2009 GS500F Full Rebuild (w/pics)

[tpm4gz]

Summary: full tear-down & rebuild
Bike: 2009 GS500F
Mileage: 33,997
Reference:  Haynes Manual

DISCLAIMER: I am not a professional mechanic. Consult an expert before attempting any of the work described here, and do so at your own risk.

I've owned my '09 GS since 2013 and this is my first post on this forum. In October 2021, I was riding on I-5 from San Diego to Orange County at 11pm when the I heard a loud banging/grinding sound coming from the engine. I was doing about 75mph & quickly pulled the bike into the shoulder and turned off the engine. At the time, I was 50 miles from home, in the dark, and assumed I'd just fried my motor... not ideal. Checked the oil level and it was low. Called a friend and she picked me up and drove me to the next exit where we found an open gas station and bought some 10w40. Topped off the bike, started it up, and heard the characteristic "failed crankpin bearing" clattering/knocking sound

Here is what my engine sounded like: https://imgur.com/a/KiitDkQ

Here's an example from another GS owner: https://www.youtube.com/shorts/2DDMWqSR2WM

I rode the bike to a local bike shop and left it overnight. Talked to a mechanic over the phone when they opened the next morning. Long story short, the shop didn't want to do a full rebuild, so I rented a pickup truck about a week later and hauled the bike home to my garage. I read up on my options, including doing an engine swap. It seems like that's the preferred option for most people on this forum. I figured it would be more fun/instructive to do a rebuild myself, so I pulled out my Haynes manual and started removing/disconnecting stuff from the frame.

Garage setup:


First clue: I drained the oil and ended up with close to 5 quarts of fluid, which was clearly a mix of oil and gasoline. Began to suspect an issue with the piston rings, in addition to the presumptive failed bearing.


Next up: metal fragments in the oil pan... needless to say I was not feeling good after seeing this.


Engine dropped out of the bike:


Removed the valve cover, camshafts, cylinder head, cylinder block, and pistons. Now that I was finally able to see into the bottom end, I clearly saw a burnt out left crankpin bearing:


More bad news when I dropped out the sump. Metal flecks and bits of epoxy from the alternator rotor (pre-goats syndrome):


Finally cracked the case open. Fairly messy, but no obvious catastrophic damage:


Crankshaft removed from the crankcase. Big-end rod bearing clearances were, uh, very different: https://imgur.com/a/hzEvtI8

Crankshaft disassembled. Here's the comparison between the big-end connecting rod bearings. The scoring on the failed bearing is pretty obvious!


This is what the alternator rotor looked like when I got the crankshaft out. Epoxy is completely gone from the rotor. Thankfully no broken magnets. This part needed to be replaced:


I had to order a new crankshaft and connecting rods due to scoring. I ended up buying these parts on eBay from a parted-out bike. I was a little nervous about doing this, but I measured everything with a micrometer when it arrived -- and everything was within spec. I used the letters stamped on the crankcase, the new crankshaft, new connecting rods, and balancer shaft to order new bearings. The Haynes manual explains exactly how to do this using the stamps. I replaced all of the bearings on the crankshaft and balancer shaft.


One of my cylinders had a score mark which caught my fingernail, so I took the cylinder block to a machine shop for a rebore. This required me to order +0.5mm oversize pistons and +0.5mm oversize piston rings. I also replaced the piston pins. Here are the fresh cylinders after the rebore:


Checking oil clearances with plastigague. They were a bit higher than expected at around 0.05mm, but below the service limit of 0.08mm.


Putting the case back together. Molybdenum assembly lube is visible on the journal/bearing interfaces, and liquid gasket can be seen on the mating surfaces. I used Yamabond 4.


Time to clean up the head. I compressed the valve springs, removed the valves, cleaned out the carbon deposits on the head/valves, ground in the valves, and reassembled everything. CarbonOff is very corrosive -- use with caution and wear safety goggles.




Case closed up. Time to jack it back into the frame! This was very awkward -- powersports jack made it easier:


Fully reassembled!


LINGERING ISSUE: after charging the battery, the bike started up fairly readily. This was after I built up oil pressure by running the starter motor with the spark plugs removed. However, after running the engine for a few minutes, I noticed some smoke coming from the front of the cylinder and turned off the engine to prevent damage. I immediately removed the spark plugs -- no smoke from the inside of the cylinders. No smoke from the bottom end after removing the dipstick either. The smoke stopped very soon after I cut the engine. I assumed my exhaust bolts were loose, and tightened them. The issue improved somewhat, but not completely. The PAIR system gaskets were in pretty bad shape when I removed them earlier in the rebuild, but I didn't replace them because they were not included in the gasket set. Maybe exhaust is escaping there? Just ordered new gaskets.

