Billet Head

[waxhead]

We have been making a new head for the 62t engine with a proper shaped combustion chamber. Its always nice to make things backwards combatable so we will make the heads use the same style of dome as the ada. This means you can buy our domes and use them in the ada head and you can use the ada domes in our head,
The had part about this is due to the ada head not having the spark plug in the vertical center of the combustion chamber to make it backward compatible we have to run a longer spark plug. This makes the plug more expensive. Would you be prepared to pay more for the proper chamber shape ??
The plugs are about 20-25 each
What's your thoughts please.

 

[Chase Musetti]

I feel like ada heads are priced well, readily available, look good and do a good job at what they are supposed to do. $25 per spark plug would be a huge turn off.


Sent from my iPhone using Tapatalk

 

[Jyzmbe]

I feel like ada heads are priced well, readily available, look good and do a good job at what they are supposed to do. $25 per spark plug would be a huge turn off.


Sent from my iPhone using Tapatalk

How often do you really have to change spark plugs? If your fouling plugs you have a issue


Sent from my iPhone using Tapatalk

 

[waxhead]

They are priced well I agree, do a good job sure I guess, its a very old style combustion chamber which leave a lot on the table, but i hear what you are saying i am trying hard to get both parts sorted, It just the issue of getting the spark plug close enough to the centre of the chamber is causing issues

 

[jetx]

How about explaining, the benefits of the new dome shape? For guys after everything they can get i wouldn’t think $50 of spark plugs is a big deal. At least not to me anyway. Have spent more on less lol

 

[waxhead]

The ideal for a plug in a two stroke combustion chamber is about 6mm off the top of the piston.
The squish band should be parallel with the top of the piston. The Yamaha is a dome piston so its actually supposed to be a curved squish band only slightly.
if you have a squish band heading off a straight line you leave some fuel left around the outside where its doing know work at best, causing deto at worst. Either way you are losing power. The best and most powerful shape on a dome piston is a bathtub shape and not the hemi style one which we are all using now, The stock yamaha has a way better shaped chamber if you look at it.
Getting late here so if i make more spelling mistakes than normal please forgive me

 

[te4250]

I like the fact that I can run a br8es in my skis, sleds, dirtbikes, kart etc. I think there’s a non insignificant convenience factor, kinda like why guys delete the oil injection on blasters etc, not because it doesn’t work, just so it uses the same fuel as their other stuff.
I’m sure you thought of this but is there not enough room to counterbore so the same plug sits deeper? Like the ada kawi domes

 

[waxhead]

I like the fact that I can run a br8es in my skis, sleds, dirtbikes, kart etc. I think there’s a non insignificant convenience factor, kinda like why guys delete the oil injection on blasters etc, not because it doesn’t work, just so it uses the same fuel as their other stuff.
I’m sure you thought of this but is there not enough room to counterbore so the same plug sits deeper? Like the ada kawi domes

Im with you on this one. I really want to use the same plug. the issue with the counter bore I have to do is it leaves it thin in the o-ring in the top. This o-ring can be left out out but then it can make it hard to put the head on as the domes now have nothing to hold them in place. i hope that makes sense. Its more of a pain if i have to replace all the domes if they crack

 

[waxhead]

I can make some super high performance domes and then also make some stock style domes.
It would be better not to have to do this however

 

[Jyzmbe]

Go performance. Who cares if you have to change to a different plug. People want innovation but don’t want change lol


Sent from my iPhone using Tapatalk

 

[Storbeck]

Domes are 40 ish each, I'm not seeing how it saves anybody money to be able to use their existing domes but then you spend half as much as the domes on spark plugs. Replace the spark plugs once or twice and now you've spent as much as buying a new set of domes, and if you foul a plug at the lake you can borrow one from your buddy or have a better chance of getting one that is readily available at a local store.

I'd rather have a non standardized dome and a standard spark plug. I don't change plugs a lot, but I change them way more often than domes.

Maybe make the head fit your domes with a standard spark plug then have some sort of little insert to make the head fit ADA domes. I'm guessing your domes would be either shorter overall height or larger in diameter where they come up through the top of the head shell (I'm assuming your dome shape puts the plug closer to the piston) so the difference could be made up with a spacer and a couple of o-rings.

 

[waxhead]

A

Domes are 40 ish each, I'm not seeing how it saves anybody money to be able to use their existing domes but then you spend half as much as the domes on spark plugs. Replace the spark plugs once or twice and now you've spent as much as buying a new set of domes, and if you foul a plug at the lake you can borrow one from your buddy or have a better chance of getting one that is readily available at a local store.

I'd rather have a non standardized dome and a standard spark plug. I don't change plugs a lot, but I change them way more often than domes.

Maybe make the head fit your domes with a standard spark plug then have some sort of little insert to make the head fit ADA domes. I'm guessing your domes would be either shorter overall height or larger in diameter where they come up through the top of the head shell (I'm assuming your dome shape puts the plug closer to the piston) so the difference could be made up with a spacer and a couple of o-rings.

