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upgraded engine parts...
just wondering if anyone knows if (someone still makes these) and where to get:
oversize pistons (possibly JE) oversize valves (moriwaki used to make them?) cams cuz i will soon finally have enough money to get this shit to put my hawk back together. after a year and a half down! thanks in advance. |
--oversize pistons - not sure who made these before. Do you mean the hicompression pistons? most went with HC pistons - you should be able to find those (JE, moriwaki)
--oversize valves - I looked and had no luck finding any for the SH specifically - I had porting of the intakes and 3angle valve job done when I built mine --cams - still around, but will take some searching - occasionally on ebay or maybe still through distributor. best bet to check with the US moriwaki distributor or the UK distributor directly. |
You could look at having a custom set of pistons made (as Shayne did; I think he called on a company called CP, do a search as he provided a lot of info in previous threads). AS far as cams are concerned, Yoshimura also made cams and there are a few sets still floating around (I picked some up about two months ago). You can also have stock units reground at a few places (Megacycle, Webcam I think). Good luck.
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The little bit that you will be able to go up in valve size isn't going to be as rewarding as keeping the same valves and having the seats machined to have a bigger opening.
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I agree its all about how smoothly air flows through the head. Angle jobs do wonders, especially on four valve heads
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I found a set of 1mm bigger valves on the intake and exhaust for about $300 a little pricey as I bought the cams from the same site and for the 600 plus clams another 300 plus the 250 for pistions and then the cost of putting it all toghether with a port & polish its starting to get to much for me. I could buy a track bike with the cash. But the pistions and valve / port job will be going in with the cams this winter got a spare motor that had the side covers cracked and the front valve cover but have a set of heads also. So I can do the work as I have cash and then put it together with not so much down time.
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This guy always has JE pistons for sale for the Super Hawk. I bought mine from him. We had a problem (wrong pistons sent) and he made it right. We even had a 3 way conference call with the rep from JE to make sure everything was OK.
http://cgi.ebay.com/ebaymotors/JE-PI...QQcmdZViewItem |
thanks for the help people!
i'll post pics of the rebuilt hawk in about another year! |
Where else could you get JE pistons, because i haven't been able to find out how to get them on thier website...
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Originally Posted by autoteach
(Post 126849)
The little bit that you will be able to go up in valve size isn't going to be as rewarding as keeping the same valves and having the seats machined to have a bigger opening.
Thanks |
The problem with small bore 4 valve engines is that the valves are already shrouded by the cylinder. bumping up size that way doesn't really afford much of a power increase, especially when you are talking about 1mm bigger valves, with which a 1mm larger seat diameter would be necessary. So your inner dia went up but the item blocking the flow of air, primarily, also went up in size. The secondary blockage of air flow, shrouding by the head design and the cylinder walls, has come more into play as the valves are .5mm closer to all this. Where as, if you kept the same size vlaves, and went from a 2mm valve seat to a 1.5mm valve seat, you increase the inner dia by 1mm without increasing primary or secondary blockage of air flow. Couple that with an unshrouding of the valves and you will have noticeable power gains.
note: undercutting the valve seat will cause the valves to wear faster, and will also require a port and polish (as would larger valves). You could do the same to larger valves, but at an increased cost as well as you have to pay for the seats and the valves. |
You can get over-sized valves and JE pistons from Erion Racing.... http://www.erionracing.com/
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Originally Posted by autoteach
(Post 127726)
The problem with small bore 4 valve engines is that the valves are already shrouded by the cylinder. bumping up size that way doesn't really afford much of a power increase, especially when you are talking about 1mm bigger valves, with which a 1mm larger seat diameter would be necessary. So your inner dia went up but the item blocking the flow of air, primarily, also went up in size. The secondary blockage of air flow, shrouding by the head design and the cylinder walls, has come more into play as the valves are .5mm closer to all this. Where as, if you kept the same size vlaves, and went from a 2mm valve seat to a 1.5mm valve seat, you increase the inner dia by 1mm without increasing primary or secondary blockage of air flow. Couple that with an unshrouding of the valves and you will have noticeable power gains.
note: undercutting the valve seat will cause the valves to wear faster, and will also require a port and polish (as would larger valves). You could do the same to larger valves, but at an increased cost as well as you have to pay for the seats and the valves. |
Wouldn't it be cool
If someone did an aftermarket head for the S'Hawk with all the latest tech? Radial head, pneumatic valve springs, steeper valve angles, EFI?
Think in terms of 130 RWHP and the same spread of power. Might not catch a Duc 1098, but still... |
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