2004 CRF250R VALVE REPLACEMENT


16 replies to this topic
  • hondamoto

Posted October 28, 2004 - 06:14 AM

#1

Use the sticky post on the valve clearance check and adjustment to complete the valve change task. I must say, the pictures and narratives made the job quite simple...even for me. :cry:

My 250R was very difficult to start, and once started, it smoked a bit until it warmed. I estimate that it has 50 hours on it. I ride MX, as a Vet Pro in Colorado. That equates to a Vet Beginner in CA. :cry: I knew that I needed to check the valves after reading about the problems on TT :cry:. I contacted every aftermarket house about valves, primarily stainless. PC had some replacement Ti valves, but I wasn't going to replace them for that price. One of the aftermarket shops recommended that I replace the the bad ones with new stock valves and springs until the stainless products were available. I took the advice and the job was not very difficult.

Both intakes were ZERO clearance! Although, less than paper thin, the .002 and the .001 feelers wouldn't even slide between the bucket and cam at TDC. Visually, everything else in the head looked very nice.

I was able to purchase valves, springs, piston rings and gaskets from the local dealer who had them in stock. Sure, a rarity, but it worked out for me. The entire job took about 3 and a half hours and was really quite simple. A little frustration was felt in getting the valve stem "keepers" off and then back on. I used a deep well socket to get them off by simply depressing the spring and they popped off themselves.

I was a little concerned about the carbon buildup on the valves and in the head. I run 50/50 pump and race gas. It seem to run a little fat, but the plug is always light tan. Maybe the leaded race gas throws that indicator off? Anyway, the valves pull right out. I lightly lubed the new ones and installed them. The deepwell socket trick works on the installation fo the keepers, but it isn't a fast process. It is purely luck if they catch. Did I mention that I replaced the springs too. They cost about $4.00 per spring and $60.00 per valve.

While in there, I replaced the rings too, but I didn't break the glaze. We'll see how that turns out. However, changing the rings was very tedious. Take your time because the oil rings will fight you. The installation of them was about a half hour because I didn't pay attention to the manual about ring end position. The cylinder has skirts and the gaps need to be placed in those areas.

Everything went back together quite easy. Essentially, do everything reverse order and use a torque wrench. Once together, it started on the third kick and no oil smoke was apparent. It is likely that the rings were shot and the new ones fixed the oil burning phenomena. I did notice a snappier throttle respoonse from the low end.

In talking with the aftermrket shops, it seems the RMZ and KXF have the same issues, possibly worse. All the shops seem to think this is fairly typical of Ti valves, especially in this application (hi rev and aggressive cam). Not that I obsolve Honda of any responsibility, but the repair wasn't very tough or expensive regardless of being only temporary. I intend to contact Honda to ask for support with this dilemma. However bad the valve issue may be, it is still less maintenance than a 2-SMOKE! RIDE ON brothers! :cry: <font color="#666666">

  • motomadman

Posted October 28, 2004 - 07:18 AM

#2

Check your valves soon and keep us posted on the clearance.

I waited 7 hours after valve job and they had gone to zero already.

Sounds BAD and it really was (for me). I do not over-rev, the air-filter is very clean and oil changed often.

I'm waiting for Stainless valves now...

  • greenbunch

Posted October 28, 2004 - 09:07 AM

#3

Great post, and glad to hear the CRF is alive again. I plan on doing the same to my CRF during the winter and I have a question about the valve install. Did you have to do anything to the head before installing the new valves ? Did you touch the seats ? I bought mine in Nov. 2003 and have about 75 hours on it without any valve or oil burning problems, so this falls under winter maintenance. I think I may opt for a 2005 head and cam also to up the mid range power over the 2004 parts. Let us know how she holds up.

  • jasonb0816

Posted October 28, 2004 - 09:12 AM

#4

Check your valves soon and keep us posted on the clearance.

I waited 7 hours after valve job and they had gone to zero already.

Sounds BAD and it really was (for me). I do not over-rev, the air-filter is very clean and oil changed often.

I'm waiting for Stainless valves now...


If you put new valves and springs in how could they be shot after only 7 hours?????????

