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Post by Chris Cristini on Jul 30, 2016 18:23:45 GMT -5
yea it was hot. did it after a ride. Also the demise of my Stater is my fault always double check the length of your Fan screws I found one was a bit longer however I don't remember taking the fan off before today and the damage was old and dirty so maybe it was before me. There is a ton of staters on eBay for like $15  |
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Post by FrankenMech on Jul 30, 2016 19:04:12 GMT -5
The engine needs to be warm, not hot, and you need to kick it over 6 times or more to get a reading with a little tiny engine. 3 or 4 times with a big V8 was close enough. It works out to be a ratio between the volume of the cylinder vs the volume of the hose and gauge. The pressure keeps building up in the gauge but if there is even the smallest leak you can't get a decent reading. Even the difference between that tester spark plug fitting and the regular plug will make a difference in a wee engine.
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Post by Chris Cristini on Jul 30, 2016 19:40:08 GMT -5
The engine needs to be warm, not hot, and you need to kick it over 6 times or more to get a reading with a little tiny engine. 3 or 4 times with a big V8 was close enough. It works out to be a ratio between the volume of the cylinder vs the volume of the hose and gauge. The pressure keeps building up in the gauge but if there is even the smallest leak you can't get a decent reading. Even the difference between that tester spark plug fitting and the regular plug will make a difference in a wee engine. Ah next time I will make sure it is just warm I kicked it atliest 10 times I kept going till the gauge stopped. It is crazy how easy it is to kick so I don't think its too far off I found that the locator pin in my 49 was gone and that had less than 2000 miles on it I almost bet my adly will be the same way. |
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Post by niz76 on Jul 30, 2016 20:21:48 GMT -5
If you've got a huge squish gap that'll kill compression also. An easy way to gain some compression is to delete the head gasket if you're running one and use copper spray only to seal the head to the cylinder...
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Post by FrankenMech on Jul 30, 2016 20:31:53 GMT -5
Deleting the gasket between the cylinder and crankcase is probably safer. A tiny leak at the head can get big fast when the fire leaks. Be sure to measure the piston to head clearance. I am not sure what the minimum is on these engines.
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Post by niz76 on Jul 30, 2016 22:45:43 GMT -5
I typically run with neither base gasket nor head gasket. (Motoseal for the base and copper spray for the head) More than likely you'll find a cavernous combustion chamber that's killing your compression and performance. 1mm is a good safe squish clearance and makes for a healthy daily driver that doesn't need high octane fuel (assuming you keep the timing advance mild  ) to prevent pinking. Removing the base gasket will tighten up the squish a bit and deleting the head will make it even better. Of course gotta measure it first! A few of us that set up these 90's and also the Hoca 54mm's have even had to take it a step further and shave the head down some to try to get to decent squish #'s. Like I mentioned a while back- there's a lot of power left on the table with these untuned 90's! |
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Post by nelson on Jul 31, 2016 18:40:55 GMT -5
I typically run with neither base gasket nor head gasket. (Motoseal for the base and copper spray for the head) More than likely you'll find a cavernous combustion chamber that's killing your compression and performance. 1mm is a good safe squish clearance and makes for a healthy daily driver that doesn't need high octane fuel (assuming you keep the timing advance mild ) to prevent pinking. Removing the base gasket will tighten up the squish a bit and deleting the head will make it even better. Of course gotta measure it first! A few of us that set up these 90's and also the Hoca 54mm's have even had to take it a step further and shave the head down some to try to get to decent squish #'s. Like I mentioned a while back- there's a lot of power left on the table with these untuned 90's! The hoca short 54mm can be had on Amazon for about 130-150$. I run it on a 43.5 stroke crank and no gaskets .75 mm squish clearance with 160ish psi. Pump gas,great street lotta nuts Been riding it hard for close to 150 hours. Not an issue yet. |
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Post by Chris Cristini on Aug 3, 2016 16:28:49 GMT -5
Good thing I'm getting BBK lost power like crazy hooked up The compression tester 62PSI vs 90 I felt power getting worse since I got the motor time for a rebuild. I'm suprized it sort of runs. |
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Post by FrankenMech on Aug 4, 2016 2:16:59 GMT -5
Compression will drop with leaking valves. It may be time to adjust the valves. Leaking valves can damage the valve seats though so we have to adjust valves frequently.
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Post by arkie on Aug 4, 2016 2:26:40 GMT -5
Psssst Frank! I dont think its a leaky valve.  |
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Post by Chris Cristini on Aug 4, 2016 7:52:45 GMT -5
Lol are you testing me frank? Haha would be funny if I said I will check them |
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Post by Chris Cristini on Aug 6, 2016 16:44:41 GMT -5
Is it possible for an engine to be ridable with compression this low I only ask because if it is not my compression tester is a POS.  |
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Post by spaz12 on Aug 6, 2016 17:11:54 GMT -5
Is it possible for an engine to be ridable with compression this low I only ask because if it is not my compression tester is a POS. Check your valves That's way low compression  |
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Post by Chris Cristini on Aug 6, 2016 22:50:45 GMT -5
its all good now sold for $400 trying to find another build lol I didn't want to sell it but I felt bad for this kid. Maybe my next one will be a Moroni based Hyosung. By the way Is Moroni any Good? 70cc and exhaust lol Found a good thred hope its the same engine its an SD50 I am going to get it tomorrow $250 |
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Post by 190mech on Aug 7, 2016 4:06:11 GMT -5
Parts are hard to get for the Morini motors,SD50 is bottom mount,seat bucket is steel welded to the frame,difficult to work on,did I mention parts are hard to get yet??
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) to prevent pinking. Removing the base gasket will tighten up the squish a bit and deleting the head will make it even better. Of course gotta measure it first!
