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Discussion Starter · #1 ·
Alright guys as many have known ive been slowly rebuilding my super head this winter for next season. Finally got all my parts in including valves springs and my new intake for a 24 mm carb. Ive come to notice though that the new intake valve takegawa sells is 28mm compaired to the 27 that the older super heads have. I even called lyle from CHP to get his imput. He said the size differences is considered to be worth 4 sheets of paper and i shouldnt have anything to worry about. Also according to my parts numbers they are the correct ones for my head. My question is has anyone else noticed this before they put there new valves in there older super heads.



If anyone has the older takegawa cataloge and could do me the favor and look up there part number which is 14711-SPR-T00 Was this number considered the replacement valve for the olderstyle super heads (not plus Rs)



And on the CHP website its P378IV.



Like i said lyle told me i shouldnt have anything to worry about and as im understanding takegawa basically made a once size fits all type of deal (maybe to save money?). Ive already put the new valves and springs in and everything seals up perfectly when i do a leak down. Im just a lil concerned about the valves hitting the piston so i may grind out a lil extra space just in case on the inlets of the valve reliefs on the piston.
 

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50rider340 said:
Alright guys as many have known ive been slowly rebuilding my super head this winter for next season. Finally got all my parts in including valves springs and my new intake for a 24 mm carb. Ive come to notice though that the new intake valve takegawa sells is 28mm compaired to the 27 that the older super heads have. I even called lyle from CHP to get his imput. He said the size differences is considered to be worth 4 sheets of paper and i shouldnt have anything to worry about. Also according to my parts numbers they are the correct ones for my head. My question is has anyone else noticed this before they put there new valves in there older super heads.



If anyone has the older takegawa cataloge and could do me the favor and look up there part number which is 14711-SPR-T00 Was this number considered the replacement valve for the olderstyle super heads (not plus Rs)



And on the CHP website its P378IV.



Like i said lyle told me i shouldnt have anything to worry about and as im understanding takegawa basically made a once size fits all type of deal (maybe to save money?). Ive already put the new valves and springs in and everything seals up perfectly when i do a leak down. Im just a lil concerned about the valves hitting the piston so i may grind out a lil extra space just in case on the inlets of the valve reliefs on the piston.


What is the serial number on your head?
 

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Discussion Starter · #3 ·
you will laugh as i see F5 on the left side where the cam cover is. This is the older style twin spark super head. Or am i gonna get screwed and they just really dont make the correct valves for this head anymore.... I looked all over the head and that is the only spot i see any numbers besides takegawa written on the right fin over the right sparkplug. Unless theres some hidden spot they put them im not seeing it hopefully the F5 is what your looking for.
 

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50rider340 said:
you will laugh as i see F5 on the left side where the cam cover is. This is the older style twin spark super head. Or am i gonna get screwed and they just really dont make the correct valves for this head anymore.... I looked all over the head and that is the only spot i see any numbers besides takegawa written on the right fin over the right sparkplug. Unless theres some hidden spot they put them im not seeing it hopefully the F5 is what your looking for.


F5 is what I was looking for. F7/G7 Twinspark heads took 28mm valves and were the latest version when they were discontinued.



F6 and lower were 27mm valves. There's a sidenote in the older catlog in red discussing this, but seeing how I don't read Japanese and don't have the time to answer your questions, I'll have to send you back to CHP whom I'm sure sourced you the only replacements available other then going custom and most likely work.
 

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Discussion Starter · #5 ·
wow that is just great takegawa stoped making parts for these older super heads. Should i look at it as if lyle from CHP said this should work fine that i should go with it then? I was hopeing someone else on here would of ran into the same problem as im pretty sure the older super heads had 27mm intake valves also. Either way im gonna run it as the older exhuast valve i had in there i dont even know how it was sealing in the first place. I was also told that takegawa told lyle that this would work even though its slightly larger.



Also thanks for all the info.
 

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Discussion Starter · #7 ·
thats what i was thinking on doing. The thing is though i did a leak down and it seals up? so should i go with it? ahah. Im gonna clay it and on my new piston im gonna make the divits on the piston larger just in case. Im sure lyle at CHP has gotten this phone call often and i dont think he would say it will be fine when it wouldnt be? its odd cuz it almost looks like the 45 degree angle on the new valve was made larger to compensate to fit multiple valve seats? Compaired to the old valve or any other valves ive taken out its much larger. The japenese do a great job to get rid of old parts to make new ones fit everything there all about lean manufactureing over there.
 

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The problem with your "OLD head" is that the seats themselves probrobly aren't flat anymore and your new valves won't have a good sealing surface for them.



Your valve seats will need to be cut.



Plus you can have it ported at the same time to match the bigger valves.
 

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Discussion Starter · #10 ·
Dont worry guys ill be taking lots of pictures in a lil while. I just got my new 52mm piston to. I donno what takegawa did but the also changed what the old super head piston looked like compaired to the one i just got but according to part numbers i have the correct one. The pin heights are slightly different and the shapping on the top is completely different to. I donno if they came out with a better design or something as time went on. I love how im having all these problems. This is becoming expensive. But a great learning experience to. As for getting the seats re cut i have a few machine shops around here friends work at that i know if i have to will get that done at. Give me a lil time and ill have LOTS of pictures up.



Whats peoples opinions of Lyle telling me i should be fine running a 28mm valve compaired to the 27 and said it should work fine?
 

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Whats peoples opinions of Lyle telling me i should be fine running a 28mm valve compaired to the 27 and said it should work fine?[/QUOTE]







He was prolly assuming you where gonna have the valve seats cut is why he told you that.

He's smarter than that to just say toss them in and you'll be fine.
 

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Discussion Starter · #12 ·
yea, well with further investigation The new exhuast valve doesnt leak at all,(the old exhuast valve wasnt even cupped the only reason why i replaced it is because rather do it while it was apart so the new one had no problem sealing) but as many of you said the new intake does. Donno why at first it didnt but this time i really filled it with carb cleaner and it started to weep.



Heres my question.

Do i go ahead and find someone that has a 27mm valve (someone PMed me who has them) Or can i get the seat cut to accept the 28mm valve? I mean with just looking at it only needs such a small amount removed. If i when with getting the seat recut is this what other people have done to get them to work? Im going for the simplest/cheapest way of doing this, so if i can just get a 27mm valve for 30 bucks that might be the best route to go. Imput on both possibilities would be nice.



Thanks guys for all the info. Good news to is the piston i got in is the correct one and looks mint im just going to have to dremel an addition inlet for the other spark plug but thats not a problem.
 

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Discussion Starter · #15 ·
Oh yea and alot of people ive been talking to think because its so close to fitting that i can get away with just lapping it? What are peoples opinions of that. Also Wondering has anyone else experienced getting a 28mm valve and gotten it to work with there old super head. I just find it hard to believe im the first person that has run into this problem.
 

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Discussion Starter · #18 ·
firepower354 said:
Mark it and check! Ask enough people and somebody will tell you it's OK to bareback my step-sister. Still don't make it a good idea...


Going to billy's an tims on monday there closed today.



Im going to get the valve turned down or have the seat cut so it will fit. Going to do it right instead of half ass. If i get the seat cut then i know if i ever have to rebuild this head again a 28 will fit. Is it that big of a deal going up that little in size?
 
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