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Post by Jwhood on Jun 18, 2016 15:53:33 GMT -5
Yeah that's crazy I don't think I've ever seen that happen too a skirt,even on a wristpin c-clip failure at 50mph,man I feel your pain brother,I'd done sent it to its death(then regretted it later) Do what Ryan said sit it aside and do some flips and come back to it later!!
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Post by niz76 on Jun 18, 2016 17:49:47 GMT -5
Yeah that's crazy I don't think I've ever seen that happen too a skirt,even on a wristpin c-clip failure at 50mph,man I feel your pain brother,I'd done sent it to its death(then regretted it later) Do what Ryan said sit it aside and do some flips and come back to it later!! Thanks JW. I've said it before and I'll say it again- never worked on a scoot that's been such a challenge as this thing sheesh. |
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Post by niz76 on Jun 18, 2016 17:51:31 GMT -5
I'm seriously thinking about just saying "F it" and running the piston the way it is. It's not like the lower part serves any function (besides stabilization!) of opening/closing any ports or anything. What's the worst that could happen?? I've already been through it all with this thing haha.
Anyone know if I can run it like this? Should I cut the piston skirt shorter on the other side to compensate? Will it have too much "slap"? Rock back and forth too much?? I know it sounds crazy but unless someone talks me out of it with some common sense thinking I really am thinking of still using this piston...
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Post by ryan_ott on Jun 18, 2016 18:14:39 GMT -5
The performance stuff has short skirts...  |
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Post by 90GTVert on Jun 18, 2016 18:59:56 GMT -5
I'd think you'd wanna at least make sure it would still cover everything when it's at TDC.  EDIT : Don't mind me. For some reason I had it in my head that you were gonna chop the rest of the skirt off. |
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Post by 'O'Verse on Jun 18, 2016 19:00:27 GMT -5
Definetley round the edges off. And maybe cut and round the other side for piston balancing. Just guessing.... Totally feel for you. Haven't even attempted to ride today. Don't want any of the bad juju!
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Post by niz76 on Jun 18, 2016 22:22:37 GMT -5
I'd think you'd wanna at least make sure it would still cover everything when it's at TDC. EDIT : Don't mind me. For some reason I had it in my head that you were gonna chop the rest of the skirt off. Honestly Brent I'm not sure what I'm going to do here but you may have saved me from making a stupid mistake because you are correct- I was wondering if I should cut some off the other side as some kind of attempt at "balancing" it out a little. I'll have to take a look at where it's at and what it covers at TDC to see if it's even an option.... |
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Post by 190mech on Jun 19, 2016 16:16:21 GMT -5
Thats a defective piston there!Looks like a crap design too as it has sooo little support in that area..Being a rotary valve and the exhaust skirt is still intact,it oughta run..maybe a bit noisey though..If you break it down,the bearings should be able to be washed out good enough to run again.. Guess the Vespa market is flooded with polished sh*t parts that have "performance" written on the boxes as so many other types do also...  |
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Post by bluegoatwoods on Jun 20, 2016 9:33:46 GMT -5
I've got nothing to add. Other than 'good luck'.
But I am watching with interest. And I'm putting in a reply here so that I have something like a bookmark.
I'm tempted to say, "Keep pushing at it!" But you'll know better than me, niz, whether to keep going or take a break.
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Post by niz76 on Jun 20, 2016 21:08:30 GMT -5
I've got nothing to add. Other than 'good luck'. But I am watching with interest. And I'm putting in a reply here so that I have something like a bookmark. I'm tempted to say, "Keep pushing at it!" But you'll know better than me, niz, whether to keep going or take a break. Ahh I'll keep at it. Just venting in real-time I suppose haha. A few parts showed up today that should help with tuning once I get it back together- a clear float bowl for the carb so I can monitor what's going on in there and a fuel pressure regulator to further smooth out the fuel delivery...  |
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Post by ryan_ott on Jun 30, 2016 9:07:24 GMT -5
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Post by niz76 on Jun 30, 2016 22:53:27 GMT -5
I finally got some quality time with the Vespa today. It's been back together and running for about a week now but been so dang busy with the fam I haven't really had much quality time with it. I did have just enough time yesterday to do a few laps around the 'hood before we had to scramble out to get my daughter to the airport. Then putt putt golf the day b4 that, and worked late the day b4 that... U get the picture!  Well, tonight's ride may have made the last few months of hell worth it all- well def not worth it but I'm certainly making some forward progress again. She's running like a champ right now! Actually, there's still a few little hiccups I need to sort out- more on that later... First and foremost on the subject of the broken piston- You'd never guess half the danged piston is missing it runs so good. Haha. I did notice however when it was idling while I was in the Autozone parking lot earlier today I though I could hear it slapping a bit. I'll have to keep an eye (ear) on it but for now I've put about 15-20 miles on the broken piston and so far so good! Even though this fuel pump wasn't putting out enough psi to overpower the floats or anything, it was pretty obvious to me that there was still just too much pressure with the incoming fuel and it was causing issues such as overfueling and hard starting and really just a nightmare to try to tune. I installed the el cheapo $9 fuel pressure regulator (which got horrible reviews on Amazon btw, but I think it's probably more due to folks trying to regulate higher powered pumps...) and after fiddling with it for a bit; it has a click dial on it that goes from 1/2 to 5 1/2 psi and using my clear fuel lines and clear float bowl, I could see that I needed to set it all the way to 5 1/2 psi just to get a decent flow of fuel.  