Has anyone had issues with crank/rod failure on a 2010 CRF250R?
I over maintain this bike.  I use synthetic oil in the crankcase.  There is no reason for lubrication failure on my part.  
The bike has 80 hours on it.  The rod bearing went out.  The rider is an Intermediate rider.  I have seen many bikes ridden harder than this one.
I understand that there are aftermarket cranks that have addressed lubrication issues that the OEM cranks are deficient in.  
Has anyone addressed this with Honda?

80 hours is more than I would go on a 250f crank.  We change them before 50 hours and if there is ever any trace of gold flakes/sparkle in the oil filter it is time for a crank regardless of the time on it.

We allways use oem cranks, never hot rods etc.  We do have them balanced, trued and welded.

There was  a problem with the 2010 crf250r cranks. Many people had them go before 80 hours.

gyd said:

WHAT? 80 hours and you swap the cranks, are you racing?

gyd said:

Wow,  I cant believe changing a crank every 50 hours.  That would 2 crankshafts a year or more for me.  How can you afford that?  It's a shame that modern production bikes are that high strung.  It prices the regular guys out of the game and isnt good for the sport.  Who wants a dirt bike you have to replace a crankshaft, top end, etc.  multiple times a year?

The performance bikes offer is pretty amazing. That performance comes at a price.

I only went roughly 30hrs on a crank on the 250's before I pulled it. It was anyones guess after that when it would go. The damage that it can do when it goes wasn't worth risking it being in any longer. 3-4 cranks a season. Hi-level racing and performance comes at a price like Mark said.

It's not lubrication failure (well - sort of)- almost all crank failures are bearing cage failures.  They see extremely high inertia loads - and over time it wears out and then fails letting the bearings loose, which then really leads to havoc.

Power comes with a price - and the modern four stroke you purchase puts out a lot of power for a 250cc machine!

To top that off, honda has both the shortest stroke AND rod of the bunch - making the inertia loads even worse...

Hot Rods has a good reputatiion in this model probably better than OEM. The OEM crank has been a problem. I have a Hot Rods in my bike an it runs just fine!

prox sells different con rod bearings and some time they have bearings in the same size with 17 till 19 rollers , i prefere the one with the min. rollers , because the cage is stronger because there is more space between the rollers and there is also more room for oil between it . . also a pin with 2 hole,s oposite of each other will work better i.m.o. because when the pin wear its mostime on the opposite site of the oil hole.

We don't go over 25 hrs on a 250 crank.
the most recent was replaced at 20 and the cage was showing wear at the point where the roller ends come in contact. We change oil after every race weekend.

I have rebuilt many many blown up crf250, I have at times used thumpertalk as a quick reference guide, but i see alot of unguided unqualified people wanting answers to very valid questions with people always giving some comment from experience dealing with what ever the cause. I am very busy but good information without smartarse comments is what i prefer and thats just what i do do get the cuase and fix the problem.  Comparing a Honda CRF250R engine to any of its competitors is impossible it is a very special engine and has its flaws longetivity can be achieved at all rider levels in crank / ROD issues replacing a crank and not checking the root cause to this failure is Ulitmately costing people lots of mula and they are not learing from mistakes.  Just keep throwing money at them and not scratch their head and find out what is the cause.  Thank **** for people like me that like solving major problems like CRF Blowing there rod bearings into and out of crank cases.   I am working on all makes of bikes and the all have the flaws.  The CRF250R is a awesome engine very simple but if not checked throughly at 10 hours at race level what ever year you will be replacing cranks.  This is not new information at all no doubt many people have their own spin But no matter what bike you They all HATE DUST.  DUST enters the valves carbon starts to build up the valves start to shag the valve lap the bike becomes hard to start all this is happening well before the rod lets go Some one tells you shim the valves yeah.... thats great but take the time and shine a torch into the exhaust port and inlet port and actually take a look at the valves from the inside and do this if you see carbon build up pull the head off take the valves out and give to a good engineer for a bead blast and clean the shit out of it if the valves need lapping replace them on a stainless valve no matter who you are if you want horsepower put a cam on it and a hi comp piston but run the stainless valve its the best thing for them.  Your crank issues will be minimised

The 2010 CRF didn't have valve issue like is older brother's. I read somewhere the mapping was a little too lean, so a ECM reflash can reduce the stress of the rod and bearings.

