I took apart my 1981 Lowrider to fix a leaking rocker box gasket and now it is back together and runs like crap!

PLEASE HELP ME!

Obviously, it is a shovel head motor. It has no modification (stock). I know that there are probably 100 things that it could be, but I will start with what I think is going to be the most obvious.

I did not replace the cylinder head gaskets (O-shaped). I re-used the old ones. Will this cause it to run like crap?

I am also thinking that it very likely could have something to do with the pushrods and valve timing. Now, I did not disassemble the valves and springs, I just left them in the head and them reassembled everything. I am thnking that maybe I somehow messed up when I reinstalled the pushrods. I followed the directions, but I don't think that the timing is correct.

I pulled the tanks, carb, exhaust, and then cylinder heads and rocker boxes attached together. I took off the rocker boxes, and took them apart (rocker arms) and cleaned them. I then scraped all of the carbon from the heads and valves. Then I cleaned all of the gasket surface between the rocker boxes and the heads, reassembled them with new gaskets and some sealant and then put everything else back together.

Can anyone help point me in the right direction? Or at least any direction. I am not sure what to do next.

 

go to the classic bike section and go to the Shovelheads, these guys can help you out. I ride an 83 lowrider, the last of the shovels, they are pretty easy to take care of ,you just have to work on them a little more than the new ones.

 

I agree with widowmaker, push rods not adj right. I think I would have replaced the head gaskets while apart. He is also right about bending a push rod. I know I did that once, but then you would know right a way if you had done that, again the voice of experince. Good luck,WR.

 

You don't say exactly how it runs like crap, and what it's doing is very relevant to the diagnosis.

Does it refuse to idle?

Does it idle but breakup when you give it the gas?

Check for air leaks or an incorrectly installed intake manifold.

 

ABSOLUTELY should have changed the head gaskets. There is a glue/sealant on the gasket that melts between the head and cylinder. When you took them apart the gasket was essentially ruined and should have been replaced. Believe it or not the wrong thickness of gasket between the carb and manifold has caused me a couple of problems in the past. Adjusting the pushrods is a snap if you have solid lifters and only slightly more tricky if you have hydraulic. PM me if you want and I will explain the procedure for adjusting the pushrods.

 

Push rods maybe......short and long.....did ya get em right..think its long inside short outside,or do you have adjustables.....

 

First off, I know I am an idiot for not replacing the head gaskets when I had it all apart. I am planning on pulling eveerything apart this winter and replacing all gaskets, so I thought I could get away with it. I know better though.

It will not idle properly. It evens out some when I give it gas, but it doesn not sound quite right when I give it gas. Also, it will back fire "sometimes" when I give it gas, when I try to ride it will miss sometimes. This is why I think it is the pushrod adjustment.

I have solid lifters. It seemed pretty straight forward in my manual to adjsut the pushrods. I turned the motor over until the intake and exhaust lifters were both at their lowest point (pushrods would fit in between lifters and rocker box). then adjsuted for no slack up and down (they would spin). Is there more to it than this?
Should I be checking the timing marks more closely?

 

Sounds like it is sucking air. Check the intake manifold for a good fit. Does it have o-rings or the bands? I know mine has the bands and it is a bitch to get them to seal sometimes. I usually put a little never seize on inside of the clamp so it will slide around the band and not pinch it. Good Luck.

 

First off, WELKUM to the Zoo, and WTG, keeping ANOTHER one alive.

Ok, NOW I'll weigh in, got some 'workable' data.
I have seen it happen, BUT NOT 'normal', those head gaskets can suck air, or leak compression, BIG TIME. Both "can be", CAN, not WILL BE, ugly bad. BUT REPLACE THEM!!!!

"Sounds" like you adjusted the valves correctly, BUT double check. Do the one valve at a time routine. When you see the exhaust valve lifter/pushrod begin to move, STOP, do the intake valve on that cylinder. It's a li'l puttsy, but you won't get things con-fussed. Likewise, when the intake begins to move, do the exhaust. When I run into one of these cases, that's 'zactly what I do, to VERIFY. (I'm trying to find a prob, leave NO STONE unturned.)

W/O being there, or knowing what you did and didn't do, verify your ign. timing. Up on that?? If not, jus' "aks". Jus' static time it for now.

Did you do anything to the carb? What do you have on it? S&S "B", "E", Keihn, Bendix, .....??? Verify you DO NOT have h2o, junk, or gunk, in the carb bowl, jets. I'm thinking you have done this already, in your 'travels', jus' covering the bases. AGAIN, verifying, not saying, "Ya, I did that"

Got all 3 of them???

IF you want to, and have the equip, you can run a comp. test at this time, just to VERIFY what you have.

Grab your can of carb cleaner.
Fire the ol' boy up, work the troddle, whatever you have to do to keep it idling. Spray the carb cleaner around the base of the carb and the intake boots. IF you get it to smooth out, or it speeds up, you got vacuum leak/s. Fix it/them. New boots are CHEAP, get 'em.

Give these a shot, post your results back, we can go from there. IF you get these, you should be running. If you aren't running, then we don't have these, yet.

BTW, by your 'handle', either:
you live in Mn,
you are a Scandahoovian,
or you are a transplant FROM Mn.
Which one??

 

I have the bands on my carb . It is an S&S shorty. I am not sure what letter it is because it does not say on the cover.

I am not sure how to check the timing. There is something about it in my manual. i think that I can figure it out, but I wanted to be sure I needed to do this to properly adjut the rods.

I did take the carb manifold off of the carb to reassemble it. I did not pull apart the carb assembly though. The bike ran fine before I pulled it apart, just leaked a lot of oil. UGH.

I think that I have the equipment to run a compression test, i just am not sure how to. This should tell me if I need to pull everything apart and replace the cylinder gaskets, right?

I will try the leak test.

Viking man refers to two things. My love for the Minnesota Vikings ( I am from Rochester, but the one in NY). Also refers to my appearance. I am 6'4", 290 lbs. and have blonde hair and bushy blonde beard (usually, I am looking for a job right now, so I trimmed to a goatee).

Thank you for trying to help me i really appreciate it!