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Post by 180°off on Apr 29, 2016 13:40:42 GMT -5
So I got my CPI running again. New piston and rings in it but when it's running I hear that metal on metal sound like I did right before it heat seized. But it wasn't running long enough for it tonheat seize. Also took it for a short test ride and it doesn't have as much power as it should have. Very slow? I know I have to much oil in the gas, could that be the problem to why it's slow?
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Post by gsx600racer on Apr 29, 2016 15:13:31 GMT -5
Is it possible to give us some more info. Pics of your melt down would be nice(if you tore it down yet)
Is it stock or kitted(big bore)?
Did you use a quality piston and rings set as well as new wrist pin bearing or something cheap?
Did you re-hone the cylinder, check piston to cylinder clearances, ring gaps ?
Was the piston rings installed correctly on the piston ?
How decent was the crankshaft ? Were the rod and main bearings in good shape.(maybe your metal on metal sound)
Did you install the cir-clips with the openings facing towards the crankshaft?(maybe your metal on metal sound)
What was your compression and squish prior to starting ?
Did you pressure check engine for leaks prior to running ?
How long did you break-in the new piston and rings ?
There is so much more than installing a new piston and rings and slapping it all together and rider her like ya stole it.
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Post by 180°off on Apr 29, 2016 16:03:11 GMT -5
Wow?? I didn't really do any of that. I bought a crapoy piston and rings off eBay. I know rings are installed properly. I do not have the tools to check for clearances. If u know where I can get some cheap let me know please. Crank and everything seem to be ok. It did not melt down yet. I did hand hone the cylinder. The molassi kit I got was off another engine that I tore apart and got lucky to find so Im not sure of what kit it is.
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Post by 2stroked on Apr 29, 2016 20:13:35 GMT -5
1st, pickup a set of feeler gauges if you are on a budget. they will do for CV clearance and tolerance measurements.
2nd, a cheap piston kit can be used. I was running a piston and ring set from joshscloseouts on eBay. Just make sure the piston measures the same as the piston intended for the kit you are running. The most important piston measurement besides bore diameter,is the height from wrist pin to crown top. Also the skirt is an important part of the intake system, so window measurement and placement is important as well.
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Post by gsx600racer on Apr 29, 2016 21:18:56 GMT -5
Harbor Freight is a start for some basic tools. 6" digital calipers for measuring.. Feeler gauges for checking ring gap and top of piston to cylinder deck height. Compression tester, but I wouldn't trust HF.Small engine cylinder hone. Preferable one with decent length stones. Brake cylinder hones stones are too short in length and will snag on ports inside of the cylinder.(any auto parts store) Torque wrench. 3/8 drive in/lbs. Cheap ones are inaccurateItems listed in RED, I wouldn't skimp on. Links are for visual reference. |
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Post by stepthrutuner on Apr 29, 2016 22:22:31 GMT -5
Harbor Freight is a start for some basic tools. 6" digital calipers for measuring.. Feeler gauges for checking ring gap and top of piston to cylinder deck height. Compression tester, but I wouldn't trust HF.Small engine cylinder hone. Preferable one with decent length stones. Brake cylinder hones stones are too short in length and will snag on ports inside of the cylinder.(any auto parts store) Torque wrench. 3/8 drive in/lbs. Cheap ones are inaccurateItems listed in RED, I wouldn't skimp on. Links are for visual reference. As far as hones go I prefer the abrasive ball rotary brush hones for cylinder mishap cleanups. They're more gentle and make it harder to take the honing process too far which is irreversable. The drawback is you have to have them sized to within a mm or so at or above the bore size being honed. Stone hones are more versatile but much care must be taken to keep them from flying out of the bore and breaking stones. |
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Post by 2stroked on Apr 30, 2016 17:12:43 GMT -5
Harbor Freight is a start for some basic tools. 6" digital calipers for measuring.. Feeler gauges for checking ring gap and top of piston to cylinder deck height. Compression tester, but I wouldn't trust HF.Small engine cylinder hone. Preferable one with decent length stones. Brake cylinder hones stones are too short in length and will snag on ports inside of the cylinder.(any auto parts store) Torque wrench. 3/8 drive in/lbs. Cheap ones are inaccurateItems listed in RED, I wouldn't skimp on. Links are for visual reference. As far as hones go I prefer the abrasive ball rotary brush hones for cylinder mishap cleanups. They're more gentle and make it harder to take the honing process too far which is irreversable. The drawback is you have to have them sized to within a mm or so at or above the bore size being honed. Stone hones are more versatile but much care must be taken to keep them from flying out of the bore and breaking stones. I too like the old " bottle brush " hones. IMHO they are way easier to keep in spec while doing light honing. |
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Post by 180°off on May 2, 2016 13:08:10 GMT -5
When u said skirt for the intake process? What is the skirt?
Th
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Post by 2stroked on May 2, 2016 16:28:05 GMT -5
When I mentioned the piston skirt and the intake process, I was referring to the little cut out windows on the piston, under the wrist pin area.
The piston skirt is the part of the piston that is hollow and holds the intake charger Windows. Different size or location if the ports on the piston will translate to different cylinder scavenging characteristics.
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Post by gsx600racer on May 2, 2016 18:09:34 GMT -5
Here is a picture of a 2 stroke piston. The "Green" area is the piston skirt. The "transfer port window" is what 2stroked is talking about.  |
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Post by 180°off on May 3, 2016 3:31:14 GMT -5
Ok got it, just never heard the term skirt as being referred to the window. Thanks. The only difference between the original piston and the cheap knock off oneingowhere the skirt is on the original it's all open and on the knock off there is a bar that goes through the center and that's it. Matching it up the the cylinder when off everything else matches up.
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