[bigRed85]

Hey guys,
Just bought a new to me 04' 250r. bike will not kick start. runs great once bump started, lots of power. Previous owner said he had the bike in the shop last year for shimming valves and was told that valves will need replacing the next time around.

Am I ok to put a few hours on the bike before doing the intake valves?

Do I need to do anything to the exauhst valves or can I just replace the intakes?

Thanks!

[JimDirt]

Welcome to the site !!

You will need to actually check the valve lash to determine what the damage is ... the short of it is , once the valves start moving/need to be adjusted , it is only a matter of time when they zero out , once the gap is too small for the smallest shim , then you have no adjustment left and no option but to replace the valves ... generally the Intakes are what goes , but it is best to do them all (2 Intake , 2 Exhaust) with a bike that old , especially if they have never been done , then you are good .... the best bet is to go (if you do not race seriously and just play ride) is to go with Stainless Intakes , they will last 2-3 times longer or even more than the Titanium that come with it stock , the Titanium are lighter , so when going Stainless you need heavier matched springs for them ( I have a 06 450X , I installed Stainless Intakes in it in 2006 and have not had to adjust the valves since)

I am hoping you have a Owners Manual for the bike ?? , it will show you how to correctly check the valve lash .... if not I have the Factory Service Manual , and I can post pictures from it to guide you thru the process of checking the valve lash .... then you can figure out what you can do , ....but my gut feeling is , if the bike won't run , then its time to replace the valves ..... you need a reputable shop to do it , someone that does these bikes regularly , do not let a automotive machine shop do it , if they do not do it regularly , they do not have the correct tooling to do the job right , and you will end up with a expensive paperweight , because they will ruin your head ... you can have it done here , or go to or call your local Honda Dealer and find out where they have their machine work done ....

[bigRed85]

Jim, thanks for the details reply! Much appreciated.

I'll definetley go with stainless valves and springs and probably replace the exhaust valves as well. stock Honda parts should be ok since those are already stainless? Also, anything I need to do while im in there? any way to tell if I need a piston?

I do have the owners manual. do you have a digital copy of the service manual, if so, could I buy a copy? ill have all the machine work done by a shop but will do the rest myself. thanks again!

[JimDirt]

The stock Honda valves are Titanium , not Stainless .....

On the Service Manual , I can post images from it for you if the Owners Manual does not have the info you need , but I can't sell copies of it ... it is not allowed on this site , and I am OK with that .. ... and yes mine is digital/PDF 04-09

As for the piston sometimes (if you know the valves are good) you can tell from the compression , or lack of compression , because of the decompressor system you only will get about 65 or so lbs of compression on a gauge , so if the rings are weak it will be much less , you can also test (this is the best way) with a Leakdown Tester , it will tell you where any compression is going , like past the rings , or the head gasket , or past the valves , I have a Snap On one , but the ones from Harbor Freight work just as good ...

But if you are kicking the bike over and it feels like its just spinning over without any real backpressure , then most likely the rings are toast , usually if the rings are toast , then the piston skirt is also worn .... which means the piston is toast ...

[bigRed85]

Thanks again for the quick reply.
from my reading I understood that the intakes are titanium however the exauhst valves are stainless I thought?

the owners manual talks about adjusting the valves so im good there.

Im new to powersports but have lots of experience with heavy equipment. on these bikes, can you just throw in a new piston or are you supposed to hone or bore out the cylinder? and the bike is real easy to kick over so Im assuming the intakes aren't sealing 100% anymore

[JimDirt]

The Exhaust are just Steel , not Stainless Steel ..

Basically , if the bike has lots of hours on it , the cylinder should be inspected/measured for roundness , etc .... if all checks out , then yea , just put in the piston/rings and break it in and you're good to go ... and of course do the valves .... and these valves can't be lapped , like with automotive valves , the seats are cut (hopefully by someone that does them regularly on bikes) and valves installed , then shimmed ...

[Aussiecrf230]

Clean the bore with a green scotchbrite and WD40 following the crosshatch.
This will clean the carbon out of the honing marks.
Do not hone these coated cylinders as special equipment is required not like normal automotive types bores.

[bigRed85]

Will do, thanks!

Looking at this kit here, seems to include all I need. Are valve guides usually good to be reused?

https://www.ebay.ca/itm/Honda-CRF-250R- ... SwWlFbtXfe