The Sportster and Buell Motorcycle Forum - The XLFORUM®

The Sportster and Buell Motorcycle Forum - The XLFORUM® (
-   Sportster Motorcycle Motor - Top End (
-   -   Repairing Cylinder Studs/Cases (

Blue Scoot 7th December 2019 01:06

Repairing Cylinder Studs/Cases
Hello again,

I'm looking to repair my cases where I have had 3 of the studs start to pull out on the right engine case.

I found a machine shop near by that can repair this. I'm am going to have them install a time sert in order to fix this issue. I'm going to have all 4 studs in the right engine case replaced/time sert'd since those seem to be the issues. Should I just end up replacing all 8 and have a time sert installed in all 8 spots?

I made a thread awhile ago when the issue first came up but figured I should start a new one to get these questions answered.

If a time sert isn't the best choice I am open to other options as well. Let me know what you think.

Sent from my BlackBerry

NGOT8R 7th December 2019 02:40

Maybe check with Fueling or APE and see if they offer larger studs that will allow the machine shop to precisely cut new threads into the casings. I would suggest doing all 8 to make sure there is no chance of the other 4 letting go. It's just too much work to get to the studs to gamble with the ones that aren't a problem right now.

Hippysmack 7th December 2019 17:55

The repair inserts are as debatable as much as what oil to use.
Done properly, inserts such as helicoils, timecerts or other are strong repairs.
As was said before, each insert has to be installed at the correct angle and properly 'set'.
The case threads have to be drilled out bigger than they are now in order to install the inserts.. non reversible.
If you have 3 that are pulling out, that means you have 5 that are not.
If you get all 8 inserted, that is more possible odds of one of them not being done right.
If you only get the three done that are pulling out, those are lower odds.
If you only get three done and one of the others pulls out, you can always get those done then.
Some say helicoils are stronger than the original threads.
But neither are required to hold more than final head torque.
High thread strength above final torque doesn't do anything productive since you'll never need to torque the heads past that.

While I'd agree with NGOT8R on a thread repair of anything other than these particular ones, going with bigger threads means a different stud has to be used.
It would need to be grade 8 material and the 'exact' length of the OEM bolts to use cap nuts up top.
The case threads would again need to be installed at 90 degrees each so as not to bend or stretch the studs when installing the heads.
I assume you've noticed that the holes in the cylinders are considerably bigger than the studs.
That will allow for expansion of the studs during installation and use. Another consideration.
Doable, but considerations apply.

Moral of the story,
It doesn't matter which insert you use as long as conditions allow you to use them and they are installed properly as in the insert manufs recommendations.
(space can be an issue as some insert ODs are bigger than others).

You can search the manufs website of the particular inserts you are considering.
It will list both internal and external sizes, strengths, instructions etc. on their inserts.
Then compare that to other types of inserts.
There are many options but it would take looking these things up for a definitive answer.

As was discussed in the other thread, these two holes are problematic since they are the closet together and angled toward each other on the bottom.
An insert with a big OD would require the two holes to butt up to each other thus lowering the pull strength in each. So I'd think insert OD would need to be considered.
Has the machine shop you picked seen and measured the cases yet?

Blue Scoot 7th December 2019 18:51

I looked for cylinder studs that had a larger diameter thread but could not find any. It doesn't mean they don't exist it's just I didn't see any listed.

Hey Hippy those are some of the reasons I was thinking of and has really gotten me thinking about just getting different cases and swapping everything over. I haven't been able to find a running engine locally.

However I did find some cases that look in good shape on ebay. About $300 and I would be able to swap everything over from my engine.

Think it would be better to swap cases or to get a machine shop to fix the current cases and hope they do it perfectly?

The machine shop has not seen the cases. I'm currently working on pulling the motor after work at night whenever I have some time.

Sent from my BlackBerry

Bored now 7th December 2019 19:32

I remember your original post. This problem is so unusual for a standard 883 that every time I think about it I become more sure there is some piece of information that is missing.

Hippysmack 7th December 2019 19:33

You probably won't find any larger studs as that is generally not done.
Honestly, thread inserts have been done to many engine cases.
I hate that I painted such a harsh picture of using them.
But I wanted to stress that they need to be done by competent people and machines.
Have you contacted Hammer Perf and asked their opinion?
I'd feel very confident on their advise.

We discussed before that you can buy a used bottom end and take your chances.
That is an option but not one I'm comfortable with since I haven't put my optical nerves on it nor measured for spec.

These are decisions you must make and hopefully armed with as much knowledge as we can give you.
Any good machinist worth his salt will be able to do a good insert install.
However, they don't come to us with a certificate of end result guarantee.
There are some awesome shops out there and then some put together on a 'good enough' basis.

Hippysmack 7th December 2019 19:34


Originally Posted by Bored now (Post 5793238)
I remember your original post. This problem is so unusual for a standard 883 that every time I think about it I become more sure there is some piece of information that is missing.

I agree.

Blue Scoot 7th December 2019 20:09

Yes this is a stock 883 engine. I'm not sure what piece of missing information there could be. I have owned the bike since new and am the only person to work on it besides warranty stuff at the dealership.

What about swapping cases? I know my crank is in good condition and since the right case seems to be the problem what about just swapping out the right side case. Shouldn't be too bad since the trans is in the left case. Would just need to swap everything over on the cam side.

Thoughts on this?

Sent from my BlackBerry

wedge 7th December 2019 20:14

I personally wouldn't even consider larger studs or replacing the case. Any insert done properly will do the job. I can tell you from my own personal testing that standard heli-coils are able to take three times the torque on a bolt than threads in aluminum. Back then I didn't have internet to bounce things off, so I just drilled holes in aluminum and tapped some, and drilled out others for heli-coils. Heli-coils consistently do not pull out until you go past three times the torque that will pull a standard bolt out of the tapped holes. With that in mind, and from there forward, when I strip out a bolt, I just do all the ones on the part while I am at it. I can not remember one single time that I have ever stripped out a heli-coil after going that way. One caution though, red locktite them in as you install them and pre-torque your fasteners then back off and then torque them down. If you do not pre-torque, they will need a snug up in a day or so. After that they are fine even when you get back in there for something else. No need to pre-torque after that first time in my experience.

Time serts are used all the time, with great success, so I wouldn't shy away from them either, but I have never used them as I can recall. The main thing with them would be clearance as Hippysmack showed in the picture above. Heli-coils don't require a lot of space. Also, if for some reason a heli-coil did fail, you still have enough material remaining to use a time sert.

Either way, the repair should be better than the original case.

Gospelman 7th December 2019 20:28

High quality work is fitted with thread insets in softer metals at the factory. When I worked as a fire truck mechanic, the "major pump" at the rear of the vehicle (mounted at the rear, driven from the engine, 1000 gals/minute max.output) had a casing made from bronze and each and every female thread in that component had a stainless steel insert. Rest of the pump was made from high grade aluminium or stainless steel. (FWIW, the stainless steel was beautiful free-machining material, I would keep any worn-out parts rather than discard them, and used them years later to make all manner of shiny components for my XL883C.)

All times are GMT +1. The time now is 15:44.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
XL Forum® - Linson Media LLC