Pics of fouled plugs????

[BadBrad]

Didn't I say that Dog might just lick it's wounds and fix itself?

Ok,Ok, we all know that bikes don't just "fix themselves" and mines no exception.

I got back to work on my dog today. I sprayed WD-40 around the intake and no change in idle.

Using what I had at the house, I took the thermostat off the cooker and while reving the bike at about 1500 rpm's I checked the exhaust temp. The front cylinder read about 300 degrees while the rear cylinder read about 170 degrees.

Next, I went and picked up a compression check meter. The front (good) cylinder registered 105 psi. The rear (bad) cylinder registered 88 psi. :bang: I turned the motor 10 cycles to get these readings. Keep in mind that I recently had work done on the front cylinder and had new rings placed on the piston. Not sure it would make that big a difference. What is normal for compression on a 117?

OK pound, what do you think? I'm thinking pull the head....again......and have new valves and springs put in. The cylinder wall looked good and had no obvious issues (smooth and no scratches or marks). What else might cause lower compression?

 

[stlmikie]

Give your compression releases a good looking at.

 

[DRBarnhart]

OK pound, what do you think? I'm thinking pull the head....again......and have new valves and springs put in. The cylinder wall looked good and had no obvious issues (smooth and no scratches or marks). What else might cause lower compression?

From an earlier post in this thread to answer the question about compression...

This could be anything that "vents" your cylinder to the outside air (or crankcase) like:

1. the compression relief valve stuck open
2. a valve sticking open (or severely burned)
3. rings that are totally blown out
4. a hole/crack in the piston
5. a cracked head
6. a crack in the cylinder wall

At this point I'm leaning toward a bent exhaust valve stem (could happen if a bolt got stuck somewhere...) but definitely check the compression release before diving back into the engine...

And have you tried this?

With the spark plug out, blow air into the hole (a compressor would be good) and see if you can hear it in the carb or the [exhaust] pipes or anywhere else for that matter!

As was mentioned you should have the engine at TDC on the compression stroke when you do this.

Dennis

 

[mobsta]

how about leaking head gasket?

 

[BadBrad]

Originally Posted by DRBarnhart
This could be anything that "vents" your cylinder to the outside air (or crankcase) like:

1. the compression relief valve stuck open
2. a valve sticking open (or severely burned)
3. rings that are totally blown out
4. a hole/crack in the piston
5. a cracked head
6. a crack in the cylinder wall

I think I found another reason why I may have low compression. After total frustration had set in, I decided to go back into the motor and see what I missed the first time. After removing the rocker box and pulling the push rods, I noticed that my longest pushrod was in the intake! I know that it goes to the exhaust but I obivously swapped them up when putting the motor back together again. Now, I'm half way into this damn heathen again. Can any of you guys confirm that swapping the pushrods would indeed cause lower compression in that cylinder? I'm going to get some lunch and have a beer and hope that when I get back, Dennis, Dead, V, Marv, Ray, Tim, Lee or some of you other "mechanics" can confirm my questions. No need to get it put back together at this point. I'm ready to get back in the saddle. But not before I get this resolved. I was heading towards pulling the head, changing valves, springs, rings and lifters. I guess even after doing all that, if I swap the pushrods, I won't be any better off. I guess my real question is, can you swap the pushrods and still adjust them to the proper lengths?

 

[mobsta]

swap the push rods back where they belong,readjust and see what happens.thats just me.i like to keep it simple.

 

[woodbutcher]

brad, it seems like you are enjoying taking that motor apart too much. have you thought about seeking psychiatric help? maybe changing professions?

good luck with the compression. :2thumbs:

 

[Raywood]

Brad, I wouldn't think that having the pushrods in the wrong position would cause any harm. The difference in length is minute and the adjustment would take up the difference if you ask me.

 

[BadBrad]

Brad, I wouldn't think that having the pushrods in the wrong position would cause any harm. The difference in length is minute and the adjustment would take up the difference if you ask me.

Ray, That's what I was thinking. After thinking about how stupid it was to get them in the wrong positions, I got to thinking that unless the ID was different, then the adjustments should compensate for ignorace. The push rods appear to be straight.
The compression relief valve is snug and activate when I first turn the motor over.
The cylinder looks nice and smooth (wouldn't bad rings show up on the cylinder walls?)
From the top, the piston appears to be ok.
No indication that the head or cylinder wall is cracked.

Since I have it back down again, I'm going to have the head polished and new valves put in. I haven't pulled the lifters yet. Would you guys go ahead and change those out too? The only thing left seems to be the rings. Hell, may as well do that. Hate to get all this done and still have a compression problem.

 

[DRBarnhart]

Can any of you guys confirm that swapping the pushrods would indeed cause lower compression in that cylinder?

I guess my real question is, can you swap the pushrods and still adjust them to the proper lengths?

Having the pushrods in the wrong place is definitely not doing you any good. Yeah, I know, "Thank you Capt. Obvious!".

But if you consider the adjusting threads on a pushrod (I believe) are 5/16 X 32. This means that three FULL turns only gives you .093". Looking at this photo from the S&S manual...

There's substantial difference in overall length so if you take into account the tolerances we're talking about it looks to me like having them in the wrong place could very easily explain your lack of compression! If it were me I'd put it back together with the rods in the right place, adjust them, and before I put the rocker covers back on I'd rotate the engine (slowly!) while watching the valves to make sure everything is working properly and neither valve is sticking. I compression check at this point wouldn't be a bad idea either...

There's my :zz2cents:!

Dennis

 

[DRBarnhart]

...I got to thinking that unless the ID was different, then the adjustments should compensate for ignorace.

