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Post by Raizer on Jul 21, 2020 20:42:58 GMT -5
Pretty confident the timing is out, it did try and idle a couple times but not happily lol
Edit: Yeap it's timing
How the A50 is currently set up:
VS a Suzuki Let's II at TDC (my parts Minarelli is seized so can't get it to TDC)
So yeah being a falling edge pick up it fires when the trigger leaves the pickup, so the Let's is firing about 7* before TDC, A50 is similar but after TDC
Edit 2:
The joy of having the flywheel bolted together still, think I've got it close now
May have gone a few degrees too far, but there should be enough adjustment to dial it in via the pick up
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Post by Raizer on Jul 22, 2020 20:10:15 GMT -5
Nylock nuts, spring washers + red thread locker should hold it I hope!
Then this happened:
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Post by Raizer on Jul 24, 2020 22:42:17 GMT -5
Brought an indicator gauge to attempt to be real precise with the timing (and it gave me a good excuse to grab on haha), didn't think about the fins on the head though
Oh well, at least I've got a gauge now, will be handy for sure/now know my bolt job flywheel has less than 0.55mm of run out!
Plan B was to hack together a piston stop It's sure ain't pretty, but it works so it'll do!
Found true TDC and am now working out timing, not 100% sure at what point the trigger fires the CDI
Going to have to rig up a better dial gauge or glue a degree strip on and get the timing light out I think, factory is 24~27° BTDC but I've been told that the top end really wants a few degrees more advance to perform at it's peak.
Still can't get over the sound of it running!!!
Edit: Turns out it's firing a fair bit sooner than I would have thought, took a video and played it back frame by frame
It's firing in the last 3rd of the trigger, so it's closer to 55° BTDC than 25° lol
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Post by 190mech on Jul 25, 2020 4:04:15 GMT -5
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Post by Raizer on Jul 25, 2020 4:15:26 GMT -5
Thanks for the tip, I hadn't thought of aiming the light at the pickup, makes total sense too! I'd just been trying to catch it by playing this as slow as I can lol
Edit: ran out to the shed and pulled out my timing light, it's firing right about where the end of the trigger is just starting to clear the edge of the pickup 
And about 37° BTDC  Need it running to see it easier I think, have got the Mrs pushing the kick by hand so I only get a couple of pulses at a time lol |
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Post by aeroxbud on Jul 25, 2020 11:20:18 GMT -5
Still sounds good though. A little angry. 👍
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Post by Raizer on Jul 25, 2020 21:58:25 GMT -5
Took the flywheel apart again and got it to 22~24°, that's with the stator plate in the middle of the adjustment range so there's about 8° either way to dial it in with. But I'm really not happy with how little meat is left in the flywheel and it would be less if I drilled for 6 screws.  Have got a Yamaha Vino flywheel that can be used, just need a little bit of lathe time to set it up. |
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Post by Raizer on Jul 25, 2020 23:53:40 GMT -5
Still sounds good though. A little angry. 👍 It gets even angrier with a bit of timing and some more throttle!!
Not riding it till the new flywheel is on, but come on I had to hear it!! |
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Post by Raizer on Sept 13, 2020 23:41:50 GMT -5
Still sounds good though. A little angry. 👍 Sound UP!! 
So much fun to ride!! Since there is zero low down torque, you have to give it a good twist of rabbit before slipping the clutch a little or it just dies, it then pulls away fine, maybe a bit stronger than a stock 49cc one, then the pipe hits HARD and FAST and it just wants to rev and rev!! Got 80kph at the top of 3rd gear on the way back down the street and it was only just feeling like it wanted to go up a gear  But what I have been telling myself is just chatter from old clutch basket bushings is more likely the piston giving the head a bit of a kiss, so I'd better check squish and port timing again and work out a plan from there, if I'm lucky the port timing will let me change to a thicker base gasket, if not the head will get a bit of a polish out. |
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Post by aeroxbud on Sept 14, 2020 4:12:00 GMT -5
Nice. With a cheeky wheelie too. 😁
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Post by Raizer on Sept 14, 2020 5:35:12 GMT -5
Lol just tried to check squish with a piece of 1.6mm fluxcore solder, it got down to .47mm before it wouldn't squish down anymore and locked the engine up, yeah I'd say that's a touch tight Ha!
Had to use a screwdriver to push the piston back down a bit to get the solder back out.
Base gasket has obviously compressed more than I'd expected!
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Post by Raizer on Sept 14, 2020 5:36:11 GMT -5
Nice. With a cheeky wheelie too. 😁 I've ridden a lot of A series Suzukis, none have ever tried to lift a wheel like this one does now!! |
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Post by Raizer on Sept 14, 2020 23:50:06 GMT -5
Lol just tried to check squish with a piece of 1.6mm fluxcore solder, it got down to .47mm before it wouldn't squish down anymore and locked the engine up, yeah I'd say that's a touch tight Ha! Had to use a screwdriver to push the piston back down a bit to get the solder back out. Base gasket has obviously compressed more than I'd expected! Tried again with 1mm solder, .14mm and it took a fair push on the kickstart to squish it, lol yeah that's a tad tight...
So OFF WITH HER HEAD!
Can see where they have been getting intimate.
Checked port vs piston height, base gasket could actually benefit from being .12mm thinner to get it spot on.
So going to try get hold of some .75mm copper sheet and cut a head gasket for it.
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Post by Raizer on Sept 17, 2020 6:20:03 GMT -5
Genuine Suzuki base gasket I removed measured up at bang on .50, found a roll of .40 paper I had kicking about and squashed a bit and got this  50 - .12 = .38, couldn't have gone better if I'd planned it! Cut a gasket, then played with shimming the head to find exactly what thickness I needed gasket wise  .75 was indeed about right giving a squish of bang on .65  Scrounged up an off-cut of copper, measures at .76,spent a while marking out a gasket, took my time trimming it the best I could with snips  Then promptly stuffed it cutting the inside, attempt 2 or 3 went a lot better once I brought a hole saw, not great but good enough for now.   Next time I think I'll just bite the bullet and get one waterjet cut!! Test fit gave a squish of .67, I annealed the gasket with a MAPP torch, whacked it back on and torqued it up, checked squish and got .64, mint!  Not so mint was dropping a nut while the head was off and it falling into the cylinder, the piston was at BDC so it went right down the exhaust port and is now in the expansion chamber ha. Oh yeah, and I finally measured up and ran the numbers  68.68cc of fury! |
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Post by aeroxbud on Sept 17, 2020 7:40:58 GMT -5
It's a lot of work making gaskets. But the results will be worth it.
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