  • hondamoto

Posted October 28, 2004 - 09:17 AM

#5

All I did with the seats is use an extremely light grit paper to get the jusnk off rather than lapping. The aftrmarket shops advised me to change to bronze, but I will do that when the SS valves become available. The new vavle job is likely a temporary fix.

The bike ran good even with ZERO clearance, but it was a bear to start when cold. I am certain there is more power loss, but it is so hard to notice. I have the Thunder Alley pipe and it really gives the mid a boost. In fact, many guys think I am riding a 450 because it doesn't give it the 'high-rev" sound.

  • hondamoto

Posted October 28, 2004 - 09:21 AM

#6

Only 7 hours...bummer. I ride mine in the uper end of the RPM range...alll the time. I am crossing my fingers for more longevity than you were able to get from new valves. Do you use synthetic oil in the engine side? Did you clean up your seats? I understand that any bit of heat makes these valves even more suseptable to the loss of clearance. It osunds like the Ti becomes easier to bend, even if it is ever so slight.

  • motomadman

Posted October 28, 2004 - 09:53 AM

#7

Yeah, Bummer. I didn't replace the springs and that may be part of the problem ... although my engine guy would argue that. I'll replace springs next time for sure.

I had a complete valve job, the valve/seat was sealing good.

I used non-synthetic oil for break-in plus a little longer to be safe, then went to Synthetic.

I do think DUST has a lot to do with it. I am using Twin-Air's which is more course than stock and, I believe, let more dirt through. I now use filter-skins for an extra layer of protection.

  • hondamoto

Posted October 28, 2004 - 10:04 AM

#8

The aftermarket shop advised me to change the springs. They seem to be a weakness, much like the rest of the valvetrain. I guess they significantly weaken in a short time. Hence, the $4.00 price. In contrast, after market valve springs are over $100 per set. The valve bounce or floating may be the source of the excessive heat that weakens the Ti and makes the valve deterioration happen quicker. Just my laymans version, but it sounds like many are jumping on that wagon.

I have heard about the dirt thing too. Not only from a failing air cleaner, but the carb vents. I am sure everything has it's toll on the engine. It sure is an intricate piece of machinery. To keep it real, I think the engine does quite well for revving and performing as it does. It is unfortunate that valve issues are part of it(for now), but I have never had this much fun doing anything else.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • rato

Posted October 29, 2004 - 01:40 AM

#9

Do you ride in dusty, or all type of conditions? It's curious for me because I would like to add up all the situations of the "valve issue". Since you have an 'R, the jetting should be o.k. I have an 'X, so I changed to richer jetting. The heat and dust theory seems the most logical. I have a friend who had the valve problem here in Portugal. He rode in dusty terrain and had lean jetting. Fortunatly, here in Portugal, Honda gives you a 3 month guarentee (except if raced). That gave him a new head, the valves are new of course, and he richened the jetting. O.K. so far. I have about 15 hours with only one day out in the dust. Used mineral oil for break-in, valves were in spec, changed oil, still with mineral, and now with about 600km, going to change to synthetic. Thinking of buying a Boyesen Water Pump Kit to keep temp down.

  • honda88

Posted October 29, 2004 - 03:03 AM

#10

Did my first shim replacement after a year of riding.When diong it a dropped a dowl pin in the engine,so i had to take off head to get it.I was lucky it turned up being by the side case rotor side.But since i had the head off i checked every thing.After getting off all carbon valves look like new not even a scratch and head has no sign of resession.Used grinding wheel with a wire attachment. :cry:.I had planned on doing this in the winter.I still have a couple of weeks of riding left so i will put it back together and see if cleaning everything make a big difference.Then in the winter everything gets repleced. Also does anyone know what the free length of the intake and exhaust springs are at new and service limit,Thanks.

