2 smoke DS's on pavement......?

I used to run my old DT250 35 miles to the next town. Crused 55 to 60 mph, speed limit was 55. Air cooled, oil injection, never heard of varying the rpm, pulling in the clutch, or applying the choke. It's a wonder I didn't go up in flames Are you really running with the throttle wrapped clear around? Find a comfortable cruising speed and don't rap it out tight. Unless you are running lean on the top end of the throttle opening I can't see where you would get into too much trouble. Both bikes you are talking about are water cooled aren't they? Thought those bikes were "enduro" types were it could see a long stretch of high speed through desert like conditions.

Gday Twin shocker he wants to ride his bike on the road. It is not the cooling system, thats going to be a problem. You can jet a 2 stroke MX motor to run on the street, & it will not over heat on the open road. If you have a exhaust port bridge, drill 2 holes in the piston. Most old MX 2 strokes will surge on the street, but you can fix that with jetting. Just look at all the old 2 stroke GP bikes. Cheers Peter

+1 on all the above

Totally agree with what everyone is saying, and I appreciate all the info....I don't plan on riding at WOT on the road, I was just concerned about connecting trails with paved roads for extended stretches of 10-25 miles (which is what we recently did on our CO trip a few weeks back). Still trying to understand everything and get back to the 2T world (which I haven't done yet, but will be soon)....by having a bigger jet and making it richer in the carb to provide more lubrication for those longer stretches, wouldn't that give me a higher probability of fouling a plug when riding ST up in the mountains at a lower RPM's and not having the throttle wide open? Would a JD jet kit give me a good all around setting for roads and ST or is a matter of trying to mate bigger jets with what might currently be in the bike?

The jets do over lap, but out on the open road, your going to be on your main jet. The thing with dirt bikes, they jet them so they are crisp/snappy. You will loose a little throttle response, but nothing to about. Just remember the more oil, you mix in your gas, the leaner your bike will run.

As I posted earlier bigger jets are fitted to provide a richer mixture to help motors run cooler, not for increased lubrication. If you dont plan on riding WOT, and take things easy and vary engine speed, then the the stock jetting will be fine.

On my EXC, in the woods the radiator barely gets warm. But I do notice the heat coming from it on the road.
I still don't run fast or anywhere near WOT on the road, and try to limit the amount of time I spend there.

Because that bike is really no fun on the street.

Hogwash.

I wonder if you have ever ridden in the SSDT, where 2T dirt bikes cover a lot of miles on the road at wide throttle openings? Competitors in that event will be very interested to learn that overheating and seizure is not likely to be a problem!

In all my years of riding 2 strokes, I've always kept them stock. Never played with jets, never monkeyed with pipes, ports or armchair tuning. I have never replaced rings (although my DT175 was overdue). I have NEVER seized an engine. Wide open running on beaches and river ice, rock crawling trials pace. Radiator only boils on long long climbs. We're talking about dual sport riding (which we used to call enduro) not race engines. I have found that reliability comes from not 'tuning' and modifying. I humbly suggest just riding and not worrying. The paved sections connecting trails are not freeways. When on the road, don't forget it's a dirt bike.

Have fun,
Piston

* cough *

Unless you really are riding WFO, out on the open road you are gonna be on the needle (and the pilot circuit, but mostly the needle).

needle , needle jet

.

In Australia most dirt bikes are geared for 140 to 150klm flat out. On open tar roads most people sit on 120 klms which puts you on the main jet.

The response's to this post are amazing. The motor doesn't care were it's being ridden, as long as it's receiving the correct amount of air-fuel and lubrication it'll run/last forever.

I own a 300exc and dual sport it. I ride the Sheet Iron 300 on it. 20-30 mile sections of pavement and dirt roads with single track. The bike runs perfect.

If the bike is jetted AND GEARED correctly for the riding your gonna do, it will perform perfectly.

Ever here of a KDX200? It's sold as a street bike in Japan. Those guys regularly get 15K miles from a top end and 25-30K miles from a bottom end. Come on guys... this isn't 1967.

To the guy that said he never re-jets his 2 strokes and leaves them stock... be careful. If you go to Colorado or my neck of the woods, we've got some "Thin Air" up here!

i

*cough*



I live in australia ...


just out of curiosity ... if you are on the main at 120 ... what do you do to get to 140 - 150 ?


... surely it couldn't be open the throttle to raise the needle out of the needle jet to fully expose it





.

+1

Jet it correctly.

My 2T are plated, and I do use them for dual sport rides (highway and off road). My KX250 geared properly did fine for this 2-day 300 mile ride.

http://advrider.com/forums/showthread.php?t=725130

GEAR IT TALL !!!
makes it more comfortable, otherwise its like your riding a chainsaw, I use one of my 300,s in baja and it worked excellent, everyone had big fourstrokes, i was fine, actually way better off in the dirt, pavement was ok