Another Nightmare

[wolverine_05_]

It seems like I post in this forum once a week now. My 2005 crf250r just was rebuilt, (bottom end, piston, rings, etc. All but the valves and cam). It was progressively getting harder to start and I checked my valve clearance and they were all out of wack so I purchased a slightly used head with valves installed. It only had a few hours on it and I actually bought it from somebody in the classifieds of this sight and I installed it, shimmed it, put it in time, and now the stupid thing still won't start. Anything else I could try? I'm at a loss for words now and I'm on the verge of just selling it as it sits and losing a crap ton of money. This thing has been a nightmare.

[nesc103y]

It seems like I post in this forum once a week now. My 2005 crf250r just was rebuilt, (bottom end, piston, rings, etc. All but the valves and cam). It was progressively getting harder to start and I checked my valve clearance and they were all out of wack so I purchased a slightly used head with valves installed. It only had a few hours on it and I actually bought it from somebody in the classifieds of this sight and I installed it, shimmed it, put it in time, and now the stupid thing still won't start. Anything else I could try? I'm at a loss for words now and I'm on the verge of just selling it as it sits and losing a crap ton of money. This thing has been a nightmare.

 

Did it ever run with the new head? it should bump start at the very least

Don't ever buy used engines or engine parts. Unless you know who your buying from.

There's really no such thing as a low hr used head from a 05. Its 10 years old and was parted out for a reason.

There's too many dickheads out there who will pass off their junk to the next unsuspecting buyer. Maybe you got burned IDK without seeing what you bought.

guessing your trying to get the bike rideable on the cheap since you already have more money invested than you expected

If you know how to replace valves, get a set of stainless steel intake valves. look on ebay and you can find them for around $35 es. Lap them into the best of your 2 heads. if you know how to do that. This is not ideal but better than what you have now.

 

Also be sure you have all the other stuff working correctly like the carb, cam timing, spark, etc...

[The Inquisitor]

All engines want to run.

So it ran before you did the piston's etc??

These might be obvious but..

1) do you have gas in the tank, petcock on, loosen carb drain bolt slight to see if there's gas in the bowl.

2) pull the seat, air filter can you smell gas in the air box?

3) pull the tank, pull the plug wire and plug. with the plug it the boot, kick over by hand, do see a strong blue spark.

4) can you smell gas on the plug?

[Nelson Carvalho]

Carburetor... Check your jetting.. Else could be a faulty stator

[Flarff]

 I checked my valve clearance and they were all out of wack so I purchased a slightly used head with valves installed.

  

If your valves were out of wack, why didn't you just shim them instead of buying another used head? 

Edited October 27, 2014 by Flarff

[FishSticks]

Are you sure the timing is right?

[Irishcrfrider]

Double and triple check your timing.

 

I thought my timing was correct but it was ever so out, by literally half a tooth. 

 

It turns out that I didn't wind in my cam chain tensioner and when I placed it back in it had extended fully out, putting it out of wack.

 

After 2 weeks of not starting and resetting the tensioner, it started first kick.

[wolverine_05_]

If your valves were out of wack, why didn't you just shim them instead of buying another used head?

I had already shimmed them twice and I've only had the bike since the spring so it was time for some new ones. I believe it has something to do with the carb now. I took it to a guy that works on my bikes when I can't and that's what he said it was. He said the timing was spot on and it acted like it just wasn't getting either air or fuel so I'm gonna clean the air filter again and take the carb apart and clean it.

[FishSticks]

I had already shimmed them twice and I've only had the bike since the spring so it was time for some new ones. I believe it has something to do with the carb now. I took it to a guy that works on my bikes when I can't and that's what he said it was. He said the timing was spot on and it acted like it just wasn't getting either air or fuel so I'm gonna clean the air filter again and take the carb apart and clean it.

if it was running fine before why would it be the carb unless it sat with fuel in it for a long time I'll reiterate double and triple check your timing I have learned my lesson thinking the timing was right and tearing through the bike just to discover it was the timing I thought I had correct

[wolverine_05_]

if it was running fine before why would it be the carb unless it sat with fuel in it for a long time I'll reiterate double and triple check your timing I have learned my lesson thinking the timing was right and tearing through the bike just to discover it was the timing I thought I had correct

I have no idea why it could be the carb but I'll tear it apart and see. And I checked the timing and I thought it was on, then he checked it twice and he said it was on so unless we're both wrong, it's not the timing. He got it to run yesterday actually and said he could tell by the way it smelled or something. I'm not questioning it, I'm just gonna clean it up.

[The Inquisitor]

So it was your carb then??

 

I have a street bike with a steel tank that sat for 10 years. Inside of the tank was rusty as shit and I had to completely clean the carbs 3 times before I could get the bike to run.

 

We have plastic tanks so rust is not an issue but you could have bad gas (water) or as said above if the bike sat for awhile with gas in the carb, you can get corrosion. As well I run NON-ETHONAL 94 octane in my bike. If I think it's going to sit for more than a week, I will turn off the gas and run dry.

 

 

IMO - When you pull the carb and get into cleaning even if theres not much crap in there, drain out as much gas from the tank as you can, get the tank off, pull the petcock and clean or replace your fuel filter. Even if the filter looks clean, gently pressuer  wash the inside until clear water comes out, then drain and let dry completely.

 

Once the carb is apart you'll see pretty quick what's it's like.