Author Topic: Oil Consumption. When to bother with a rebuild?  (Read 2716 times)

Offline The Buddha

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Re: Oil Consumption. When to bother with a rebuild?
« Reply #20 on: August 28, 2019, 06:19:56 PM »
Will it work out if I just do new standard size rings on the existing pistons and swap in the low mileage cylinders? Keep the same head I have now since the valves are probably fine.

For what it's worth, that sounds like a solid plan to me.

What ??? dude, low oil means you really don't want to use much of anything from that motor unless as a last resort, of course if you pull and check and mic and check it all for runout, it may turn up OK. But it would barely save you pennies.
Lets see, my engine guy will do all 4 valves, seats, deck the head, bore and hone the cyls all for under 100. There is no way I'd take a chance on a bike that was run low on oil 4K or not. If it overheated, if it had a hot spot, of it has a warp in the head etc etc, too many unknowns.
In a way, you walk into a Starbucks and order a espresso, you will get a very consistent product for $5. Walk in there and order a sugarcane juice and all you'd get it dumb looks.
Engine guys rebuild shaZam! every day 1000's of times over, a GS motor can be rebuilt by a car guy, its just that dumb and stupid. Start throwing in variables, like mic this, measure that for run out, plastigauge that, check if this turned purple when the guy redlined it when it was low on oil, an you start to veer so far off course, sugarcane juice from Starbucks looks better and better.
Cheapest option = tell engine guy to rebuild your running but oil consuming engine. He'd bore it 1/2 mm, put I nnew 1/2mm over pistons, had file the rings, surface the head, cut seats and valves and clean the carbon off it and put new gaskets in and torque it all back and give you a new motor.
I had him do my F150 with 300K, I have a few video clips, It works best if you don't ask them to do a lot of weird one off's
A whole motor swap is fine, easy and saves $$$ but parts of a oil starved motor is a gamble.

Cool.
Buddha.
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Offline Bluesmudge

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Re: Oil Consumption. When to bother with a rebuild?
« Reply #21 on: August 29, 2019, 04:52:59 PM »
The cylinder swap with new rings I can do myself for the price of engine gaskets and rings. The only thing I'm using from the low oil engine is the cylinders. It doesn't seem like it would hurt anything to try and it might work out ok.

What you are talking about involves paying Suzuki for all the new piston parts etc and then a machine shop to do the work. Nobody in Portland Oregon is doing that machining work for anywhere near $100. I think it would be 10x that, all-in, before the engine was back running in the bike. It doesn't seem like the cheapest option to me.

Is anyone else as concerned as Buddha about installing the low milage/low oil cylinders?
mr72, how much did you pay for your top end re-build?
« Last Edit: August 29, 2019, 04:57:30 PM by Bluesmudge »

Offline The Buddha

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Re: Oil Consumption. When to bother with a rebuild?
« Reply #22 on: August 29, 2019, 05:30:26 PM »
Yea, I'm spoiled living in nascar country, I'll admit.
But if you send me a worn out head, cyls and the piston and ring set you wanna fit to it, I'll guarantee you someone who will mic the f%$k out of everything and put cut it and machine it and bore and hone it, and well, if we had started this 2 months ago, I'd have got you video clips of all of it - anyway all of it done very very cheap - well add in mailing and you're probably looking at closer to 4 fig than in the high 2 and low 3 figures I have had this done.

Anyway remember, metal, especially cast crappy aluminum, has a "memory". You may be fine normally, but under certain situations it may act up.
Cool.
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Offline mr72

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Re: Oil Consumption. When to bother with a rebuild?
« Reply #23 on: August 30, 2019, 12:06:54 PM »
My top end rebuild cost about $800 IIRC when all was said and done. That included cleaning the pistons, new rings, having the jugs and head machined, some very mild porting/clean-up of ports, all new valves, valve seats, seals, head gasket, and ensure the valve clearance was correct. All of that work was done basically correctly. They screwed a bunch of other stuff up so I won't really get into the quality of the work but that was the cost. I felt like it was too high considering how long it took and the general poor quality of the non-machine work in the end.

If I had it to do over again I would use a ball hone on the cylinders myself just to break the glaze, measure and fit new rings myself and have a shop do the head. I had my Miata head rebuilt with new valve seats, grind the valves, clean and decked for, IIRC, like $150? Included new valve seals. I think I could probably get a twin moto head done for the same kind of price. Add to that a head gasket kit and the cost of all new valves ($20-30/ea) and I think it's a DIY job for $300 or less. I only had the shop do it because a) I was hoping to form a relationship with a very local shop who I might be able to use in the long run (fat chance, this shop sucks), and b) they already had the bike apart looking for the other issue when they called and made the quote, so I thought the quickest way to get it back on the road was to let them finish.. turns out it took two months but anyway... again hindsight 20/20 ... if I knew then what I know now, I would have done it myself.

