1977 FXE Shovelhead Rattle Near Front Cylinder

[boneseauc]

So I did some digging around in the forum, and found some threads describing older Harleys that have a weird rattle, but none that were rattling under the same conditions as what I am seeing.

Bike:
1977 FXE
Allegedly bumped up to 80ci, haven't confirmed

Here is what is happening:
There is a rattling sound coming from somewhere around the front cylinder, REALLY hard to tell exactly where though.

When it happens:
-When it's cold and I start it, it rattles for around 6 seconds, often less.
-When I am decelerating, with the clutch lever all the way in. If I engine brake, no rattle. It definitely only happens when I am slowing down and there is no load on the engine. Also, it happens pretty much every time I slow down with the clutch in; it's not a here-and-there sort of thing.

I never hear it any other time, only in those situations. Even I have the clutch lever all the way in and coast downhill, no rattle. Only if I am slowing down.

Any ideas what might be contributing to this? Any ideas if I'm making things worse by still riding it?

I'd prefer not to tear into the engine before the season is over, but I don't want to compound the problem (granted that it's actually a problem, and not just something normal to hear from a shovel).

[Tattooo]

I say it's the Crank pin or wrist pin but one causes the other................ What do you think Jesse????????

Oh yea It's not gonna get better by riding it.... Just worse..........

[boneseauc]

Fuck, that is not what I was hoping to hear. Was hoping it was just loose rocker arms or something relatively easy to fix. I think I'm still going to get a stethoscope to hone in on the source, and try to get a video of the noise.

[Tattooo]

Fuck, that is not what I was hoping to hear. Was hoping it was just loose rocker arms or something relatively easy to fix. I think I'm still going to get a stethoscope to hone in on the source, and try to get a video of the noise.

Wait until Jesse chimes in but why I don't think it's a rocker is that it changes under a load.........

[Dragstews]

That's a good one .....



If it was rod bearings you would hear it the loudest when the throttle was feathered as in no load either way....
Piston slap would be louder as the motor got up to running temp...
Rocker arms... Seen as much as .020" end play and no noise ....

Wrist pin bushing ..... well, could be ....???

[Cory]

On my 93" Shovelhead it has some piston slap on the front jug. it goes away once its warm up a little. It scared the shit out of me hearing it. but it runs strong and the bore isn't that bad. I've learned to live with it. I'm not saying this is your problem but it does sound like it. See if you can get a bore camera and pull the plug and take a look around in there.
Mine is a big bore deal that is more prone to piston noise.

[Tattooo]

That's a good one .....
If it was rod bearings you would hear it the loudest when the throttle was feathered as in no load either way....
Piston slap would be louder as the motor got up to running temp...
Rocker arms... Seen as much as .020" end play and no noise ....

Wrist pin bushing ..... well, could be ....???

Great, I'm glad you chimed in..... I hope your right and I am wrong... It could be piston slap....

By his post I thought it was something that just started.... And the motor had many miles on it???? But I guess I could have made an ass out of U and me again humm Jesse??? I guess more info is needed..

[Dragstews]

Shoot .... For no more work that it takes to pull the top-end for a good look-see ...
Dang if I wouldn't be getting the tools out ....

[Tattooo]

Shoot .... For no more work that it takes to pull the top-end for a good look-see ...
Dang if I wouldn't be getting the tools out ....

Yep..... Depending on the style of bike whether you have to take the tank off or not... You can be to the rods in two or three hours depending on your motor skills max???

LOL Hell after taking my heads off for the 5th time looking for oil leaks on my Pan within 3 weeks... I could have the heads, carb, tanks and all off in 45min..... That's what taking shit apart to many times in a row will do..........

[DustyDave]

Yep..... Depending on the style of bike whether you have to take the tank off or not... You can be to the rods in two or three hours depending on your motor skills max???

LOL Hell after taking my heads off for the 5th time looking for oil leaks on my Pan within 3 weeks... I could have the heads, carb, tanks and all off in 45min..... That's what taking shit apart to many times in a row will do..........

Back in the sixties I set some flatrate times for GM they had me remove and replace the part three times with a large audience. Then the actual timed run with every tool laying on the bench, every part & bolt clean, every move fresh in my mind. Repetition certainly speeds you up and sets some very unrealistic time standards.
Dusty

[Dragstews]

So ......

That was you at the Cincinnati GM Training Center .... ???
I always wondered who set the labor rates for a job ...

[Tattooo]

Back in the sixties I set some flatrate times for GM they had me remove and replace the part three times with a large audience. Then the actual timed run with every tool laying on the bench, every part & bolt clean, every move fresh in my mind. Repetition certainly speeds you up and sets some very unrealistic time standards.
Dusty

Yea I worked for a GM dealer back in the early 80s.... Back then I knew that was how they came up with labor rates.... It's very unfair but that was the way it is....... That's why I opened my own shop... LOL

[DustyDave]

So ......

That was you at the Cincinnati GM Training Center .... ???
I always wondered who set the labor rates for a job ...

Naw Chick Coker Pontic & Rolls Royce in Oklahoma City, the GM darling of Oklahoma dealers in the sixties. Rumor had it that we were really corporate owned, from the the amount of corporate suits n engineers I don't doubt it. I didn't stay long nobody should have to deal with a Rolls customer.
Dusty

[boneseauc]

Update on this thread. I tore apart the top end, rebuilt it from the heads up. Didn't fix the problem.

Took it to a local mechanic that knows/works on older harleys. He found cracked valve guides and other things that I completely missed. Rebuilt the whole top end for me (in other words, redid the work that I did at my request). He also checked the piston and rods, since I mentioned that people were talking about bottom end issues. He said everything looked good down there, nothing loose. He also confirmed that this was upped to 80ci (S&S isn't far from here, he apparently knows some people down there and hopped on the phone, managed to identify it as one of their kits).

Conclusion is that this is a good mechanic, knows his stuff, and he didn't see any red flags.

Now it doesn't make the rattling as much, definitely not on startup like it used to, but I'm still hearing it a bit when decelerating with the clutch lever pulled halfway / all the way. It seems to only happen when the bike is moving too.

I put it in gear in the driveway with the clutch pulled in, got the rpms up and then backed off the throttle, but couldn't replicate the noise. Further evidence that this only happens when the bike is physically slowing down.

Am I just overthinking things? Is this just normal shovelhead top end noise? I feel like I'm taking crazy pills, but I'm planning on taking this on a 1400 mile trip in about two weeks, so it's eating away at me.

FWIW, it's definitely getting oil, as I had to fix a small leak from the rocker arm shaft.

It also stutters a bit in the mid to high rpms when holding speed (accelerates just fine, cruises at low rpms just fine), but I'm going to chalk that up to carbs that are in need of a good cleaning.

[boneseauc]

It knows I posted to this thread again. Took the long way to work this morning, and it barely made that top end noise at all. That, and the stuttering issue was minimal compared to when I rode it home from work yesterday.