780 Kit + big valve head installed!! video!!

[Wallacey]

I looked at this 780 kit on the www, but I'm not convinced that the durability thing is there. I have a mechicest dude up here in Canada who is spot on for this stuff. I was woundering if your kit is from the dude in Oragin USA ?. from Crashtestgordon

As far as I know, there is only one 780 kit on the market, developed by procycle.

[Older and Slower]

The only thing i can say is that quite a few years ago i had a big single that i had bored and had an Arias (i think that's how it was spelled) piston installed. It developed piston slap withing 15,000 miles. How, why? Beats the heck out of me ... it was only a 40cc increase in displacement. Been sitting on the fence with the 780 kit.

[Riosdad]

I took the chance. The piston is top quality, a brand name. A piston we looked at for our harley but it was too expensive compared to genuine harley pistons. The bore is better then stock. Instead of being a plating a couple of thousands thick it is a good cast iron sleeve.

What can go wrong with a setup like that??

I beleive strongly in torque plates and if you take the cylinder into any machine shop NOT equiped with torque plates your bore is NOT ROUND.

Using torque plates I bore the stock cylinder, a light skim at first just to see how the tool was cutting and I noticed spots around the cylinder where it didn't touch. Spots about 1 or 2 inches in diameter where the tool missed the skim cut??? My cylinder was in torque plates and stock it was not round??

After boring and honing in the torque plates and using a good bore gage to check everything I pulled the torque plates and once agian checked the bore.

My round bore of about .003 went to oval of about .001 in one direction and .006 in the other?? Where did my round bore go??

You need to bore and hone with torque plates, assemble the motor with minimum turnover before installing the head and turning it over. This will bring the bore back into round and proper clearance

This is my post on torque plates. If you are boring a motor without torque plates then I certianly can see a longevity issue.

https://www.thumpertalk.com/forum/showthread.php?t=1027297

[2000dr650]

get a chance to ride it yet? Did you do a cam as well?

not yet.there is ICE on the ground and its too cold to really rip around though this weekend its getting pounded on for sure . Im going to hook up my contour HD camera to the bike so everyone can come on the ride with me..

[dawnofadreamx97]

Valves sound the same as my #190 grind cam does all the time. The pop sound sounds like it's a mild miss every once-in-a-while. Heck, i'll trade you my blue tank for your black one.

sorry to jack the thread... but

Dude i love your bike! can you explain what you did to the rear in more detail? where did you make the cuts ? what are you using for a tail light? is the bike lowered? will the side panels / stock exhaust still fit on the bike or does it look weird and stick it out to far?

thanks!?

[Older and Slower]

Ok, i'll try to get this in order and get back on topic. I cut the subframe off after the down tubes joined the top hoop (hoop is what i cut off). I welded a cross tube for support at the point where the two bosses are, but higher for tire clearance. the tail light is actually a homemade LED light with 7 super bright LEDs. I formed a channel out of aluminum, welded it, milled it, installed the LEDs along with dropping reistors, made a diode bridge with a current dropping resistor so that i could "Y" the brake circuit to the tail light circuit, epoxy potted the inside of the whole thing and painted it black. Bike is lowered via the factory method and also i installed lowering links from Pro-cycle. I don't think you can install the OEM side panels as there are no more factory down tubes. Same with the exhaust. The rear fender i molded out of two layers of carbon fibre. The license plate has been moved forward towards the front of the rear tire now and hangs from a hinge and is lit with super bright wite LEDs ... like they do on sport bikes. The wiring harness has been extensively modified, i built an undertray under the sub frame rails for the starting relay, fuses, etc, and the regulator is bolted to the underside of it.

All of this is in a state of flux as i now have some T-6 aluminum bars and stock. The subframe will be aluminum and tucked up under the Corbin seat sides where it will be hidden. I also plan on shortening the can and using a carbon fibre sleeve for it from Yosh instead of the aluminum.

Oh yeah, H/C piston, #190 cam, TM-40 carb and ...

Well, no snow here yet (Reno, Nevada) and i am still riding, so no more mods until there is ice on the roads.