the shaft - no wobble. I don't bother with the thread lock compound, I just make sure the retainer bolts are tight.

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