I hate 2 strokes.

ucfmotorcycle1 · 10-02-2004, 9:53 PM

My old KTM 300 seized a couple weeks ago and I haven't torn it apart yet. So I decided to take out my little RM80 for fun. I loaded it in the truck and fired it up, ran for 5 secs then died. I fiddled with it for 20 min and I couldn't start it back up. I changed the plug and it has spark so probably a carb problem. Thing is I ran it in the garage for about 5min just three days ago to make sure it would start and now its dead. Again I HATE 2 stroke

. I bought both for $1500 and they were running I thought it was a good deal but 2 stroke is just too much problems.

sheepofblue · 10-02-2004, 10:21 PM

I once trailer mine and my brother's 200 miles so we could ride at my grandpa's trailer. His starts right up. My MX125C would just barely start when bumped and only run wide open. On inspection a mouse family had moved into my airbox. Sucked the nest and some little meeses to pieces. My brother joked all weekend that I was hitting him with flaming mouse tidbits when I led.

Intimidator · 10-02-2004, 10:45 PM

That's funny...cause' I hate 4-strokes. I do love the rideability and dependability of them, (they're also perfect for beginners), but I hate the sound, the powerband (or lack thereof) and they cost too damn much to make them fast. What is a pipe for a raptor like $600??? Give me a break, $600 for a piece of small round tubing and a muffler. I know lots of people have issues with temperamental 2-strokes...but I've had nothing but 2-strokes and never have problems. My Honda 250r recently received it's 3rd spark plug in 3 years. It's all about proper tuning...once you get it right on... you're set. Just my $.02

G-Force Junkie · 10-02-2004, 10:46 PM

You do know you have to mix oil with the fuel right

EDDIE110171 · 10-02-2004, 11:24 PM

If it's been sitting for some time one of the jets or one of the orifaces could be clogged. If thats the case you'll have to go though the carb. The easiest way to check is to spray some WD40 in the carb and crank it. If it starts then its the carb. Never use ether though, it burns too hot and doesn't offer adequate lubrication.

Jungleboy · 10-03-2004, 5:00 AM

Ive had about 8 Two strokes and hardly ever experianced any problems in the reliablility area, if they are looked after like any bike should be then they should be sweet! Also dont potter around on them as they will foul plugs! Another tip turn the fuel off and let them run for a minute just until the engine revs rise before you put them away and they should start nice and cleanly next time

What were the circumstances that caused the 300 to seize? Extended periods at WOT? if so if you feel the need to use full trottle for extended periods hit the kill switch for 3 or 4 seconds every now and then while holding the throttle wide open to dump some cold unburnt fuel through the engine,
Another possibility is you have an air leak somewhere? (stator side crank seal or somewhere between the carb and the cylinder/crankcase ) if this was the case you may have also noticed a low speed bog and difficult starting? its a good idea to check these things when you rebuild it otherwise you may end up doing more than once

Anyway hope you get them sorted and returned there former glory

Two strokes rock!

ucfmotorcycle1 · 10-03-2004, 7:55 PM

Quote:

Originally Posted by G-Force Junkie

You do know you have to mix oil with the fuel right

cmon man give me some credit of course I put oil 32:1. Extra virgin olive oil

.

ucfmotorcycle1 · 10-03-2004, 7:58 PM

Quote:

Originally Posted by Jungleboy

Ive had about 8 Two strokes and hardly ever experianced any problems in the reliablility area, if they are looked after like any bike should be then they should be sweet! Also dont potter around on them as they will foul plugs! Another tip turn the fuel off and let them run for a minute just until the engine revs rise before you put them away and they should start nice and cleanly next time

What were the circumstances that caused the 300 to seize? Extended periods at WOT? if so if you feel the need to use full trottle for extended periods hit the kill switch for 3 or 4 seconds every now and then while holding the throttle wide open to dump some cold unburnt fuel through the engine,
Another possibility is you have an air leak somewhere? (stator side crank seal or somewhere between the carb and the cylinder/crankcase ) if this was the case you may have also noticed a low speed bog and difficult starting? its a good idea to check these things when you rebuild it otherwise you may end up doing more than once

Anyway hope you get them sorted and returned there former glory

Two strokes rock!

