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Crf250r 2004 won't start

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Yesterday I took my bike out to go riding. Went to start it and it wanted to start but it stalled shortly after and it did that two more times than it didn't want to start at all. I took the spark plug out and it seemed fine and it still didn't start. So I took the valve cover off and inspected the top of the engine, everything seemed fine and I grabbed the rocker and was able to feel some play but didn't check the intake valves. The compression on the kick start feels a little soft. Is it possible for an intake valve to be held open a hair and not getting enough compression to run the bike? Hope someone can help me thanks.

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Yes it is possible for the valves to be held open.

you need to check your valve clearances are in spec.

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I checked the intake clearances and the left one is at .003 and the right one is at .0025.  I read that the intakes are supposed to be at 

.006-.004. Is that true? I haven't checked the exhaust clearances but I am going to do that too. I am going to set the valves back to the right clearances and hope it works. I plan to finish the season with the oem titanium valves and over the winter I am going to put a set of stainless steel valves in it. Any suggestions on witch brand to go with? I also plan to buy ones that I can adjust once in the spring and last the whole season without having to adjust them until the next spring.

 

 

thanks

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You can definitely find the service manual for your bike in a pdf from google, that's what I did. All the factory specs will be there to eliminate any uncertainty.

As for the valves you plan to change...I'm fairly certain that no matter what brand you choose, you will most likely have to shim your valves at least once during the season (depending on how much you ride). You could probably push it to a full season without shimming, but your bike won't run at it's best and you'll wear down the valves that much quicker. (I learned this the hard way) ....Again it'll say when to check and shim your valves in the service manual. Remember too that you're doing stainless valves (a metal weaker than titanium) so following the maintenance schedule will be to your benefit.

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I have the 04 owners manual but not the service manual. In the owners manual it says for the intake valves that its .005-.001 but I read on thumpertalk that its .006-.004.

What specs do you have? What site did you get your service manual from? When I got the bike I rebuilt the bottom and the top of the motor on this bike and put a weisco piston in it, I didn't have any money at the time to redo the valves but I realized they had to be done. I do oil changes on my bike every 19 hours and change the oil filter every second oil change. I take care of my bike a lot. But I didn't realize that the valves had to be adjust so often. I thought the titanium valves wear quicker than the stainless steel valves?

 

thanks

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The specs are +/- 0.001. So your intakes need shimming if u want it to start better. Valves dont get held open until the clearance is zero. so if your loosing compression it could be ring seal or through the valves if the seats or valves are damaged.

The older bikes have big issues with valves. Got better in 06, and even better with the currwnt generation bikes.

Edited by nzgsr

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I am currently shimming my intake valves back to .005. If I had to guess the valves aren't seating properly not the rings on the piston because they're brand new.

I read that from 07 on they had oem stainless steel valves. I only read that after I bought my bike and if I knew that before I bought my bike I would have got something 07 and up. This bike has been a pain in the butt for me this year I rebuilt the motor a second time this year because it started jumping out of gear and I thought it might have been something in the transmission and it ended up being the front sprocket came loose and was jumping on and off the shaft, so I rebuilt the motor for nothing. There is also a huge dent in the front left fork, the subframe is cracked and the top triple clamp and bar clamps were screwed up. I also had to change nearly every bearing in the bike (everything was seized). I got the bearings, the clamps and the motor pretty much squared away and now this stupid valve problem. This bike has gotten on my nerves! I have put at least a grand into my bike just to make it run properly.

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All years have the titanium coated intakes and stainless steel exhaust valves. Welcome to the joys of owning an old thumper.

Edited by nzgsr

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Shimmed my intake valves back to .006 and the bike started the third kick. (thank god) The bike starts on the first kick when hot know.

Does anyone suggest a certain brand of stainless steel valves, seats and guids? I heard that kibblewhite has some pretty good reviews.

 

thanks

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I am currently shimming my intake valves back to .005. If I had to guess the valves aren't seating properly not the rings on the piston because they're brand new.

