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Author Topic: 72cc kit..trans kit project..55 here I come  (Read 6224 times)

flextrainer

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72cc kit..trans kit project..55 here I come
« on: November 15, 2009, 02:53:19 AM »
I'm gonna start tearing down my engine tonight to install the 72cc kit that's been sitting on the shelf for two weeks. I almost don't want to put it on because she's finally running good. I'm gonna port and polsih the heads and work on the exhaust while it's down. I'll keep posting through the project to let you all know how it is going. So sad I just got all the bugs worked out and got her running 42-45 easily on flat just cruising. Have an iridium plug, but I'm gonna wait until I get it broken in and get the new transmission kit installed ( hi po vatiator & clutch ) so I can see if it really makes a difference. Otherwise I won't know what worked the best. Just curious on what everyone else thinks on the break in procedure. I always use the hard break in procedure based on the theory that the first few miles are when you can seat the rings to the cylinder best. Two full throttle pulls with letting off the gas ( till a rolling stop) and letting the vacuum in the cylinder pull the rings up to seat the top and bottom good. Then running fairly easy for 500 miles. Any other theories out there.
« Last Edit: November 15, 2009, 02:55:04 AM by flextrainer »
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zombie

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Re: 72cc kit..trans kit project..55 here I come
« Reply #1 on: November 15, 2009, 05:57:22 AM »
First thing, if you are running on the oil injector pump; zip tie it wide open. You will need the extra oil to keep everything moving free. I would also add just shy of 1 oz. oil to the fuel. Most certainly run through the rpm range. Give it three-four miles around mid range, and run it up for a few tenths of a mile. varying the rpm's will prevent the new parts from taking a premature seat. I would say two tanks of fuel is PLENTY of break in for a piston/cyl. In moto-x there is NO break- in at all. The most important thing is to use quality 2t oil, and plenty of it. I have been running my injector wired open for a few months now (since i burned a piston) and am planning to keep it that way. I also add about 1 oz. of seafoam to every tank to keep it all clean. You may be a little disappointed w/ the jug kit alone. They don't do too much until you can get the engine to breath right, and start turning some SERIOUS rpm's. Please keep us posted!
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flextrainer

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Re: 72cc kit..trans kit project..55 here I come
« Reply #2 on: November 15, 2009, 06:09:11 AM »
well my first snag is the end gap. they are about .006" too big. why couldn't they be too small, easy fix. now I have to wait for new ones.
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Shaka

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Re: 72cc kit..trans kit project..55 here I come
« Reply #3 on: November 15, 2009, 07:36:40 AM »
Huh, that sucks!  I never even checked mine. :-\
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zombie

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Re: 72cc kit..trans kit project..55 here I come
« Reply #4 on: November 15, 2009, 04:00:00 PM »
A little "point" file will cure that. Or did you mean the GAP is too big?
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flextrainer

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Re: 72cc kit..trans kit project..55 here I come
« Reply #5 on: November 15, 2009, 07:19:00 PM »
the gap is too big. now I have to wait on new ones to get here. I have been trying to see how big is too big, but the verdict is pretty much the same all around. cylinder bore in inches x .004 on the top ring and cylinder bore x .005 on the bottom ring. which comes to .007 top and .009 bottom. there were wider recommended gaps for nitrous and high po apps. but none would give a .014 and .016 which is what I have. ex. of mine 47 ( bore in mm) divide by 25.4 to convert to inches = 1.8503. Multiply that by .004 to get your ring's end gap = .0074. too small of a gap and rings butt together and break too much and you have excessive blowby and oil consumption plus loss of compression/performance.
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Shaka

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Re: 72cc kit..trans kit project..55 here I come
« Reply #6 on: November 15, 2009, 07:58:39 PM »
I would put it together and do a compression test.  That's going to give you the true answer to your question! 
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zombie

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Re: 72cc kit..trans kit project..55 here I come
« Reply #7 on: November 15, 2009, 11:06:18 PM »
Who makes the kit you are using? A 47 mm piston should have you at 70cc. What I dont understand is why the rings would'nt match the cyl. they were made for, unless the material they are made of is EXPECTED to expand. Have you contacted the MANUF., instead of the supplier? There will also be a different set of rings for a nicasil/ alum. cylinder vs a cast iron cyl. Just trying to throw some ideas!
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"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

flextrainer

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Re: 72cc kit..trans kit project..55 here I come
« Reply #8 on: November 15, 2009, 11:39:14 PM »
thanks guys. didn't think of the rings and aluminum cylinder material thing, just going by the general rule for ring gapping. I thought of doing the compression test but didn't want to have to tear it back down ( have to get new gaskets) if it was bad and compression usually drops a little after break-in becausee of wear on the rings and cylinder, so I figure if I start with too big of a gap it will only get worse. Good idea of finding out the manufacturer and contacting them. My supplier is ususlly the best at fixing things or explaining why they are right.
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zombie

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Re: 72cc kit..trans kit project..55 here I come
« Reply #9 on: November 16, 2009, 01:18:05 AM »
Cool... Too much worry is a KILLER! Keep posti'n.
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"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

flextrainer

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Re: 72cc kit..trans kit project..55 here I come
« Reply #10 on: November 16, 2009, 07:24:53 PM »
Heard back from my supplier and he's sending out another set of rings. He's real good about customer service and is quick. Never had any problem, but now I know it's not a problem when I do have one...peace of mind. I get my stuff from www.enviromoto.com and he can get pretty much whatever I need if it's not on his site. Y'all should check him out.
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Shaka

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Re: 72cc kit..trans kit project..55 here I come
« Reply #11 on: November 16, 2009, 11:57:03 PM »
Looks like a pretty nice website!  Always good to have another reliable source!
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flextrainer

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Re: 72cc kit..trans kit project..55 here I come
« Reply #12 on: November 17, 2009, 02:29:10 AM »
Should have my rings in two days, he sent them out first thing this morning. Got him looking for a trans kit for me too since I haven't got it yet. He has one I really want, but is out of my budget.
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flextrainer

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Re: 72cc kit..trans kit project..55 here I come
« Reply #13 on: November 18, 2009, 12:47:11 AM »
Got my trans kit picked out. Now I just gotta get it ordered, get my motor broken in, and go.
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Shaka

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Re: 72cc kit..trans kit project..55 here I come
« Reply #14 on: November 18, 2009, 12:49:22 AM »
Do you have a link to post up for everyone to see what you decided on?
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