2003 cr 85 help

[bigdaddy77]

Here's the deal. We burned up the crank in our good stroker motor in the mud at ballance. I had bought a back up motor from a guy real cheap. He didn't know much about it Just that it is a 2003 cr 85 made to a 90cc motor. Didn't know if it was stroked or bored. I put it in at ballance and it seemed to run fine. Made all the laps at Wildcat but Adam said it was losing power. He has a tendency to not always up shift and review the crap out of it in 3 rd gear. He struggles a little switching between the four stroke and the cr motor. He has admitted the way the 2 stroke is he is a little afraid of it.
So any way we ran it Saturday and it seemed to be bogging. Put a new plug in it and it seemed to be fine. Went to run it Sunday and it would rev OK then when he got to to shifting to 3rd and 4 th it acted like the plug was fouled. . When I changed the plug Saturday it looked OK. A little darker than coffee colot but not wet.running a d slide keihin 28 mm 142 main 42 pilot proper cr 85 needle clip in middle position with a 2" uni filter with outer wear. BelRay oil mixed 32/1 the only change is from C12 fuel to shell 110. But we have been running shell 110 in our high compression 4 stroke motor with No problem.
My questions are what else could have this effect? Reeds? Bad ring or topend? What should compression be? Could crank bearing give this effect. I have a new 47.5mm cylinder and piston I picked up from Jeff Roberts but before I tear it out of the quad I wanted some input from the experts. Any help would be appreciated. Would like to get this motor straight and save the good motor for when he is more comfortable on the mod. Thanks for any input.

[Ryko racing]

Here's the deal. We burned up the crank in our good stroker motor in the mud at ballance. I had bought a back up motor from a guy real cheap. He didn't know much about it Just that it is a 2003 cr 85 made to a 90cc motor. Didn't know if it was stroked or bored. I put it in at ballance and it seemed to run fine. Made all the laps at Wildcat but Adam said it was losing power. He has a tendency to not always up shift and review the crap out of it in 3 rd gear. He struggles a little switching between the four stroke and the cr motor. He has admitted the way the 2 stroke is he is a little afraid of it.
So any way we ran it Saturday and it seemed to be bogging. Put a new plug in it and it seemed to be fine. Went to run it Sunday and it would rev OK then when he got to to shifting to 3rd and 4 th it acted like the plug was fouled. . When I changed the plug Saturday it looked OK. A little darker than coffee colot but not wet.running a d slide keihin 28 mm 142 main 42 pilot proper cr 85 needle clip in middle position with a 2" uni filter with outer wear. BelRay oil mixed 32/1 the only change is from C12 fuel to shell 110. But we have been running shell 110 in our high compression 4 stroke motor with No problem.
My questions are what else could have this effect? Reeds? Bad ring or topend? What should compression be? Could crank bearing give this effect. I have a new 47.5mm cylinder and piston I picked up from Jeff Roberts but before I tear it out of the quad I wanted some input from the experts. Any help would be appreciated. Would like to get this motor straight and save the good motor for when he is more comfortable on the mod. Thanks for any input.

We had this issue a few years back with identical set ups. We ran u 4.2 oxygenated fuel and amsoil 32 to 1.
When they discontinued the fuel we had to go back to 110 turbo blue. Our jetting was clip in 2nd from top, 40 pilot, 135 main. 80 degrees outside temp. comp around 145 but that depends on head cut. Try that jetting carefully but it should come to life. THE RIM OF THE PLUG SHOULD BE LIGHT BROWN N DRY TOO. I THOUGHT MY PLUG WAS FINE AND WENT WEEKS TRYING TO FIGURE IT OUT. C D MUSICK LOOKED AT IT AND TOLD ME TO DO THIS AND WE NEVER TOUCHED IT AGAIN.

[Logan #34's Dad]

I'd say your jetting is going to be close....You mention that you changed fuels. Fuel is not just all about octane levels...many many things can be different from one fuel to the next. Also, It was a lot hotter this weekend than it has been so far this year...so you may have been a little rich BUT I'd 1st go back to the previous fuel..

[bigdaddy77]

Picked up some VP C12 mixed it up with some Belray oil 32:1 . Drained the other fuel and Ill be damn if it didn't run just fine. I guess that's what I get trying to save a few bucks. I did notice our V Force reeds starting to chip while I was double checking everything. Thanks for the help.

[ValloneRaceTeam]

We run VP C12 also but I was told 40:1 I wonder if I should try the 32:1?

[bigdaddy77]

Its what Honda recommends and what I believe most the others are running, except maybe a few amsoil guys.

[Logan #34's Dad]

We run VP C12 also but I was told 40:1 I wonder if I should try the 32:1?
We were ripping low end crank bearings out a lot even running Amsoil 50:1until I went to 32:1 using H1R... Honda calls for 32:1.

[ValloneRaceTeam]

We were ripping low end crank bearings out a lot even running Amsoil 50:1until I went to 32:1 using H1R... Honda calls for 32:1.

Thank you, I just went with what my engine builder told me and I will make the switch, thank you!

[tyler70t]

Picked up some VP C12 mixed it up with some Belray oil 32:1 . Drained the other fuel and Ill be damn if it didn't run just fine. I guess that's what I get trying to save a few bucks. I did notice our V Force reeds starting to chip while I was double checking everything. Thanks for the help.

Glad to hear that the engine is working out for you.