Jump to content

Ready to go back to stock EX Cam!!! Help please.

By jbrooks26,
in WR400F/426F/450F

 Share

Recommended Posts

  • Replies 96
  • Created
  • Last Reply

Top Posters In This Topic

  • 5

  • 14

  • 3

  • 43

Popular Days

Top Posters In This Topic

Popular Days

Mentor

jbrooks26

Posted
  • Author
Posted

I put about a tablespoon of oil down the spark plug hole in case it had been washed down enough with gasoline to lose compression around the rings. I have heard of this on several occasions, just wanted to make sure I wasn't missing something simple like that. I have not done a leak down test, I don't have that equipment and have not had a chance to make my own. I figured I could pull the head and find out the same thing, I am already half way there just by having the cams out. I figure that if I have a bent valve then i will be able to see evidence of it hitting the top of the piston.

Link to comment
Share on other sites
Mentor

jbrooks26

Posted
  • Author
Posted
I want to know if that Hot Cam bent your exhaust valves :applause:

Indy,

I don't believe it did, I really think that I had it out of time the first time I ran it by 1 or 2 teeth. I will let you know what I find out when I get a chance to pull the head.

Josh

Link to comment
Share on other sites
Contributor

rtrolli69

Posted
Posted

Hey Josh,hang in there bud.It sucks that things can get so complicated!?!?!This thing has gotten interesting to say the least.Slow dwn take a breath,I admire you for admitting your mistakes and working thru them.Indy and others can help thank goodness we have a place to take our troubles too.Ive been thinking of a internal mod of sort,my 05 450 runs strong,I should just probably train a little more and ride harder.Best of luck..Russ

Link to comment
Share on other sites
Mentor

jbrooks26

Posted
  • Author
Posted

Ok, here is a small update for you all. I built a little hose, similar to a leak down tester without the gages, to pressurize the cylinder and check for leaks. I was unable to keep the engine from turning over from TDC with the air pressure(using 20 psi) so I pullled the EX cam and held the chain out of the way of the intake cam to let the air push the piston all the way down without engaging the valves. turned the lobes of the intake cam straight up in the air and left the ex valve out. I still have the cam cover off, and the only place I hear any air coming out is from the crank case. Does this tell me anything? It is not a large ammount of air, and I would expect to hear some leaking through the ring gaps. Any thoughts on this latest development? Increased to 50 psi with similar results. I could press my ear against the end of the exhaust pipe and I was not sure if I was hearing air or if I was just hearing a transfer of the sound from the engine through the exhaust. The more I do here the more confused I get. Why can't anything work right the first time???? :applause:

Link to comment
Share on other sites
Mentor

jbrooks26

Posted
  • Author
Posted
I would think that if you bent a valve bad enough to lose squeeze you would be able to hear air out of the pipe or intake! Did you ever take the cams out and try to kick it over?Just be sure to hold the chain so it doesn't get bunched up!There has to be a answer for all of this!

OK, I just went back out and tried this again for certainty sake. I pulled the EX cam, held the chain up off of the intake cam and kicked it through the compression stroke. It does not fly through the stroke mind you, I have to kind of stand on it, I weigh about 190lbs. I should also note that I am standing on the bike, holding the chain out of the way of the intake cam, and kicking the bike through all by myself. I don't have any helpers right now. I don't remember being able to kick through the comp stroke before so I am certain that something is still amiss here. Thanks, Any other thoughts on my air pressure test?

josh

Link to comment
Share on other sites
Enthusiast

chiefsfan.58

Posted
Posted

jbrooks, you did the compressed air test with the ex. cam out and could hear air seemingly from the crankcase........ does anyone think that if he were to do the same test but this time add that teaspoon of oil into the spark plug hole and repeat to see if the sound decreases. If it does not decrease, then the compression loss is more likely from the top end and not the rings? I know this concept works when cranking an automotive engine but I'm unsure if it also has the same affect using compressed air. The concept being that the oil helps to seal the rings to the wall of the cylinder.

If I am way off, please someone tell me as I could use the info to expand my understanding.

best of luck to ya jbroo....