Yeah I was at WOT when the KTM stopped. I wouldn't really call it a very extended period though. It started up on the first kick before it happened so I think it was ok. It may have just run lean and overheated

. It also uses coolant I noticed because I always had to add some before I went out. Is that normal on an old 2 stroke. I wouldn't think so. But it is a beater bike anway so I didn't really mind.

EDDIE110171 · 10-03-2004, 11:14 PM

Quote:

Originally Posted by ucfmotorcycle1

Yeah I was at WOT when the KTM stopped. I wouldn't really call it a very extended period though. It started up on the first kick before it happened so I think it was ok. It may have just run lean and overheated

. It also uses coolant I noticed because I always had to add some before I went out. Is that normal on an old 2 stroke. I wouldn't think so. But it is a beater bike anway so I didn't really mind.

The only sign of it overheating is the resevoir being low, remember there is no gauge. So the bike was probably running hot for sometime. The WOT was probably too much and cooked it. Find out why it was overheating before you rebuild or you may end up seizing it again.

SomeStrangeGuy · 10-04-2004, 2:45 AM

Quote:

Originally Posted by Intimidator

That's funny...cause' I hate 4-strokes. I do love the rideability and dependability of them, (they're also perfect for beginners), but I hate the sound, the powerband (or lack thereof) and they cost too damn much to make them fast. What is a pipe for a raptor like $600??? Give me a break, $600 for a piece of small round tubing and a muffler. I know lots of people have issues with temperamental 2-strokes...but I've had nothing but 2-strokes and never have problems. My Honda 250r recently received it's 3rd spark plug in 3 years. It's all about proper tuning...once you get it right on... you're set. Just my $.02

You're comparing all high tech 4 strokes to an older then the hills yamaha 660 single engine now being used in that useless as hell quad? Show me one thing the cRaptor can do well (besides flip over backwards or sidewards) and I'll submit this argument as valid

3 years huh...I'll have to ask the owner of my 01 WR426 if he's remembered to change the plug I put in after break-in

I know 2s/4s is like the great oil debate, and will never die - yes I know this

Jungleboy · 10-04-2004, 8:11 AM

The only point Ill add to the 2 Vs 4 stroke argument is that a 2 stroke has the potential to make TWICE as much horsepower as the same size 4 stroke thats why in motocross 450cc 4 strokes race against 250cc 2 strokes and in motoGP a 990cc 4 stroke was needed to replace the 500cc two strokes, imagine if they made modern 750-1000cc 2 strokes, potential 400hp!

phobiaphobe · 10-04-2004, 9:13 AM

of course they have the potential to make twice as much power... a 2 stroke fires twice for every one time a 4 stroke fires. That is also why they use twice as much fuel.

luvtolean · 10-04-2004, 10:24 AM

Quote:

Originally Posted by Jungleboy

The only point Ill add to the 2 Vs 4 stroke argument is that a 2 stroke has the potential to make TWICE as much horsepower...

No, it doesn't...maybe lots more, but not double.

EDDIE110171 · 10-04-2004, 7:01 PM

Quote:

Originally Posted by SomeStrangeGuy

You're comparing all high tech 4 strokes to an older then the hills yamaha 660 single engine now being used in that useless as hell quad? Show me one thing the cRaptor can do well (besides flip over backwards or sidewards) and I'll submit this argument as valid

3 years huh...I'll have to ask the owner of my 01 WR426 if he's remembered to change the plug I put in after break-in

I know 2s/4s is like the great oil debate, and will never die - yes I know this

...and ask him how he likes hot starting while your at it too. I've seen a couple races lost because the rider could not restart bike fast enough.

ConqSoft · 10-04-2004, 7:12 PM

My XR400 has fired up with no problems, hot or cold.

Baketech · 10-04-2004, 7:23 PM

I think smokers make perfect sense on a performance dirt bike....but little sense on the water. Lots of inland lakes are banning them....personally, I wish they all would....

luvtolean · 10-04-2004, 7:25 PM

Quote:

Originally Posted by ConqSoft

My XR400 has fired up with no problems, hot or cold.

