need help wot bog......

powderman

New Member
Oct 20, 2008
7
0
0
pageland sc
i have a new engine with about a quart of gas through it. when i put the throttle at wide open throttle it bogs. if i back off about 1/4 turn it picks back up again. if you turn the choke on about halfway it will run better at full throttle but it's still not right. i have taken the carb apart and it is clean as a pin. it's almost like it is lean. it runs great everywhere else. any ideas? thanks.bld.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
235
63
up north now
Or your needle is set too low (clip too high), or the engine is not getting enough gas (fuel flow problem). The stock petcock can be very restricted.
 

TexasDav

New Member
Aug 19, 2008
528
0
0
Houston
If it is not the common airleak then be sure your motor mounts are tight to stop vibration which causes it to bog at high rpm's. Spray carb cleaner around the intake and see if rpm's pick up, equals a airleak. Good luck
 

RockNRoller

New Member
Jun 19, 2017
3
0
1
32
I'm hitting a wall on this topic for sure:
3/4 runs OKAY but at full throttle, the engine acts as though it's falling on its face.
Seems to be using more fuel than it should honestly.
I've also decreased the amount of oil to fuel ratio because I thought this may solve it.

Should I move the clip on the carb needle?
If so, Upward or downward a notch?

The area I live in (midwest) has been rather humid this year. Not sure if this affects operation or not.

Please send me any recommendations or info.
 

mike carter 2

Member
Nov 23, 2011
253
13
18
west virgina
whats your fuel mix rite now,a quart of gas is not enough fuel through the engine to break it in.takes 4 or 5 tanks just to seat the rings.i break my bikes in at around 30 to 1.i run my bikes at 40 to 1.if i was going to move my clip this soon,i would likely move one notch up(leaner) but no more than that during the break in period.remember the oil you put in the gasoline is the only lubracation that the engine gets,so you dont want to lean it out during the break in.after the break in is the time to tune
 

RockNRoller

New Member
Jun 19, 2017
3
0
1
32
Thanks for the quick reply Mike.
I am currently running 2.6 oz to a gallon of fuel. I've run 4 tanks full at this point, working on #5. in the beginning I had great power.
I noticed my filter was soaked in fuel. Removed it for a short ride and it ran stronger but still not right at full throttle.
Mounts are tight.
Could I have an air leak at the carb to intake?
Or maybe foam from vibration?
 

mike carter 2

Member
Nov 23, 2011
253
13
18
west virgina
can some one help?some where on this forum is a diagram of how a 2 stroke runs.it explains how the exaust pulse returns into the cylender,then back flows into the intake.im trying to show how a reed valve helps prevent the back flow through the intake,any way,back to rocknroller,if your air cleaner is wet your reeds may be stuck open...mabey some dirt under the reed,the reed may be a little warped...ect.i would pull the reeds and inspect them carefully,they should seal agianst the reed mount(the plastic part)fully,if not you can turn them over to get a good seal,
 

mike carter 2

Member
Nov 23, 2011
253
13
18
west virgina
now back to your to your bogging problem,i cant say this enough times,reed valves will not run rite without a ported piston.i had the same problems with my gt80 in the begining.i must have went through every thread on this forum,studying,trying to fix it.i tuned and tuned,then some more,untill i came up with the tune thats on it now.now im going to try a set of main jets,these motors are not a tune once and forget ,to get and keep running rite takes tuneing.im saying this with over 1300 miles of expereance with the exact same motor,ported piston,a good x pipe will help a lot.go online and look ported pistons,make sure you order the rite one as there are two types of pistons,a type a, and a type b.on one of them the hole for the wrist pin is higher than the other,or you can use a dremmel tool to port your own,
 
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waynesdata

Active Member
Jul 10, 2017
254
107
43
42
Have you looked at your spark plug? What color is it? A picture of your plug would be great. Check your spark plug color before moving carb needle clip.
 

Tyler6357

Well-Known Member
Mar 15, 2012
1,142
170
63
Santa Barbara, CA
Sounds like it's a little rich, set the clip on the leanest setting, if bogging persists, try a smaller jet. Also, the bogging might stop as the engine gets broken in and the rings mesh with the cylinder depending on how much it is bogging at the high end.
 

mike carter 2

Member
Nov 23, 2011
253
13
18
west virgina
thanks,there is one that shows how the x chamber causes a pulse that causes the unburnt fuel to go back into intake,helping to charge the cylender with fuel,a reed stops the unburnt fuel from leaveing the cylender. some of that pulse flows back through the intake also,i dont know how to get it from facebook to this site