Tuning Question

[Little Fork Runner]

don't buy the spark plug reducers.......just buy a 14mm head................much better in the long run...........

i knew that you could buy a whole new head, and thats what i was planning on doing. But how to these spark plug reducers work???
Thanks

[sam]

If you are real lucky ... only the bottom cylinder will stick and the ring may be reusable. You could get away with a single piston and head gasket.

[bill van steenwyk]

Spark plug "reducer"................

is a bit of a misnomer, as the device called that is actually a bushing that is threaded into the head the size of the larger hole, in this case 18MM, and then threaded on the ID of it the size of the smaller thread to be inserted in it, the 14MM threaded spark plug.

Some don't like or approve of them as the are felt to affect heat transfer, which is one thing that if not correct, will burn or stick pistons. Then you definitely need the extra pistons, rings, and head gaskets.

I agree with others that say just purchase the 14MM head and you have several less things to worry about, and with a race motor, less things to worry about is BETTER, plus I have bought a lot of pistons and it gets expensive. In addition to a burnt or stuck piston, if the ring comes apart you run the risk of scoring the cylinder or beating up the combustion chamber in the head, (steel piston ring harder than the aluminum head) then have possible re-sleeving and/or another head to buy, so why not just do it right to start with unless you need piston changing experience.

[Little Fork Runner]

is a bit of a misnomer, as the device called that is actually a bushing that is threaded into the head the size of the larger hole, in this case 18MM, and then threaded on the ID of it the size of the smaller thread to be inserted in it, the 14MM threaded spark plug.

Some don't like or approve of them as the are felt to affect heat transfer, which is one thing that if not correct, will burn or stick pistons. Then you definitely need the extra pistons, rings, and head gaskets.

I agree with others that say just purchase the 14MM head and you have several less things to worry about, and with a race motor, less things to worry about is BETTER, plus I have bought a lot of pistons and it gets expensive. In addition to a burnt or stuck piston, if the ring comes apart you run the risk of scoring the cylinder or beating up the combustion chamber in the head, (steel piston ring harder than the aluminum head) then have possible re-sleeving and/or another head to buy, so why not just do it right to start with unless you need piston changing experience.

yea i will most likely get a new head so that everything is done right. i found a cite that has them for pretty cheap so when i decide to buy one i will just order it from there. How often do mods usually have to change their plugs???
Thanks

[tj15m]

I have reducers, steel $33 brass $44 been running them for years without any problems. Also almost any Yamato part, 14mm head milled or not, pistons rings, gaskets, seals NO 102 COILS.

[ZUL8TR]

reducers

I have reducers, steel $33 brass $44 been running them for years without any problems. Also almost any Yamato part, 14mm head milled or not, pistons rings, gaskets, seals NO 102 COILS.

Was any one type metal better than the other or did you compensate for the differences with plugs, etc?
Did you have to use a colder plug due to heat transfer issues as Ric Montoya notes on his site?

[tj15m]

I usually run 10s and have have run them in both adaptors and did not see a difference in heat ranges, although I have ran 9s in early spring and late fall (cold water).