'90 DR 350 sprocket & chain sizes

[Rocket Scientist]

Ive got a 1990 DR 350 & want to put a higher tooth front & rear sprocket on to get lower rpm & more mph on the street. My chain is too tight & larger sprocket hits the guide. Looking to get a comfy 55-60mph out of her without vibrating my teeth out of my skull. Ideas?

[TorqueNut]

Is yours a DR350S? If so, stock gear for 1990 - 1993 is 14 front / 43 rear. That's a 3.07 ratio. If the engine is unmodified, it can still pull a 15 tooth front sprocket, leaving the rear at 43. That's with a stock length 108 link chain, which will still fit. The new ratio is 2.866, so it's less buzzy at 55-60 mph. The only temporary mod is that you'll need to run this setup without the front sprocket's case guard. I went to Sears hardware and bought a couple of nylon standoffs to replace the guard's thickness, and the front sprocket cover fits just right that way.

If instead, you have a DR350 dirt model (no S), you start with a 14 on front and a 47 on the rear. This setup is for the trail and gets very buzzy on the street. Be careful ordering parts! The non S (dirt model) has no cush drive and the rear sprocket mounting is completely different.

[Rocket Scientist]

I bought the bike used with a 15-47 set. Its awesome off road, but a little too high rpm for me at hwy speed. I bought  16 front & 49 & 53 rear & have been seeing better hwy rpms with the 16-49 combo but the 53 hits the chain guard & the chain isnt long enough to accomidate the 16-53. Ive got a street tire set & extra dirt tire set & plan to use the 15-47 for dirt setup, & 16-49 or 53 preferably for street. Its not a cush drive, nor does it have electric start, but previuos owner titled it (badly....lots of trips to the dmv to get it right) & added the street equiptment. Will aftermarket chain guards allow me to adjust the location forward so I can use the 53 rear?

[TorqueNut]

With the sprockets you already own (if you can fit the 16 on the front) your "best" street ratio is 16 and 47. That's 2.9375 which is a little more hi-way than even the stock dual sport setup of 14/43, or 3.07. Don't "add" teeth to the rear.... That moves you away from your goal. Also lets you keep the stock chain guard.

[Rocket Scientist]

Ill swap out the rear to 47 & leave the 16 front on & report back. Thanks for the help!

[plugeye]

i have a 46t cush sprocket if you want to save some money

[Rocket Scientist]

Got the 16-47 combo on. Works great. I can hit 55-60mph at just a click over 5k rpm. Much more comfortable on the street now. Thanks.

[merwine126]

Anyone running a 15/52 ? I haven't tries it out yet and was wondering how it felt in the street too speed etc?

[plugeye]

Anyone running a 15/52 ? I haven't tries it out yet and was wondering how it felt in the street too speed etc?

on the street be in 6th by 25mph

[TorqueNut]

I've been running my 14/48 combo up here in the mountains. This is almost the same as 15/52. (3.428 to 1 versus 3.466 to 1). At an indicated 5,000 rpm you're going 48-49 mph in 6th. But it climbs nice in first!

[merwine126]

on the street be in 6th by 25mph

what would you recommend ? I have a 1999 dr350se more greet then dirt tops out around 70-80

[plugeye]

my stock 99 set is 15/41: about 52mph @ 5k, too short for street imo. too much low gear shifting goin on.

i prefer 16/41  or 15/38  or 15/39 for all street. much more relaxed & still pulls well.

[TorqueNut]

Depends.... What sprocket combination are you running now, and, what part of the performance do you want to improve? As you reduce the number of teeth on the front ( or increase the back sprocket size) the bike will launch better, climb better, and be really buzzy at highway speeds. Mileage will drop as the engine speed increases to hold the same MPH.

At the other extreme, a larger countershaft sprocket and/or smaller rear sprocket reduces engine speeds, improves mileage, and takes the tingling out of your handlebars. But, acceleration will be sluggish. When I run my 15/43 combo on my stock 1992 DR350s I have to downshift to 5th to pull long overpasses into a headwind. 14/43 was stock on my '92. Even the one tooth difference on the countershaft sprocket is noticable.

[merwine126]

Depends.... What sprocket combination are you running now, and, what part of the performance do you want to improve? As you reduce the number of teeth on the front ( or increase the back sprocket size) the bike will launch better, climb better, and be really buzzy at highway speeds. Mileage will drop as the engine speed increases to hold the same MPH.

At the other extreme, a larger countershaft sprocket and/or smaller rear sprocket reduces engine speeds, improves mileage, and takes the tingling out of your handlebars. But, acceleration will be sluggish. When I run my 15/43 combo on my stock 1992 DR350s I have to downshift to 5th to pull long overpasses into a headwind. 14/43 was stock on my '92. Even the one tooth difference on the countershaft sprocket is noticable.

I'm running a 14 or 15 front and a 52 rear I like the power for dirt and hills but I miss the speed I'd like to be able to do 75-80 if that's possible I'm 150 and have a 99dr350se exhaust in the way so that should add the power I'd miss and still ge good highway gears since most my riding is on the road to commute

[plugeye]

my stock 99 set is 15/41: about 52mph @ 5k, too short for street imo. too much low gear shifting goin on.

i prefer 16/41  or 15/38  or 15/39 for all street. much more relaxed & still pulls well.

oh, i ride in north Texas... flat

[merwine126]

Yeah I'm from pa lots I mountain but awesome riding

[plugeye]

Yeah I'm from pa lots I mountain but awesome riding

i know, i'd kill for that riding most times of the year

[Rocket Scientist]

My 16t front fit right on there with the stock plastic cover. I just put in longer bolts & shimmed it out about a 1/4 inch. Still would like to get it a tad faster & a lower rpm with the 16t front & 47t rear thats on it now.

[Rocket Scientist]

Im seriously contemplating either selling mine & getting a bigger bike (DR 650) & putting it on a diet. Or just pick up another DR 650 or KLR 650 for my road riding & keep the old DR 350 as a backup & dirt machine. Dont know what to do just yet.