Here is a video from before I tightened the exhaust bolts: https://imgur.com/a/apK1ZiR .

After tightening the bolts and riding the bike down the street, I got more smoke. It was similar in color, but I couldn't tell if it was still coming from the left exhaust as before (by this point, I had reattached the side panels so it was harder to see). It seemed like there was also some smoke coming from the bottom of the engine. I localized it to the outside of the exhaust pipes under the sump--seemed like oil burning off from the outside of the pipes, but I wasn't sure so I stopped running the engine and walked the bike most of the way back home. The engine *sounds* good, but the smoke is very off-putting so I haven't driven it more than 1-2 miles since initial startup. I can't quite figure it out, and I don't want to blow up my engine after spending so much time on it. Any input would be greatly appreciated! I'm happy to answer follow-up Qs.

Here's another video from after the exhaust bolts were tightened: https://imgur.com/a/TSUmTPV . As I mentioned in the previous paragraph, the problem resurfaced after this video, when I rode about 1 mile down the road. Also of note, I keep convincing myself that I can hear a little clicking towards the end of this video. Could this caused by out-of-spec valve clearances? Or am I just hearing things that aren't there...

This project was a huge undertaking for me. It took me about 6 months to get it done, but that's because I am inexperienced, I wanted to be as careful as possible, and I have a fairly busy work schedule. I also had to wait about 2 months for all of the new parts to come in. I'm very appreciative of everyone on this forum who provided guidance to me over the course of this project!

[SK Racing]

I'm unable to play the video and I've tried multiple apps.

[tpm4gz]

I'm unable to play the video and I've tried multiple apps.

My post has been edited/updated with working video links!

[Bluesmudge]

6 months is pretty good for a full rebuild actually. Took me about that long just to replace a top end because I was also super inexperienced. What you have done is commendable. So first off, thanks for keeping a GS500 on the road!

If the engine sounds okay and it's not exactly obvious where the smoke is coming from I would be tempted to ride the bike for 5 or 10 miles in your neighborhood to see if the smoke burns off. I recently had my XL600R out of the frame to just replace an o-ring in the top end. It smoked like hell on startup. Same thing happened after doing the valves on my GS1000. In both cases I had some stuck header bolts that needed copious amounts of PB blaster. Between that, WD40 that I sometimes use to clean parts, the fresh liquid gasket, and any oil you spilled on the engine, there is a ton of stuff that needs to burn off.

My next guess would be head gasket, so maybe take the valve cover off and make sure the nuts on top of the studs are all torqued to spec. Since you followed the manual I assume you replaced the base gasket, head gasket, o-rings, and copper crush washers? While you are there you could double check your timing and valve clearances.

[SK Racing]

I have to concur with Bluesmudge. The smoke will probably go away after a little while. After I spray painted the headers of my GS500 it smoked just as much, but it soon stopped.

Go and enjoy your bike! Job well done, I'd say. 

[herennow]

Nice Job, you just reminded me of the spreadsheet I had to work out exact clearances and which shells I should buy for the crank bearings.

I was also nervous  but 15 000 km later I guess its OK.

Did you measure oil pressure after the rebuild? good insurance.

Congrats.

[cbrfxr67]

What a great thread!  but,..where pics




edit: work's new firewall is blocking pics,...ffs

[SK Racing]

Lots of great pics in the first post.

[tpm4gz]

Update for everyone: I took my bike out yesterday for a 10ish mile ride. Took it easy, kept it below 5000rpm, used the transmission generously, etc. in accordance with the break-in instructions in the Haynes manual. There was a lot less smoke and the engine sounded good. I'm hoping it stays that way.

I've been fairly anxious about the rebuilt engine since I first fired it up & have been thinking to myself constantly: "did I do everything right??" During the last few miles of yesterday's ride, I was able to click it all the way up to 6th gear on the main road near my house. Finally cracked a smile and felt confident in my work for the first time. Hopefully this GS has a lot more miles ahead.

Thanks to Bluesmudge, SK Racing, and herennow for the advice/encouragement!


Sent from my iPhone using Tapatalk

[ShowBizWolf]

Fantastic thread!!! Love the writeup, pics and work you've done. Bike looks clean! Thank you for sharing.

[The Buddha]

Great write up and pics. Also that assembly lube has to burn off. Sometimes it takes a good bit of heat and it will keep smoking and smoking.
Cool.
Buddha.