new 310 cylinder on 250r and all it will do is bog???

[bushwacker51]

I replaced the 350 pv motor with a 310 cylinder in my 85 250r atc. The old kit had a plv ignition so replaced with used cdi new coil and ebay cdi box. Starts up but kicks back bad. All it does is bog like its getting to much fuel. I went up and down with jets might run a little better with bigger jets but not much. Tried another carb same thing bogs. Changed stator put a rickys stator in and a new honda coil and cap same thing just bogs. Hit the throttle it jut goes boooo boooo booo wont hardly rev. Its a new air stryker carb also. I am pulling my hair out any ideas ????????????????

[Dirtcrasher]

Gotta start with the basics...

You say you swapped carbs and ignitions, so I'd rule that out. Any air leaks??

Kick backs are often timing. IDK a ton about these ignition changes you've made, but they play a very big role.

Sometimes if you change too many things at once, it can be a nightmare, can you read the plug at all?

[bushwacker51]

[I have not checked air leaks I guess spray carb cleaner around the carb and intake ill try that andno the plug is wet but no color yes my next step is get a cdi box and try that I guess. Open for ideas

[bushwacker51]

I put stock cases back on and a new crankshaft and bearings rebuilt motor

[HondaRidr]

What kind of CDI did you put on it?

[bushwacker51]

I put one of those ebay cdis in . Kicks back like a sob. I ordered a used Honda cdi try that

[shortline10]

Their are no aftermarket CDI boxes for the 85 250r and if they claim to be they don’t work .
Lots of threads on this subject here on 3WW .

[HondaRidr]

I agree with shortline. I have never heard good things about any cdi other than OEM. Hopefully that will get it running good

[devilman]

Did you check the squish? Clearance between head and piston when at TDC? Not sure if that would cause kick back, but may cause the bogging.

[shortline10]

Kick back equals spark at the wrong time , so unless you have a sheared flywheel key that POS aftermarket CDI is the problem and hopefully it didn’t damage those fragile kicker gears .

[Curtis-Tecate3]

What Shortline said....
Kickback = Timing Issue that needs to be corrected.

[bushwacker51]

I was not trying to play clue or being an A-hole. The previous motor mounted in the 250r atc was a 350 pv motor. It had a pvl ignition on it. I I bought used cases and put new bearings and a new long stroke crankshaft in the new motor. I Bought a new 310 cylinder and high compression headand Rebuilt the motor. I bought a coil and cdi box off of ebay. I have since replaced the coil with a factory Honda coil and Rickies stator. It made no difference. I also checked the keyway and it is still okay. It does have the balancer that you can advance or retard the timing it is set on -0- I am going to take the pipe off and make sure its not plugged also going to put on the factory cdi when it arrives. Your right hope It did not screw up the kick starter gears. Never saw one kick back so bad before. It must be the cdi box thanks for all your help I will post what I find thanks Glenn O.

[bushwacker51]

I did not check the squish clearance if the cdi dosent work that could be next Glenn

[bushwacker51]

Okay got a used cdi box from ebay and that took care of the kick back problem starts so much easier but it is still bogging at low to mid rpm range. very difficult to get into the high rpm range. Have to down shift to raise rpms . When you get into higher rpms it snaps into the power band and then takes off. It has a new carb on it Took it apart and cleaned it out no difference. HELP PLEASE!!!

[floydechoes2000]

Is your exhaust clogged?