GT 380 with RG 250 cylinders

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v.f.
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GT 380 with RG 250 cylinders

Post by v.f. »

Saw the page of a tselovek who made it on Facebook. To talk to it it did not turn out what you think of such tuning? It seems to me that it is interesting
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titan performance
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Re: GT 380 with RG 250 cylinders

Post by titan performance »

I've never seen that done before.
Keeping old 2 strokes alive !
v.f.
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Re: GT 380 with RG 250 cylinders

Post by v.f. »

The gt380 crankshaft, upper crosshead approaches to rg250 pistons. Can be from the pro, somebody will comment?Probably it is interesting to put such engine in suzuki rg250 frame
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Re: GT 380 with RG 250 cylinders

Post by sportston »

Looks awesome. Would like one of those!
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Re: GT 380 with RG 250 cylinders

Post by v.f. »

Means it is necessary to try to make.Here it is interesting to me, the gt380 motor without alteration of a frame will get into rg250...
v.f.
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Re: GT 380 with RG 250 cylinders

Post by v.f. »

I found a little more photos of this engine...
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Re: GT 380 with RG 250 cylinders

Post by sportston »

Wow that is quite a lot of engineering to make that base plate. So it has reed valves and liquid cooling. Nice! I bet that makes it quite quick and reasonably reliable still.
v.f.
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Re: GT 380 with RG 250 cylinders

Post by v.f. »

The owner wrote that with porting on a back wheel 70 HPs. By the way, anybody has no map porting Suzuki rg250 mk1?
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Re: GT 380 with RG 250 cylinders

Post by sportston »

v.f. wrote:The owner wrote that with porting on a back wheel 70 HPs.
Wow, that is one quick 380! I'll bet it is great fun to ride.
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Re: GT 380 with RG 250 cylinders

Post by v.f. »

Means it is necessary to build such motor))). Maybe tz375 will advise, something?
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tz375
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Re: GT 380 with RG 250 cylinders

Post by tz375 »

I like that idea. The Gt380 was a square motor 54 x 54 - the same as many 250s including the GT250 and RG250. So a water cooled triple top end seems like a great idea.

One of my sons had an RG250 years ago and it went well and handled way better than the RD400 we had cluttering up the back yard at the time. The supposedly made around 45hp at 8,500 but I suspect that was at the crank rather than the back wheel, but they were still pretty nippy. On ours I opened up the crankcase reed port and that seemed to make a significant difference but we never slapped it on a dyno to see what the change was.

That RG380 is a really neat conversion. Wish I had though of it. It needs to be in an RG chassis too. 70hp sounds very possible without it becoming unrideable. Let's ignore the fact that an RZ motor (YammaGamma) makes more sense and with porting or a CPI cylinder could make much more power. That's been done before. This one is way more interesting.
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Re: GT 380 with RG 250 cylinders

Post by Zunspec4 »

A fascinating project :up:

it's worth remembering that back in the day Barton Engineering produced a 500 3-cyl machine using the GT380 bottom end as the basis. They were pretty damn rapid.

http://www.ozebook.com/compendium/suzipics/sparton.html
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Re: GT 380 with RG 250 cylinders

Post by Cyzygy »

Zunspec4 wrote:A fascinating project :up:

it's worth remembering that back in the day Barton Engineering produced a 500 3-cyl machine using the GT380 bottom end as the basis. They were pretty damn rapid.

http://www.ozebook.com/compendium/suzipics/sparton.html
More on the Barton Motors GT 380.
http://yorkshireferret.blogspot.com/201 ... -more.html" onclick="window.open(this.href);return false;
v.f.
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Re: GT 380 with RG 250 cylinders

Post by v.f. »

tz375 wrote:I like that idea. The Gt380 was a square motor 54 x 54 - the same as many 250s including the GT250 and RG250. So a water cooled triple top end seems like a great idea.

One of my sons had an RG250 years ago and it went well and handled way better than the RD400 we had cluttering up the back yard at the time. The supposedly made around 45hp at 8,500 but I suspect that was at the crank rather than the back wheel, but they were still pretty nippy. On ours I opened up the crankcase reed port and that seemed to make a significant difference but we never slapped it on a dyno to see what the change was.

That RG380 is a really neat conversion. Wish I had though of it. It needs to be in an RG chassis too. 70hp sounds very possible without it becoming unrideable. Let's ignore the fact that an RZ motor (YammaGamma) makes more sense and with porting or a CPI cylinder could make much more power. That's been done before. This one is way more interesting.
O, key. The connecting rod of gt380 is 10 mm longer, than rg250 connecting rod, it is possible to put Spicer. 3 cylinders will give more equal torque and on lower turns. Only that confuses me whether the gt380 engine will get into rg250 frame. Do you have street porting map rg250?
v.f.
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Re: GT 380 with RG 250 cylinders

Post by v.f. »

1981 polaris indy 500 centurion There was such snowmobile, it had water cooling and dimension 64х54... I could not find the cylinder block from it. Theoretically it it was possible to marry with the gt380 engine)))
Last edited by v.f. on Tue Nov 13, 2018 1:34 pm, edited 1 time in total.
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