  • mxboyz

Posted January 22, 2010 - 11:29 PM

#11

okay, so how much are new valves? how do you know when you need mew ones
how much are the valvue springs? how do you know when you need new ones,
And when the valve clearance is at zero, dont you need to do some edging or something to the case?? i really nedd to know this, thanks

  • moto_x2005

Posted January 23, 2010 - 09:12 AM

#12

just some things to note: cut the seats every time new valves are installed, the seat angle/shape changes with wear.. hone the cylinder and remove the glaze off the cylinder wall- allows the cross hatching to catch oil and rings seal to there best abilities..

mxboyz- check out the TT parts store (red button in upper right corner) to get prices on everything you need, a total oem top end rebuild with a piston can be done for around $450..

If you valves are going out after 7 hrs and you maintain the bike correctly check these two things- make sure air filter is installed correctly and lip is fully seated, and reseal your airbox (the mate between the airbox and airboot) the older crfs especially had a defective seal and caused the majority of valve problems

  • catjohnson

Posted January 23, 2010 - 11:54 AM

#13

I have done half a dozen top end rebuilts on 2006 & 2007 CRF250R's. I would recommend trying Kibble & White Staiinless Steel intake and exaust valves. In my experience with Honda valves are that the valve springs are poor at best. With the KW valves you need to use there beefedup springs. Each valve spring has a spring within a spring, so 2 springs per valve. I have had great sucess with these valves. I tear down the top end every 20 hours and replace the piston and rings. I have one bike that has over 60 hours of racing on a set of K&W valves and springs and have not had to shim any of the valves after the intial install. Valves are still tight with no leaks and running very well.

  • moto_x2005

Posted January 23, 2010 - 12:11 PM

#14

I have done half a dozen top end rebuilts on 2006 & 2007 CRF250R's. I would recommend trying Kibble & White Staiinless Steel intake and exaust valves. In my experience with Honda valves are that the valve springs are poor at best. With the KW valves you need to use there beefedup springs. Each valve spring has a spring within a spring, so 2 springs per valve. I have had great sucess with these valves. I tear down the top end every 20 hours and replace the piston and rings. I have one bike that has over 60 hours of racing on a set of K&W valves and springs and have not had to shim any of the valves after the intial install. Valves are still tight with no leaks and running very well.


ive had different experiences with KW.. apart from the bad customer service i received the valves didnt last as long as I thought they would.. with racing I got the same life out of them as my oem valves.. my original top end died around 120 race hours, and for the price of it i couldnt justify another round of SS valves..

  • catjohnson

Posted January 24, 2010 - 06:49 AM

#15

The cost of the KW SS valves is a little less than the Honda OEM valves. The prce difference is the spring package for the valves. The heavy duty race springs from KW cost about $ 200.00. This includes springs,spring seat, spring retainer and valve seals. Overall cost it is about $ 100 more to move to the KW topend rebuild. I have had no issues with KW customer service, as they have been very helpful.

If you are only getting the same amount of hours "racing" with the KW topend rebuild something is not right.

  • moto_x2005

Posted January 24, 2010 - 09:47 AM

#16

When I pulled the top end apart I found that the seats were totally flattened, my 02 crf450r did the same with SS valves and my buddies 07 crf250r did the same, all bikes are raced in intermediate.. Imo, why run SS when you can get good life out of Ti (what the bikes were designed to run?)

  • SumtinCoo

Posted January 24, 2010 - 04:59 PM

#17

5 year old thread?





Related Content

Forums
Photo

Crf250r transmition and clutch oil problems by TeamRed


Dirt Bike   Make / Model Specific   Honda   CRF250R
  • 1 reply
Wiki
Motocross Cylinder Head Quiz by Fastheads.com - last post by Fastheads (BK)

Motocross Cylinder Head Quiz by Fastheads.com


Wiki Articles
  • 0 replies
Reviews

Honda CRF250R 2015 by Bryan Bosch


Honda CRF250R 2015
  • * * * * *
  • 3 reviews
  • Last review by Flarff
  • On October 04, 2014
Forums
Photo

2010 / 11 Big end and leaky fuel injection problem by bikeboy32


Dirt Bike   Make / Model Specific   Honda   CRF250R
  • 1 reply
Forums
Photo

Bike review of my 2015 CRF250R by Justwant2ride


Dirt Bike   Make / Model Specific   Honda   CRF250R
  • * * * * *
  • Hot  55 replies
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.