1973 380gt tidy up

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andyd
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Suzuki 2-Strokes: 1973 gt380 CB550f, W650, XJ6, S3, RZ 350
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1973 380gt tidy up

Post by andyd »

Hi, from Australia, thought I would add this photo of the 380gt K that I have finished tidying up, she runs along pretty good a little bit of an idle problem so I think maybe sucking some air through the carb intake rubbers, they were as hard as a rock. The rubbers are fairly hard to find, any clues from anybody ?
A good old bike and you get plenty of looks from other bikers. Andy Sydney
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grumps
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Re: 1973 380gt tidy up

Post by grumps »

Hi Andy

Welcome. I'm new here too and also have a 'new' running 380 that I'm learning about. Not as simple as they look!

Mine also has issues with idling but only when hot. I wonder if that is down to the rubbers? They look good though.

Enjoy the bike.

David
If money can't buy happiness - explain motorcycles and beer!
Glyn.G
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Re: 1973 380gt tidy up

Post by Glyn.G »

Hi Andy,
Those rubbers can be a pain. I bought a new set for my 76 GT380 from Cruizin Image at £25 a set of 3 off e-bay. Just a word of warning though if you go down that route, bin the clamps that come with them as they are rubbish. I've done over 1500 miles with these manifold to carb rubbers and they seem to be holding up well, plus they cured my erratic idle.
Regards,
Glyn.
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grumps
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Re: 1973 380gt tidy up

Post by grumps »

Cheers Glyn

Great info
If money can't buy happiness - explain motorcycles and beer!
andyd
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Joined: Sun Aug 20, 2017 1:48 am
Country: Australia
Suzuki 2-Strokes: 1973 gt380 CB550f, W650, XJ6, S3, RZ 350
Location: Sydney, Australia
Contact:

Re: 1973 380gt tidy up

Post by andyd »

Thanks for the replies, I have seen them in Cruizin Image but they list them as 74-77, I thought the J & K models were different from the later models as the earlier ones had the separate carbs where as the later model had the carbs bolted together.

Any thoughts on this ? Thanks Andy
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jabcb
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Re: 1973 380gt tidy up

Post by jabcb »

DiscountBikeSpares in the UK lists them. https://www.discountbikespares.co.uk/ou ... GT380.html
An eBay seller in Germany has them. https://www.ebay.com/itm/Suzuki-GT-380- ... 2895066710

From what I’ve read, the cruzinimage parts are OK if you have the stock airbox. They aren’t as stiff as the stock intake pipes, so its advisable to stock intake pipes if you are using pod filters.

Also, you may be able to rejuvenate your existing intake pipes with Rubber Renue or a similar homemade brew that includes wintergreen.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

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grumps
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Suzuki 2-Strokes: GT 380, 1977 (now sold)
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Re: 1973 380gt tidy up

Post by grumps »

Sorry to hijack this but it may be relevant.

My GT380 ticks over just fine when cold. Take it out for a run and it will tickover at 1100 rpm for maybe 15 secs before stuttering and dying. It restarts straight away when kicked over but does the same tickover routine.

I thought maybe a blocked vent in the fuel cap but it's the same when that's open. I was thinking maybe blocked tank filters but the idea of the rubbers is a new thought. Thanks for raising it in the OP.

David
If money can't buy happiness - explain motorcycles and beer!
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 »

I agree that the Cruizin Image intake rubbers are slightly softer than the originals when new, but I found that after a few heat cycles they stiffen up quite a lot. Just be careful not to over tighten the clamps when fitting from new. On the plus side with them being softer you can get a really good seal without too much effort on the clamps.
sportston
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Re: 1973 380gt tidy up

Post by sportston »

nice looking bike!
andyd
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Suzuki 2-Strokes: 1973 gt380 CB550f, W650, XJ6, S3, RZ 350
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Re: 1973 380gt tidy up

Post by andyd »

With all the research I have done on these intake pipes it tells me that the J & K models were different to the 74 - 77 models ?
Some firms list them that they will fit all GT380's but after several emails to different firms ( including Cruizinimage, and Diablo cycles ) they say no they will not fit.
I would imagine all the 380 heads are the same diameter on the head, but maybe the carby size is different ? The airbox side doesn't matter as I have the standard filter set up.
I have the standard Mikuni VM 24 SC carbies.
I will pull the carbies off again and measure everything ( the engine side and carby side ) and then see what I can find out.
If anyone has any definite ideas about these please let me know, it would be greatly appreciated.
Glyn.G
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Re: 1973 380gt tidy up

Post by Glyn.G »

Hi Andy,
According to my supplier, Discount Bike Spares who are generally very good at identifying the correct parts for the correct models tell me that their GT380 intake rubbers, Part No 13111-33100, old No 13111-33000 will fit all 380 models including the J & K models.
Apparently it's the GT550 that has different intake rubbers for just the J & K models which strange enough has the same part number as the GT380 as stated above.
Hope this helps,
Regards,
Glyn.
sportston
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Re: 1973 380gt tidy up

Post by sportston »

Take note; if you are planning to install bigger carbs, you will need to get the GT550 rubbers as the internal cone diameter is different. If you are happy with standard carbs then get the gt380 ones from cruzin image. I bought some and they appear to be pretty good but the clamps are naff.
andyd
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Suzuki 2-Strokes: 1973 gt380 CB550f, W650, XJ6, S3, RZ 350
Location: Sydney, Australia
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Re: 1973 380gt tidy up

Post by andyd »

Hi, thanks for all your replies, I have had a look on Partzilla and this is what they say :

Pipe intake 13111 - 33100 - Models LMAB

Pipe intake 13111 - 33000 - models K ( don't know what happened to the "J" model )

Even the pipe clamp part numbers are different between the K and the LMAB models.

It still leaves me a little bewildered, If someone can say , "YES" I fitted the intake pipe rubbers I bought from Cruizinimage that they list
for the 1974 - 1977 models to my GT380 " K " model with the single mounted stock carbies and air box, I would buy them straight
away, but no good to me if they don't fit.

They are all coming off this weekend and I will measure everything. Andy
Glyn.G
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Suzuki 2-Strokes: Suzuki GT380 B- Yamaha FZ1
Location: High Peak Derbyshire.

Re: 1973 380gt tidy up

Post by Glyn.G »

Hi Andy,
Part No 13111-33000 is the old part number for the J / K model, 13111- 33100 is the new number designed to fit ALL models. If you look at the new rubbers you will see a moulded slot on one end of the rubber. This was designed to correctly orientate your individual carbs in the upright position on the J/K models by fitting a flange on each carb into the slot. The later models have gang carbs connected together by a top plate which automatically puts them into the upright position so no need for the slot. I suppose that rather than produce two types of manifold rubbers they stuck with the J/K type which has the slot on and said FITS ALL MODELS. For £25 take the risk, they will fit.
Regards,
Glyn.
andyd
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Posts: 12
Joined: Sun Aug 20, 2017 1:48 am
Country: Australia
Suzuki 2-Strokes: 1973 gt380 CB550f, W650, XJ6, S3, RZ 350
Location: Sydney, Australia
Contact:

Re: 1973 380gt tidy up

Post by andyd »

Thanks Glyn, after writing that last email I thought well they are only $60 so what the heck, so I ordered them, if you are worried about that small money after spending a heap on other parts you are getting pretty tight.
Will still pull it apart on the weekend anyway and wait for the bits to arrive.
I tried the wintergreen and oil treatment, they lasted about a day and then went hard as a bulls forehead again, obviously too old and too much heat and cold over the years.
Thanks for all your help and I will let you know the outcome.
Andy
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