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Last ditch effort tear down, removing cci and premix only
Posted: Mon Apr 06, 2020 10:57 pm
by Craighjr
Long (very long) story short. GT380 doesn’t run right. Have the chambers off and most of my 2 stroke oil was there or in the trans. Been through multiple cci pumps, seals and gaskets. I need to split the cases to replace my block (due to old cracks in the trans mount area anyway). I have NOS case halves already. Is there anyway to get this thing 100% premix????? I’m needing to get it running right as this is a 4 year project with 52 miles on it. Advise please.
Re: Last ditch effort tear down, removing cci and premix onl
Posted: Tue Apr 07, 2020 4:57 am
by jabcb
There are check valves in the oil line fittings that prevent the draining of oil into the crankcase. You need to either service the oil lines or replace them.
(Do NOT use compressed air on the oil lines!)
Don’t know the details, but you need to rebuild the crank if you are switching to premix.
The T500 has the infamous transmission problems + crankcase oil-level mods.
The GT380 crankcase also had oil-level mods. See Service Bulletin GT-10
http://www.ozebook.com/compendium/techb ... 007-13.pdf
If you have a sweet restoration with the original motor, then having a welder fix the crankcase cracks is worth considering.
Re: Last ditch effort tear down, removing cci and premix onl
Posted: Tue Apr 07, 2020 10:19 am
by Craighjr
I have merged 2 spiderwebs and have good check valves for the bearings and premix. I had to eliminate the nipples from the cylinder bottoms because 2 of my 3 were broken. The transmission is getting 2 stroke oil in it from a second pump with new top and bottom gasket and seal. This bike is a cafe custom because it was built from eBay parts around a roller I acquired so not collectible at all just looking to have it run. The crank was rebuilt by someone in like Montana I want to say...he was well regulated by suggestions on this forum. I supplied him with one of the Cruzin Image bearing sets from eBay and he sourced a few last oem parts to make it right.
I will look up the thread you mentioned and research that now as they are things I have not heard of.
Re: Last ditch effort tear down, removing cci and premix onl
Posted: Tue Apr 07, 2020 2:42 pm
by karl pa
If you run 100 percent premix you need to remove the oil guide plates from the crankshaft, these plates are designed to pull oil from main bearings that are fed from pump. if you leave the plates in it will starve the bearings of oil. Some that race these bikes leave the bearing feed of the system in place but use premix for top end.
Re: Last ditch effort tear down, removing cci and premix onl
Posted: Tue Apr 07, 2020 4:41 pm
by Craighjr
Ok, oil guide plates removed. It’s not that I don’t want cci on the motor I am just having so many problems premix seems so easy if there is a safe way to do it. Again the bike is for putting around not racing.