1973 380gt tidy up

Photos and progress of your restorations, even bikes you had but no longer own.

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sportston
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Re: 1973 380gt tidy up

Post by sportston »

andyd wrote:they lasted about a day and then went hard as a bulls forehead again....
Lol. I've never heard of that turn of phrase before. "As hard as a bull's forehead". I like it. Will have to wait until I get the opportunity to use it.
Glyn.G
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Re: 1973 380gt tidy up

Post by Glyn.G »

Glad you decided to take the plunge Andy. As I stated before if you've gone down the Cruizin Image route bin the clamps that come with them as the tack welds on them are rubbish.
Regards,
Glyn.
andyd
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Re: 1973 380gt tidy up

Post by andyd »

Hi Glyn, received the intake rubbers and they look pretty good, nice and supple, and yes the clamps are rubbish I am using stainless worm drive at least you get a good bite all the way round the rubber. Will fit them up tomorrow and see how I go, What a great way of spending " Australia Day " public holiday working on a Suzuki, man that's really living.
Glyn.G
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Suzuki 2-Strokes: Suzuki GT380 B- Yamaha FZ1
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Re: 1973 380gt tidy up

Post by Glyn.G »

Hi Andy.
Glad all is ok, but just a word of warning if you are using standard worm drive / jubilee clips, try not to over tighten them as the sharp edges can cut into the rubber when the rubbers go through their heat cycles. If you check your original ones or the cruizin image ones they have turned up edges giving a rounded / bevelled edge so as not to damage the rubbers. I know through experience that it's tempting to give an extra turn on the screwdriver to make sure the clip is really tight. I did and the rubbers fell in half within a week.
Regards,
Glyn.
andyd
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Re: 1973 380gt tidy up

Post by andyd »

Thanks Glynn will take care with those and let you know the outcome if it solved the problems with the idle
andyd
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Re: 1973 380gt tidy up

Post by andyd »

Fitted the intake rubbers but the problem is still there, the 2 right hand cylinders are running fine, ( hot header pipes ) the left header pipe remains cold which to me says that cylinder is not working which in turn makes the other 2 work overtime and eventually drags the engine back to stall.
I have plenty of nice fat blue spark, remove the plug and it is wet, take out the sris plug and a small amount of fuel drips out , the other 2 cylinders are drier, exhaust pipe is not blocked, no gaskets are leaking anywhere, and there is 130psi compression. Battery is new and showing 13volts and will check all the connections today for voltage drop to the coil, timing OK
Ripped the alternator off to check and replace the seal and the lips were very hard, but no sign of leakage anywhere but maybe sucking a gutful of air and not compressing the mixture in the crankcase.
Slowly running out of things to look at but it will not beat me, I will knock in the seal today and check the electrics etc and report back.
Andy
sportston
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Re: 1973 380gt tidy up

Post by sportston »

A wet spark plug could be caused by too much fuel. Have you checked the float level and the condition of the float needle on the carb?Maybe a small bit of dirt in the carb is stopping it from sealing.
Also; Is the choke valve closing fully and sealing?
andyd
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Re: 1973 380gt tidy up

Post by andyd »

Hi Sportston, I have already overhauled the carbies ultrasonic cleaned and replaced all the jets and needle & seat, sprayed everything out with carb cleaner and blew all passage ways out, checked the choke tube sealing rubber and adjustment on the cable.
I will pull that carb off again and run through it and see what we can find, I have a feeling it is only something stupid that obviously I am overlooking, but I will continue digging away until I find the problem.
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grumps
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Re: 1973 380gt tidy up

Post by grumps »

I am having the same issue with cylinder 3. Starts fine but once the choke is off unless I keep the throttle open No3 cuts out and I get a wet plug, cylinder does not fire and I get oily petrop/residue from the exhaust weep hole.

I'm thinking float level/jammed float valve etc.

Watching this thread with interest. Thanks
If money can't buy happiness - explain motorcycles and beer!
andyd
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Re: 1973 380gt tidy up

Post by andyd »

Hi, I pulled the carby off and ripped it apart, float bowl full of fuel, float height spot on, so removed all jets and checked each passage way (drilling) got my oxy/acetylene tip cleaners and a piece of thin electrical wire and carefully stuck them down the holes, drillings.
At the front (engine side of the carby ) the mixture screw hole runs up to the inside of the housing, there is also another hole in front of this hole that is drilled at an angle that runs into the mixture screw hole, maybe an air bleed or such, I found a little bit of dirt in there.
Also the thin brass tube pressed into the bowl that feeds the choke tube had a small amount of calcification inside and after reaming that out and spraying everything again with carb cleaner and blowing with air I re-assembled and set the float, and adjusted the choke plunger.
Put it back on and straight away the cylinder fired up and it was a totally different happy engine.
Not 100% sure which passage had the most crap in it but they both had a little bit that the ultrasonic cleaner didn't remove and obviously I overlooked these passages previously, even though I used carby cleaner and air but was not enough.
I should have taken a couple of photos when apart and I apologise for that but it goes to show that these bikes that are sitting around for years and even if the carby looks fairly clean when you pull them apart it pays to really take your time.
Glyn.G
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Suzuki 2-Strokes: Suzuki GT380 B- Yamaha FZ1
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Re: 1973 380gt tidy up

Post by Glyn.G »

Hi Andy,
Glad you got it sorted, now it's time to ride and enjoy.
sportston
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Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: 1973 380gt tidy up

Post by sportston »

Excellent. Glad you got there in the end!
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