2004 CRF250R Won't Start D: -CRF's Only Forums

Loganm · by **Loganm** » Thu Apr 05, 2012 12:56 pm

Ok so I bought this 2004 CRF250 a while ago that was in need of a rebuild. So I went through everything and replaced everything that it needed, and finally got it together last night, but I can't get it to start or even fire at all.

I've tried everything from pouring gas down the cylinder, to towing the bike behind a truck in gear.

It has good compression, good spark, and fuel, but it won't run at all. I've gotten it to idle for a second off WD-40, but that only worked one time.

I am honestly completely out of ideas.

by **crfsonly** » Thu Apr 05, 2012 2:17 pm

welcome to CRF's Only! first, no more pulling it behind a truck in gear. if everything is functioning as designed one to two kicks and it will fire right up. check and recheck the timing. even being off one tooth can make it difficult or impossible to start. also recheck the valve clearance. report back.

ken

Loganm · by **Loganm** » Thu Apr 05, 2012 3:26 pm

Ok so I know the timing is right, I've checked it at least 10 times. I'll go make sure the clearances are right again.

If neither of those are the problem then it would have to be a fueling issue right?

dirtae · by **dirtae** » Thu Apr 05, 2012 3:56 pm

Loganm wrote:Ok so I bought this 2004 CRF250 a while ago that was in need of a rebuild. So I went through everything and replaced everything that it needed, and finally got it together last night, but I can't get it to start or even fire at all.

I've tried everything from pouring gas down the cylinder, to towing the bike behind a truck in gear.

It has good compression, good spark, and fuel, but it won't run at all. I've gotten it to idle for a second off WD-40, but that only worked one time.

I am honestly completely out of ideas.

Make sure it is also getting air.

What all did you replace? Did you adjust the carb at all while it was off the bike?

Check and double check timing and clearances like Ken said.

Loganm · by **Loganm** » Thu Apr 05, 2012 5:43 pm

dirtae wrote:
Loganm wrote:Ok so I bought this 2004 CRF250 a while ago that was in need of a rebuild. So I went through everything and replaced everything that it needed, and finally got it together last night, but I can't get it to start or even fire at all.

I've tried everything from pouring gas down the cylinder, to towing the bike behind a truck in gear.

It has good compression, good spark, and fuel, but it won't run at all. I've gotten it to idle for a second off WD-40, but that only worked one time.

I am honestly completely out of ideas.

Make sure it is also getting air.

What all did you replace? Did you adjust the carb at all while it was off the bike?

Check and double check timing and clearances like Ken said.

I replaced the piston, all valves, and a new sleeve in the engine. Then it has new chaing and sprockets and tires and grips too. It also already has a hot rods crank in it, I'm not sure if it's a stock one or a stroker one though.

Timing is alright and I checked the clearances again just to be sure.

I just finished going through the carb. Blew all the jets out with air. The pilot jet was clogged up, but I got it cleared up.

These are the jets that were in it:
Pilot: 40
That one that screws onto the big long one: 160
Then that other one that's not the pilot: 88

I don't know the stock jet sizes for the bike.

I took of the stator side engine cover (idek why, but anyways...) and the gaskets not reusable(it's broke in a few places), so I ordered one from another site. I won't be able to do any work on the bike 'till I get that though.

by **crfsonly** » Thu Apr 05, 2012 6:56 pm

jets are very difficult to clean just using solvants and air. replace them to eliminate them from the equation. sounds like this engine had a serious problem. if the engine blew and came to a sudden violent stop your cam gear may have moved causing timing to be off. are you check the flywheel as well when determining timing?

Loganm · by **Loganm** » Thu Apr 05, 2012 8:00 pm

Yeah I did check the flywheel, and idk it seemed to me like it was turned forward a bit. But then when I took the cover off I saw two marks on it instead of just one.

dirtae · by **dirtae** » Fri Apr 06, 2012 5:43 pm

Loganm wrote:Yeah I did check the flywheel, and idk it seemed to me like it was turned forward a bit. But then when I took the cover off I saw two marks on it instead of just one.

There are two marks on the flywheel, I believe one is for ignition timing and the other indicates TDC.

Notch on the right indicates TDC

Loganm · by **Loganm** » Fri Apr 06, 2012 6:55 pm

Ok, I understand the TDC, but what's with the ignition timing mark? I mean the flywheel's just spins and generates current right?

dirtae · by **dirtae** » Fri Apr 06, 2012 8:23 pm

I am not 100% sure but I believe ignition timing has to do with when the spark plug ignites, and the TDC notch is for valve timing (when the cam lobes open the valves).

Loganm · by **Loganm** » Fri Apr 06, 2012 9:41 pm

Yeah but what I was saying was that the position of the flywheel wouldn't matter as the it would generate current regardless and the timing's all in the computer.

dirtae · by **dirtae** » Sat Apr 07, 2012 6:05 am

Loganm wrote:Yeah but what I was saying was that the position of the flywheel wouldn't matter as the it would generate current regardless and the timing's all in the computer.

Ahh I know what your saying now lol I misread your post. You got me there. I have yet to see in the manual how the other notch is used. I could be wrong though, maybe it isn't for ignition timing? I just seem to remember the clymer saying that. And I don't have it with me at the moment so I can't check.

I have yet to use the other notch, I just make sure when checking clearances or timing I was the TDC mark on the flywheel. Now I'm curious about how the other notch is used too.

KuntryQuestTSi · by **KuntryQuestTSi** » Sat Apr 07, 2012 6:34 am

I'm not a 100% on the CRFs but on new start up's in the RMZ/KFX I have had the cam gear spin 3-4 teeth on the cam itself causing the bike not to run.

Loganm · by **Loganm** » Sat Apr 07, 2012 9:00 am

Ok so everything I've read says that when the cam's set at TDC that the cam lobes should be facing the rear of the bike. Which mine does, so I don't think that the gear spun. Idk if anyone can confirm this, but the lobes are sitting pretty parallel to the rest of the head when it's at TDC.

Loganm · by **Loganm** » Sat Apr 07, 2012 5:09 pm

Ok, redid the valve timing AGAIN today. Except this time what I did was I stuck a bolt down into the cylinder through the spark plug hole to find TDC, then confirmed it with the marks. It turns out I might have been 2 teeth off. Also made sure my clearances were alright AGAIN.

So now I'm just waiting on that gasket. I'm sure it should start now.

Re: 2004 CRF250R Won't Start D:

Re: 2004 CRF250R Won't Start D:

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