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Discussion Starter #1
Here is the setup:

2002 Dyna FXDX
95 jugs
SE HTCC HEADS (NON PORTED NON CNC)
SE 257 CAM
MIKUNI 45 CARB
NON ADJ PUSHRODS

we put her together, no apparent problems. Went to start her and nothing in the front jug. Both cylinders are getting spark, gas is squirting out of the carb. Turned the wheel, no air coming out of spark plug hole.

Took cam cover off, verified that cam chain is timed properly, pulled chain and verified that cams are properly lined up.

Theories:
1. assembly lube preventing gas getting into cylinder, but we cleared it out with ether pretty good and cranked it with spark plugs out.

2. piston rings are all with same line up. Doubtful, but it looks like we need to pull the head to know for sure.

3. We bent a valve. Also, would have to pull the head. When we turned the wheel before firing her up, no noises, no stoppage.


I welcome any takes on this subject. If there is something we could do without pulling the motor apart again I am all in favor.

thanks
 

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You've got a fairly agressive cam there with fixed length pushrods....did you get the "perfect fit" ones?...and if you did, are you sure they got you the correct length? If not, you'r valves may not be closing due to longer rods. I think the intake and exhaust rods are also different length and can't be mixed up...I remember having to make sure they were tagged and seperated and put back exactly as I removed them when I did my work.

Those are my early guesses.
 

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verify the valves are closing all the way. Crap, didn't see Seahag's response...what he said.

Thorns
 

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IronButt
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valve hung open. from mis adjusted pushrod, if you rolled bike over too soon you can bend the valve and bust the guide. Quick way to see if valve is hung open roll motor over to tdc and use compressed air into plug hole air coming out exhaust that is the valve and so on.
 

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You said "non-adjustable" pushrods. Are they custom cut to work with that cam? I'd defintely be using adjustables. If they are the stock ones, then you most likely bent a valve. Could have damaged the piston, too.
 

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IronButt
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valve hung open. from mis adjusted pushrod, if you rolled bike over too soon you can bend the valve and bust the guide. Quick way to see if valve is hung open roll motor over to tdc and use compressed air into plug hole air coming out exhaust that is the valve and so on.
 

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HDWRENCH said:
valve hung open. from mis adjusted pushrod, if you rolled bike over too soon you can bend the valve and bust the guide. Quick way to see if valve is hung open roll motor over to tdc and use compressed air into plug hole air coming out exhaust that is the valve and so on.

HdWrench- he says in his first post, he has NON ADJ PUSHRODS.
 

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IronButt
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HEY I did not re post it did , SORRY!!! and I did mis the NON part. SOOOOOO if you rolled it over before lifter bleed down that would do it. Is the top end completely back together?? Second did you use the custom fit pushrods?? if not there is your problem. not much to go wrong with cam and using the "fit" rods other than lifters not bleed down and then rolling engine over. I had a customer do that not too long ago bent valve and cracked guide OUCH!!! bleed down time can be from 10-30 minutes, where you able to spin pushrod before you rolled engine over?? Was the cam on base circle when you tightened down support plate?? If not that would do it, if the piston was at TDC and you tightened it down the valves can hit the piston or each other if you did it fast enough .

SORRY for re post my fault I guess I will drink a beer and feel better about it
 

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Ronnie j said:
I might spend a couple bucks on a compression gauge before I went too much farther.
Yeah, if you have no air coming out the the plug hole, then you have some work to do.... bent/stuck valve, rings, hole in piston. Could be any of them. Do a compression check first. Note the reading, then squirt some oil in the plug hole and do it again. If it comes up (doubtful), then it's the rings, or at least the rings are contributing to it. A well-worn engine will have at least 90 psi, so yours should be a lot higher. When I put mine back together last winter, I was at about 190 psi, but that's with almost 10:1 compression ratio and an EV27 cam. The cam will make a difference in the static compression.

Here's a stupid question... was the head gasket installed and in good condition? Yeah, I know.... but I had to ask. :hmmm: The first rule of troubleshooting is to eliminate the simple and obvious stuff first. I've overlooked some supposedly obvious things in the past. No one is perfect. :)
 

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dotrpaul said:
Here is the setup:

2002 Dyna FXDX
95 jugs
SE HTCC HEADS (NON PORTED NON CNC)
SE 257 CAM
MIKUNI 45 CARB
NON ADJ PUSHRODS

we put her together, no apparent problems. Went to start her and nothing in the front jug. Both cylinders are getting spark, gas is squirting out of the carb. Turned the wheel, no air coming out of spark plug hole.

Took cam cover off, verified that cam chain is timed properly, pulled chain and verified that cams are properly lined up.

Theories:
1. assembly lube preventing gas getting into cylinder, but we cleared it out with ether pretty good and cranked it with spark plugs out.

2. piston rings are all with same line up. Doubtful, but it looks like we need to pull the head to know for sure.

3. We bent a valve. Also, would have to pull the head. When we turned the wheel before firing her up, no noises, no stoppage.


I welcome any takes on this subject. If there is something we could do without pulling the motor apart again I am all in favor.

thanks
Alright, you've had a week and several responses here giving you an idea where to look....Have you found anything yet?
 

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Discussion Starter #13
95 no pressure

Sorry for not getting back guys, I have been away from my computer.

