Author Topic: GT engine in C5  (Read 1924 times)

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matthewreichlin

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on: April 02, 2019, 06:21:05 pm
Posted in the C5 forum, but thought I might ask here too.  Need new top end for C5, but considering whole engine.  Bought the bike with no barrel and trashed head, crank case still in.  There is a seller on ebay not far from me with a GT engine.  The consensus seems to be it will fit right in and the bottom end in the C5 looks exactly like my GT engine.

What others are not sure on is if the fuel and spark delivery systems will be the same.  Are those he same or different?  Anyone done it? Anyone have any good thoughts?


gizzo

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Reply #1 on: April 02, 2019, 10:32:20 pm
I wouldn't know but I'll hazard a guess and say the engine will run just fine with the new head and bigger barrel on the old block, or the whole new engine will run just as fine, on the Bullet ECU and injector. Like the others said on the Bullet thread, the worst that will happen is you will need a Powercommander to optimise it. If that GT engine was near me, I'd be buying it at that price anyway, just to have as a spare. Have at it.
simon from south Australia
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matthewreichlin

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Reply #2 on: April 02, 2019, 10:50:14 pm
Just noticed today that it has an after market power commander.  After checking prices, that is great news all around. Don't know how to tune it, but I am sure I can figure it out. 

Is the GT engine just a little higher CC, or is it also tuned to be a bit sportier or faster?  Nice to be able to say I upgraded to GT engine if I sell, even if it doesn't really mean much.  I hadn't thought about switching heads, but I am guessing RE would have just used the same crank case for efficiency.  Not like the Gt is all that fast that it would need special gearing. 


gizzo

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Reply #3 on: April 02, 2019, 11:31:49 pm
You'll have to find some "GT" badges for the sidecovers, though....
simon from south Australia
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matthewreichlin

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Reply #4 on: April 03, 2019, 12:35:45 am
Nlw, there's an idea.  I will tell people it is a special edition non production factory prototype

You'll have to find some "GT" badges for the sidecovers, though....


ace.cafe

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Reply #5 on: April 03, 2019, 03:31:13 am
Just noticed today that it has an after market power commander.  After checking prices, that is great news all around. Don't know how to tune it, but I am sure I can figure it out. 

Is the GT engine just a little higher CC, or is it also tuned to be a bit sportier or faster?  Nice to be able to say I upgraded to GT engine if I sell, even if it doesn't really mean much.  I hadn't thought about switching heads, but I am guessing RE would have just used the same crank case for efficiency.  Not like the Gt is all that fast that it would need special gearing.
It has a 3mm larger bore(87mm) which comes in a slightly larger cylinder barrel, which fits into a slightly larger case mouth. Head is the same casting, but has slightly larger intake valve and 34mm port and intake tract and 34mm throttle body. It is a little bit more powerful than a 500.

The external dimensions are basically the same as the 500. The 535 cylinder barrel won't fit into the 500 engine case without a small enlargement of the case mouth.

Use the whole GT engine as a unit. Your 500 bottom end is compromised from the top end failure anyway. It shouldn't be used without a teardown and rebuild.
« Last Edit: April 03, 2019, 03:37:30 am by ace.cafe »
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matthewreichlin

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Reply #6 on: April 04, 2019, 09:15:25 am
Thanks for all the info.
 If it is still available when I raise the funds, I will give it a go.  tax time though.
 

It has a 3mm larger bore(87mm) which comes in a slightly larger cylinder barrel, which fits into a slightly larger case mouth. Head is the same casting, but has slightly larger intake valve and 34mm port and intake tract and 34mm throttle body. It is a little bit more powerful than a 500.

The external dimensions are basically the same as the 500. The 535 cylinder barrel won't fit into the 500 engine case without a small enlargement of the case mouth.

Use the whole GT engine as a unit. Your 500 bottom end is compromised from the top end failure anyway. It shouldn't be used without a teardown and rebuild.