Author Topic: Oil Consumption. When to bother with a rebuild?  (Read 589 times)

Offline The Buddha

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Re: Oil Consumption. When to bother with a rebuild?
« Reply #20 on: August 29, 2019, 01:19:56 AM »
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, 11:52:59 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, 11:57:30 PM by Bluesmudge »

Offline The Buddha

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Re: Oil Consumption. When to bother with a rebuild?
« Reply #22 on: August 30, 2019, 12:30:26 AM »
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.
Buddha.
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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, 07:06:54 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.