All really good points which I agree with.
Im wanting to allow people to put a performance dome into their ada head as well.
I can do it im just not wanting to lose the oring that keeps the dome in when you put the head down on the studs.

 

[Storbeck]

You would have to have a pretty convincing reason for me to put up with $20 non standard spark plugs. Something more than theory.

You would not have to do any convincing me at all for me to rely on one o ring to seal the water jacket on the spark plug rather than the two that ADA uses. One is plenty for me.

My $.02

 

[Jyzmbe]

Domes are 40 ish each, I'm not seeing how it saves anybody money to be able to use their existing domes but then you spend half as much as the domes on spark plugs. Replace the spark plugs once or twice and now you've spent as much as buying a new set of domes, and if you foul a plug at the lake you can borrow one from your buddy or have a better chance of getting one that is readily available at a local store.

I'd rather have a non standardized dome and a standard spark plug. I don't change plugs a lot, but I change them way more often than domes.

Maybe make the head fit your domes with a standard spark plug then have some sort of little insert to make the head fit ADA domes. I'm guessing your domes would be either shorter overall height or larger in diameter where they come up through the top of the head shell (I'm assuming your dome shape puts the plug closer to the piston) so the difference could be made up with a spacer and a couple of o-rings.

What nerd would go to the lake without spark plugs? Or if you know you have a non standard plug why would you not have an extra or 2? I would rather have a couple extra plugs than have to worry about possible reduced dome quality to fit a standard plug. You must have not owned many tpe motors. Cracked at least 1 or 2 domes a season. Definitely changed domes more than plugs


Sent from my iPhone using Tapatalk

 

[Storbeck]

You could put an o-ring around the perimeter of the entire dome, the large outer diameter, to hold it into the head shell.

 

[waxhead]

You would have to have a pretty convincing reason for me to put up with $20 non standard spark plugs. Something more than theory.

You would not have to do any convincing me at all for me to rely on one o ring to seal the water jacket on the spark plug rather than the two that ADA uses. One is plenty for me.

My $.02

The difference in the hp on the domes is more than theory we proved it years ago when I was using rs125 engines in shifter karts, but I understand your points. the only reason I can see they use the top o-ring is to hold the dome in place as you slide it down the girdles. which is a valid reason as it would be a pain in the ass with out it.
I can do it using the stock plugs but its gets down to about 1.25mm in the top and while there is no load on this part I just dont want to make it an issue I will look at getting some smaller section o-rings,
It does mean however that the plugs hex will be very close to the top of the head which will look different than we are used to seeing on skis

 

[waxhead]

What nerd would go to the lake without spark plugs? Or if you know you have a non standard plug why would you not have an extra or 2? I would rather have a couple extra plugs than have to worry about possible reduced dome quality to fit a standard plug. You must have not owned many tpe motors. Cracked at least 1 or 2 domes a season. Definitely changed domes more than plugs


Sent from my iPhone using Tapatalk

All these things we are trying to avoicd of course, " cracking domes" Where did the tpe domes crack

 

[SteveC]

the only reason I can see they use the top o-ring is to hold the dome in place as you slide it down the girdles. which is a valid reason as it would be a pain in the ass with out it.

Am I the only person who threads the spark plugs in while the head is still on the bench so I can pick up the head and dome assembly by the spark plugs like two little handles?

 

[Storbeck]

The difference in the hp on the domes is more than theory we proved it years ago when I was using rs125 engines in shifter karts, but I understand your points. the only reason I can see they use the top o-ring is to hold the dome in place as you slide it down the girdles. which is a valid reason as it would be a pain in the ass with out it.
I can do it using the stock plugs but its gets down to about 1.25mm in the top and while there is no load on this part I just dont want to make it an issue I will look at getting some smaller section o-rings,
It does mean however that the plugs hex will be very close to the top of the head which will look different than we are used to seeing on skis

Then it won't be too hard to prove it on a ski.

To be clear, I'd be thrilled to go for the theoretical benefits if there is not a very real pragmatic downside.

That's just me. $.02 from some guy on the internet.

But I also have seen a bit of how engine development goes when things are actually measured and a testing background makes one naturally skeptical.

And I am projecting my opinions (based on very little) of the market and doubtful you'll sell a lot of heads that require 20 dollar plugs.

 

[waxhead]

Then it won't be too hard to prove it on a ski.

To be clear, I'd be thrilled to go for the theoretical benefits if there is not a very real pragmatic downside.

That's just me. $.02 from some guy on the internet.

But I also have seen a bit of how engine development goes when things are actually measured and a testing background makes one naturally skeptical.

And I am projecting my opinions (based on very little) of the market and doubtful you'll sell a lot of heads that require 20 dollar heads.

Everything you are saying is very valuable to me and I really appreciate any feedback or ideas