removing the oil filter cover issue

Steven LaPlume · Nov 17, 2020

This might be a really stupid question, but here it goes. The 12mm bolt that holds the oil filer cover on a 1983 XS400 maxim. Is it regular or reverse thread?

I can't seem to get it to break free and did not want to bust it off.

Thank in advance.

Spitfire_X24 · Nov 17, 2020

It's regular. If it's tight, it was likely over torqued.
Make sure you have a good fresh socket, and there will be naysayers on here, I'm sure of it, but if you have an impact wrench, make sure you have it switched to reverse, and give it a gentle shot with the power turned down at first and increase it incrementally until it comes loose or you feel like you are damagingthe head of the cover bolt.
When things are seized, impact even at a low setting will help break things loose better than a slow constant steady pressure offered by a bigger breaker bar or snipe as some call it. Care must be taken not to overdo it though.

Steven LaPlume · Nov 17, 2020

Spitfire_X24 said:
It's regular. If it's tight, it was likely over torqued.
Make sure you have a good fresh socket, and there will be naysayers on here, I'm sure of it, but if you have an impact wrench, make sure you have it switched to reverse, and give it a gentle shot with the power turned down at first and increase it incrementally until it comes loose or you feel like you are damagingthe head of the cover bolt.
When things are seized, impact even at a low setting will help break things loose better than a slow constant steady pressure offered by a bigger breaker bar or snipe as some call it. Care must be taken not to overdo it though.

Spitfire_X24 Thanks for the insight. Ok I will give it a shot as you suggested. I do have an electronic impact so I can regulate it. Ill try with a socket and muscle first and though.

amc49 · Nov 17, 2020

Japanese motorcycle bolts are so soft you are asking for stripping the bolt corners off there. Even more on a 12 mm. head if that is what it is, the bolt is too small to have any substantial corners to withstand impacting.

That type use commonly sets in deeper to appear overtorqued, like Honda filter bolts that double the seeming torque amount as they run to commonly strip them out.

Spitfire_X24 · Nov 17, 2020

amc49 said:
Japanese motorcycle bolts are so soft you are asking for stripping the bolt corners off there. Even more on a 12 mm. head if that is what it is, the bolt is too small to have any substantial corners to withstand impacting.

That type use commonly sets in deeper to appear overtorqued, like Honda filter bolts that double the seeming torque amount as they run to commonly strip them out.

Yeah, that’s why I suggested a fresh socket and starting with a low setting. The impact will have a better effect on shock loading the seized part and breaking it loose. As a welder for years in an equipment repair facility, I drilled out and removed seized and broken bolts all the time. A gentle shock load with an impact wrench works better than applying steady torque on the seized piece.

amc49 · Nov 17, 2020

I agree with that last sentence but the usually best bolt on most Japanese bikes is commonly less than our grade 5 in hardness and why they strip so easy. They do not harden the part throughout like we do, commonly any hardening there is outer case hardened only and it may only be a few thousandths deep. Why many Japanese bikes cannot grind the valves themselves, it's replace only, you can even cut through the hardening by lapping them in.

Spitfire_X24 · Nov 17, 2020

Soft bolts do suck. Luckily most of the equipment I worked on was Caterpillar and was grade 8 or better. Also most of the bolts were big enough that you had the ability to drill a Center hole and then heat it to allow it to shrink. Then weld a nut to the broken off bolt from the inside of the nut and hit it with the impact.

Steven LaPlume · Nov 18, 2020

A bit of muscle and a grunt and she broke free thanks.
I noticed the oil filter has a flatter side and a concave side. When I removed it the concave side was up toward the inner engine with the flatter side down toward the cover plate. Is this correct orientation? I don't trust the previous mechanics abilities given the issues I am finding else ware.

amc49 · Nov 18, 2020

The recess goes toward the outside and the spring and washer fit in it. Pushing filter to the back.

BBS360 · Nov 18, 2020

Be real careful torquing the cover on. Maxim/Seca covers like to break in half.

removing the oil filter cover issue

Steven LaPlume

XS400 Member

Spitfire_X24

XS400 Addict

Steven LaPlume

XS400 Member

amc49

XS400 Junkie

Spitfire_X24

XS400 Addict

amc49

XS400 Junkie

Spitfire_X24

XS400 Addict

Steven LaPlume

XS400 Member

amc49

XS400 Junkie

BBS360

XS400 Guru

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