The bowl now fills a lot more like it's gravity fed. Not rushing in too fast like it was, but fills fast enough that I shouldn't have any issues with it keeping up at WOT. Just right as Goldilocks would say! I toyed with the idea of plumbing it in as "bypass" or "return line" style with T's before and after the fuel pump as after a lot of research this seems to be the 'correct' method. I have it installed "dead headed" but that's actually how it was designed to work and again, I think folks that were having issues with this cheapy regulator were probably trying to regulate higher psi pumps than what I'm working with here. My new favorite way to mount everything on this scoot is with super strong neodymium magnets lol. I bought a pkg. of four and I love these things! The magnet is scuffed up and superglued to the back of the regulator and it holds it perfectly! I actually have such little slack/extra fuel line that the lines alone can actually support it, but I'm loving these magnets! I have my CHT gauge, fuel pressure reg, light for CHT gauge, and seat all held on by magnets! So now that I've got the fuel delivery seemingly squared away I've been working on tuning this byatch. I've tuned a lot of different 2t's in just the past year alone, but I gotta say this thing is straight out of the Twilight Zone. It seems every instinct I have as to which way to with jet sizes and fuel is exactly 180 degrees wrong! For instance, on my tuning ride tonight I was getting a lot of cutting out/loading up at anything under WOT. It basically seemed like I was practically fouling the plug while trying to drive at any speed other than WOT. I pulled over at a gas station and rejetted the mj 2 sizes down and the needle one click lean from middle slot. It seemed to be running a tad better as I pulled out of the parking lot, but once the light turned green and I hit the 4 lane main highway and I couldn't even get the bike up over 20 mph with spitting and sputtering. Wtf? Luckily traffic had pretty much cleared by then so I didn't get run over and pulled over in the next brightly lit spot- some grass at the edge of a used car parking lot- and proceeded to re-jet going exactly the opposite way. Ahh much better but I still have some work to do... I'm currently sitting at a 124 main jet. (no filter on carb for now- I was using the stock rubber air bellow, but it just doesn't fit right with this crazy carb angle and actually kinda collapses. no bueno. I need to find a decent small filter with a 45 degree bend that'll fit under the fender- preferrably a Polini one, but it looks like I found a UNI brand one on ebay that'll work.) Needle one clip leaner than center slot. It's decently tuned for WOT and mid-throttle but I really need to address this super rich idle jet that's also giving me some weird Twilight Zone feedback... Way back during my very first startup after the rebuild it would only idle with the choke on so I ordered some larger idle jets. Now it's acting totally different and even the 40 jet that came with the carb seems way too rich. The strange thing is I have to have the air screw only 3/4 turn out for it to start on first kick and idle properly without hanging?? But if I even touch the choke (I've never really needed to use the manual choke on my scoots) it instantly floods and time for a dry plug if I want to get it started anytime soon. Same thing if I jump up to a 45 idle. No start. Wet plug. Put the 40 back in and it starts right up. Loads up real bad at stoplights and generally shows all signs of being too large. Except the a/f screw needs to be rich at only 3/4 turn out?? I know there's no air leaks. She has passed leak down tests with flying colors on mutiple occasions now... Fricken Twilight Zone I tell ya! I'm thinking my electronic gizmo I want will possibly be just what the Dr. ordered and give me some advance at lower throttle range and some retard up in the revs. Should really wake this beast up. Stupid linear timing is for the birds!!  |
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Post by 190mech on Jul 1, 2016 3:39:20 GMT -5
With the carb so steeply angled the fuel level will make the pilot jet drool raw fuel into the intake,causing a constant rich condition,,just a thought.....
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Post by niz76 on Jul 1, 2016 17:43:53 GMT -5
With the carb so steeply angled the fuel level will make the pilot jet drool raw fuel into the intake,causing a constant rich condition,,just a thought..... That's been on my mind ever since I mounted this carb like that. Happy to say I'm done with the clear float bowl now. It's very satisfying to be able to see the fuel level and know what's going on in there but it is cheaply made and the gasket fits poorly at best. That big "quick jet change" nut on the bottom is fake and it's not removable so the bowl has to come off for every jet change. It also holds the carb up at a weird angle about 1/8" more than the stock bowl does (I filed the stock bowl so it fits better). |
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Post by drc174 on Jul 1, 2016 18:43:23 GMT -5
I need to read 27 pages first but:
PWK, aside from the 37 and 34 airstrikers real keihins, have really bad rep in the german scene.
Anywhere between 28-32 in the dellorto range is just way more fitting, and maybe a better intake to get a better angle.
Send me a PM, I am getting an okd PHBH in next week, we canstrike a no money deal.
That way you can get it maybe runningas intended instead of messing and pumping more money in this Keihin copy
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