Crf 250r 2013

[Andi2504]

Hey, i'm chaning the piston of my bike atm.

I have the handbook here, but one torque i would need is missing.

 

The screws which are holding the cam (with the '10' in the picture)

 

 

And the other question i have is about the Cylinder head stud bolts.

In the handbook there is a remark to oil the screws.

Is the given torque now for the oiled screws?

 

Because i read very often that the given torque in the handbooks is for clean/dry screws.

 

 

 

 

Hope you can help me.

 

 

 

[mlatour]

It may not be the same model/year of bike but still the same general engine design from an earlier Honda:

 

My 2007 CRF250X service manual indicates for those bolts :

 

- oil on bolt threads while torquing

- 16N-m / 12 lb/ft of torque, acheived in 2 or 3 steps (say 5, 8, then 12)

- loosen and tighten them in a criss-cross pattern

- respect the LH & RH positioning (stamped on cap)

 

 

- cylinder head bolts/washers oiled as well,

39N-m (29lb/ft) in 2-3 steps, criss-cross pattern

 

Careful with the cylinder head cover, I've often read of people overtightening those bolts

-installed dry, 9.8N-m (7ft/lb)

rare that the average home mechanic has a torque wrench accurate at lower readings, I tighten those by 'feel' instead.

Edited January 21, 2017 by mlatour

[Andi2504]

ah now i found it, yes 16Nm. Thank you.

I've got another little question.

On the piston there is some soot. It feels like sand when i touch it.

It's the first time i see a piston.

So my question is:

Why this doesn't cause any problems?

If there comes normal sand in it, it will damage something, but the soot not?

[mlatour]

Carbon buildup is normal, unlike sand which is airborne

you'll notice the carbon usualy stays in place until you touch it.

 

Post a picture of the piston,

excessive buildup can be a sign of an overly rich running engine,

the actual fuel used problematic or,

oil consumption past worn rings / intake valve guides.

Edited January 21, 2017 by mlatour

[Andi2504]

 

Is that normal?

Edited January 22, 2017 by Andi2504

[mlatour]

That's a bit more I'd expect to see in an MX race bike.

I recently replaced mine in my slow trail ridden CRF250X and it had much less of a build-up.

 

Running rich, burning oil?

[Andi2504]

How do i recognize if it burns oil?

The smoke of the exhaust always was pretty normal and i never recognized that oil is missing.

 

I have fuel injection. Is it possible with fuel injection that the settings are changing and it runs for example to rich?

And i also don't think it runs too rich, it alwys ran very well

 

 

The only thing was, i controlled my valves and the output is 0.004 / 0.003 and the input 0.002 / 0.003 to small.

 

Thanks.

Edited January 23, 2017 by Andi2504

[mlatour]

My 250X used about 10ml of oil for each hour of use, not past worn piston rings but

rather passing by worn exhaust valve seals and straight out the exhaust, reason piston wasn't carboned up.

I only saw a lightly puff of smoke during initial start up / cold engine, never when riding.

 

How many hours on your top end ?

 

If a carburetion issue, for condtions rich enough to notice black smoke the bike would be un-rideable,

in your case it may be minor but over time enough to create carbon build-up.

[Andi2504]

I have 80 hours now on it.

 

Sorry, my english is not the best.

I dont understand what you mean with "reason piston wasn't carboned up".

Do you mean you had no carbon deposits on the piston because of the worn valve seals?

 

Is it possible that i have carburetion problems with a fuel injection?

 

And do you think the carbon could be from the too small valve clearance?

[mlatour]

Don't worry your english is fine (actually not my first language as well!)

 

In my case it was bad exhaust valve seals, due to direction of airflow

the oil never makes it to the combustion chamber, simply out the exhaust,

reason for my relatively carbon free piston despite the oil consumption.

 

If it were bad intake seals, in that case oil would get sucked into the intake air flow and into the combustion chamber.

 

I'm not too familair with fuel injected bikes but like anything electrical/mechanical, I'm sure they can become out of calibration.

In a automobile, dirt/debris can cause an injector the 'stick' open, making for a rich condition, I imagine an a dirt bike

application, proper fuel filtration must be critical.

 

No I don't think carbon build-up is related at all with valve clearance.

Edited January 23, 2017 by mlatour

[Andi2504]

Okay, thank you.

What would you do now?

 

I will send my cylinder to a shop for checking it and to buy a new piston.

They also offer to check the cylinder head, maybe i should do that?

What do you think?

 

(i bought the bike with 55hours, so i don't know if the previous owner

drove maybe with a dirty air filter or so, then it would also ran to rich because of the bad air flow right?

Edited January 23, 2017 by Andi2504

[mlatour]

From your earlier posted picture your cylinder looks great.

but since you have the engine dis-assembled I would also have the cylinder head inspected.

 

If it had been re-shimmed by the previous owner and now you have to re-shim it,

perhaps a sign the valve/seats need attention.

 

As I said I'm not familiar with FI engine, maybe they have a diagnostic port the dealer can read error codes from ?

[Into the sunset]

These are from my son's 2013. We bought the bike new and they both have 40 hours on them.

[mlatour]

Thanks for posting some comparatives Dklassen

 

I think camera angle and the use of a flash makes the OP's piston look worse than it actualy is,

it makes the 'crusty' texture stand out more.

Edited January 24, 2017 by mlatour

[Andi2504]

Okay, thank you for the pictures.

So maybe the carbon deposits from mine are normal after over 80 hours.

What do you think?

 

Anyway i will send my cylinder head to the shop and they will check it.

[Andi2504]

Hello, i have another question to the cylinder head.

I want to check it on my own.

 

How do i check for example the valve seats?

Or the shaft seals ?

Edited January 27, 2017 by Andi2504