Hi.

i'm rebuilding my shovelhead from 1979. Yesterday when I was going to install the cam and breather gear I encountered a problem. everything lines up correctly and the motor rotates properly.

but when I put the cover on it starts to jamming when you rotate it.

anyone have any idea what may be the problem ?

I have a suspicion that it has to do with the breather. The breather was damaged so i replaced it with a new original steel one.

without bretaher there is no problem with the cover on, with the old breather it turns ,not perfect but ok. With the new one it jams.

because I have a shovelhead from 1979 I bought the latter version of the steel breather but the strange thing was that it was a breather of the earlier version there from the beginning this may be of any importance ?.

Would be very grateful for help.

Please excuse my spelling I'm from Sweden

Kind regards
Johan

 

put a indicator on the pinion shaft & check run out

 

Thanks for the reply !

I forgot to mention that I am a complete beginner

so honestly I have no idea how to use an indicator, I do not have access to such either.

what do you suspect is the problem ? can you explain it in very simple terms.

Kind regards
Johan

 

if the flywheels are out of true,you will get a "hot spot" where the pinion shaft (from not running true)binding in the cam cover bushing & the cam getting pushed up & binding in the cam cover bushing.really doubt its got anything to do with the new breather

 

ok i understand what you mean.

the strange thing is that it basically works flawlessly with the old breather .
if the flywheels are out of true it would malfunction with the old breather as well, right?

 

if your not getting the hot spot with the old breather,then the problem may be with the breather (never seen the problem before) check the teeth for any machining mistakes or burrs

 

Hi !

thanks for the reply !

maybe it's because my English is not so good but I do not understand what you mean by "Hot spot".Did you mean the new breather ? the old one works.

I have noticed that the teeth is a little shallower of the old one then the new one.I do not know if it is because it is worn or that there is a difference.
Could that be the problem ?

 

when you switched the breather gear did you get a shim kit with it --- or did you just install it with the original shim that was on the old breather gear

my guess you used the old shim --

if that is correct take it ( the thick shim ) to a harley shop and get one that is .010 thousands of an inch SMALLER ( thinner ) -- what is happening the new gear is a bit longer - or the new gasket is thinner than the old one and its binding up --johnjzjz

 

 

Hi !

First, I just want to thank everyone for all the help,it is much appreciated.

the engine begins to get heavy to pull around already when the cover has a gap of 5mm left. in that position the shim is 5mm from the cover.

so the engine starts to turn heavy even before the cover is completely in so it should not be the breather shim that is the problem.

I have also tried without a shim with the same results.

this is so weird, the old breather gear works but not the new one.

I have cleaned them, I have inspected them carefully, and I've measured them and the only minimal differences that I can find is:

The old one has a little more open gap in between teeth,However, very small barely visible with the naked eye probably due to wear.

The small lug in the front of the breather are different, it is wider on the new one but the height of the lug looks to be the same.

I have not a clue how to solve this,any help is appreciated !