gt 380 oil lines

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Woodpecker
Posts: 25
Joined: Tue Oct 29, 2019 12:11 pm
Location: Rainham Kent

gt 380 oil lines

Post by Woodpecker »

Hello Im new to the forum and having difficulty getting oil through the cci system. Following a full restoration of a 1972 GT380j I have got it running on premix but lots of air in the oil lines. I have opened the pump lever to maximum on a fast tickover and had the pump apart. I have two sets of oil lines and taken off the banjo connections as instruction I found here. Some of them appear to have been air line blasted which has damaged the springs so I expect they will leak. I have enough good valves to make up a good set but will the plastic to metal push fit leak or should I glue them. Any advice would be appreciated
Stu
barney01
Posts: 3118
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: gt 380 oil lines

Post by barney01 »

Firstly welcome to the forum. Secondly i would advise you not to run your bike until you get your oil pump CCI sorted as these bikes have fitted a system which injects oil directly to the crank and a lesser amount direct to the cylinder walls. The premix alone wont be enough and damage to the crank may occur.
If you have air in your feed lines its more likely to be the small rubber o rings which fit between the pump and the spider. Check the pump is sited properly and secure. Another possibility is air in the tank to pump hose. You did bleed it first?. Also try removing the oil tank cap it has a breather diaphragm that can prevent oil flow.
The oil banjo's that bolt to the engine can be changed but its a complex job
This link may help you inderstand the oil pump
http://www.pinkpossum.com/GT750/Oilpump.htm
This is a link on valve replacement
https://www.oldjapanesebikes.com/blog/2 ... ktomysuzy/
NO SMOKE .......NO POKE
Woodpecker
Posts: 25
Joined: Tue Oct 29, 2019 12:11 pm
Location: Rainham Kent

Re: gt 380 oil lines

Post by Woodpecker »

Thanks for the quick reply. I wont take the bike out until I'm sure the oil lines are working. I will check the tank and have some new clear silicone tube so I can see oil is present in the pump feed. I did bleed the pump and fitted new o seals. As I said I have the oil lines apart so will press on.
Woodpecker
Posts: 25
Joined: Tue Oct 29, 2019 12:11 pm
Location: Rainham Kent

Re: gt 380 oil lines

Post by Woodpecker »

Hi
Further to my problem with gt380 oillines I have done the following. Replaced the oil feed from the tank to the pump with clear tube checked the oil lines and dismantled two of the check valves which looked good. Put it all back and ran on a fast tickover. The lines are dark red and difficult to see oil but some looked like there was some flow. Disconnectd the end (no 1 pot) line and ran for 1 to 2 minutes no oil. Also holding the pump wide open I could feel the pump pulsing.Another thing the gravity flow from the oil tank was very slow at the pump supply I had taken the tank cap off. So the question to those who know about these things is what should I do now I dont want to take the bike out until i'm 100% happy it working as it should.
Thanks Stu
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PaulD738
Posts: 3962
Joined: Thu Sep 25, 2014 6:57 pm
Location: Warrington Cheshire

Re: gt 380 oil lines

Post by PaulD738 »

Where the oil union is on the bottom of the tank there is a filter protruding into the tank. You need to make sure this is spotlessly clean or it will restrict the flow. When I stripped the one on my T500 the amount of gunge trapped in the filter was amazing.
They're rubbish them Jap bikes lad they won't last five minutes! you want to get yourself a nice Royal Enfield!
A quote from my old dad 8-)

I started out with nothing and I’ve got most of it left!
barney01
Posts: 3118
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: gt 380 oil lines

Post by barney01 »

There is a cam in the pump cap which pushes the little pistons within the pump this is what you feel pulsing when its wide open. When you disconnect a banjo you should fairly quickly see oil appear . The oil is quite slow moving down the tubes during operation. You need to remove the pump and make sure the oil lines are definately full. Use a syringe or a sqirty oil can to force oil through until you hear it sqirting into the engine. Then bleed the pump to make sure. Then run the motor with the pump arm full open and disconnect the banjo and you should see some oil ( it wont squirt it just weeps) if it doesn't then its time to remove the pump and strip it down.
FYI never try to force the pump back to the closed position as the arm only returns to the off position every 62 rotations of the crankshaft.
If you see no oil come back and we will walk you through the pump disassembly and test.
NO SMOKE .......NO POKE
Woodpecker
Posts: 25
Joined: Tue Oct 29, 2019 12:11 pm
Location: Rainham Kent

Re: gt 380 oil lines

Post by Woodpecker »

Thanks for your help but still not happy with the cci system. A bit of a recap I have two pumps and have stripped both down. The original on the 1972 bike (estimate its stood for at least 20 years and was in a very sorry state when I rescuded it from the sister of the original owner and thats about all the history I have) is a 3 piston pump and in good condition with all parts free. I bought a spare on ebay and this is the later 2 piston pump which again is in good condition so I have fitted this one. With the engine running as its very difficult to see if its working properly the oil lines are dark red and the oil pink.
When I fitted the oil lines I unintentionally had not tightend No.1 upper pipe and was pleased to see the pink oil leaking from the banjo fitting so assumed the pumps ok but being a bit paranoid about this system I loosend No.1 lower pipe,this is the only one I can get to without taking off the carbs. Running the engine for about 2 minutes I am not getting any oil! This feed was one of two which I Removed the banjo fitting from the pipe and examined the non-return valve and spring both were free and in excellent condition so I am at a loss why no oil!
Any suggestions would be appreciated I don't wont to take the bike on the road unless I am 100% happy with this .
Stu
barney01
Posts: 3118
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: gt 380 oil lines

Post by barney01 »

You say you have stripped both pumps down. Did you replace the gasket between the cap and the pump body? Did you do them each in turn as the caps are different in those two types of pump. Did you remove the actuator arm? as its possible to replace it back to front.
As oil is issuing from the top(cylinder) banjo that would indicate the pump is working. I would remove the pump body and using a squirty oil can pump oil via the hole in the spider that leads to number 1 lower(crankshaft) banjo. Loosen that banjo and see if oil comes out. We are checking for a blockage in the feed pipe.
These pumps are very robust and rarely fail. It is widely thought that they over oil the engine.
NO SMOKE .......NO POKE
Woodpecker
Posts: 25
Joined: Tue Oct 29, 2019 12:11 pm
Location: Rainham Kent

Re: gt 380 oil lines

Post by Woodpecker »

Yes the gasket on the spare pump wasa good so reused no leaks I did remove this lever but it appears to ok. As you suggest I will remove the oil lines and check for a blockage. I should get a better idea on the other feeds which are difficult to get at with the carbs on. will report back later.
barney01
Posts: 3118
Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: gt 380 oil lines

Post by barney01 »

The reason i mentioned the lever was because if its put back the wrong way ot will be pumping maximum at rest and minimum at full throttle. Which as you can appreciate is not good. See how you get on. One other thought i have is what 2T oil are you using? If you mix mineral or bean oil with fully synthetic it causes "glooping" which is similar to clotting.
Whilst the pump is off, leave the oil tank feed connected and invert the pump. Remove the pin from the driveshaft. Put a screwdriver in the pin hole and spin it around counterclockwise and oil should appesr from the little holes. Not much but some.
NO SMOKE .......NO POKE
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