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Suzuki DR Questions
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Posted by: David Lovett---------------------

I recently picked up a '93 DR250 for some low-buck, but serious woods riding (not racing). It is mostly stock except somebody already opened the top of the airbox up and hung on a set of Dunlops. Does anybody have any good performance tips for getting the most bang out of this outdated but very fun woods bike? The only complaint I have other than carb and spark issues is overall weight as I am coming off of a trials bike. This bike could use a heavy dose of titainium!

Posted by: Tree Crippler---------------------

Since the airbox is opened up I hope they put in a bigger main jet. Changing the exhaust pipe should be your next step. For comfort change the bars, seat foam and suspension springs.

Posted by: Danman---------------------

Suspention tunning (it will make it even better). It will be a fun bike. If its the same as the 350 pipe you can mod it for more power as well. Also, this site might give you some ideas too. www.kientech.com The guy is super sharp with the DR has some pretty good trick parts for you bike. There is information on the stock pipe mod that he does as well as instructions for the air box.

P.S. The mods that Crippler list are great. I can stand any more height so the tall seat foam is out for me.

Posted by: sgoeb13---------------------

Definately check out http://www.kientech.com, also http://www.maximum-suzuki.com. Opening the airbox, upgrading the exhaust and changing the gearing are the easiest mods, suspension upgrade is a must. -Steve

Posted by: David Lovett---------------------

Hey thanks guys, I will definitely check out your website recommendations!
Since ya'all (its a Kentucky thing) suggested suspension mods can you be a little more specific? Yes, I think this bike sits up way too high for trail riding and I have'nt found any 15' stadium jumps on the trails yet (god I hope not.. I'm too old 40ish, the fall would give me a heartattack) I would like to have the suspension cut down if the cost was'nt too crazy. Any suggestions?

Posted by: Danman---------------------

I'm a littel heavy for the stock springs. I put a race tech kit in the front that allows me to run the springs at .40kg, .43kg, and .46Kg. (set it up for .46) I also went with the Kouba links ( the #1) to get more travel and stop the sideways kick. They recommened at heavier spring weight due to the forces of the longer links. The rear spring is 6.3kg. I also moved the forks up about a 1/4 to 1/2 inch in the clamps (turns much better). As for that you can just play with it a little. The links can me used to lower the bike a little if you would like. I think the lowering or not lowering is based on how you set the sag. For none lowering they recomended that the sag be set up at 2.5 inches. I though it would not be enough. Stock sag is 3 and 3/4, but it works pretty well for me. For lowering it you set to stock sag. It was like riding a different bike once I got the suspension dialed in. Tall square edge bumps still kick the back end up, but not as bad. Think that I might be rider error.

If your springs are sized right and you still bottom you can add just a little more fluid to stiffen things up or even put of pre-load on the springs with a small piece of 1" PCV. Just make sure to get the little particles off from were you cut it. Those are the enexspensive options and you would have to play with it to find what is right for you. The next would be a re-valve. For suspension stuff you might put a post in the suspension forum. I hear good things about Jeremy (moderator) over there. They all say the man know his stuff and I think that he does.

Norm over at Kouba should be able to hook you up with the links and give you some good suggestions on suspension settings ( I think they also do vavling). I hear good thing about him and I'm happy with my links. Just give them your weight, riding lever and what you ride and they should be able to point you in the right dirrection.

here is the link"

http://www.koubalink.com/

I would love to have my suspention revalved, but it cost about 300 or more for both endes. Just with the changes I have made it was like riding a different bike.

Also, I don't think there are a lot of difference in between the 250 and 350. A lot of the parts are interchangable.

Good luck

Posted by: David Lovett---------------------

Thank you again! By the way, if raising the forks in the triple clamps is limited by the fork caps hitting the handlebars, can you go the other way and machine-off the bottom of the stanction tubes to lower the front end?

Posted by: DualSportr---------------------

I wouldn't try lowering the bike - the suspension is already marginal for aggressive riders.

Posted by: David Lovett---------------------

My riding style is not aggressive. Since i posted the question I have really investigated the shock linkage lowering kit that everbody is taliking about, heck I 've got my Amer. Express ready to go. My question is after you drop the back and adjust shock, in theory you would have too much rake or a "dirt chopper"!
You can in theory only slide the fork tubes up until they hit the bars (no risers have been added) however, if the rake is still too much I am only asking if anybody (suspension experts need only to apply) has shortend the stanction tubes to get the correct height? I think I will purchase the kit that drops the rear about 1.75".

Posted by: DualSportr---------------------

Quote:

some low-buck, but serious woods riding

Sorry, only going off of what you initally said.

How tall are you? I've shortened my XR250 with a lowering link from DeVol (an absolute necessity for me at 5'4"). However, it did definitely soften an already soft suspension. The rake on the front end did change a bit - but adjusting the rear and front suspension to match each other (after lowering the back) made the biggest change for the better. Dropping the forks in the tubes didn't really make a difference (your results may vary).

Instead of machining the fork tubes, why not install risers for the bars? This would give you another 1/2" of space at least - enough to get everything back to about the right ergos.

Another option - instead of messing with the suspension to shorten the seat height - just shorten the seat. Remove some of the foam. If the seat's too hard, install a gel insert. This option wasn't open for me, as the XR is used for dual sporting (where you need all the padding you can get), however I did use it on my WR.

If you're over 5'7" tall though, none of these should be necissary!

