Cr80 bogging problem

[2stroke newb]

I just rebuilt my cr80 with a wiseco racers choice piston stock bore the engine is a 1991 I also rebuilt the bottemend I put all new seals and all new gaskets I drilled wholes in the head gasket so that I could turn the head to miss the exaust I broke it in on break-in oil at 32 to 1 but I switched to Pennzoil semi-senthetic 32to1. In nutral you can rev it with no problems. When you shift in to first gear and it runs very well till you get a littel past the powerband then it acts like it is running lean and almost stalls but when In second it will barily hit the powerband and then bogs out and almost stalls when in third it bogs way more and won't even hit the powerband I haven't been in fourth yet. I am running a ngk 8 not the ten I herd the 8 will last longer it has good spark and I have gapped it to factory I have a fmf fatty and a 7mm exaust spacer and it has almost everything factory even the jets are factory according to my manual any help would be much appreciated

[KPRacing]

Are you using 2stroke premix oil?

[Jimmy boy]

Did the bike do any of these things before the rebuild?

[Pigsfly]

Sounds like a jetting issue. What size is the main jet. And how many turns out in the air screw?

Also check the back wheel is it spinning freely with no binding

Edited November 2, 2015 by john torrisi

[2stroke newb]

I use 2 stroke outbord Pennzoil at 32 to 1

It dident do it before the rebuild

And the jets are main-125 needel? It is worn off I don't know how to check the rest of the jets but the last owner said that he rejetted it to factory using a kit

[2stroke newb]

The airscrew is 2 turns out and the rear tire will turn easly should I replace the reeds

Edited November 2, 2015 by 2stroke newb

[KPRacing]

Why not try new jets that you can read to confirm it's jetted close enough to run poper. If it still runs poor, you can eliminate it simply being jetted incorrectly. Start easy, work to complicated.

[Jimmy boy]

If it didn't run like that prior to the work you did, then you need to go backwards over everything you did. It should run as good or better if everything thing was done correctly.

[2stroke newb]

I ordered new reeds because it still has OEM ones also I will get a new sparkplug the 10 and see if that fixes it I know it was running to lean before the rebuild because of how the piston cracked it was due to too much heat and I don't know if this matters but before the rebuild I had a OEM pipe

[KPRacing]

Where did the piston crack? If it was on the skirt, it cracked from too much wear.

[2stroke newb]

It cracked on the exaust side where the skirt is and there are cracks on the other skirt but the piston ring wasn't bad yet and the piston only had about 20 to 30 hours on it

[KPRacing]

Too much piston to cylinder wall clearance. Better check that out before the next one fails.

[2stroke newb]

It was a namura piston that was cast also the wiseco was a nice fit it dident rub but dident wiggel in the bore I had to file the ring gap a lot but that seems normal I did not drill the exaust port holes but others have done that and it turned out fine

[KPRacing]

You need to put a dial bore gauge down the bore & a micrometer on the piston to know forsure.

[2stroke newb]

The guy at the mechine shop who worked on the cylinder checked the bore and said it was good also do you know where I can get a stock jetting kit for the 95 and older carb or do I have to order a Chinese carb to take the gaskets and jets out of

Edited November 4, 2015 by 2stroke newb

[2stroke newb]

I moved the clip on the needle to the bottom also I changed the air screw to .5 turns out and it ran a lot better but still bogged so I taped the chock up and it ran good on the pipe even in 3rd gear but it boggs a lot off the pipe

[2stroke newb]

I found the problem the float was too far down I just needed to bend it and that seemed to fix the bogging also I have the air screw 1 turn out with the clip on the bottom of the needle i think I need to run 40 to 1 to get more to come out of the jets

[Scott Mclellan]

On 11/3/2015 at 5:43 PM, Jimmy boy said:

If it didn't run like that prior to the work you did, then you need to go backwards over everything you did. It should run as good or better if everything thing was done correctly.

I have one fully rebuilt started 1st time easy ,then back to it had clean plug an clear as if flooded an started again ,on an off that day ,next day same thing as if flooding any ideas