Had a question for the masses....plan on buying a KTM 300 EXC or XWC and was wondering what the individuals with 2 stroke DS bikes do when they have to connect trails via pavement for 10-20 miles??? I know that there are a lot of people on here who ride 2 stroke bikes up in the mountains and have to do this....but was wondering how they preserve the life of the piston/rings (top end) when they have to use pavement to get to other places.....One guy just recently told me in CO that he'll pull the choke out on the pavement to give a richer mixture and lubricate the piston on pavement sections and not burn the rings out as quick, but wasn't sure if that was the case or accurate? What does everyone else do??? Thanks in advance for the advice!!
Pulling the choke out helps to stop bikes overheating when used at wide throttle openings on the road, and thus prevents motors seizing up. If you can just taking things a bit easier on the road is a much better idea, and will mean motors last longer.
I've had to do 10-20 miles of 2 lane a couple times on my 200 EXC. Not much traffic here, so I just took it easy. 40-50 mph except for a couple times. The off road tires weren't much fun either,
hitting the kill switch periodically works as well. on a 82 yz490 I had a cable rigged up to pull the choke for long flat baja dry lake bed crossings. pretty easy to do. Mike
I don't do anything. I did a couple of hundred K on a highway to get home once... She handled it without a problem. But I'm going to look into the bar mounted choke lever.
Those bikes are very stoutly engineered especially compared to all the vintage stuff I ride. I don't see how this would be a problem. If you're concerned about holding a constant RPM for an extended period then don't. move it around a bit, hold the clutch in on looong downhill runs (a mile or more) and otherwise ride it like a normal motorcycle. Not sure what the mechanism is on the 300 but choking it will typically just get it way rich on a warmed up bike. I don't see how this will help if the bike is properly tuned jetted mapped whatever. 2 cents..
The reason why its not a good idea to ride dirt bikes flat out on the road for any length of time, is due to the cooling systems not being designed to get rid of the amount of heat this is likely to mean, which makes seizure a distinct possibility.
I have put thousands of miles on the pavement on MX bikes, enduros, and 2 stroke street bikes and never had a problem with ring wear. On 2 stroke MX bikes I do vary the throttle a little to both keep it from surging and keep the vibes to a minimum.
Fitting bigger jets might stop a dirt bike seizing when its ridden on the road, but it wont alter the fact that the cooling system isnt designed to dissipate the amount of heat resulting from wide throttle openings for long periods of time.
I had a air cooled kx500 {in rd 400 frame} that i rode on the road all the time. I ran 2 head gaskets on it, so it would not ping, it never over heated.
All my bikes get much hotter doing slow stuff than they do on the highway. I have never overheated a bike on the highway, but I have on slow stuff and waiting in traffic, so I really don't see a problem with cooling.
If you ride enduro/mx bike like a trials bike, its going to get very hot, in exactly the same way as if its used at WOT for long periods on the road.
If so then I wonder why MX-enduro bikes used WOT for long distances (beach racing is a good example), are jetted and set up to stop them seizing on the very long straights?
So just don't ride with the throttle wide open. You're asking for trouble doing that with most bikes on the street anyway, from the law if not mechanical...
It has been a while since I spent much time on 2-strokes, but have seen them sieze from extended WOT use. As a kid, we rode our 2-strokes to the next town all the time. We rode them as if we were switching gears the whole way. In other words, while riding in top gear, we would pull the clutch in and let off the throttle occasionally to give the piston a quick break. Fuel/oil mix was still drawn in through the carb, and this gave the motor lube while coasting (for about a half second). We did this about every 10 seconds, and avoided top speed runs (unless someone wanted to see our street license credentials). 2-stroke oils have come a long way since then, so there is probably less chance of siezure. Even if it happens, it isn't much work to swap the rings and/or piston.