The Great Engine Rebuild

[Steel]

tl;dr - What jets for yoshi TRS slip on + lunchbox on a 2009 GS500F? How to tell visually I need piston rings, or just do it with open engine during valve job?



For a number of reasons that point to at least one bad valve, I'm pulling my cylinder head this week. I've located and befriended an experienced machinist to help me evaluate what I find inside, with cutting valve seats and other questions I'll prob have with reassembly.

This engine burns a lot of oil, about a quart every 1000 miles, so I'm also going to be ready to replace the piston rings. Some people have asked if I'm sure they're leaking, and no I'm not. I'm not sure if this is something I can see visually once I get in there, or something that should be replaced just because I have it open. I would welcome opinions here.

My GS came with a Yoshi TRS and K&N drop in. It was jetted by the previous owner with what I now believe is a Dyno-Jet stage one kit. My spark plugs have always looked bright white during inspections. I know that a lean engine runs hotter, but I'm not sure how hot, or what kind of damage that heat does.

At this time I'm financially prepared, if necessary, to buy all four valves, oil seals, guides, springs, two sets of rings, gaskets, etc. Correct me if I'm wrong, but new piston rings mean a new break in cycle for the engine? Wouldn't I want a "new" engine to break in at a reasonable operating temperature? If rejetting is the key, I can replace the DJ needles with stock and be happy to accept Mr. Buddah's or others recommendation for jets. While spending gobs of money I'd also pull the airbox and install a lunchbox instead.

When I find interesting stuff I'll post some pictures and ask more questions here. Thanks everyone!

[The Buddha]

Mine went through a quart in 300 miles, I didn't bother rebuilding it, it ran till the last day I had it, and about a month after I sold it I saw it on the road still running. 48 k and still kicking in 2005.
Cool.
Buddha.

[Steel]

Like I said I've going to have it open anyway soon, it needs a valve job. The oil starvation I wasn't paying attention to caused an overheat and softened valve B and its been crashing hard.

Buddah, you're the jet master. I'll buy the stock needles, wanna sell me the rest?

[burning1]

My observation is that the first failure from oil starvation is the big end rod bearings. I've torn apart 2 engines that starved, with bad bearings and no sign of damage to the head. Getting to them is a huge pain in the ass.

[The Buddha]

If you have DJ's its sorta better to work it from that, I will soon have a working bike wiht DJ parts. I'll tell you what it would take.
Cool.
Buddha.

[Steel]

I remember you mentioning that, burning1. I've looked for any signs of that kind of trouble and talked to a lot of people and can't find any evidence of a problem like that. The cylinder and head are coming off for sure. Would you say its worth a look?

[Steel]

I really don't want to unless you insist. Even the transmission problem I had amounted to a mere bent shift shaft.

[burning1]

Getting to the bottom end means splitting the cases. If you don't have reason to suspect a bad rod bearing, I'd advise the following 2 precautions:

1. UOA on the oil in the crank case. If you have a spun bearing, it'll show up as high levels of copper. $30 is a bargain compared to the wasted effort of a rebuild on a bad engine.
2. With the cylinder off, pull on each rod looking for any signs of play. I can definitely feel an out-of-spec pin in a piston, and I suspect you could feel an out-of-spec bearing on the rod.

[Steel]

Okay, I will check that, burning1.

Buddah, I'm willing to throw a little money at my carbs because I just want it done and working. I really don't want a rejet holding up this project. I can always keep the DJ needles and experiment later. What's a good setup for my Yoshi TRS and lunchbox (my likely setup) vs TRS and K&N drop in (my current setup) please? I'll personally add them to the wiki.

[The Buddha]

With original needles you need 20/147.5/3 turns/1 washer with K&N lunchbox and pipe.  And maybe 65 mids.
With Drop in K&N and pipe - you need 135 mains - rest as above. And no need for mids.

With DJ needles and K&N lunchbox and pipe I have had mine running quite well in summer with a 137.5 main, and clip in 2 from top - and that was a 96 bike. However I am no longer in possession of that or any other GS runner and am not sure how it would be adjusted etc etc for the 01+ and even still fiddling with jetting wasn't my main goal on it. I was doing a front end swap. I had it briefly and felt it could be a good starting point ... past that no clue.

Cool.
Buddha.

[Steel]

Thank you!

Where does the 1 washer go? What's a 'washer'? Does it have a thickness, sold by a certain source?

[Steel]

When I do my piston rings, am I going to need one of those racheting compressor sleeves? Like this one:

http://www.amazon.com/Lisle-19500-Ring-Compressor/dp/B0002STSFS/ref=pd_bxgy_auto_img_c

[vasama]

I didn't have to use one on mine. The space is kind of small for one anyways. I was able to *carefully* sit the cylinder atop one piston, and then push the rings in with a screwdriver, one by one. It worked fine.

[cbrfxr67]

Steel: need pictures

[Steel]

I havent started yet. I'm in the final planning stages, making sure I have everything Im going to need to Im not begging rides from everyone I know. There will be pictures.

[adidasguy]

I'm going to rebuilding the spare engines with freshly honed jugs and new piston rings.
One of the manuals says you can push the rings in with your hands. It also says to have someone else there to lower the jugs down as you get the pistons in the cylinders. I've never done that and I wondered what was involved so I actually opened a book and read something!

Now can you adjust valves on just a top end on the bench? Seem you could since the cam can be turned by hand and timing doesn't make any difference since the head is not on the engine so it can't bang the pistons.

[Steel]

I bet you could, adidasguy! Thats a great idea, I could visit my shim dealer and get hooked up in one trip.

Right now I'm wondering what to do with the PAIR or 'second air' system if I put a lunch box on during my rejet. Rip it out totally or give it it's own filter (rag or something) like the breather cover?

[Steel]

I'm going to see the machinist in a day or two, he can tell me if that's possible and I'll pass that along.

[BaltimoreGS]

When I do my piston rings, am I going to need one of those racheting compressor sleeves? Like this one:

http://www.amazon.com/Lisle-19500-Ring-Compressor/dp/B0002STSFS/ref=pd_bxgy_auto_img_c

The bottom of the jugs are tapered so that tool is unecessary.

-Jessie

[Paulcet]

Yeah, ring compressor is not necessary.  Might make it easier though.  Pair: Just block the ports.