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Post by duosport on May 21, 2010 21:14:30 GMT -5
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Post by duosport on May 21, 2010 21:19:32 GMT -5
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Post by duosport on May 22, 2010 8:20:57 GMT -5
From what I gather, the cast iron cylinder is much more durable than the ceramic coated aluminum. The aluminum cylinders are for performance it would seem. I am not racing or even concerned about speed so it sounds like the iron cylinder is the way to go.
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Post by 90GTVert on May 22, 2010 8:35:24 GMT -5
I agree that iron is a better choice for street scoots.
The mods that you will have to do with a 70cc should be pretty limited. You will need to check the jetting and possibly swap main jets, might have to adjust the idle midture settings again, and possibly change needle clip postion. Jets are only a few bucks a pop. To make your setup ideal, you may need to change roller weights. Sometimes the extra power makes the weights seem really light so you can swap in heavier weights to keep the revs down. Sometimes it runs very well and you'll be very happy with the weights as they are. Not a big deal if you do need to change them though.
One other note, make sure you get the correct wrist pin size. I know the air cooled minarellis come in 10 and 12mm versions. Not sure if liquid cooled scoots vary as well or not. If you can't find specific info for your scoot you can just pull the engine apart before you order and measure the wrist pin diameter.
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Post by duosport on May 22, 2010 8:47:43 GMT -5
Yes they have a 10 and a 12mm sized LC version of the BBK. I have the 10mm wrist pin. Upjetting the carb is pretty easy. I will clean it again when I get the cylinder sorted out anyway.
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Post by 90GTVert on May 22, 2010 8:51:37 GMT -5
It's not as bad as it sounds sometimes with the supporting mods. A lot of the time when you see folks do a BBK, pipe, carb, filter, variator, etc... it's just that they get the bug and have a hard time stopping.... not necessity. If you were going to get a more race oriented kit it might be a different story. That's a nice price on that iron kit BTW. Good find.
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Post by duosport on May 22, 2010 9:07:03 GMT -5
Thanks I searched around a lot to find it.
I have a Motori Minarelli PY Gurtner #12, carb. Is there anyway to know the existing jet size in it short of removal? I am hoping to not disassemble the carb at this point as I wish to buy the new cylinder replace it and try the carb first without a jet change. That way I can compare the difference after the jet change.
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Post by duosport on May 22, 2010 9:28:42 GMT -5
OK I have researched it and my carb is supposed to have a 62 main jet.
I see there are lots of different styles of main jets. How do I know which style to get?
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Post by duosport on May 22, 2010 9:32:58 GMT -5
A schematic I have found of the carb shows a #64 main jet in it. So pretty much the same.
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Post by 90GTVert on May 22, 2010 12:37:51 GMT -5
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Post by duosport on May 22, 2010 17:51:02 GMT -5
All of the minarelli engines I've messed with use Mikuni VM11/22 style main jets. ... I have found UK suppliers that list the jets for the Gurtner carb. But they do not give the specs of the jets. Here is a photo of one of the jets.  |
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Post by redorchestra on May 22, 2010 20:43:09 GMT -5
looks similar to my main jet! I never found a replacement I just drilled mine out.  |
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Post by duosport on May 22, 2010 21:50:37 GMT -5
Kind of scary. Don't make a mistake on the drilling and then if it is too big then too bad. This whole Italian scooter thing is getting old. I have had this scooter for 4 months. The whole time I have resisted the chant of "Just get a big bore kit". I resisted it for this very reason. I did not want to create an endless money pit that required more and more parts that I could not obtain. I hate to say it but I long for the ease of getting parts for the cheap chinese scooter.
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Post by stepthrutuner on May 22, 2010 22:30:19 GMT -5
Over drilling can be remedied by heating the jet with a propane torch a bit and filling the hole with electronics solder. Then it can be redrilled to the desired size.
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Post by redorchestra on May 23, 2010 8:05:17 GMT -5
I can send you my old stock size for $5. try it if, it fits then drill it, if it doesn't work, you can still go back to stock. PM me an adress and I'll Pm you a paypal adress
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