That night, we determined that if we pull the rocker box we get compression back. We called a mechanic friend of ours, who said that the stock pushrods should be okay with this mix, and that we needed to make sure to have the tappets bleed all the way down before we reinstall the pushrods.

BTW, the pushrodswere installed correctly, exhaust to exhaust, intake to intake.

We did as he indicated, and put her back together. We put it to TDC and ran compressed air into the spark plug hole, nothing out of the exhaust, very slight out of intake.

She fired right up and seems to have been doing fine. We have had other complications as we were putting a 21 tooth primary gear up front and in the process the lip on the bearing plate for the trans was sheared, so we lost a few days getting all of that back together.

I took her around the block 2 nights ago and she runs strong, sounds great. I would like to thank everyone for all of the input.

I know that the stock pushrods are still a question for some, but my phone source said it should be no problem...not hearing any clatter and when we turned her over manually we heard nothing. So far so good.

Thanks again everyone, I will keep you posted.
 

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dotrpaul said:
Sorry for not getting back guys, I have been away from my computer.

That night, we determined that if we pull the rocker box we get compression back. We called a mechanic friend of ours, who said that the stock pushrods should be okay with this mix, and that we needed to make sure to have the tappets bleed all the way down before we reinstall the pushrods.

BTW, the pushrodswere installed correctly, exhaust to exhaust, intake to intake.

We did as he indicated, and put her back together. We put it to TDC and ran compressed air into the spark plug hole, nothing out of the exhaust, very slight out of intake.

She fired right up and seems to have been doing fine. We have had other complications as we were putting a 21 tooth primary gear up front and in the process the lip on the bearing plate for the trans was sheared, so we lost a few days getting all of that back together.

I took her around the block 2 nights ago and she runs strong, sounds great. I would like to thank everyone for all of the input.

I know that the stock pushrods are still a question for some, but my phone source said it should be no problem...not hearing any clatter and when we turned her over manually we heard nothing. So far so good.

Thanks again everyone, I will keep you posted.
Good to hear that you got her running. It just seems a little odd that the stock pushrods will work with your mods. I guess they would be ok if the stroke, gasket thicknesses, cylinder height, cam lift, etc. were exactly the same as stock. Otherwise you would surely need different length pushrods.

I'm concerned that you are getting air out of the intake port. It means that either the valve seat isn't right, or the valve isn't closing all the way. You shouldn't be getting any air out of there. I would perform a proper bleed-down check by the book.

Also, you said that you removed the rockers to check the valves with the compressed air.... did you remove the entire rocker box assembly (arms included) or just the top covers? You shouldn't have to remove them to check for leaks. If the engine is at TDC and the valves are in the closed position, then you shouldn't have any air leaks, even with the rockers installed. If you have to remove them to get compression, then something isn't quite right. It would be in your best interest to investigate further. Get a real compression gauge and check it as per the manual.

I believe the proper way to check is with the engine slightly warm and the throttle wide open, cranking until the pressure displayed on the gauge stops increasing. It'll still work with the engine cold, though. I've done it both ways and the difference is negligible. You should be getting at least 150 psi with your setup and both cylinders should be very close to each other. If they aren't , then you still have a problem that needs to be fixed, or you may end up damaging something. At the very least, you will not be getting all the power out of the engine that you should be getting. I definitely would not be running it above a couple thousand rpm until you are absolutely positive that everything is correct.

I have a motto that I stick by.... "Do it right, or don't do it at all". :)

Good luck and let us know what you find out. :yes:
 

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OldFart
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"Removed rocker box cover and now there is compression" You didn't put roller rockers in there by any chance did you? If so, you have to clay the valve ends of them and clearance the webbing in the upper cover. Seen many of these happen. When you bolt down the upper rocker cover, the cover webbing opens a valve....
 

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not only that did you check valve spring to lower box clearance valve spring hitting the lower will not let valve to seat fully and will prematurly wear out the guide and valve
 

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HDWRENCH said:
HEY I did not re post it did , SORRY!!! and I did mis the NON part. SOOOOOO if you rolled it over before lifter bleed down that would do it. Is the top end completely back together?? Second did you use the custom fit pushrods?? if not there is your problem. not much to go wrong with cam and using the "fit" rods other than lifters not bleed down and then rolling engine over. I had a customer do that not too long ago bent valve and cracked guide OUCH!!! bleed down time can be from 10-30 minutes, where you able to spin pushrod before you rolled engine over?? Was the cam on base circle when you tightened down support plate?? If not that would do it, if the piston was at TDC and you tightened it down the valves can hit the piston or each other if you did it fast enough .

SORRY for re post my fault I guess I will drink a beer and feel better about it
How do you make sure the lifters are bled down to avoid bending the valves? I know you need to be on base circle to tighten the rockers and wait 5 or so minutes. Then do you turn the engine to open the valves and let it sit some more?
 

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Otto said:
not only that, did you check valve spring to lower box clearance? valve spring hitting the lower will not let valve to seat fully and will prematurly wear out the guide and valve
Hey! Otto!
Glad to see you made it here! :clap:

Another super experienced "wrench" joining in is a welcome sight!! Now, get back to work! :laugh:

By the way, I saw you checked mine for the clearance of the spring to the lower box a week and a half ago when you installed the Ultima 1.68 rockers.
 
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