yamaha cylinder porters step forward

[gman]

G'day race fans. I'm looking for someone from the forum who'S spent allot of time porting 2 stroke cylinder? If not a forum member then the guy who does a good job. I have 2 sets of as1 125 cylinders i'd like ported to yamaha gyt specs. I have the specs and the desire to do the work myself but that would require a grand in new tools plus another grand in a compressor upgrade plus the good chance i may not get the best result. I'm happy to pay the required price for the right result. Would also like heads shaved and cc'd to spec. The as1 engine in stock trim running 17mm mikuni's produced 15 odd hp, the gyt spec with 26mm mikuni's, magneto and chambers had a respectable 24-26 hp, all on the standard spec crank. Please if your able to do the job let yourself be known. I'm sure there is someone on google who could do the job but i'm hoping it's a forum member who wants the job.

[2TInstitute]

I can do that for you but I can do much much better than old gyt specs. More top end more mid range.

[gman]

Hello. thank you for replying to my post 2t institute. I'm interested in getting my as1 cylinders ported. I plan to run the as1 muffler's as i have a new set. The original 17mm mikuni's are spiget mounted. I have removed spigets to braze a mounting plate for vm22 mikuni's, the inlet port will need to be enlarged.
Thinking the following other mods. shave the heads for a .8mm squish with 20 dgr taper reshaped to combustion chamber edge.
Run with top ring only.
Either/ remove 60 tho of top of barrell and place a 60 tho alluminium spacer under barrell to rase all ports + Remove 4-5mm of piston skirt to lenghten inlet timing. / or port cylinder"s for timing and open up inlet port tracts plus piston work i am not sure of .
There would be difference in cost for either barrell work, my pocket book is not endless. I'm learning about 2 strokes and performance mods that have been tried. I have a project for this as1 engine, it will be going into a smaller yamaha frame. I'm hoping for a true 100mph top speed from a 46 tear old 125cc yamaha twin.
Anyway i was in the midgle of pm 2t about porting and i thought i should forum post this as i'm hoping this could open disscussion on piston ported cylinders. graham

[2TInstitute]

I wouldn't remove material from the top of the cylinder or put spacers under the cylinder all that stuff went out with flares and fondues. We can do much much better these days.

[gman]

Thanks for replying once again 2tinstitute. I will pm you soon to hopefully arrange some cylinder work. For the forum and myself i would like to ask which cylinders would benifit the most from porting. THe yas1 or rd125 reed valve cylinders. I would like to fit 22mm mikuni carbs to either engines. The rd125 inlets i am led to believe will accept with modification yz80 or dt125 reed blocks and manifolds to accept the carbs. The AS1 need the 17mm inner diamention sigets cut of and an adapter plate added and ported to accept 22mm carbs. I have complete AS1 and AS3 (rd125) engines. I am leaning to the AS! for the project bike i wish to put it in.

[gman]

picture"s showing the removel of carb spiget and brazed on adapter for larger carb from an article in the THREE T"S for the two stroke book by Yamaha

[2TInstitute]

no contest the reed cylinder , that should finish up alright