Should I Dualsport my 1988 KDX 200??
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dirt bike dave
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- May 3, 2000
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I've done a '90 200 and a '91 KDX250.
My buddy had an '88 and I also had an '84, but those were not dual sported.
The KDX is not well suited to sustained 50+ mph cruising, even if you gear it up. It can do it for short distances, but if you plan lots of highway miles, I'd look to something with a larger motor.
For connecting trail networks via short stretches of road that require a plate, the KDX is great.
You can carry oil in small plastic bottles in your fanny pack, and mix in the tank at the gas station. Did it many times, with no problems.
One thing to be careful of with a pre-mix two stroke on the road is using engine braking after a sustained high speed run. Hot motor + lots of revs - cooling fuel and lubricating oil = potential crank bearing or piston failure. Just pull the clutch in if you are coasting with a very hot motor and you should be fine.
My buddy had an '88 and I also had an '84, but those were not dual sported.
The KDX is not well suited to sustained 50+ mph cruising, even if you gear it up. It can do it for short distances, but if you plan lots of highway miles, I'd look to something with a larger motor.
For connecting trail networks via short stretches of road that require a plate, the KDX is great.
You can carry oil in small plastic bottles in your fanny pack, and mix in the tank at the gas station. Did it many times, with no problems.
One thing to be careful of with a pre-mix two stroke on the road is using engine braking after a sustained high speed run. Hot motor + lots of revs - cooling fuel and lubricating oil = potential crank bearing or piston failure. Just pull the clutch in if you are coasting with a very hot motor and you should be fine.
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dirt bike dave said:
I guess that is why the old KE100 had the carb within the engine, to preheat the fuel oil mixture?? I know I could not blow that thing up and it seemed like everytime my YZ hit the road it blew up.
I keep having nightmares about the trouble I had with the YZ, That is my major holdup.
The KDX would not see alot of road use just short runs to the store, and sometimes to a friends. About 10 miles at speeds ranging from 35-50mph.
Maddog355 said:
It was there because it had a rotary valve intake. ;)
dirt bike dave
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The KE100 also had oil injection (unless you removed it), like many other street legal two strokes. With an oil injection pump, Oil is usually fed in based on rpm, so it will still be getting lube when engine braking, even if no gas is coming in with the throttle closed.
dirt bike dave
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Yeah, I always had steering dampers on my dual sport bikes.
Also, out of balance wheels, out of round wheels, worn out steering head bearings, bad wheel bearings and bad linkage bearings can cause high speed wobble. That sort of thing is much more noticeable on a hard surface than on the dirt. On 20 year old bikes, you could have any or all of those issues.
Aslo, make sure your rear wheel is not out of alignment.
FWIW, you can help balance your wheels by putting the bike on the stand. Spin the wheel a few times and mark the low spot each time (it will probably be the same each time). Opposite of that, wrap a few coils of solder around one of the spokes to counterbalance. Keep at it until the spot that ends up low is random - the wheel should be in better balance.
Also, out of balance wheels, out of round wheels, worn out steering head bearings, bad wheel bearings and bad linkage bearings can cause high speed wobble. That sort of thing is much more noticeable on a hard surface than on the dirt. On 20 year old bikes, you could have any or all of those issues.
Aslo, make sure your rear wheel is not out of alignment.
FWIW, you can help balance your wheels by putting the bike on the stand. Spin the wheel a few times and mark the low spot each time (it will probably be the same each time). Opposite of that, wrap a few coils of solder around one of the spokes to counterbalance. Keep at it until the spot that ends up low is random - the wheel should be in better balance.
Oil injection pumps used throttle position to meter oil.dirt bike dave said:
Just don't use acid-core solder. Solid-core works best.dirt bike dave said:
No! It is not necessary to do this. There is no reason to; the air/fuel mixture is not any "colder" at closed throttle, nor is the engine any hotter. I don't know who told you this, Dave, but it is bogus.Maddog355 said:
Mud
dirt bike dave
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Uhh, a hot motor at high revs is more likely to seize up if you deprive it of fuel.
Nobody told me this. It happened to me.
I was on a dirt road with my CRE250 with close ratio gears chasing a bunch of A riders on wide ratio KTMs. After about 2 miles of WFO in top gear, I decided to roll off the throttle to give the engine a rest. Problem was I was still going 60 mph on a red hot motor. Now I just had no cooling fuel or lubricating oil. The big end bearing failed within seconds, and took out the crank brearigs and piston, too. It cost about $900 to get the motor running again.
Never had the same problem on my dual sported KDXs, but I am convinced that if I had run one hard at top speed for a sustained time, then rolled off the throttle to slow for a corner, it is a real possibility.
It's an expensive lesson to learn. It costs you nothing to protecty your motor by pulling in the clutch and use the brakes when de-cellerating on the road if your motor is that hot. This sort of thing is unlikely on the trail, but it is much more likely if you sustain top speed for an extended period.
Nobody told me this. It happened to me.
I was on a dirt road with my CRE250 with close ratio gears chasing a bunch of A riders on wide ratio KTMs. After about 2 miles of WFO in top gear, I decided to roll off the throttle to give the engine a rest. Problem was I was still going 60 mph on a red hot motor. Now I just had no cooling fuel or lubricating oil. The big end bearing failed within seconds, and took out the crank brearigs and piston, too. It cost about $900 to get the motor running again.
Never had the same problem on my dual sported KDXs, but I am convinced that if I had run one hard at top speed for a sustained time, then rolled off the throttle to slow for a corner, it is a real possibility.
It's an expensive lesson to learn. It costs you nothing to protecty your motor by pulling in the clutch and use the brakes when de-cellerating on the road if your motor is that hot. This sort of thing is unlikely on the trail, but it is much more likely if you sustain top speed for an extended period.
dirt bike dave
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mudpack said:
Some are activated by throttle position (such as many Suzukis and Yamahas), some are not. More than one way to skin a cat.
Some are mechanically driven of the crank. I think some systems are even vacuum operated.
Looks like the examples for single cylinder Kawasaki's on this page is rotary valve, similar to a KE100, and driven off the crank.
http://www.dansmc.com/2_stroke_pump_views.htm
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