I read that from 07 on they had oem stainless steel valves. I only read that after I bought my bike and if I knew that before I bought my bike I would have got something 07 and up. This bike has been a pain in the butt for me this year I rebuilt the motor a second time this year because it started jumping out of gear and I thought it might have been something in the transmission and it ended up being the front sprocket came loose and was jumping on and off the shaft, so I rebuilt the motor for nothing. There is also a huge dent in the front left fork, the subframe is cracked and the top triple clamp and bar clamps were screwed up. I also had to change nearly every bearing in the bike (everything was seized). I got the bearings, the clamps and the motor pretty much squared away and now this stupid valve problem. This bike has gotten on my nerves! I have put at least a grand into my bike just to make it run properly.

the bearings failing is not the fault of the bike but your poor maintenance,you live in the same climate as me and every year my bike gets ripped apart and bearings get either replaced or cleaned and re greased.

 

before tearing into a motor you should always make sure you know what is up, start with the easy and work inwards.

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I had those problems when I got the bike. The person before me didn't even have a garage, he was working in his  bikes in his basement. ( that's why it was poorly maintained) I have a 2 full size car garage to work on my bikes.

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I change the oil every 19 hours because I run synthetic Pro Ams Oil in it and a buddy of mine races with that stuff for years now and hasn't blown up one engine with it and he competes pretty well. He won the FMSQ one year. So I trust him. I change the oil filter every second oil change to save some money, because the oil cost about 30$. I clean and oil my air filter every couple of rides and I am actually due for a new air filter because mine is starting to fall apart on the edges. What kind of oil do you use on your air filter? The oil I use needs gas to get it out of the filter, its a bit of a pain in the ass.  

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If I were you I would still change the oil filter with every oil change because even a quality filter is relatively cheap. To me this is especially more important for you since you are going so long on each oil change. These are just my opinions though.

As far as my air filter, I am a fan of the No Toil oil and filter cleaner. I like it because you can basically saturate the filter in the oil leaving everything nice and sticky but then when you take it off later and wash it in the cleaner it comes right off. And it's non-toxic so I feel more comfortable when I decide to pour it down the drain considering I have an aerobic septic.

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I use FFT (Foam Filter Treatment) on my air filter. It does a good job but it is a pain in the ass to remove and clean. I tried the No Toil and it doesn't do as good as a job I find. Do you clean your air box when you do your filter? I do it every time I clean my filter. I put a Hi flo oil filter in my bike, I guess I could replace my filter every oil change. What kind of bike do you have? Do you know any good companies to send the head of my bike out to get the seats changed and the guides?

 

thanks

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I generally wipe down the airbox every filter clean but I don't go crazy.

The main bike that I ride the most is the '06 version of your bike. So far I haven't found any other bike that I feel more comfortable on. My favorite bike in that department.

I either do my own work or I send it to a reputable shop that's semi local to me. I think Fastheads has a good reputation although I can't speak from experience. Depending on how much you're going to ride this bike you might give some thought to getting used to rebuilding these valves yourself because our year models chew through these intakes valves. This is by far my most expensive maintenance cost for this bike.

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I went  my local garage to get some prices and ask some questions. He told me about CVTech. They have some of the best prices and do good quality work. I love this bike but the amount of maintenance is crazy. Very expensive sport! I have the tools to change the valves and springs but not to grind out the seats and change the guides. I am thinking about selling the bike because this is going to cost a leg and a arm. I am looking at a Ktm sxf 250. What do you think?

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Doesn't matter how good the oil is, 19hours is way too long and asking for trouble. Even top quality synthetic is starting to break down and looks like sh1t after 10 hours.

All the 4 stroke motocross bikes requires lots of maintaining. The older ones even more so. Ktm parts are particularly expensive. If u want cheap to run then get a 2 stroke.

Edited by nzgsr

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The problem is I like the torque and power of a 4 stroke and I race and compete and I am hard on my bikes. So I want a racing bike to be able to handle and force and not half to be rebuilding motors every weekend. I read that Ktm is good for that. Does anyone have a Ktm to tell me about? I would appreciate the knowledge before I by another piece of shit.

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Don't go jumping ship just yet. Get the head rebuilt using stainless valves, kibble white has a solid reputation. With seats cut to match you shouldn't have to adjust your valves again. Stay on top of oil and air filter, and you shouldn't have any more major issues until your put tons of hours on the bike.

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