2 stroke 101

Bryce R

Bryce R

Hey guys will dents in the expansion chamber effect how the bike performs?
Will your oil mixture change with jetting?
If your running WOT more should it be set up to run a little rich at normal paces?
How do you know your 2 stroke is hot?
What things kill a 2 stroke?
What do the different reeds change?
Is there better reeds to run for different styles of riding?

For a 145# Rider is there any reason to go to a 300 over a 200? Mostly riding would be trail.
 
josmoloco

josmoloco

1 small dents no big deal
2 yes
3 huh?
4 pinging/detonation
5 four strokes... just kidding.... dirt in the engine.... old top ends... not enough oil for the situation
6-7 new reeds are better than worn out reeds!
8 No way! Im 160lbs and 200 is awesome!
 
SRAD97750

SRAD97750

Moderator
Staff member
Really large dents will effect performance. Smaller ones will not be noticeable.

Jets meter fluid. If 1/20th of that fluid is oil, then you need 1/20th less air to compensate for the diluted fuel.

Richer is better if running WOT.

If it's water cooled, it'll boil over. If it's aircooled it'll just shut off or seize up.

Lean mixture, Lean oil ratio, constant throttle positions in a lean jetted carburetor, and heavier riders.

Reeds regulate the amount of fuel delivered as per the engine speed. Some are softer, allowing more fuel/air through earlier. Some are stiffer and let less fuel through at lower rpms.

Boyensen has great descriptions on their website as to which reeds do what. http://www.boyesen.com/

Bigger the engine, the more torque it produces. Torque is the force required to turn an object. The easier it is to turn the wheel, the easier it is to ride a bike. Which is what we refer to as "rideability." A 2T 65 would be unrideable on the road. My 2T 500 would be an awesome road bike. Torque is king.

-BIG DAN:thumb:
 
1

14D

Bryce R:
Hey guys will dents in the expansion chamber effect how the bike performs?
Will your oil mixture change with jetting?
If your running WOT more should it be set up to run a little rich at normal paces?
How do you know your 2 stroke is hot?
What things kill a 2 stroke?
What do the different reeds change?
Is there better reeds to run for different styles of riding?

For a 145# Rider is there any reason to go to a 300 over a 200? Mostly riding would be trail.
Click to expand...

really big dents will effect performance but you'd have to beat it up pretty bad to get at that point.
Yes. If you're running stock jetting and you add more oil than recommended(what the jetting is set for) it WILL need adjusted for best performance
Yes. Unless you like buying cranks wholesale.
uhh it's hot. If you mean overheating, it'll spit coolant like a 4 OR if you do it at start up(when it's cold, called a cold seize) you gun it and I think the piston expands too quickly for the bore, thus seizing it.
running lean(this runs hands in hand if your running WOT allot), running pure gas, not doing a top end enough(this varies per bike and rider(style, etc.)
power output, like where the power is at, sora...
Couldn't tell ya what.

200 would be fine. people over 200 lbs ride 125's and love them so a 200 for a 145(dude your small, i'm 160) person, a 2hundy is fine.
 
Bryce R

Bryce R

Okay guys how do you tell if your motor is getting enough oil? What makes you deside to mix more or less oil?

With a new motor do you lube everything first before its started or will the fuel and oil mixture lube it in time for the first start up?
 
jackson409

jackson409

Bryce R:
Okay guys how do you tell if your motor is getting enough oil? What makes you deside to mix more or less oil?

With a new motor do you lube everything first before its started or will the fuel and oil mixture lube it in time for the first start up?
Click to expand...

I always put a thin coat on all the bearings, piston and clyinder wall with straight premix when assmembling the motor.
 
SRAD97750

SRAD97750

Moderator
Staff member
I would consult the maintenance manual. The manufacturer isn't going to recommend anything less than whats totally safe. -BIG DAN:thumb:
 
YZcarver

YZcarver

Dents in the exhaust pipe will have a varying effect based on the size and location. Dents nearer the cylinder exhaust port have a much greater effect than dents further out. Frequently a small dent near the exhaust port will kill performance much worse than a large one in the fat part of the pipe.
 
YZcarver

YZcarver

Bryce R:
I read that but it doesn't talk about how to tell if your getting enough or not. I don't want to mix 32:1 ride it and seize it up and know I should have run 18:1
Click to expand...

You are more likely to seize it by jetting it too lean and overheating it than you are by making a poor choice of premix ratio.
 
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