Exhaust flange bolts, 1981 GS650G

[hank2]

Today, I continued diving into many problems I've found from likely multiple PO's on my recently purchase '81 GS 650G. One of the top jobs was replacing the oil pan due to a stripped drain plug hole which was doctored up with goop, etc. I soon found I was best off removing the 4 into 1 pipe to get the old pan off. I found 3 different length exhaust flange bolts, including one that had a 13mm head instead of a 12mm. One of the bolts was slightly cross threaded, it felt, but I gingerly got it out. I ordered a set of Suzuki bolts.

Suzuki only lists one part. no. for this bolt, so I assume that they should all be identical. Right?

01500-0840A
​

This part. no. comes back to all sort of 70's bikes, mostly frame bolts. Looks like up through '83 GS650G exhaust.
Anyone happen to know the thread size and bolt dimensions on this bolt? I know it's a different part. no than many other GS's.
I'd like to run a tap into the one problem hole to dress up the threads.

I plan to do clutch springs while the oil is out. Last week, for the first time in my life, I paid a shop to remove wheels and mount new tires. Had to be there for State inspection. Of course, paid full boat MSRP for the tires. I grabbed a look at the rear wheel splines while they had the rear wheel off. Not good news. Looked to be about 20%. I also have a new wheel spine ordered. The only smaller bore Intruder wheels on ebay that you could see the splines were good, were up there on price, so went new. Must have had a hard un-lubed life or the 24k on the odometer isn't correct. ( 24k). I could believe the mileage.

Thanks for any info! hank2

 

[Nessism]

BOLT
01500-0840A


The 08 typically references the diameter and the 40 should be the length. Not sure if it's 1.0 or 1.25 thread pitch. If nobody comes up with an answer I'll go measure some for you.

 

[salty_monk]

It's standard pitch from memory

 

[hank2]

I believe standard for an 8mm bolt would be 1.25
I can get it checked. I didn't know about the part no. revealing some size info.

 

[rphillips]

Everybody's different, but I've always replaced the bolts with studs & nuts. For me much easier to get everything lined up straight & kind'f hanging up there on the studs instead of holding things up & trying to get the bolts stuck thru & lined up straight. Less chance of cross threading anything. Just a thought.

 

[Steve]

Confirmed, ... the bolts are M8 x 40, 1.25 pitch.

.

 

[hank2]

Everybody's different, but I've always replaced the bolts with studs & nuts. For me much easier to get everything lined up straight & kind'f hanging up there on the studs instead of holding things up & trying to get the bolts stuck thru & lined up straight. Less chance of cross threading anything. Just a thought.

Good idea, thanks! I'm new to 4 cylinders and didn't consider that. I have the OEM bolts already ordered. On what was expected to be a low cost rider, I'm already into multiples of the purchase price. To be expected. If I hadn't needed to replace the oil pan, I likely wouldn't have ever pulled the exhaust.

 

[hank2]

Confirmed, ... the bolts are M8 x 40, 1.25 pitch.

.

Thank you Steve! I may try to source something suitable near home, depending on how soon Partszilla can ship them. Might be tough with the exact shank set up, etc. I know from other adventures that stainless into aluminum is not the best idea, even with anti-seize.

 

[Steve]

Thank you Steve! I may try to source something suitable near home, depending on how soon Partszilla can ship them. Might be tough with the exact shank set up, etc. I know from other adventures that stainless into aluminum is not the best idea, even with anti-seize.

I'm not sure about 'common' parts like hardware, but be aware that ordering from any of the online parts vendors will take about two weeks. Virtually none of the vendors has stuff that is specific to our GSes in inventory (hardware might be an exception). They need to order it from a central warehouse, then separate that order into yours and everyone else's order, then ship to you. Overall, about two weeks.

Stainless into aluminum usually works OK, but you do have to use the correct anti-seize. The copper forrmula is more appropriate, but the intense heat at the exhaust ports does change things a bit.

.

 

[hank2]

I did get lucky with the exhaust mount bolts that I need, as Partszilla's supplier had exactly 8 in stock and they ship today. It's amazing what is still available with or without an extra 4 day supplier wait. Of course so much is long gone! I've been getting their parts in about 4 days for in stock and a week or so for must wait. When I used to occasionally order parts from Bike Bandit on the West coast for my V Strom, there was an extra 6 day wait on UPS ground shipping.

Yes, I've used copper type anti-seize on most fasteners. I know that on higher torque values, the final torque number has to be reduced due the anti-seize. I was once told, very long ago, by an aviation jet engine wrench that they used mostly Milk of Magnesia as anti-seize. Maybe for close tolerance things? I have used that on cars when I needed something and didn't have copper or other at hand. Not on critical items though.

Thanks very much for your help and advise!​

 

[Nessism]

I was once told, very long ago, by an aviation jet engine wrench that they used mostly Milk of Magnesia as anti-seize.

I was about to call BS on this but a google search shows that MoM was called out in at least a couple of jet engine CMM's. In aircraft part maintenance you are only allowed to use what's specified, no matter if suitable replacements are available. If it's not in writing in the manual you can't use it.

 

[salty_monk]

I'm guessing perhaps it didn't upset the torque ratings like grease would but that the powder still avoided the steel/Aluminum oxide?

 

[hank2]

I always thought that the M of M sounded a little crazy, but always remembered it. I've used it occasionaly on things like auto brake caliper mount bolts. It seemed to do ok. I heard that M of M story more than 45 years a go and it was in a military setting. Those wrenches did all sort of things in a "field expedient" method. I hope that I've been ok with using a cheap generic store brand.

 

[Grimly]

Everybody's different, but I've always replaced the bolts with studs & nuts. For me much easier to get everything lined up straight & kind'f hanging up there on the studs instead of holding things up & trying to get the bolts stuck thru & lined up straight. Less chance of cross threading anything. Just a thought.

Same here; I replace them with ss studding cut from a length.
Amusingly, the only stockist of ss threaded rod locally was a kitchen maker - commercial and high-end kitchens, stainless everything. Luckily the bar was cheap.