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XR250 oil on head big deal?

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Attached is a pic I took of my son's 2001 XR250. It is just above the spark plug on the cylinder head, on the right side as seated on the bike. This spring we had the cylinder bored, put in a new piston and rings, gaskets as the cylinder bore was worn and we weren't getting compression, so the bike would not start.

We went on a ride for a couple days up north this week, and I cleaned this area off thoroughly before we left so I could see evidence of what you see here, as I thought I had seen some oil in this area and wanted to monitor it and check it after the ride.  Is this a biggie, or just an old bike? Where is it originating from? Bike runs good.Thanks

 

IMG_3095.JPG

Edited by dogeddie

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I'd say that's minor for a couple days riding. I think I'd let it go and just keep the area clean so as not to end up with a huge build up and so you can also gauge if it gets worse. And keep a regular eye on oil level.

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Thank you. We put alot of work into that bike - I was hoping not to have to perform more surgery.

 

One other thing has always bothered me about that bike. It can be a finicky bugger starting on the trail - ESPECIALLY if it gets out of position (we fall over :goofy:)  I have since got a CRF 250x which has electric start, which only makes the XR250 starts seem worse of course. The bike has always kicked over super easy, and the exercise to start it seems to be kick in rapid succession till it goes. Has anyone ever disabled the auto decompressor? Wondering if that would help or hurt?

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There's def a trick to getting an XR restarted when hot and after being dumped. The best technique I've come up with over the years is pulling the manual decomp lever, holding full throttle and kicking the engine over several times to clear the engine and carb, drawing fresh air thru the system. Then release both and as always, make your starting kick from TDC, every time. Kicking from anywhere else in the stroke is a wasted effort.

I've found that, unlike when the engine is cold, being hot and after dumping it you can give just a little throttle at the end of the kick and get it going.

Having just rebuilt the engine, your valve clearances should be correct. Make sure the manual decomp is adjusted right.

I don't like removing engine parts that the engineers, who are a lot smarter than me, designed into the engine. I think it's better to learn how to use techniques and the controls provided to get an engine going.

A float that's set too high can compound hot engine starting too.

Edited by Trailryder42
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1 hour ago, dogeddie said:

Thank you. We put alot of work into that bike - I was hoping not to have to perform more surgery.

 

One other thing has always bothered me about that bike. It can be a finicky bugger starting on the trail - ESPECIALLY if it gets out of position (we fall over :goofy:)  I have since got a CRF 250x which has electric start, which only makes the XR250 starts seem worse of course. The bike has always kicked over super easy, and the exercise to start it seems to be kick in rapid succession till it goes. Has anyone ever disabled the auto decompressor? Wondering if that would help or hurt?

I have both of your bikes and have the same struggles you do.  I'm working through a recent issue on the XR that came after a crash.  Bike doesn't want to start hot now...i'm coming up on days off and will get into it.  Will be checking the plug, float level, etc.  It's important to remember that bikes need three things to run; fuel, spark and air.  Fun part is when the bike is not running, which of the three is the issue. :)

Edited by Rodeojones

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For you oil leak..either get a new valve cover gasket, or what Id do, take it off, clean it and finger squigee a film of Hondabond on both sides. Bolt it back together (oil bolts) and hand tighten. Let it cure. Cure not dry. Now go back over bolt with torque wrench and tighten to spec. Done til next valve adjustment.

Or do what everyone else does and just add oil every ride.

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The bike has always kicked so easily you could do it by hand. Is that an indication of a problem, or that the auto decompressor is working? Normal for these bikes?

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Get a comp test. Remove the auto decomp and push with your hand. You got a manual decomp? I always remove my auto decomps. Like what if its stuck open? Besides a visual check thats what a comp test will tell you.

Also double check your timing that all four valves are closed at tdc

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There's def a trick to getting an XR restarted when hot and after being dumped. The best technique I've come up with over the years is pulling the manual decomp lever, holding full throttle and kicking the engine over several times to clear the engine and carb, drawing fresh air thru the system. Then release both and as always, make your starting kick from TDC, every time. Kicking from anywhere else in the stroke is a wasted effort.
I've found that, unlike when the engine is cold, being hot and after dumping it you can give just a little throttle at the end of the kick and get it going.
Having just rebuilt the engine, your valve clearances should be correct. Make sure the manual decomp is adjusted right.
I don't like removing engine parts that the engineers, who are a lot smarter than me, designed into the engine. I think it's better to learn how to use techniques and the controls provided to get an engine going.
A float that's set too high can compound hot engine starting too.

X2

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6 hours ago, notoriousE-R-I-C said:

Get a comp test. Remove the auto decomp and push with your hand. You got a manual decomp? I always remove my auto decomps. Like what if its stuck open? Besides a visual check thats what a comp test will tell you.

Also double check your timing that all four valves are closed at tdc

Is there an easy way to disable the auto decompressor? The bike does have a manual decompressor.

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http://advrider.com/index.php?threads/xr600-auto-decompressor-cam-disabling.721149/

This is what I did.

And he makes a good point about aftermarket valve cover gaskets

Ive never had a backfire that worried me

I have 600s now. Before owned an xr250l. Didnt do anything to it, all stock. And theres an xr250r at the garage I work on bikes at but thats one of the bikes that needs the least! A youngen doing hare scrambles in the desert wilderness. Not mx tracks.

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Will do, but it will be a bit. Can't get a comp tester till the weekend. And interpretation mid next week after the long holiday. But I am pointed in the right direction!

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Try the decomp disable first and see it it does anything before comp test. Or I guess you could do it the otherway around. But if Kenzos(his names Kenzo on here) trick sounds like something you want, do it anyways. Then see if it helps if not, its done anyways, now onto the comp test.

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I will do the compression check as it is alot less dinking around. I really am just wondering if it is normal for this motor to kick over with so little resistance.

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I guess thats up to you. You could be a 250lb guy with a 60lb leg...some cant budge a big bore, some womp it like the decomp is on but its not. But pushing with your hand...Id say no. I have a 250f with low comp and I cannot easily hand push it.

Put a teaspoon of oil into the cylinder through spark plug hole and then push with your hand. Is there more comp? Yes= get new rings. When youre in there peep the cylinder. Scuffs? Get a hone? Scratchess/gouges? Bore. See cross hatch marks nice and clear? Id do nothing but oil soaked steel wool scrub and stay that piston size.

No? Id think a valve was open or leaking

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This spring we had the cylinder bored, put in a new piston and rings, gaskets as the cylinder bore was worn and we weren't getting compression, so the bike would not start.

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