No Hot start and Oil Burnoff near front of motor - 01 Quadrunner 250

[RockOn]

So I bought a 2001 Quad Runner 250 for my son/wife. Sorry I run a Grizzly 660.

I’ve rode it many times with no issue.

My son’s first time out, I could always hear him but feeling he ran it red line in first gear a lot.

So this is what it was doing during/end of the 2-3 hour ride:

- halfway though noticed smoke (oil) coming from front of the motor sort of under exhaust manifold. Once back at the truck, it was really noticeable. Definitely oil burning off. I’m thinking from the top end maybe.

So quick inspection:

- No leaks or seepage of oil that I could see

- I pulled the plug and it’s black but not wet

- No blue/white smoke in exhaust

- seems to still ride fine

- Engine still has plenty of oil

But now that I’m looking at it back at the house - it’s a hard/won’t start when hot. It starts right up cold no problem but once it stalls when hot, have to let it sit for 10-15 before it will start again.

It wasn’t idling before that trip so I jacked up the idle a bit as well but I think that’s a carb clean/adjustment but...

Any input is appreciated.

Thanks for any help.

 

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[Frank Angerano]

The black plug could be two things. One is a need to adjust the carb maybe two rich.  Second is its fouled up from oil blow by if the rings are on the way out. Possibly from over reving. I would try a couple of things. First and foremost I would take a compression reading and see what you have. Should be well over 90 possibly to 110.  If not then there is a problem like rings or a seal.

Secondly is a slight carb adjustment on the air fuel screw.   

The last thing I would also do is ride the bike and wait until it gets that hard to start condition and have a new spark plug ready to go. Pop it in (don’t get burnt changing it ) and see if the bike fires right up.  If so then it’s most likely an oil foiled condition.  

As far as the smoking on the head when oil burns off if it’s leaking from the head it’s hard to spot because it burns right up.   But the over reving is not good at all and could have blew a seal or wore the hell out of the rings.   

[RockOn]

Thanks a lot.

Compression test and new spark plug are easy checks for sure.

Carb adjustment, will do some research and look in to that.

Appreciate the input.

Would low compression just be the piston ring or could be the balance seal as well correct?


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[Frank Angerano]

Either or.  My guess is the rings and if so then might as well throw a new piston in.   But do your research before you start tearing into it and ordering parts. Test and process of elimination.   Head gaskets etc.  a compression test will tell you a lot.  Also keep in mind that you can shut the gas off, take the wire off of the spark plug.   Spray the top half of the engine down with a soapy soliton and crank the engine.  You would see bubbles if something is pushing air out of the engine like a head gasket.    

[caperwing]

You could also when doing a compression test take your first reading and if low put a little oil in the plug hole and test again. If the reading is higher then the rings are bad.

[RockOn]

Roger that!


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