Looking for Teikei Y27PV Secodary Main Jets

[manco]

I was thinking of getting a local firm with cnc machine to make a 100 jets, either undrilled or drilled to the smallest jet size and user could drill to own size.

What do we all think?

Are you refering to machining secondary jets? If so then I feel it is a good idea. Considering secondary main jets can't be found anywhere right now new ones would be worth their weight in gold. I think the secondary jets should be drilled with a pilot hole of around 100mm/#100. This would allow easier drilling to size as the 100mm hole would already be centered. I can't imagine that a secondary main jet could ever be needed less then 100mm. Maybe it is? You could always go a little smaller on the machined hole just in case.

If you are refering to machining primary main jets I am not sure what to think. #100s and a couple others are still sold. They can be drilled to whatever is needed. Other brands seem as if they will work too.

[xtzrick]

How about drilling an insert & pressing it into the thread end of an old secondary jet?

Is there space to internally tap the threaded part to take different jets?

Rick

[manco]

How about drilling an insert & pressing it into the thread end of an old secondary jet?

Is there space to internally tap the threaded part to take different jets?

Rick

What are doing reading my mind?

Two days ago I wrote;

Something I thought as another idea for custom secondary main jets for these old TK YDIS carbs is to create a new jet style that could screw into the existing jets. I am wondering if it would be possible to drill out & tap one of these old jets & then have jets that screwed into the original jet as if the original jet was a mount for jets instead of a jet itself.

http://www.horizonsunlimited.com/hubb/y ... post445472

I have thought further about this concept since. It might work but then again probably not. There is only at most 5mm to work with in the upper tube while maintaining enough metal to keep the old jet's threads in tact. Then once an insert is made figure 1mm on each side for threads = 2mm gone leaving 3mm to house the jet orifice. If there is 1mm on each side of the orifice that only leaves 1mm/#100 for the orifice itself. This setup would also elongate &/or move the jet surface to the top of the old jet. Originally the jet surface is in the middle of the old jet with tubes above & below it. Such a physical changes would mess with the flow characteristics.

Then there is another problem that wrecks the whole situation even if an insert could work. The needle of the secondary carb comes down into the upper tube of the jet. This is the space where any sort of insert would go. This effectively negates any hope of modifying the original jet for an insert. Maybe something could be made up but the needle coming down is a huge problem to the insert idea.

I think insert jets for the secondary main jet are good idea. Yamaha & Teikei should have designed the carb like this. Then then both primary & main jets could have been the same. Even on the later TK YDIS carbs when they did switch to a similar style as we are discussing stupid Yamaha & Teikei still used two different jets. One can only ponder WTF? on that decision.

[manco]

I just had idea. If another jet could be screwed up into the the shaft of the carb & a tube could be soldered to the jet everything would be proper. Possibly drilling & re-threading the carb with a helicoil to hold the jet or a insert & jet could be done if needed. The needle could still come down.

[Mezo]

Its not a complicated part to knock up on a lathe, just source some brass hexbar & take it to you local machine shop & get them to make a whole set for you, a CNC machine could knock out that part in ten mins, by hand around half an hour once he`s set up & running.

Mezo.

[xtrider]

Ya a CNC can knock them out in short order, however it takes an hour to setup the machine just to run them. I run cnc's and it drives me nuts all the things I want to do because it'll only take a few minutes to turn them(or mill), but you spend the entire lunch break trying to get the damn thing setup and programmed. By then break is over and someone else needs the machine and the setup gets torn down.




Pisses me off !

[xtzrick]

I just had idea. If another jet could be screwed up into the the shaft of the carb & a tube could be soldered to the jet everything would be proper. Possibly drilling & re-threading the carb with a helicoil to hold the jet or a insert & jet could be done if needed. The needle could still come down.

Personally I wouldn't, don't think solder would be strong enough.

How about this


Simple lathe work

I'd use jets calibrated by diameter that you can buy locally, round slotted so you can change them with a screwdriver, hex head jets would need more room to get a tool in to remove them.
Yes they might flow differently to teikei jets but so would drilled blanks.

& if you struggle to find a brass tail with a wide thread (I'm thinking M12 or imperial equivalent so you can get the jet in) you can use a drilled brass bolt with a small tail.

Rick (probably agreeing with your initial thoughts )

[ActionManMelb]

Simple lathe work

That's as maybe, but now we have 3 parts instead of one!!

[xtzrick]

Simple lathe work

That's as maybe, but now we have 3 parts instead of one!!

Yes that's true, less parts is always better especially when it comes to parts in a fuel line
3 parts but only 1 more potential fuel leak.

I was thinking about ease & cost of production & tuning.

When manco comes to tuning he will want to start rich & get leaner till he gets the right mixture.
Just thought it might be easier/cheaper if he had access to jets locally.
All depends on how much it costs you to get some jets made & delivered

Rick

[manco]

Yes its true. Solder probably wouldn't be strong enough for the long run. I was just trying to think of a quick hack that I could throw together to test. If anything needed to be soldered, brazing would be the way to go.

This other design looks good. I bet it would work. What is good about this second design is that it is a jet holder that as has been mentioned could use a standard jet. If it was designed to hold standard jets like say the Keihin jets it would be much more affordable for anyone in any country to tune as every jet size would not need to be a custom piece. Brass should be fairly easy to design to stay sealed. Maybe add some copper washer or rubber oring if needed. Teflon tape or PermaTex High Tack could also be used for a final seal.

There is a local moped shop in my area I know of that does custom stuff. I am gonna swing by with jet and carb to see what they could make. I will try to find a machine shop that wants to mess with the idea to see what it would cost to get something made too.

Something I have been wondering is when it comes to modern machining is it possible to create & save a file that is used in a computerized machining process so that a jet holder designed in one country can be emailed or uploaded as a file so that the jet holder could be produced in another country? Do machines have the ability to just utilize such files? If so are the files compatible between different machines?

...start rich & get leaner till he gets the right mixture.

I know I am on a European forum when advice this sane & logical is presented. This is the method I always use. It is is so simple to tune carbs this way. I generally start rich. Work till its too lean then come back to the the proper jet after having experienced the full range of the possible tune. Its such a no brainer to use this method. Staring rich & working lean the worst that will happen is spark plug fouling. Going from lean to rich there is a risk of engine damage for obvious reasons. I have tried to explain this method to many people both online & off in America. So many people just want to argue against this method though. Over here people are more worried about plugs fouling then engines blowing. WTF??? Of course in America if a bike is running rich the general advice will be run richer & if a bike is running lean the advice will be run leaner. I cannot fathom what is wrong with the American tuning scene. Its almost as if the average American tuner has the symptoms & what to do reversed in there head or something. I have a theory actually that racers in the late seventies who knew how to tune carbs told everyone the opposite of what was correct is how they tune, not because the racers had it screwed up but because they wanted to screw the other guys up to have an advantage on the track. To this day the tuning scene in America has had it all back@sswards.

Everything about modern mechanics & tuning is so retarded over here in the USA its refreshing to read sound logical advice on this forum for a change. In a matter of three pages this thread has already come up with a design for a new secondary jet. With all seriousness had I have posted this thread on a forum like ADVRider or talked to people in person if I got any responses they probably would probably have been, "Dude take your airbox off, then spend $500+ & six months building a new custom carb setup that may never work proper." OR "Hey man since you can't get that jet have you considered buying a different motorcycle?"