SUSPECTED ENGINE PROBLEM! 😮 | 1973 Kawasaki S2A Engine Repair - Pt1
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- Опубліковано 14 жов 2024
- A number of viewers of the video of my recent visit to the 'Piston Club' commented that they could hear a rattle from the engine. I decided to investigate further...
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Hi Derrick, they all rattle, rebuild your oil pump, check that there is proper sealing of lube pipes, even add additional 2 stroke oil to fuel to see if it rattles as much, compression test, to see if compression is even around 125psi. Good luck,
Zen, and the art of motorcycle maintenance 👌
I've checked operation of the oil pump on a number of occasions, it's definitely working (see Stranded at the Roadside video). I believe the piston damage was due to an air leak, possibly through the barrel base gasket. 🤔
Haha, love the imitation bond music. I was always looking for 6th gear on my S2A, my S2 was perfect (previously owned by Rick Brett). Great videos Derek.
The music is from the all time classic N64 console game Goldeneye.
Glad you're enjoying the videos. Many a time I've selected that ghost 6th gear lol 😂
Lovely bike, great video keep up the good work.
Cheers mate. Glad you enjoyed the video! 👍
With the cylinder bore in spec, hope it was just an out of spec piston from the beginning. Glad you found the issue before the piston failed completely and caused more damage.
Yes, true. I'm going to pay very close attention to piston & bore measurements from now on. 😇
The plan is to go with a 0.5mm oversized piston, and rebore the cylinder to the correct clearance 🙏
Shame , love the bike guess it could have been a lot worse, good luck with your repairs.
Cheers mate. Could have been worse. It's good that I have viewers familiar with how these 2-strokes should sound! 👂
Not sure what to say Derek, has that particular cylinder been receiving the correct amount of 2 stroke oil?
I think so. I checked the oil pump operation prior to the first engine start. 🤔
If it was me, I'd hone the barrel to make it good and fit a new piston that is within the tolerance. I'd also run it in carefully on premix to ensure it stays lubricated. Take a thermal laser with you and check the cylinder temp as you run it in.
Sounds fair enough. 🤔
So you suggest draining the oil injection system prior to run in? What premix ratio would you suggest?
@@derekb2765 If your using mineral oil as the regular additive to the tank, I'd go for 30 to one. If using modern synthetic, 50 to one should be OK. I'm not familiar with the oil pump control but guess it would have an additional cable from the twistgrip cable, in a junction box. If you disconnect the cable, you wont have to bleed the system again when your happy with the running in. The small amount of oil will be insignificant in the premix. Remember, the more oil you mix, the lower the octane so use E5 99 or similar.
I use a cheap Carlube semi-synthetic, so 50:1 then?
I always use E5 petrol as a matter of course. Esso Synergy 99 is preferred.
Disconnecting the oil pump cable is a good idea 💡 I like the idea of using premix, as I'll definitely know enough oil is being delivered.
Thanks for the tips! 😊👍
Problem with using premix in an engine not designed to take it is that it will effectively make the engine run weak. Reason is that if you use say 3% oil by volume (ie a premix of about 33:1), the main jet still passes the same *total volume* of fluid as when running straight petrol. However, the oil condenses on the bearings, the cylinder walls etc etc - leaving only 97% of the petrol going into the cylinder compared to running straight petrol. As the engine is still pulling a full charge of air, the combustible mix in the cylinder is therefore *3% weaker* than before. Whether or not running a 3% weaker mixture would actually be a problem, I don't know, but we all know what happens when two strokes are thrashed when weak, don't we? Technically, if changing to premix, you should increase the area of the main jet orifice by 3% to compensate for passing oil as well as petrol.......
Well that seems to be a fair point, although I would only use premix in the running in period, during which no thrashing will be taking place! 😉
Sounded like little end bearing rattle to me. Did you use new genuine small end bearings on rebuild?
Gary Clarke supplied the bearings. I don't know if they're genuine. Cylinder 1 bearing looks to be in good condition. The status of the others is obviously unknown 🤔
Dez what’s your degree in.??
Mechanical engineering. Why? 🤔
Impressed by your precision and attention to detail I wouldn’t have the patience ..🙏🏻
Unfortunately I wasn't precise and detailed enough at the start lol 😂