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Post by coolray on Aug 30, 2021 12:23:46 GMT 1
Hello Gentlemen,
Thanks so much for these boards.
I bought a bike (38000Km's on the clock) that took a fall and stood in a garage in a temperate climate (South Africa) for a good 15 years minimum i would guess ... Fixed the prang damage and on to the motor.
1. After all the usual fluid changes and carb cleans .. The Bike started and smoked a bit on startup but seemed to settle down after a few minutes, didnt take it down the road but seemed to be responsive on a gentle throttle
2. found that the left side barrel wasn't all the way torqued ... nuts seemed to be just nipped up rather than all the way loose, No damage to barrel or piston as far as i can tell.
3. found oil had filled up little little reservoirs rear of the left barrel (under the base gasket) .. looked like engine oil. Exhaust port right is gummy and black, exhaust port left is grey and dry ... seems ultra clean under the left side cover, no oil on or under the electrics at all.
im filled with dread at the thought of splitting the motor for crank seals, i turned the crank around to inspect the circumference and notice it is a bit moist on that side. moister than the other side at least.
Any thoughts?
Thanks Gentlemen
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Post by midlifecrisisrd on Aug 30, 2021 12:47:10 GMT 1
Hi
When left parked up the oil pump check valves or carb float needle valves can pass oil/fuel which gathers in one or both crank cases
Steve
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Post by coolray on Aug 30, 2021 12:56:13 GMT 1
Hi Steve,
The oil was actually in the little null spaces behind the RH piston (the top of the engine case .. under the gasket), in the actual base part the gasket sits on top of.
Ray
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Post by midlifecrisisrd on Aug 30, 2021 13:27:29 GMT 1
As you found the barrel nuts loose I'd suspect it's been blowing out the gasket
Steve
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Post by dusty350 on Aug 30, 2021 18:39:24 GMT 1
I'd be doing crank seals and giving the crank bearings a good look over if it's stood for 15 years, plus all the other bearings and seals. You could save yourself a whole lot of pain with some work now They are easy engines to strip and rebuild. Loads of info on this forum Dusty
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Post by dusty350 on Aug 30, 2021 18:40:07 GMT 1
And welcome to the forum
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Post by shaunthe2nd on Aug 30, 2021 21:15:34 GMT 1
Welcome to the forum. I've done several stints in SA, mostly Jo'burg and Capetown, and a bit in PE and Durban and always loved it but don't remember seeing many, if any 2-strokes.
Crank seals are always a worry, but before pulling the engine I'd be tempted to fit new head/lower gasket, re-torque the head, change oils and plugs etc, carry out a compression test, strip and clean carbs, drain old and put in new fuel, check 2-T tank for clean oil, replace if necessary and take it on a short run and keep an eye on things. Does it start easily, run well, no oil leaks, no funny noises, check plug colour etc before deciding the next stage.
Keep us informed. Good luck.
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Post by coolray on Aug 31, 2021 7:41:44 GMT 1
Thanks.
already got the motor out and found i probably need a rebore to the next size up (currently .25), i may as well dig in to the rest and do the whole schpiel .. bit expensive for parts in SA so always trying to avoid a wallet jam up.
Thanks Guys.
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Post by chrisg on Aug 31, 2021 11:43:20 GMT 1
I'd be doing crank seals and giving the crank bearings a good look over if it's stood for 15 years, plus all the other bearings and seals. You could save yourself a whole lot of pain with some work now They are easy engines to strip and rebuild. Loads of info on this forum Dusty I would agree. Splitting the motor isn't as difficult as you imagine. Get a manual and read it first. Do things in stages and take lots of pre strip photos. Bag up all the little bits,screws etc and label them. Advise is always at hand. Good luck. NB make sure that you use gen. Yamaha seals for the crankshaft at the very least.
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Post by midlifecrisisrd on Aug 31, 2021 15:15:51 GMT 1
Splitting the cases can be daunting
In reality if you know the gearbox works fine you don't have to disturb it
Once you have removed the clutch basket, removed the half moon retainer behind it and loosened the primary gear on the crank it all just stays in the lower case when you split the cases
The crank can simply be lifted out, new seals fitted and placed back in
Its a good idea to change the seal behind the sprocket at the same time
Steve
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Post by bare on Aug 31, 2021 17:28:38 GMT 1
Crank Must be Disassembled ! and inspected for micro rusting on it's Pins. Typical result of sitting unmoved/lubed for years, let alone 15. The rust Will destroy the rod bearings and too often takes out the bores when it fails. Usually a week or 3 after first fire up. Not the time or place to take shortcuts.
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