Have you crashed it? That's when they suck. I was loving boomer's 450 until I stalled it. It was a bastard to start compared to my 250.

I love my 2 smokers, but don't think I'll get to ride them much longer. We must ban anything unnecessary but fun in this state.

SomeStrangeGuy · 10-05-2004, 12:40 AM

Quote:

Originally Posted by EDDIE110171

...and ask him how he likes hot starting while your at it too. I've seen a couple races lost because the rider could not restart bike fast enough.

That's just cause they don't like 2s converts trying to ride them with their wussy half-kicks

I have had my fair share of fun with the learning curve of the 4s engines and my first WR250 was the best teacher I could have had for that mission. Oh man that thing was rough for the longest time...I remember getting it started only to shut it down because kicking 47 times in a row just wore me out too much to ride just then.
The first 426 I had would start if I sneezed at the kicker, and my 450 (once broken in and properly flywheeled/jetted) has to be the easiest to start bike I have ever ridden, ever.

I think the thing with the 4strokes is no one really "feels" how they are supposed to run (assuming many are coming over from likes of the 2s power curve etc.) and thus the jetting is miles off. The "stock" jetting for my 450 doesen't seem to be even semi-decent for anywhere in the planet, go figure

. Coincidentally the jetting changed in the '04's and then most of the starting issues were gone...hmmm.

Jungleboy · 10-05-2004, 9:52 AM

Quote:

Originally Posted by luvtolean

No, it doesn't...maybe lots more, but not double.

Two strokes DO have the potential to make approximately double the horsepower of the same size four stroke as they fire on every down stroke as opposed to every second down stroke! as long as you get similar volumetric efficiency (which is possible) and turn the same RPM (also not a problem) a two stroke will make double the HP of the four stroke,
the 500cc GP bikes were making around about 200hp and much more was possible although but the power delivery became too savage beyond this point, the current 1000cc (ok 990cc) MotoGP bikes being twice the size are around 250HP but are more developed than the 500cc two strokes were!

Baketech · 10-05-2004, 10:25 AM

luvtolean · 10-05-2004, 11:10 AM

Quote:

Originally Posted by Jungleboy

Two strokes DO have the potential to make approximately double the horsepower of the same size four stroke as they fire on every down stroke as opposed to every second down stroke!

Yeah, I understand you get a power pulse every 360º instead of 720º.

Quote:

as long as you get similar volumetric efficiency (which is possible) and turn the same RPM (also not a problem) a two stroke will make double the HP of the four stroke,

Absolutely not possible. And the reason I said what I did.

There's lots of reasons, and maybe if I was less busy I'd get into it with the thermodynamic efficiency equations and such, but let's start at the fact you can't run nearly as much compression with a 2 stroke.

You also pump out burning charge which is the reason you hear the "ding ding" in the expansion chamber. And the reason you basically can't buy them for anything but closed course competition anymore.

It is also the reason you can run a 4 stroke at significantly higher RPM than a 2 stroke. Think about it, you have roughly half the time for all Otto cycle events in a 2 stroke.

Quote:

the 500cc GP bikes were making around about 200hp and much more was possible although but the power delivery became too savage beyond this point, the current 1000cc (ok 990cc) MotoGP bikes being twice the size are around 250HP but are more developed than the 500cc two strokes were!

Honda had over 15 years development in the 500 motor Rossi won the championship with!

half · 10-05-2004, 9:05 PM

LTL,
I'm not trying to stir the poop, but my pocketbike engine turns at about 15,000 rpm. Why is that? None of my other 2 strokes (sled, dirtbike) turn nearly that fast.

G-Force Junkie · 10-05-2004, 9:27 PM

Quote:

Originally Posted by half

LTL,
I'm not trying to stir the poop, but my pocketbike engine turns at about 15,000 rpm. Why is that? None of my other 2 strokes (sled, dirtbike) turn nearly that fast.

Less recipricating mass... Thats all im getting into in this thread