[jordaromera]

Hi! I have found oil in the air box, enough quantity:

https://megabyteandorra-my.sharepoint.com/personal/j_romera_megabyteandorra_com/_layouts/15/guestaccess.aspx?docid=0545e520f55ff4bc1be5877530ee94781&authkey=AVges_byEkMb107NbX-Yc0c

In the end of the air box i have a cap:

https://megabyteandorra-my.sharepoint.com/personal/j_romera_megabyteandorra_com/_layouts/15/guestaccess.aspx?docid=0560386b953154354a738b4ca772a2d5c&authkey=AcIANJaCXAISlzzrelZEnu8

The question is: Is it bad to run without this cap? How do you wear it? That could be happening?

I use Castrol 10-50W Racing 1

Thanks in advance

[NMKawierider]

If you are getting oil in the airbox on an 800 that can only happen if one or more of these conditions exist:
1. A high level of vacuum is being held on the airbox. If the intake tube has not been modified most likely the prefilter bag on the end is in need of cleaning.
2. The engine is way overfilled on oil.
3. The engine has excess blow-by because of ring failure and that flow is taking oil out the only vent the crankcase has..the vent to the airbox. This can happen in under 800 miles if the OE airfilter wasn't changed to a oiled foam type immediately upon purchase.
4. The engine could also have a broken ring or cracked piston.

[jordaromera]

I run with the stock air filter aprox 400 miles. After, with UNI air filter 400 miles aprox without oil filter (I know, I did not know there was a spray for the filter).

The problem has started after the last oil change, but i believe the oil level it's perfect, at this moment the oil level it's good. The prefilter never cleaned in the last 1100 miles. yesterday i have cleaned the prefilter i test today.

The cap on the end of the air box must be?

Thanks.

[NMKawierider]

I run with the stock air filter aprox 400 miles. After, with UNI air filter 400 miles aprox without oil filter (I know, I did not know there was a spray for the filter).

The problem has started after the last oil change, but i believe the oil level it's perfect, at this moment the oil level it's good. The prefilter never cleaned in the last 1100 miles. yesterday i have cleaned the prefilter i test today.

The cap on the end of the air box must be?

Thanks.

So..you ran the OE air filter for the first 400 miles, then you ran an unoiled Unifilter for the next 400 miles... which is like running no filter... and in 1100 miles never cleaned the prefilter on the intake pipe. Well at this point I got the feeling weather the drain cap is on the drain port or not really makes no difference. I have a feeling your engine's top end may have a problem. If it doesn't..it should..it has every right. But check the volume of blowby by taking the vent tube off the box and starting it. Then lightly set your thumb over the end. An engine in good condition will only build a slight pressure. The more the rings and valve seals leak, the more it will blow out that vent. If it doesn't build pressure, then your problem was that prefilter

[jordaromera]

Yesterday i have cleaned the prefilter, the problem persist.
Today i've gone to the dealer at it says if don't have oil in the exhaust or white smoke i don't have problem. This it's "normal". i'm agree with you i have a problem, at appears serius. Today in 10 miles 20cl aprox of oil. i have performed your test and the result it's positive, i have presure in the top tube.

It's curious because the problem has started from one day to another, no previous symtoms. The problem has started the day i have oiled the filter, after oil the filter problems to start the engine. Some piece of paper in the air box?? i don't know. But the problem starts this day. Curiously the engine Works fine...

i can assure the problem it's in the top of the engine¿?

Thanks for your help!!!

[REDRIDER]

Is it under warranty? If so just a side note, I would put the stock air filter back on before giving it to them to look at or they will blame it on the non CFmoto part (and certainly don't tell them you put a unifilter on it and didn't oil it)

[jordaromera]

it's in warranty... but if you open a engine with the grated cylinders you covers the warranty? Who knows... The good new it's i have found the cylinder for 125USD (each) and 30USD the rings... who opens the engine and changes it?? Ufff... i have a problem!

[Cosmosdan]

Do a compression or better yet a leak down test to see what condition the top end is in. It might save you some money or give you good reason to go through all the work of doing a top end.

[jordaromera]

Hi again! I have tested the compression and the results are very good: 10bar (1000KPA or 150PSI) in both cylinders. I think don’t have problems in the engine.

That could be happening? Oil continues to flow and air continues to flow through the upper tube.

[NMKawierider]

The only place it gets gasses into the crankcase is either valve seals or rings. That's it. Now maybe...there is a baffle..or something on the engine port side that is supposed to prevent oil splash from going out the tube that's come apart...or something.

[jordaromera]

Thanks! You are a gurus!

I have a final question before to open the lateral cover to check a baffle or something.

It's possible to have a broken ring and get 10 bar of compression? (that it's the max value in the cfmoto manual).

Thanks

[REDRIDER]

I have seen a piston with a broken ring land still give good compression, it was making a lot of chattering noise though. I'm sure it would have started breaking apart and giving low compression but we tested it right after the failure and it was within spec, This was on a Chevy 350 though.

[NMKawierider]

On small engines I have not seen one yet that didn't have a significant compression drop with a broken ring..but still be in an operable range. Check both and if one is much less then the other...I would start there.

[jordaromera]

I have 10 bar (145PSI) in both cylinders.

What happens if i run with this failure? Could i break something else apart from Cylinder barrel, pistons and rings?

Thanks.

[REDRIDER]

It sounds like your dealership is not competent if they think that getting a lot of oil in the air box is normal. That puts you in a tough position. Sounds like your compression is good so your rings are likely ok. I don't know these systems well enough, I don't think they have any one way check valve for the PCV system like a car so maybe your valve seats or worn, a leak down test would help determine that. Really the dealership should be taking care of this for you. Just a side note, these call for 40 weight oil, 50 is a bit thick.