Link to comment
Share on other sites
Mentor

jbrooks26

Posted
  • Author
Posted
jbrooks, you did the compressed air test with the ex. cam out and could hear air seemingly from the crankcase........ does anyone think that if he were to do the same test but this time add that teaspoon of oil into the spark plug hole and repeat to see if the sound decreases. If it does not decrease, then the compression loss is more likely from the top end and not the rings? I know this concept works when cranking an automotive engine but I'm unsure if it also has the same affect using compressed air. The concept being that the oil helps to seal the rings to the wall of the cylinder.

If I am way off, please someone tell me as I could use the info to expand my understanding.

best of luck to ya jbroo....

I have already tried the oil trick. in fact it was just a few days ago and I may have put too much oil in there, Haha. When I first pulled the spark plug it was oil soaked. But that will be another problem that I can fix when I get the compression straightened out. Thanks for the suggestion though, keepum coming.

By the way, are you in Kansas? I ask because of your screen name.

Thanks again,

Josh

Link to comment
Share on other sites
Mentor

CRFThumper

Posted
Posted
OK, I just went back out and tried this again for certainty sake. I pulled the EX cam, held the chain up off of the intake cam and kicked it through the compression stroke. It does not fly through the stroke mind you, I have to kind of stand on it, I weigh about 190lbs. I should also note that I am standing on the bike, holding the chain out of the way of the intake cam, and kicking the bike through all by myself. I don't have any helpers right now. I don't remember being able to kick through the comp stroke before so I am certain that something is still amiss here. Thanks, Any other thoughts on my air pressure test?

josh

OK,but is it harder than with the cams in?That should be enough squeeze to start it.

Link to comment
Share on other sites
Mentor

jbrooks26

Posted
  • Author
Posted

OK guys,

Compression tester shows somewhere between 60 and 90 PSI when kicked through. This tester does not have a high reading indicator so I have to try to watch it while I am kicking to see what it reads. I don't believe it is going above 90psi. I expected it to be higher, does this sound right to you guys?

Josh

Link to comment
Share on other sites
Mentor

jbrooks26

Posted
  • Author
Posted

From Bad To WORSE!!!!!!

I decided to pull the head and it is going downhill fast. First off, I can't seem to get the head free from the timing chain guides. Do I need to remove the guides? And to make matters worse, something just fell off of the head into the engine and I don't know what it was or where it came from. Any Ideas???? I am ready to light a match here!!

Never Mind, I discovered what it was that fell. It was the return spring for the decomp shaft. I still don't know where it went for sure however at least I know what I am looking for. I also got the head off, I didn't realize that the one chain guide would just pull out. The good news is that I don't see any evidence of a bent valve. No disturbance on the carbon on either the piston or any of the valves. The bad news, I am even more confused now than before and my bike is in pieces. Anyone, anyone??

Josh

Link to comment
Share on other sites
Mentor

jbrooks26

Posted
  • Author
Posted

I had that same thought Indy, so I removed it. No change. I also just finished a fluid test using mineral spirits, and all of the valves hold up. Starting to doubt myself as to whether or not I could kick this thing over before without the decomp lever. I am learning a lot about how things go together though, I guess that is a plus. I am sitting here right now thinking to myself. "Self, did you let a fouled spark plug cause you all this trouble to start with? Are you really that stupid?" I guess I will have to answer that question next week sometime. It is time to get ready for our Christmas trip to the folks' house. Merry Christmas Everyone!!

Josh

Link to comment
Share on other sites
Mentor

jbrooks26

Posted
  • Author
Posted

Does anyone have any suggestions as to what to look at before I put this back together? I used Mineral spirits to check the valves, no leaks after 5 minutes. Cylinder walls look and feel smooth. Head Gasket is intact and looks good. Piston does not show any signs of wear that I can see. Is there anything else I should look at before I go on? Thanks,

Josh

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

ThumperTalk

Register a new account Sign In Now
 Share
Go to topic listing
×
×
  • Create New...
Terms of Use
Copyright
Privacy Policy