Offline Bluesmudge

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Re: Oil Consumption. When to bother with a rebuild?
« Reply #24 on: December 08, 2019, 10:46:35 AM »
I pulled the trigger and dropped my bike off at a local shop for a top end rebuild. Itís going to be a stupid amount of money but I realized I really love this motorcycle and want it done right. They will check in with me through the entire process and at the end they will get the carbs dialed in on their dyno to make sure a lean condition isnít contributing to the engine wear.

I wouldnít have gone this route but my bike was recently knocked over and totaled (just a bunch of small cosmetic things).. I bought t back for $400 and can use the remainder to get this rebuild done. I feel good supporting the local shop with some real engine work for the winter.

Iíll let you know how the process goes. This is my first time using a shop outside of emergency road trip repairs.

Offline Bluesmudge

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Re: Oil Consumption. When to bother with a rebuild?
« Reply #25 on: February 28, 2020, 11:49:32 AM »
My GS500 engine rebuild is complete and the bike is back home!
The bike ended up needing new exhaust valves and rings. They also checked on my clutch at my request (still well within spec), did safety check, and cleaned up some broken bolts and messy wiring I've been too lazy to fix.

After the rebuild the bike got put on the dyno for tuning. Even with 44,000 miles my '06 GS500F running like new again and making a full 40 hp at the wheel with Vance & Hines exhaust, foam Uni filter and Dyno jet kit. I know many on this forum stick with mikuni jets. The shop was adamant that Dynojet was the way to go. Well, the dyno graph doesn't lie. I'll have to scan them and post here. They put my idle jet back to stock and played with the Dynojet kit until the fueling was spot on across a variety of throttle positions. Bike warms up like it should and makes good power (for a GS500). Bike still smells a little rich while warming up with the choke but I think that's normal and the plume of oily smoke is gone.

Shop recommended changing oil after 100 miles but otherwise, "just ride it."
These guys know what they are doing. If anyone lives near Portland Oregon I recommend CycleTune PDX.

After a few thousand miles I will report back to confirm the degree to which the rebuild fixed oil consumption. Before the rebuild I was consuming a quart or more per 1,000 miles. Running hard it was a quart in 300 miles.

In two weeks I start a new job that does not have a company vehicle, the GS500 is going back to commute duty and will be getting a lot of miles. I've had the luxury of driving a RAM 1500 for free the last 6 years. Hopefully the GS500 is up to the task. The roads are a scarier place compared to when I commuted on the GS500 2009 - 2012. Cars are faster and everyone is using cell phones. 

« Last Edit: February 28, 2020, 11:57:07 AM by Bluesmudge »

Offline IdaSuzi

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Re: Oil Consumption. When to bother with a rebuild?
« Reply #26 on: February 28, 2020, 03:54:05 PM »
Glad to hear the shop did a good job for you! Should be ready to go for a long time now since the bottom ends hardly ever wear out as far as I know.

I love the local shops and have used a local machine shop that builds drag cars all the way down to small engine repair. My college money scheme is to buy Mitsubishi, Honda, Toyota, and Subaru cars that have snapped timing belts and pick them up for cheap, then pull the head and if its in good shape have the shop throw new valves and guides in then reassemble with new gaskets and sell. Its always been a joy working with them, so glad you found a good one in your area.

Good luck with the commuting! I'll be dragging my bike out of storage for commuting duty soon and can't wait.
1998 RM125
1995 RM250
1999 Yamaha Banshee (Kind of a bike???)
1993 DR350
2008 GS500F naked conversion, Kat 600 shock, Yoshi Slip On, Progressive Springs, 20/62.5/140 rejet, Fenderectomy, LED Front and Rear Signals

Offline The Buddha

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Re: Oil Consumption. When to bother with a rebuild?
« Reply #27 on: February 29, 2020, 06:57:36 AM »
Oh cool bluesmudge, enjoy, didn't realize you got 44K on an 06 nice going man.
Now I had 1 89 gs dyno at 44+ back in 98 with home made D&D slip on (can was D&D fitted up by muffler shop on stock header), and mikuni and K&N lunch box. This bike had 30K+ miles when I did this.
I had a stock air box one a 1990 with just a slip on again home made, and jetted to 40/125 come in at 42.8 and this bike always felt faster and more powerful than the first one. This bike also had just about 2000 miles when I did this.
In any case the bike will make more power with a few 100 to 1000 or so more miles. I don't even know why they would dyno a bike that's just been built. But of course the bottom end bearings etc are well worn, just the top end will have to break in, its likely its pretty much at its max as well.

Cool.
Buddha.
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