Should a 2 stroke smoke after rebuid during break in?

[STLTrike]

Just had my top end redone on my 86 250r. Bore, piston, and rings. Took it to a nice ORV park with some open areas where to break it in yesterday. Well the thing smoked a lot. seemed OK when ideling though. Wondering if it is normal to smoke a lot during break in for a few hours? It seemed to smoke a little less after riding for a few hours... My mechanic mixed the gas oil like 40:1 he said he put 3oz to 1 gallon. I normally run the 20:1 that honda recomends. So he had one gallon in the bike at 40:1, so I added about 1.5 gallon to his mix at about 27:1. Thinking that should not matter that much though. Also I had him rebuild the carb when it was there... I stressed that the carb is not the same as the 85 and not the same as the CR250s. and ordered him all of the parts. And told him the jet settings. He said he ran it up and down the street a few times.. It does not seem to smoke when its idle. Here are some pics of the bike smoking after me riding for a few hours during break in. Thanks for any thoughts. Gona call him here in a few hours when they open up. Thought I'd ask in here first.

[HuffieVA]

20:1 may be what Honda said to run but that’s a lot of oil and will result in a lot of burn off (smoke), I run 40:1 in everything with premium gas and occasionally aviation fuel when I remember to stop by the airport. Its always gonna smoke and it’s a bit hard to tell whats roost and whats smoke in a few of your pictures but your jetting could still be a bit off, perhaps you can get enough adjustment out of your mixture screw on your carb to lean things out a bit.
On the other hand is it running strong otherwise? Or is their oil literally pouring out the exhaust as this could be a bad seal between your cases allowing the oil from your crankcase to be sucked into your cylinder

[Slingblade]

In my experience, a 2 stroke will always smoke. Once they get good and warm they dont smoke as much. Do you know what kind of oil he used? I would use a good quality oil at at least 32 to 1 and follow a good break in procedure to seat the rings,(heat and cool cycles, etc.). 40 to 1 is fine after that. But it looks like it might be too late for that. You might want check your silencer packing. I over looked this for a long time. When I repacked my silencer I was really rich but after I rejetted, my Tecate really came to life.

[ATC-RYDA]

most of the time during the break in period u want the bike to be running a little richer than normal anyway.. i run mine at about 27:1 during break in then 32:1 normaly .. but u need that extra oil for everything to seat nicely , as stated above ... although 20:1 is a little extreme nowadays .. i was told by a reputable honda tech that the reason the bikes have the 20:1 sticker on them is because back in the 80's the 2 stroke oils weren't nearly as good as the good oils we have today , and thats the reason for no longer having to run them so rich ... hope this helps......

[harryredtrike]

that seems like alot of smoke for 40-1 mix.id go with a little richer oil ratio for a new engine though 24-1 to 32-1.do you have the black ooze coming from the exhaust head pipe?

[demonband2000]

If tons of smoke, keep eye on the level of oil on crankcase. Sometimes the seal goes bad. Then crank oil gets sucked up in the piston and smokes a lot

[Dirtcrasher]

40 - 1 would be LESS oil so LESS smoke......

Seems to me, something isn't right. I ride with 250R's all the time and they don't smoke in the least aside from a cold start.

All I ever ran was one bottle of golden spectro to 5 gallons of gas, never worried about mixtures; Never lost a top end on the 5 or more 2 strokes I beat on..........

[beets442]

I've used Golden Spectro on break-ins like DC does 1 bottle to 5gal., never had a problem yet. Air filter clean and passage clear to carb?Jetting a little rich?... +1 Shouldn't smoke alot at 40:1 after it's warmed up....A little more oil at break in doesn't hurt...By the pics I wouldn't break it in like that but thats me...Beets

[Xpress]

2 strokes always smoke, but that looks a bit excessive. Perhaps the rings haven't been seated fully?

[whyzee]

way too much smoke. What premix oil are you using? what size main jet are you running? Also , as stated above, keep an eye on the crankcase oil level!!!

[STLTrike]

way too much smoke. What premix oil are you using? what size main jet are you running? Also , as stated above, keep an eye on the crankcase oil level!!!

Thanks for all of your posts! Sorry for the wait on the reply, I was away for a bit. OK he used BeNOL oil, and I bought a bottle off of him and thats what I used. I'm wondering about the jetting my self. I thought he mentioned a 142 main jet, but the stock on an 86 is 145. I told him that though. I hope he did not just try to make it work with a 142 jet.

[STLTrike]

I've used Golden Spectro on break-ins like DC does 1 bottle to 5gal., never had a problem yet. Air filter clean and passage clear to carb?Jetting a little rich?... +1 Shouldn't smoke alot at 40:1 after it's warmed up....A little more oil at break in doesn't hurt...By the pics I wouldn't break it in like that but thats me...Beets

Thanks man, yes I know I was not really roosting it until a few hours after break in. I wanted to hit the top end a bit.

[STLTrike]

that seems like alot of smoke for 40-1 mix.id go with a little richer oil ratio for a new engine though 24-1 to 32-1.do you have the black ooze coming from the exhaust head pipe?

Thanks, I did not see a ooz, but I did see liquid, assuming that was the pre-mix coming out. I guess that could be a ooz though.

[STLTrike]

If tons of smoke, keep eye on the level of oil on crankcase. Sometimes the seal goes bad. Then crank oil gets sucked up in the piston and smokes a lot

Cool thanks, I have heard that can be a problem too. Figured he would have checked that. I'll add that to the list of things to check.

[STLTrike]

20:1 may be what Honda said to run but that’s a lot of oil and will result in a lot of burn off (smoke), I run 40:1 in everything with premium gas and occasionally aviation fuel when I remember to stop by the airport. Its always gonna smoke and it’s a bit hard to tell whats roost and whats smoke in a few of your pictures but your jetting could still be a bit off, perhaps you can get enough adjustment out of your mixture screw on your carb to lean things out a bit.
On the other hand is it running strong otherwise? Or is their oil literally pouring out the exhaust as this could be a bad seal between your cases allowing the oil from your crankcase to be sucked into your cylinder

Thanks for the info! Yes it is running strong, and yes there is oil running out of the exhaust. I would not say pouring out though. It is dripping out.