Main things to look out for?

[MaxD]

As a relatively new GS500 buyer and recent first time poster, I really appreciated all the help figuring out the valve adjustment situation on the GS500.  Keeping the exhaust valves shimmed in to the high end of the range to minimize valve recession was a great thing to know. 

What I'm wondering now is what other issues like that are out there, the critical other maintenance tips needed to get maximum life out of the GS500.  Any other advice from the old pros here who have done the work of figuring out the key issues would be greatly appreciated.   If I can get that I'm going to write it up in my maintenance log and keep a special eye on those points.  I'd also like to add it to the GS500 Wikipedia article, which could use some improving.  I've just done a little editing in the Introduction to try to do the bike justice (providing a pointer to this forum), and would like to add a section on design and maintenance. 

[sledge]

I will give you a tip 

If you can still get the header bolts out do it NOW. Replace them with high tensile studs and stainless or chrome plated nuts and washers

With age those cap heads have a habit of seizing and rounding off. It's perhaps the biggest design fault the GS5 has. Why Suzuki chose this method beats me, probably to save 1\2 a yen.

In 15 or so years time when they need to come off you will thank me 

[MaxD]

Thanks Sledge, they're coming out!  Do you have a particular source/brand of replacement you prefer?

[MaxD]

After having a look on-line and also searching the forum, it is not immediately clear what are the best materials and sources for replacement header bolts or studs.  The Clymer manual does not even give the size of these bolts.  One thing that struck me from the comments here is just how bad the header bolt corrosion problem is--some guys are describing these bolts as falling apart.  That makes me suspicious it is more than just rust and may also be an issue of galvanic corrosion due to dissimilar metals--aluminum and whatever the bolts are plated with.  This would be especially bad if the bolts are splashed with salty water that penetrates into the threads.

Checking galvanic potentials I note these differences:
1. Aluminum and nickel plated steel: ~0.65V (bad for galvanic corrosion)
2. Aluminum and tin plated steel: ~0.3V (pretty good compromise for rust and galvanic)
3. Aluminum and stainless steel: ~0.4V (pretty fair compromise for rust and galvanic)

This aluminum to steel junction has historically been a problem.  The U.S. Navy has had tremendous recent problems with aluminum hulled vessels and steel bolts.  If Suzuki here used nickel plated steel header bolts in these aluminum threads, that would explain the extremity of the problem.  If those bolts are tin plated the problem should have been less, unless the tin plating is so thin that it is quickly consumed by a galvanic corrosion, which then allows the steel to rust away. 

Off the top of my head I would guess the best answer is the stainless steel studs and nuts, since you don't have to get the studs out to remove the manifold.  The SS studs may corrode in the aluminum threads, but may still last longer than the life of the bike.  It might also be a help to use an anti-oxidant compound on the studs or bolts when first installing them.  Checking on-line, I don't see anything on whether Loctite serves as an anti-oxidant.  Anti-seize compounds often advertise themselves as anti-corrosion and salt resistant, so that sounds like they have anti-oxidant properties. 

[Jimbob]

Question - when you say header bolts these are the exhaust pipe clamp bolts?

[max]

When I had to replace the header studs on my last Yamaha, the OEM replacements were zinc coated, which I believe is the common protection method.

Zinc and aluminium have the closest electrode potentials, reducing galvanic corrosion, but not being rust-proof the studs/nuts/bolts will still eventually just rust in-situ instead.

+1 to replacing with stainless if you can get them out (do it before they get as bad as mine!). A2 (stainless 304) is supposedly slightly less likely to fatigue crack than A4 stainless (316), and the clamping load is low so I'd recommend A2 studs and nuts.

Anti-seize or thread locker on header bolts/studs is an ongoing controversy. However, assuming they're correctly temperature rated, either should provide some barrier to reduce galvanic corrosion between the stainless steel and aluminium header if you're that worried, but someone with some more long-term experience might have better insight for you.

Question - when you say header bolts these are the exhaust pipe clamp bolts?

That's my interpretation of it.

[MaxD]

Jimbob, I assume so.  I'm going by Sledge calling them header bolts when he noted that this is a common and very troublesome problem that is worth heading off early.  My Clymer manual does not give them a name.  The apparent problem is that they often are so weakened by corrosion that they sheer off, and then you have an expensive repair job on your hands.   

If they are stuck, this video (https://www.youtube.com/watch?v=3GYzpdtuoVo) shows a way to loosen them with a torch--heat them for about 30 seconds, then gently unscrew them.  I assume this works because the thermal expansion of aluminum is about twice that of steel, so even though the bolts expand the aluminum they are screwed into expands even more and opens up.

[MaxD]

Max, thanks for the excellent tip on the particular best stainless steel.  I'm hoping for somebody to tell me the exact size and source for studs and nuts, but if I had not heard that by Monday I'll see if the local Suzuki shop keeps that information.  I did see on Amazon that there are high temp anti-seize compounds, if someone does not want the studs loctited. 

From Wikipedia I get the following galvanic potentials to keep in mind: Aluminum at ~-0.9 to -0.95, plain steel at -0.85, stainless steel at ~-0.6 to -0.5 depending on chromium content, carbon steel ~-0.6, copper at -0.35, brass and bronze at -0.4, zinc plated at -1.25, tin at -0.65, nickel at -0.30. 

So, if Suzuki is using zinc plated bolts, the difference to aluminum is about 0.25 to 0.3V.  That's pretty good, and certainly better than nickel at 0.6 to 0.65V.  But as you say, once the plating of any of the zinc or nickel or tin are galvanically corroded away, then you're into a fast rusting process. 