Doesn't seem like if that were the case there wouldn't be a difference in length in the first place?

Since I have it back down again, I'm going to have the head polished and new valves put in. I haven't pulled the lifters yet. Would you guys go ahead and change those out too? The only thing left seems to be the rings. Hell, may as well do that. Hate to get all this done and still have a compression problem.

I'm sure it'll work just fine if you do all that but then I'd hate not knowing what actually fixed it!!! That, plus I hate wasting money...

Dennis

 

[V]

I know that the pushrods are different lengths due to the distance from each lifter to its perspective rocker arm. How ever I have a set of Crane Timesaver Pushrods and they are all the same length. Only difference is that once adjusted they each have a little more thread showing. If the valves were properly adjusted I don't see where the difference would be other than more thread showing and the rod maybe being weaker due to greater % of thread showing vs the actutal rod strength its self (saying that the hollow tube/ rod is stronger than the threaded adjuster). If the rocker to be adjusted is at it lowest point on the cam you still adjust it to zero lash then the number of turns you want for your adjustment 3, 4, etc. Or somthin like that

 

[mobsta]

hey brad hows does the head gasket look?i dont know what your compression should be but my 04 107in. is supposed to be 120.i had some issues with head gaskets ,just a thought

 

[BadBrad]

hey brad hows does the head gasket look?i dont know what your compression should be but my 04 107in. is supposed to be 120.i had some issues with head gaskets ,just a thought

Mobsta, head gasket looked good. It was new and had some high temp, Permatex gasket sealer for added security. I rode yesterday to the point of where only one side was hitting at idle and took compression. 105 on the front and 80 on the back. Not sure what compression is on the 117 in good working order but I know the difference in my two is not good. It's like that cylinder isn't pulling fuel into that side unless I rev up the motor. You can feel the difference in temp of the two.

Ray, I owe you an appology. I bragged about having 12 point sockets but they are 3/8 drive the lifters have to be with a 1/4 drive. So, I'm just as "tool-less" as you. Oh well, Just another trip to Sears. None of the car parts place have the 1/4 drive - 1/4 diameter in a 12 point. :angry: I'm really curious about the lifters. One of you mentioned that if the lifters failed, then I could be losing compression due to that. Thanks for everyone's input. I'll let you know if I find anything that looks "funny". :roll::roll::roll:

 

[Vegas]

The difference in pushrod lenghts is all about reliability. As mentioned, having to few threads in the pushrod tube could eventually bite you. You need to change them back.

A compression check should be done with a warm motor and the compressioin releases disconnected. Who is to say one of the releases doesn't bleed off more pressure? I wouldn't use anything on a head gasket unless the S&S manual calls for it.

Since we know your valve hung open due to the bolt. It's a possibility that your lifter or camshaft took up the slack. I wouldn't be surprised if you have a collapsed lifter of wiped cam lobe.

 

[BadBrad]

The difference in pushrod lenghts is all about reliability. As mentioned, having to few threads in the pushrod tube could eventually bite you. You need to change them back.

A compression check should be done with a warm motor and the compressioin releases disconnected. Who is to say one of the releases doesn't bleed off more pressure? I wouldn't use anything on a head gasket unless the S&S manual calls for it.

Since we know your valve hung open due to the bolt. It's a possibility that your lifter or camshaft took up the slack. I wouldn't be surprised if you have a collapsed lifter of wiped cam lobe.

If the lifter is "collapsed" will it be obviously shorter than the lifter on the intake side? Or is this something internal to the lifter?

What is involved in pulling the cam for an inspection? Taking shit appart is easy! :lol: Putting pushrods back in the right position, now that's priceless. Actually, I may be able to put a price on that. So far, I'm just out about $50 for the gasket set. But I would so love to be riding today. I'll get the 1/4 drive 1/4" 12 point and get the lifters out tomorrow. With a little guidance, I'll pull the cam and check it for tolerance. Thanks all!

 

[Vegas]

You can look at your camshaft after removing the lifters for signs of wear. If in doubt you can measure the lift of all four lobes with a deal indicator with the lifters in place.

 

[BadBrad]

You can look at your camshaft after removing the lifters for signs of wear. If in doubt you can measure the lift of all four lobes with a deal indicator with the lifters in place.

Thanks Vegas! I have access to a dial indicator at work. I'm done for the night. I stopped after finding out I needed the small drive quarter inch 12 point socket. I appreciate your help and everyone's help today. I hope to give some good news soon.

How hard is it to change out the cam? There's a good deal on an S&S 600. Is it something that has to be done by a certified mechanic? Any special tools needed?

Thanks,
Brad

 

[BadBrad]

Update!

Well guys, for all of you that have been following along, I believe I've figured out the reason for the low compression. First off, I would have never done this without the pound. And even when I figured it out, I didn't know it until I got some more feedback from the Pound. The first time I removed the head, I turned it upside down and filled it with acetone to clean it. Most of the acetone seeped past the exhaust valve and out the exhaust port. It didn't occur to me that the head should be holding fluid, but "thedeadone" PM'd me and asked me to do this very same thing, not knowing I had already done it. Anyway, the head is with someone that is going to pull the valves and re-seat them. Hopefully, they won't have to cut the seats, but as long as it gets fixed, I'm cool with it. Since I have it apart....again..I ordered a 600 cam off ebay and will be installing it before putting everything back together again. Thanks everyone for your help. Hopefully, by this weekend I'll be able to do a "start up" like Raywood give a final status on this dog running.

 

[woodbutcher]

make sure you have the right springs for the 600 cam!!!!!!! too weak is not a good thing.