2010 CRF 250 crank/EFI problems?

I posted a few weeks ago about a brand new 2010 CRF 250 loosing a crank. Well after spending hundreds of dollars the bike fixed and now driving 3 states away due to missing the local qualifier the bike will not run again!

My buddy took his kid to a qualifier in Il which and his son placed 2nd in the qualifier. Knowing he had a real good shot at first and making it to the regionals was in the bag the bike would not start for the 2nd moto.

They checked the oil before the race and it was between low and high. When the bike wouldn't start they checked it again and it was to the full mark. I think the EFI is still leaking into the crank! On top of that they drained the oil and guess what they found? Gold shavings!

So either the new crank is going out or the shop didn't clean the motor out. Keep in mind the new crank has about 2 hours on it.

They are supposed to find out today what the problem is but the question is why didn't they try and find out what caused the crank to go out in the first place. I don't if Honda is going to do anything but if the don't maybe the shop will step up.

I hate to see this because the father is doing everything within his means to try and qualify his son for Loretta's and the bike will not hold up!

WOW that is incredible!! Keep us informed what the heck happened??!!

They are still waiting for an answer from the shop.

chances are whoever did the work did not do a good job cleaning the metal out of the motor after the first crank failure. If he found traces of gold in his oil there's a good chance there are metal shavings collected around the magnetic trigger units under the left ignition case cover. The shavings will collect there and short out the ignition.

The good news is the oil filter is ahead of the crank and rod bearings in the oil flow path. so there's a good chance the oil pump wasn't sending those shavings through the motor.

Have a look a the oil filter. there should be more shavings there.

all i know is we had a crank go over the weekend and doing cleanup now,it is a major bitch cleaning the filings out! its in every nook and cranny,also the stator and flywheel area is coated,took the oil pump out to.



Bomax I Pm'd you. Say it aint so! Tell me that was a customers bike!

It is easy to overlook cleaning the oil blowoff valve and shavings get collected there. Simple to clean but not obvious.

Hondas are getting worse every year, in terms of reliability, reputation, and performance. I swear...........................

dude, my brand new RMZ transmission went. I would like to say suzukis reliability has went down but it was never there! My hondas have always lasted. Your posts are useless!

Hondas are getting worse every year, in terms of reliability, reputation, and performance. I swear...........................

Dude ive read some of your other posts in this area what are you trying to say? Do you even own a honda? Have you been to any local races and see how many hondas there are? Almost all the races ive been to the number of hondas outnumber more than twice the suzukis. Im not hating on suzukis though, ive never personally owned one. And yeah i heard the newer suzukis are great bikes to.

As far as my 2010 is, im at around 60hrs havent opened up engine yet. About to put new piston and rings in though.

Edited by WannaBeRacer425

I have noted that our 05-07's cranks averaged 80-90 hours prior to going out. The 09's averaged 50-60 hours and now with the 2010's the bike crank went out at 30 hours, taking out both case halfs, the cylinder and balance shaft. Our other 10 lost a valve at 20 hours, destroying the entire head.

I had orderd a crankshaft for that bike due to it having 45 hours on it, but I let the boy ride it one more time prior to receiving the crank and it went, at least I get to change a bad crank and that was the only damage.

Also I have found that the right hand Intake valve and or seat has aways been a problem with all years.


we got lucky,it felt "tight" in the pits so we shut it down,basically took just the crank,mains,piston etc..a bit of scuffing on cylinder and a big mess,the washers on the crank are still intact but ovaled,the bearing is gone.

one thing to note though is from the bearing going and the crank i guess sitting further over,it was forcing the pin in the piston over and actuall popped the clip out and was ready to fall out.(there was no clip gulley left)it pushed the whole thing out,aluminum and all.

should have it back running tomorrow.

I am just glad this bike wasnt a 2011! So far so good.

what number is stamped on your connecting rod? my 2011 has a krn 17 on it,also the new crank i just opened shows krn 17,the one that seized is a krn 16.id be interested to hear of what numbers are on some of the other rods that bkew up.

When the first crank let go, if the oil pressure relief valve wasn't stripped and cleaned properly (or even done at all), there is every chance that is the root cause to your second failure.

Bike would have been running great, but the attrition would have been there from the get go. Couple hours of shavings and particles sloshing around and there's the second crank toasted.


Hope you get it solved.

i have krn17 and 70hours, no problems

my 2011 has KRN18 on it, just wonder if thats just a casting number or what it means, my crank is still holding up 24 hours

iam guessing a cast number or production number,i wanted to see if anyone that has blown up with the 10.s would post theres.

i used to race rs125 gpbikes and when i bought the bike from hrc they sent me 5 cranks with it in the spares,they later called me saying not to use a certain crank with a number and dots on the rod.i had one of the bad cranks in the batch and sent it back. i was just curious to hear about these ones.

I have the KRN16 stamped on the rod in the practice bike it has 74 hrs on it now.I did and oil change at 73.3 hrs and had my 1st sign of some small slivers of metal in the oil filter.I suspect the thrush washers are starting to wear but i already have a new crank that will be going in next week.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now