Posted by: Brianc---------------------

Quote:

if raising the forks in the triple clamps is limited by the fork caps hitting the handlebars, can you go the other way and machine-off the bottom of the

I installed a set of TAG bars, which required the adapters that sit on top of the OE handlebar perches. The adapters raise the bars 3/4 inch which allows you to lower the front by sliding the forks higher through the triple clamps. Greatly improves front grip. Adjust rear spring for more sag to help keep geometry right for balance through whoops and tight stuff. I actually lowered my front approx 5/8 inch. Be sure to measure both forks when lowering to make sure to keep them even. A 1/16 inch difference will give you unpredictable surprises that you won't want to experience.
The Tag bar I use is CR Double High, makes a huge difference on the comfort while standing. Try different bends at the shop on your bike to see what fits you.

For performance, try a smaller front sprocket for more bottm end. One tooth less on front equals 7% change in the rpm, doesn't sound like much, but really will make a huge difference in low end torque, especially climbing hills or accelerating in 2,3,and4th gears. One front tooth generally equals 3 or four rear teeth.

Last free performance mod is open the outlet of the stock muffler. My OE opening was 3/4 inch. I drilled it out to 1&3/8 inch with a hole saw, Huge improvement all across the powerband.

Do not rejet until you look at your plug. Try a new spark plug and check it after a hard ride. You may be ok as is, you really cant tell without listening to the engine and looking at the plug.
I did not have to change my jet after opening the airbox and the exhaust.

Have fun.

Posted by: placelast---------------------

Stiffer, taller foam did not work for me as the DR sped along better in the semi & often seated (Scott Summers?) position; something odd about this bike (& perhaps XRs?) as it worked better when seated for going fast, standing only for big hits. And the harder foam is not as comfortable.

2nd thing is the stock muffler works just as good as any I’ve tried, from that to wide-open systems; there was little to gain other than a lot more noise. Save your $ for suspension mods.

I owned a new/leftover ’94 dirt DR350; spent nearly as much bringing it up to race speed. Nothing brings on better performance per buck than 1) revalve/springs; 2) Vortex air box; & 3) big bore kit. Leave the exhaust alone – aftermarket (louder) mufflers only make it sound faster. And after all that, it’s still heavy, & some of the oddities remain – racing one is not recommended even after fixing all that. I ended up fitting RMX USD forks & a rear shock - made it a much finer handler, but it was still too heavy for my skinny body to muscle into submission for miles of desert sand whoops in competitive events. Perhaps fine for bigger fellas. In any event, it makes a fine/fun trail bike with real good low-to-mid grunt.

I did try the Kouba links. They do a fine job of improving the rear end’s leverage ratio. And Norm knows how to revalve/respring the DR right. Tho I wanted/needed more, the RMX shock worked better w/o his link. The latter is a high $ fix, not needed for trail riding, & it's be less trouble to get another bike as your skills improve.

Jesse has got a good thing going with the Vortex air box. Both he & Norm are awfully good & helpful assets to DR owners. Highly recommended.

Me? I sold mine for an RMX; couldn’t be happier to shed some poundage, tho I miss easy, controllable wheelies, compression braking, & that macho, muffled “thump” sound. And it would float thru rock gardens w/ease; must be all that weight. However, miles of sand whoops take less effort on the RMX, & it is easier to lift up off of the ground

Posted by: David Lovett---------------------

Thanks placelast! Thats the kind of info I really need! The airbox is kinda steep for my thrill right now and i will just rely on Jesse's trick to modify the stock airbox and change the jetting. I'm glad you brought up the comment about the silencer as I will be sending this off to Jesse for a good root canal through the spark arrestor.The Kouba links will be orderd soon.
Now the only thing left to find out is how to replace the stock seat with a new style low profile as the newer MX bikes have. I think this also would bring me closer to earth when working through the rock sections. Does anybody know who offers "low profile" seat replacements or, who has tips on how to cut the foam out of a seat with wasting it??

Keep the help coming.......

Posted by: placelast---------------------

David: the Kouba links can be setup to lower the seat height; ask Norm for some ideas on how that can be done (different link lengths/models) for your situation/to suit your want. I do not recommend trimming the seat foam since you will prefer the standard or taller foam once you get better off road, tho it seems a bit tall now, you will be able to plow thru the rocks without touching like the skilled trials rider you are...

Do you have the dirt or street version? The street version comes with lower foam. I had owned at one time all of these: a Ceet tall/firm, stock dirt, & stock street seats.

I'm sorry, was thinking you had a 350, but a 250 is even weaker, power wise. There is a shop here in SoCal (Mark @ Sounthland Suzuki) & he has punched out ~ a dozen 250 =>350 (same barrel casting but has smaller sleeve than 350), which would do wonders for the power. I believe Thumper Racing has the same kit.

I bought a 250 barrel for my 441's sleeve, just so the "249cc" marking on the side would thow off my riding buds. I got a real laugh out that; you should've seen the looks on their faces when they one day stumbled across it...another XR400 guy & I swapped rides; afterwards he walked away shaking his head, mumbling "250?!"

Cutting open the top of the air box does pretty well too; I tried that before getting the Vortex & was surprised how much it helped. I'm simply one of those guys that can't help but tinker, and for a bargain budget the stock box cut open will do just fine. Remember to clean the filter often if conditions are dry/dusty.

I had Scott's Performance do the muffler mod ($80); this was before Jesse did them for even cheaper. I did not notice much if any diff in the power/noise, but for the price, why not give it a go?

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