wevie
Scoot Junior
Posts: 11
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Post by wevie on Feb 22, 2015 20:44:22 GMT -5
While I'm learning, what's the difference between the "shortcase" and "longcase" ?
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Post by moofus02 on Feb 22, 2015 22:38:47 GMT -5
While I'm learning, what's the difference between the "shortcase" and "longcase" ? Shortcase has the gearbox cover on the left side under the belt cover. Longcase the gearbox bolts on from the right behind the wheel. Longcase will take a tall 12 inch wheel and tire. Shortcase uses a short 10 inch. Some of the atv motors (adly for example) use shortcase gears with a longcase motor. They take a really long belt. The normal clone short and longcase motors tend to use a 788 long belt Sent from my SPH-L720 using proboards
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Post by stuckchuck on Feb 23, 2015 10:01:58 GMT -5
The right one is a short case, note how the clutch input shaft is in line with the output shaft. left side is a long case, note the distance the output shaft is behind the clutch. and the noticeable casting difference in the cases.
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Post by Fox on Feb 23, 2015 10:30:55 GMT -5
So it looks like they both use a 788 belt. Is that right? There is one other engine I know of that is a hybrid between the two shown above that is a long case with the same gear box as a short case and it uses a longer 878 belt. The Adly and Scrappy's sites both refer to it as the "Her-Chee" engine.
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Post by stuckchuck on Feb 23, 2015 10:50:09 GMT -5
"So it looks like they both use a 788 belt. Is that right?"
now that you mention it, your right i think a short case uses a shorter belt than the 788? now im lost and dont know what to think. hmmmm
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Post by moofus02 on Feb 23, 2015 14:55:34 GMT -5
The shortcase clones use the 788 belt. When you talk about Yamaha motors that all is different
Sent from my SPH-L720 using proboards
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wevie
Scoot Junior
Posts: 11
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Post by wevie on Feb 28, 2015 20:30:40 GMT -5
Here's some pics of the current condition: The cylinder looks like it will hone up just fine. The head... wow. That is going to need some polishing. Here's what I just ordered: Hopefully next weekend with the new parts we can get it fired up.
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Post by Corrosion on Feb 28, 2015 20:39:56 GMT -5
Make sure you get a new wrist pin bearing. Go over the oil pump and drive. Looks like it had O lubrication. Put a thin film of RTV on the Gaskets. Particularly the intake & reeds. But, not the head gasket. Check the intake manifold boot, they get hard and crack. I replace them for assurance.
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wevie
Scoot Junior
Posts: 11
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Post by wevie on Mar 1, 2015 11:02:55 GMT -5
Make sure you get a new wrist pin bearing. Go over the oil pump and drive. Looks like it had O lubrication. Put a thin film of RTV on the Gaskets. Particularly the intake & reeds. But, not the head gasket. Check the intake manifold boot, they get hard and crack. I replace them for assurance. I'll just be mixing the gas for now. I have not yet inspected the intake and reeds.
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Post by Corrosion on Mar 1, 2015 11:32:01 GMT -5
FYI- Pre mixing normally require's a re-jet. The oil displaces the fuel in the mixture. Not a big deal, just remember to do it.
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wevie
Scoot Junior
Posts: 11
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Post by wevie on Mar 6, 2015 18:49:18 GMT -5
OK, I'm about to chuck this whole thing in the trash barrel.
New piston and rings installed. Cylinder honed out nice. Head polished up (with some effort). Has much more compression than before!
Thin RTV on cylinder gasket. Dry head gasket. Pulled reeds and put thin RTV there too. Carb looks good.
Have excellent looking spark.
Even with a teaspoon of gas in the spark plug hole, there is not even a single pop out of this motor.
HELP!!
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Post by oldgeek on Mar 6, 2015 19:53:33 GMT -5
Do you have the air box installed? The air on these 2T's is a bit picky.
Sent from my SGH-T999 using proboards
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Post by Sitticuss on Mar 6, 2015 20:36:47 GMT -5
sparking?
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Post by niz76 on Mar 6, 2015 23:56:03 GMT -5
So you used that cylinder head? In my experience it's hard enough to get a good seal at the cylinder head with a totally straight head and gasket! Even the smallest head gasket leak might be enough to bring the compression down below 100psi or so- about the minimum required to get the engine to start.
You could use copper spray (available at auto parts stores) to spray a healthy layer on the cylinder head and each side of the gasket to promote a good seal...
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Post by Corrosion on Mar 7, 2015 0:32:34 GMT -5
Compression test time: If that is not an option, I would check the keyway on the Flywheel.
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