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Post by waltinhawaii on Jan 4, 2013 0:43:58 GMT -5
checked out the carb on *bay... wow, great price. The last time I tuned a carb, it was this same type; round slide. I'm comfortable with them, but has anyone anything to say about the flat slide ones? They were just coming out when I lost interest in racing and sold my TZ and my Puch, so I never had a chance to use one. I have no idea if they are more tractable or easier to tune than the round slide; but they're still around, so I guess that's gotta be a vote of confidence.
aloha, walt
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Post by 190mech on Jan 4, 2013 5:34:24 GMT -5
I think the flat slide came to be due to better CFM for size and a shorter length.The OKO carb is a Keihin knock off,its a flat slide and well liked by many.The round slides can be modded to flow much better; www.thunderproducts.com/u_f_o.htmMost folks like the Dellorto carbs due to their easy tuning,I chose a Mikuni VM22 as Im an old dude and thats what we used to race with in the 70-80's.The 26mm knock off was suggested because of the low price and its jetted for a YZ80 which should be close to a 103 Mina..
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Post by waltinhawaii on Jan 5, 2013 13:41:15 GMT -5
Come to think of it; I've only really tuned mikunis in the past, so know nothing of dellorto. I think that's an italian carb? My espresso machine is italian too. It's always breaking down. If you saw the electrical schematic to my espresso machine, you'd turn blue in the face and wouldn't be able to say a coherent speech for weeks, its that bad. If espresso machines are any way to judge italian carbs, I'm sticking with mikuni or a knockoff thereof.
maybe I should hold my schematic of the espresso machine hostage and threaten to make it public unless they buy me a japanese carb.
Good news, I think; I dug down into my toolbox and found a flywheel tool that is 27mm reverse thread, so I don't think I need to buy another one for this job. Are case splitters really necessary or can you get by with a claw type puller for the cases?
aloha, walt
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Post by jmkjr72 on Jan 5, 2013 13:46:39 GMT -5
dont knock itlian stuff you do know that the engine you are running is of itlian desent right
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Post by waltinhawaii on Feb 6, 2013 10:10:40 GMT -5
Just kiddin, jmkjr. I know where the mina was originally designed, but I think the japanese bought it and developed it? Not really important to me, I just need a grocery getter that runs and I live near a lot of big hills.
190mech: thanks! just bought one of them YZ80 carbs and it's on it's way. Also put in a bid on a used small yz or cr radiator, now need a lc pump. They sell a new aftermarket one one ebay but it is only the pump, does anyone know where to get the right side cover it bolts to?
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Post by aznatama on Feb 6, 2013 21:04:58 GMT -5
Can't you just purchase a new rod that's 12mm? It would probably have to be custom-made though, and thus end up costing as much as the crank assembly itself.
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Post by waltinhawaii on Feb 7, 2013 4:34:51 GMT -5
I actually bought another crank, the new one is 45mm stroke, so that's the one I'll try to use. It is the larger size so should fit this case. I'll just save the 42mm/10mm pin crank I got and use it with a short case project I'll put together later (have the short case engine, but it's stock and it has no frame to go with it, just the motor/rear tire). so right now I have to concentrate on getting this long case together. since the cylinder kit I bought is lc, I need to find a couple of pumps and radiators.
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Post by waltinhawaii on Feb 11, 2013 2:49:54 GMT -5
hmmm. I know using the larger 53mm lc (taiwanese) bore will require machining the cases both for larger bore and inside the crank housing for larger webs, so wanted to have a little fun before splitting the cases. Playing with the stock engine today and couldn't get it started, so now it became a matter of pride in being able to find out just what I bought before taking it apart to machine the cases. While kicking it over, found that crank binds at intermittent intervals and locks up solid, refusing to move forward... although I can turn it by hand backwards. I thought it was the e-starter malfunctioning so took the starter off and also took out the little gears inside the case that engage with the large starter ring; but still ran into the stoppage problems. I am pretty sure there must be a piece of shrapnel inside the crankcase that's causing the stoppage. Because the stoppages are intermittent, I was able to get a compression reading and got about 70psi... pretty crappy. But the inside of the cylinder looks pretty decent, no galling or bad seizures. rings must be pretty worn. The head had a little bit of shrapnel indents, indicating someone probably lost a circlip in the past; but ports looked ok. Not that it matters, as crank and bore will be replaced with new stuff. But fun figuring out what's there. sigh. Have to take it apart to find out what's binding. Has anyone one run into stuff binding on the stator side?
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Post by 90GTVert on Feb 11, 2013 9:17:35 GMT -5
Nothing should bind on the stator side unless something's really out of whack. Any play in the crank/bearings? I had one of mine recently develop enough play that the flywheel wobbled and broke the pickup off of the stator plate.
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Post by waltinhawaii on Feb 12, 2013 1:31:15 GMT -5
ah, I've had that same problem in the past with a used moped I had for only a month; never worked on it as one good shake of the flywheel convinced me it would be a long rebuild requiring main bearings so I sold it in as-is condition.
I just measured up the distance from center of bore to the edge of the engine case; seems to be about 3 1/2" wide?on the trans side. If that's in the ballpark then I can just fit it onto the carriage of my lathe to do the bore widening since I only have a cheap chinese mini mill and no way can I fit the engine cases onto the mill's table, not enough headroom. The case halves can fit one at a time to mill the crank web spaces bigger, I think, but can't fit the case end-on onto the mill table of a mini mill. But I think I can bolt it onto the lathe saddle so that the chuck can have an end-on shot into the bore. Only problem is my boring head is an R8 taper, hope it chucks up true. I'll try to get the cases split this weekend but still looking this strange beast over. I think the last 2 stroke I took apart was my old Puch. Great site, Brent, I'm learning a lot. Thanks.
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