GT 550 cylinder head difference

[Roos]

Easy .. machine out the 550 head and put in squish inserts

Yes, of course the best solution. We have some machine shops doing it for approximate $600 so it is rather expensive.

[Suzukidave]

I wonder , do the chrome bore 550's come with any special head ?

[Suzukidave]

^^+1^^

Or weld up the head and machine it to a new shape.

GT750 .. but same idea ... http://www.youtube.com/watch?v=sfV43YGdAkw" onclick="window.open(this.href);return false;

[Roos]

I wonder , do the chrome bore 550's come with any special head ?

Actually nikasil but guess you meant that, I have this on my cylinders but the cylinder head looks very equal to pictures seen.

It has two extra transfer ports, I do not know if the iron cylinder have them? They do have diffrent piston ring, way more expensive, close to $80 for each piston.

gt550cylinder.jpg

[Suzukidave]

Thanx " nikasil " those are special cylinders as the iron bore 550's dont have the extra ports , it is too bad Suzuki also didnt top them off with a nice squish head .

[Vintageman]

I am so jealous of those extra ports the EU GT550 jugs have, regardless of heads. Need engine case change too.

This must have been asked before, but, they change the exhaust port timing versus the other design? like they did with the GT250 change? Never seen any write up that they did.

Back to squish head goal. What about putting RD350, RD400 (taller fins), or R5 heads. I think Tz375 once showed a T350 with RD400 heads. I looked into this a bit for T350 and I think you do have to drill/ hog out for different stud spacing. Well I think it would look ugly maybe? Maybe put the Ram Air cap back over heads too . The T350 did look nice with RD400 heads .

One thing I found about my 73 GT550 a bit of carbon build up will make it ping. I tore my top end down and cleaned carbon off head and piston, I had some build up (nothing radical, but definite build up .. maybe because my check valves in oil injection line leak for after setting a while it may smoke heavy from 2 stroke oil build up... need to fix that).
No more ping after. I was try to solve that problem solely by drowning the bike with more and more gas (jetting) . This year I plan to go back to a more stock setting for I think carbon, leaking check valve was my main issue in hindsight was a big part of it. Just fyi

[Alan H]

Too much carbon build up can mean cold plugs, left on tickover for hours at a time, too much oil, cheap oil, running rich, running with choke slightly on or not being spanked enough (mainly the bike!) to clear the carbon deposits out. Remember also that if there is a carbon build up in the ports and head, it will be worse in the exhaust.

[Roos]

This must have been asked before, but, they change the exhaust port timing versus the other design? like they did with the GT250 change? Never seen any write up that they did.

regarding timing it should be something like std 176 exhaust, 146 intake. its a ruff estimate but close to the truth at least. i'm working on a mild modification so we will see what that will give in performance.

[old racer]

^^+1^^

Or weld up the head and machine it to a new shape.

GT750 .. but same idea ... http://www.youtube.com/watch?v=sfV43YGdAkw" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

It seems like a lot of work just to have central plugs.

[tz375]

It's not so much about plug position as having a squish band.

What were the heads like in your drag race motors? Stock OEM/TR or squish type?

[old racer]

I watched all seven vids of the head machineing
there was no squish cut into those heads.
All the head on my dragbikes were skimmed stock,

[Suzukidave]

I was surprised when after all that work he didnt machine in a squish band but he did stand up the outside plugs and made the volumes of all 3 equal .

[old racer]

I agree,But he only needed to weld up the plug holes,And Drill and tap.

[Suzukidave]

Even though it doesnt look it he may have changed the dome shape and maybe even volume to adjust compression , i have seen volume checks of the stock chambers and they vary quite a bit .

[old racer]

Quite possible,But it just seem like a lot of work for probably little or no improvment,
If your going to fill it in then why not cut a squish.