I change my crankshaft this year because rust on the transmission side bearing wear the crank a little. But I don't plan to change it before december 2013. I know a lot of racer with the same bike never change the crankshaft after 3 hard racing season.

Hello, Yeah thats interesting the variables i am seeing on older models compared to new I just grabbed this one today all blown up for 2000 and it was at 60 hours interesting to see it will have to post pics of the job as working on the setup now.  Going to run delwest intakes on the head
This one used to be owned by a top ranked queensland based Junior racer raced at coolum sands Running the big no no oil ( Will post Pro X data release) on how all CRF250R must not run certain motul oils specifics are 7100V interesting as this is from the Netherlands head office I have requested this today so i can post it on my counters as Owners love motul but the 7100 v is major contributing factor when valves are not involved.  I see both sides I love major rebuilds got to the bike after a 2 hour drive and cases were not usable so going to be an easy one cylinder is baked so May go BIG BORE Yummy order dyno results and stick a new hour meter and lets see how long this engine can run as These racers i got this bike from are blowing all types of bikes up.  Running in a sand track and perhaps one would be happy at 60 hours on this engine.  But I truely expect more reliability from my race engines.  Pure HP vs reliability will put the neck out.  Will confirm you are right my Honda Tech says the bike is lean also so bolting on PC V will give us some tunability.  EFI tech bulletin Yamaha Engineers note yamaha still refuse to use efi on the 2012 YZ250f and i can see why its just sacfricing reliability these EFI models are requiring good mechanics to get real involved and update them Hopefully they catch this and STOP the 7100v use.

You may be interested to know the following
The Head dropped a valve on exhaust side ( What I refer to as a reverse slam which goes and feeds the big end a good amount of force this one smashed the crank to lower part of crankcases shaving the crank and smashing the casting between gearbox area and engine area i will post pics as they spell it right out buts still a bargain i am happy to say cylinder and cam are ok will check the laps tonight takes some pics as it was and this spec i provide will be of interest and is easy and readily available through parts unlimited dealers and or good dealership.  Delwest is a new item for me but noting they have a long relationship with pro circuit and thats good enough for me.  Cylinder options are open as my normal supplier has no stock except an athena stock cylinder kit and at the price we can put a new crank in it and Bigbore as the local distributor wants a fair bit for it.  Full Crank case rebuild both sides coming in way under budget so Hi Comp on stock cam or stage 1 hotcam .............Hmmmm note all other stages of the hotcams for people that may be running builders series please let us know your thoughts if running a setup close to and what hours are running on hour meters.

I have changed my workshop out to use castrol oils and getting 12 month test data in on some of my test bikes and all above expectations

KX250f 2010 Model 80.3 hours and first valve shim adjustment was required one one inlet valve only.  Castrol Racing oil the whole time at 5 hour intervals this is a great result and this bike is flogged hard.

Look forward to responses and appreciate everyone input I am into reliability as i want my kids to race but i am not throwing cranks in bikes like this everyday of the week.  There is a cause and effect rule as Honda engineers would not of planned for us customers to be rebuilding cranks and rods at these intervals and we know it happens but i have had many different hondas and thats why we like the hondas they are well engineered swap the oil if this is happening to you change the air filter and watch this space as these will start to go bang if they haven't already.  

I will be looking for stem to guide clearance movement and i have seen under the valve yet but my guess there is going to be movement there also .  Stop just shimming all the time as a tip do three shim adjustments then full tear down for the rods sake..

we ar riding a crf 250 2012 for a 6 weeks now afther 3 years sxf 250 . ktm use stock dell west valve ,s and they ar verry strong , normaly 100 hours no problem even here in the dutch sandtracks. for me myself i dond,t like ss valve,s with steel or castiron giude,s  and i think the next time i assemble the head i puth dell west in and exh valve,s in it . i am not using motul ,but i beleive the most overhere who use motul they use 300(0) . we use lucas and so far so good

Edited by speedboot, 12 December 2011 - 04:43 AM.

Yeah thanks for confirming the Delwest longetivity They will be going into this build Pulled the old valves and Honda have done a great job on valve seat surface still great there so awaiting new cases and bigbore pricing will be in tommorrow from LA Sleeve anyone wants good pricing at trade do to these guys you get your gear and its at trade