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swap a gs400 engine into a gs450

  • Thread starter Thread starter Guest
  • Start date Start date
A 77 or so GS400 engine?Not a direct swap as the engine mounts are different.Should be do able with some fabbing.The later 80+ TSCC Canadian model engine should be a direct swap though,same bottom end as the 450.
 
Thanks, the ones I am looking at are both 83's. Is for a future product if I can get them at the right price
 
make sure you get the exhaust and intake manifolds because those dont interchange between the two engines.
 
So, did I read that correctly? I can fit a 450 onto my 82 gs400T? What about a 500?
 
You can fit the engine in the frame with no problem. The base and mounting points are the same.
The head on the 500 has exhaust ports that point straight towards the frame.

But a gs 450 with a gs 500 block and pistons combined with the 450 head is the way to go.
 
Mekanix said:
But a gs 450 with a gs 500 block and pistons combined with the 450 head is the way to go.
Click to expand...

You can also use a GR 650 head. Use the GS 500 head & base gskt. Switch the cam sprockets and you can use the 650 cams too. Oh yeah, you have to plug the EPA sigots that go into the intake tract. Burns-o-matic and soft solder works great.
If your a bit industious you can also use the GR650 pistons by trimming the skirts of the pistons. It makes it a 527cc. http://www.youtube.com/watch?v=tQEVHd1cSyw
 
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wera90ex said:
You can also use a GR 650 head. Use the GS 500 head & base gskt. Switch the cam sprockets and you can use the 650 cams too. Oh yeah, you have to plug the EPA sigots that go into the intake tract. Burns-o-matic and soft solder works great.
If your a bit industious you can also use the GR650 pistons by trimming the skirts of the pistons. It makes it a 527cc. http://www.youtube.com/watch?v=tQEVHd1cSyw
Click to expand...

Gr. Head ?
It does not work without modification and you will have a ccompression ratio of 6:1 even if you used the gr pistons.

The 400 base does not have the stroke the gr has.

450 heads have the smallest combustion chamber.
Gr650 has the largest.
500 is in the middle.
 
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So if you get your hands on a whole GS500 engine, you can just install your GS450 head on top of it and be done...?

Use the 500 cams on the 450 head?
 
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I can't remember the exact numbers now but I believe the cams are the same spec.
You have to swap out the shift drum too.

The gs500 is backwards compared to the 400 and 450. So up would be down.
 
jfman said:
So if you get your hands on a whole GS500 engine, you can just install your GS450 head on top of it and be done...?

Use the 500 cams on the 450 head?
Click to expand...

The one in the pic is a GSX400 bottom. Also have a (612cc) and a (578cc) engines for this season. All with the same head- cyl combination.
You can use the 500 cams in the 450 head. The 650 cams are marginally bigger, but they are bigger. Actually have a set of 650 cams in my GS 500 practice bike.
 
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Mekanix said:
Gr. Head ?
It does not work without modification .
Click to expand...

Really? I wish you'd have told me 10 years ago........... I keeeeed! I keeeeed! :D Yes, there are a few things you have to mod.
 
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Wow that looks good wera90ex :) I meant it would not be a direct swap on with little work. But anything is possible!

I thought about using the whole gr top end. As in: taking the cylinder block and pulling the sleeves out. Shorten the block on the bottom end about 8mm and deck the head as much as possible to compensate for the big combustion chamber. Use the GR pistons and get it all to work and look like it was made like that :)
Then I decided to just take the sleeves and go camakazy 4 valve on it :P


What happened with the timing chain and the extra long center channel on the GR head ?
Was it long enough ?
Did you have to weld up the front and back of the head ?
How did the crank hold up?
Did you do anything to the top end oil jets ?
what CP ratio did you end up with ?
How was the vibration with the new pistons
How hot did it run ?

Keep the info coming, I'm really interested in everything you did there :D
 
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Mekanix said:
Wow that looks good wera90ex :) I meant it would not be a direct swap on with little work. But anything is possible!

I thought about using the whole gr top end. As in: taking the cylinder block and pulling the sleeves out. Shorten the block on the bottom end about 8mm and deck the head as much as possible to compensate for the big combustion chamber. Use the GR pistons and get it all to work and look like it was made like that :)
Then I decided to just take the sleeves and go camakazy 4 valve on it :P


What happened with the timing chain and the extra long center channel on the GR head ?
Was it long enough ?
Did you have to weld up the front and back of the head ?
How did the crank hold up?
Did you do anything to the top end oil jets ?
what CP ratio did you end up with ?
How was the vibration with the new pistons
How hot did it run ?

Keep the info coming, I'm really interested in everything you did there :D
Click to expand...

That cam chain tunnel was the first thing I thought I'd have problems with. It's JUST on the edge. Didn't weld anything.
I just used the 450/500 timing chain with the 450/500 sprockets.


Cranks held up just fine. The key to keeping the crank in good shape is don't over rev. It will break on the right side rod journal. Only had 3 break in 25 yrs. My fault entirely.
Kept the same oil jets. They're just for crank/rod bearing pressure anyway.
On CP ratio, I don't really know. Never bothered to figure it out.
I was more concered with lifting the head/cyl off the bottom end due to stud stretch. Which at street speeds it's probably not too much an issue but at the track your WFO.Used APE studs.
Vibration isn't a problem. Even with the 83 mm pistons. Only vibration problems I've had is when I removed the balancer. Don't do it. That motor will want out. Ran great! But broke the frame.
Heat: It gets hot as hell but never melted anything. Even when I used some $25 a gal. dragon **** for fuel.
When I've put all the different combos together I normally clay the top end to make sure everything is going to fit. Degree the cams and double check piston to valve clearances. Don't really worry too much about the bottom end they're so over built. But that's one of the things I love about these bikes.
 
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