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Yes I polished it myself. I've been polishing things for years. The carb took about 7 hours. Don't be fooled by the polishing "how to" on this site. Real polishing is done on a wheel. I used a 3/4hp buffer and a spiral sewn wheel with 'green compound' for the flat areas and a dremel and felt bob for the hard to reach areas.Quote:
Originally posted by nacs420
Did you polish the carb your self?
45 to 50.Quote:
Originally posted by Project300EX
That's awesome. About how much hp is that pushing?
Looks good, just should have painted the frame while the quad was appart.
That's awesome. I wish my project motor would put that out.Quote:
Originally posted by pb_paulie_b
45 to 50.
Cool project.I had a it400 motor in mine a few yrs back.i think i must have made a dozen pipes for that thing trying to get it just right.It ran like a raped ape up top,probably could do 80plus mhp with its wide ratio gearing.The vibes were kind of on the high side considering it was a air cooled big bore.I still have some vintage yamaha parts as i love these motors,EVEN the yz490,which i have gotten mine to actually run decently.I may build a yz490 blaster in the future.yours looks good,i like it;)
Thanks! I don't know what effect it has on the power band but I had to lengthen the pipe about 2 inches at it's head. The gearing is pretty high on mine. I can't even get into the power band in fifth, I'm goin so fast that it just feels like the front end is going to come apart :) I'm currently running 13/40 gearing.Quote:
Originally posted by 2muchquad
Cool project.I had a it400 motor in mine a few yrs back.i think i must have made a dozen pipes for that thing trying to get it just right.It ran like a raped ape up top,probably could do 80plus mhp with its wide ratio gearing.The vibes were kind of on the high side considering it was a air cooled big bore.I still have some vintage yamaha parts as i love these motors,EVEN the yz490,which i have gotten mine to actually run decently.I may build a yz490 blaster in the future.yours looks good,i like it;)
Yeah extending the headpipe gave you more bottomend.even a quarter inch can make a difference on a 2 stroke.i opened up the exhaust port on mine and that thing just went crazy up top.it almost felt like a newer 250 on steroids.I also ran a carb from a 89 yz250.i figured a newer carb might help a bit.If you ever blow it up i belive i have a extra topend and crank for it;)
I love these old motors too. Unfortunately parts are hard to find, especially the 79'. I took the motor down to spec it out. The bottom end, rod and all the bearings are tight. The cylinder and piston are looking worn. I honed it and re-ringed it for good measure. I plan on detailing the motor and polishing some stuff while it's out as well as frame painting and powder coating as much as can fit in my oven :)
2muchquad, you really have an extra top end sitting around???? Details pleeze...PB
http://i31.photobucket.com/albums/c3...b/IM000636.jpg
Yeah i have a cylinder with a new piston and rings.I couldnt tell you the size as its been in the garage out of site out of mind for a while.I also have my yz490 that used to have a yz465 topend on it too.I have a collection of misc vintage yamaha stuff including cdi,a couple flywheels and a stator i think.i also have a 76 it400 bottomend that i bought thinking it was the same as the 79 it400 i had...it wasnt:( I'll look tomorrow to see for sure about the cylinder
Just picked up an custom 426 big bore kit! Complete with piston, rings, bearings, and matching big bore head gasket. I'm stoked to say the least. Now just have to get a cheap thrashed cylinder. I'm NOT taking my virgin cylinder out that far, it would be too much of a waste of a good cylinder...PB