How do you hot up a GT380?

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sportston
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Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: How do you hot up a GT380?

Post by sportston »

Pete O'Dell wrote:its std practice to cut the heads in half and separate them for any tuning
You know, I had been giving this some thought and wondered if it would cause the centre head to run hotter if it was cut from the other two. Wouldn't it stop a certain amount of heat from being conducted away?
I'm in two minds whether to separate mine or not. On the one hand it is less likely to blow a head gasket and need regular retorquing as much but I am wary of getting that centre too hot. I've heard they seize in the middle more often the outer two. I'd hate to make it any worse. I can't help wondering why Suzuki made the head in one piece?
Have you had a lot of personal experience in owning and running GT380s with the heads cut Pete? Did you ever find they seized under hard use?
I do plan on riding mine hard. I always do, so I want to engineer in a reasonable factor of robustness as well as speed. I suppose it is that, ever difficult to achieve, balance between power and reliability.
Craig380
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Re: How do you hot up a GT380?

Post by Craig380 »

I've just had my 380's head cut into 3 to fix weeping from the head gaskets. The bike is otherwise standard apart from J&R expansion chambers.

I do ride the bike hard, so I'll let you know how I get on :up:

The myth about centre cylinders seizing is just that - a myth, fostered largely by ignorant teenage riders who of course were entirely blameless for breakdowns with their careful maintenance (removing air filters and exhaust baffles for 'performance', never checking the timing, using lawnmower oil) :wink:

380s are in a low state of tune and there's plenty of finning for cooling. Kawa triples always had 3 separate cylinder heads and are generally in a higher state of tune than the equivalent capacity Suzuki triple. OK, they may not be as reliable as a Suzi but Kawa's engineers felt a one-piece head and cooling ducts wasn't necessary.
1976 GT380 - wounded by me, and sold on
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
sportston
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Joined: Wed Jul 10, 2013 12:04 pm
Country: England, UK
Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: How do you hot up a GT380?

Post by sportston »

Thanks for the info guys.
I think I am coming to the conclusion that it is worth cutting the heads after I have had them skimmed. Especially since there were signs of weeping on my head too.
Pete O'Dell
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Suzuki 2-Strokes: T500X2 GT500 GS750 GS500/4 KAWASAKI A1 GT250

Re: How do you hot up a GT380?

Post by Pete O'Dell »

totally with Craig on his above post most problems were down to ignorance and the availability of haynes (book of lies)manuals, those magic publications that suddenly turn complete dip sticks into skilled mechanics at the flick of a page.

To answer your question have I had personal experience of running 380's with cut heads, that would be a yes and also tuned many of them in the period and one recently, I also turned one into a 350 in 76 when I had a go at racing one for a bit of fun, alongside my serious racing.

Its also the first thing too do with the later GT250's aswell.
sportston
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Suzuki 2-Strokes: FZ50, GP100, RG125 Gamma, GT380, Bandit 1200S

Re: How do you hot up a GT380?

Post by sportston »

Super great info chaps. Thanks. Will definitely be taking an angle grinder to my head then!
My Gt380 has had to take a bit of a back seat for a little while at least, since I've recently inherited a Bandit 1200S. Now I have TWO suzukis. At least the Bandit is a goer and only needs a new battery. But I will be continuing to restore the GT380 as finances allow. I love them both equally and aim to cherish them both.
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