I recently saw a book titled "Rust: the Longest War", which is astonishingly well reviewed for a book literally about rust.  It points out that the annual damage caused by rust and galvanic corrosion is hundreds of billions of dollars a year.  Really a big problem that can only be limited and not solved. 

[Kookas]

It's an awful issue. The header bolts on my old 45k miler were not even bolts anymore. There was nothing recognisable as 'bolts', just a few lumps covered in flakes of rust.

Where would you source some SS studs and what size?

[ShowBizWolf]

I updated the wiki with the size, lemmie cut and paste lol....

They are M8-1.25mm.

60mm for the length was confirmed I think by someone in the facebook group for the stock exhaust. Mine are 50mm cuz I have aftermarket pipes.

You should double-check for yourself what would work though. I do know from my project thread that if you stick a screwdriver or whatever into the holes, the depth is 25mm. Then just add on whatever extra length you'd need to go through the stock mounting bracket things and have extra length for the nut.

I bought mine on eBay but that seller doesn't have them listed anymore

[sledge]

Type M8 stainless studs into ebay and go from there 

[crackin]

Another common problem is the front engine mount bolt seizing in the engine mount. These seized bolts are due to neglect of the motorcycle more than poor design IMO.
If you pull these bolts every 12 months and use an anti seize compound there is no issue.

[Sarasi]

I updated the wiki with the size, lemmie cut and paste lol....

They are M8-1.25mm.

60mm for the length was confirmed I think by someone in the facebook group for the stock exhaust. Mine are 50mm cuz I have aftermarket pipes.

You should double-check for yourself what would work though. I do know from my project thread that if you stick a screwdriver or whatever into the holes, the depth is 25mm. Then just add on whatever extra length you'd need to go through the stock mounting bracket things and have extra length for the nut.

I bought mine on eBay but that seller doesn't have them listed anymore

This is the OEM bolt for the exhaust headers. Obviously, you'd need four.

[MaxD]

Thanks ShowBiz.

A package of 5 of M8-1.25 X 60mm stainless steel bolts that seem an upgrade from stock can be had from Amazon for $8.65.  Link is:
https://www.amazon.com/DIN933-Stainless-Steel-Hexagon-Screw/dp/B015A39NUY/ref=sr_1_9?ie=UTF8&qid=1534663558&sr=8-9&keywords=M8X1.25

This ARP 400-8005 M8 x 1.25 x 57mm Stainless Steel Stud Kit - 4 Piece looks nice for a stud upgrade with stock manifold, comes with 12 point nuts, 57mm seems about right for stock, but price is $38 at Amazon:
https://www.amazon.com/ARP-400-8005-1-25-Stainless-Steel/dp/B003TPLKF2

[MaxD]

Sarasi, thanks for that OEM header bolt reference.  It looks zinc plated--too bad they don't say. 

Crackin, thanks for the note on the engine mount bolt.  That goes right into my list also. 

[ShowBizWolf]

I'd personally never want to go back to bolts, no matter what they were made of or how much less they cost than studs.

The whole point of the studs is so you don't have to be messing with the part that threads into the engine anymore when removing the exhaust... you're only working with the threads on the stud and the nut to remove the pipes instead.

I couldn't find in that amazon listing how long the threaded portions are... the ones I bought were all thread. Now I'm wondering how hard something like this could be to find again! I'm gonna heat up my coffee and have a look around for something similar to what I bought.

EDIT: The seller I bought mine from has them again. Here's the link:
https://www.ebay.com/itm/Stainless-Steel-Exhaust-Manifold-Header-Stud-Kits-Metric-M8-x-1-25mm-A2-70/232494547577?hash=item3621c14279%3Am%3Am-Mr12zU3b744btJcTqv6Jw&var=531805757485

[MaxD]

Thanks Showbiz, those look nice and about 60% of the Amazon price, with complete threads. 

On one of AdidasGuy's nice YouTube videos on putting an aftermarket Motad stainless steel exhaust on a GS500 (https://www.youtube.com/watch?v=4eMGNolMuEU), I noted that new probably stainless steel bolts and header clamps came with the exhaust system.  He also used anti-seize and not Loctite on those header bolts. 

But, it seems that Motad has gone under.  I don't see any complete Vance and Hines systems either. 

Are we now stuck with only these quick to rust soft steel OEM exhausts for the GS500?

[ShowBizWolf]

We aren't stuck Here is the wiki link with some options for our bikes:

http://wiki.gstwins.com/index.php?n=Upgrades.Exhaust

Those are the ones I was able to find. If anyone else has any links etc, I'd be glad to add them to the wiki.

[Sarasi]

I put an RVS Delkevic pair of headers on mine, combined with a (now discontinued) Laser muffler. Main reason is that Delkevic is way cheaper, but I needed something E-approved to be able to legally ride around in my neighbouring country, Germany, and none of Delkevic' stuff is E-marked. The Laser muffler was. But you can combine any muffler with the Delkevic headers obviously.

I bought my stuff from here: https://www.uitlaatstore.nl/webshop/303061-suzuki-gs500

It's a one man's shop so he might be willing to ship it to you if you contact him and ask, but I can't say for sure obviously.

[sledge]

He also used anti-seize and not Loctite on those header bolts. 

Don't put anti-seize on header bolts, or any other torque critical fastener


If you lubricate threads it reduces the amount of torque needed before they yield meaning if you do apply the recommended amount of torque you will weaken the bolts or strip the threads because of the now reduced amount of friction between the male and female. If you do then reduce the amount of torque applied you also reduce the clamping force between the port and flange meaning the gasket will be prone to leak and the bolts themselves may even loosen off due to the heat cycles.

I had this argument with him when he was alive, he wouldn't have it. I hate to think how many people took his advice on board and went on to have problems because of it