Project Fuel Injected Turbo FZR250, half

It is possible using Neway cutters, I had to trim the cutter for ex seats (ground the tungsten with a diamond impregnated burr)to clear the valve shrouding, the same could be done for your smaller Yamaha ex valves.
I had another go at seat cutting by hand, this time, I used my fingers to apply light pressure on the cutter, and used a flexible shaft "screwdriver" type driver to turn the cutter (they are very sharp), lifting each 1/2 turn, & turned cutter back 10 degrees before cutting another 1/2 turn,,,this took the flex out of the pilot.
The diamond impregnated burrs (used to regrind tungsten inserts used in mining drill bits, they require a constant stream of water to keep them cool, and flush away the cuttings) could be used to machine a tungsten pilot.

 

MC19/22 & FZR models "could" use the Neway CU144 $US82.00Small Series Valve Seat Cutter 19.3mm 32 deg.(16.5 / 18mm) 2 required, CU133 $US82.00 Small Series Valve Seat Cutter 22.2mm 60 deg.(18/22mm) 2 required,,,then the bodies need to be machined, tungsten cutters trimmed (diamond cutters needed) to narrow the seats once cut with 45 degree cutters (std set width MC19/22 intake-0.8 mm ...... exhaust-1mm)

 

This conundrum got me intrigued and then I found this reference on the Neway site

http://www.newaymfg.com/cutters#fixed-blade-mini

That's the reference, but I cannot find them on the actual site among the product listings

Edit:

I just found them among the PDF price list
https://www.newaymfg.com/literature/PriceList.pdf

all of the cutters CU130 -> CU144 are fixed blade mini cutters

I wasn't reading the product pages properly, it's on each of the respective product page, and now I've gone and put that booboo of mine all over the internet

Seems @Gen was all over this before I got all confused

 

What is really needed is a bare 70/30 degree cutter body that could be turned down before gluing the cutters in.

 

Out of interest, what do you think the cutters are glued in with?

Wondering if you could sweat them out with some flameless heat, turn down the cutter then re-attach, although they do state non-replaceable so that may ruin the alignment

 

Probably loctite, or super glue of some sort, heat should help to release the tungsten,,but I'm thinking the cheaper, make your own cutter body plan using Neway inserts (the 30 degree end would require trimming of the tungsten to clear the drive unit & guide)

 

I like the way you're thinking and now I wish I had a lathe, but if actually did I'd be considering Moldstar seats and guides and getting very expensive very quickly

 

Everything needed to freshen up the FZR/CBR's is expensive,or made of unobtanium, which is the reason they are hiding in sheds.
The head I'm working on now has been vapor blasted recently (before my race partner bought it), the seats are pitted, there is NO carbon in the combustion chambers, but plenty on the piston crowns, hone marks are fresh, it was bought as a "rebuilt" engine,,,,, yeah, right,,try "partly rebuilt".
Before stripping it, I did a leak down test, #3 had a couple of leaky valves, the rest were ok.
The last head I fostered out came home with an $800 bill attached, due to special tooling being made before the work could be done (CNC), mind you, it was a bloody good job, 5 angle job, with an ultra fine mating surface plane.
Nobody in their right mind would cough up $800 for a head freshen up for a $1000 bike

 

This is a good article and a great device - that single sculpted piece of carbide for all of the angles, I had wondered if such a tool exists previously

https://johnmaherracing.com/tech-talk/3-angle-valve-job/

 

That’s cutting bits for use with Sunnen VGS20. You’ll need arbor with pilot to hold bits. I’ve tried 5 and 7-angle valve-seats for improved flow. Now I prefer to use profile that cuts perfectly radiused valve-seats for highest flow. Along with back-cut valves. Depending upon engine, waisted stems can be done as well along with trimming guides all way back.

 

Here it is in action. Unshrouding valve along with seat cutting.

 

I use shop in Santa Barbara that I found when living there. Similar to this process:

 

large variety of cutting bits in multiple angle-settings available.
https://goodson.com/collections/valve-seat-cutter-blades?page=7

 

They also do custom, big trick would to be, are there arbors small enough for the exhaust valves

 

Notice that arbors themselves don’t ever have to go inside ID of valve-seat, just the cutting bit. These narrow Micro cutters on this page FTM-185 to 188 have their cutting edges very close to arbor’s centreline. So they should be able to cut seats as small as 20mm.

https://goodson.com/collections/valve-seat-cutter-blades?page=6

I’ve seen Serdi machines use these cutters as well, but doesn’t seem to have as fine control as Sunnen.

 

Interesting article, which contains a lot of advertorial, but he goes into the details of multiple angles in intakes versus blended radii on exhausts

Lots of good info which focuses on the minute details, which obviously make all the difference, according to him anyway

https://www.enginebuildermag.com/20...ts-what-you-need-to-know-to-go-with-the-flow/

 

Serdi control depends on who's using the machine. When a local mob got one, I bought two 3-angle profile cutting tips as i was doing a lot of Brit singles and twins at the time. The original operator was very good. His later replacement not so much. They broke one of the tips and finished up buying the spare off me for other jobs.
I've already told Mike that i think there are 3 Serdi owners in NZ who have the smallest arbour. Where he's gone isn't one of them. But I know them and they're very good engineers.

 

Mike, look what I found,,,
https://www.newaymfg.com/parts/solid-pilots_carbide

 

Well spotted
If he's working with 2KR heads which have 4m valve stems they will work, otherwise a good starting point to have one machined down to 3.5mm for 3LN valve stems