*** 1978 ATC 90 "3D" Dickson Design & Development Mono Frame ***

[Joseph Farrow]

Looking good as usual you guys do a good job. The cb piston peeked my interest what all is involved in using those pistons?

It's not an easy thing to do. First you have to source one of the three options below. An oversize sleeve cylinder.



To be able to run the oversized sleeve cylinder you will have to have your center cases bored to accept the larger outer diameter of the sleeve.



Then you have to have the CB piston machined to work with the correct deck height, valve pockets and crank.
This first pic is a side by side comparison of a stock CB750 piston and one after it has been machined.



This is the reasons I like the 90-110's so much. There were so many mods you could do to these machines to make them not only look good but kick as well!



As the old saying goes....."Speed Cost - How Fast Do You Want To Go???" lol

[Ghostv2]

The latter is correct. It helps with cooling as well you can see you are getting oil to the head. These engines do run very hot and the oil comes from the oil pump and runs up the cylinder stud to the top of the engine. You could still use a finned oil cooler with this set up if you like for extra cooling.
Check out where the oil gallery runs in this "Cheater Cylinder"....the old sleeve is bored completely out and a new larger one is pressed in. The out side of the sleeve is actually part of the oil gallery. lol

That's what I thought. I guess I'll have to pick your brain when I move on to engine work with my build. I'm still sourcing parts. Right now I only have bolt on mods. Powroll intake, vm26 carb, cobra pipe, low-mid cam, all on stock bore. You'd be surprised how much it wakes this thing up even with a stock piston. It's a wheelie machine with the tucker rocky front suspension kit and the pauter +2 frame.

Feel free to send me a pm now and then with extra parts left over from these builds.
People on eBay try to rob you with their prices for hop up parts most of the time.

[big specht]

Thanks that's nice to know cause I have a 70 that I built along time ago with a used 110 big al's big bore piston(I think) and a custom la sleeve sleeve. And it's starting to burn some oil and I wasn't sure what to do about a piston. So thanks for the info. Is there any certain year CB750 to get pistons from?

[Dirty200]

wow! freaking beaut

[Dirtcrasher]

That came out awesome, thanks for sharing!!!!

[Ol Deuce]

Joseph your 3D Project turned out Perfect ..........Ol Deuce

[Joseph Farrow]

Thanks that's nice to know cause I have a 70 that I built along time ago with a used 110 big al's big bore piston(I think) and a custom la sleeve sleeve. And it's starting to burn some oil and I wasn't sure what to do about a piston. So thanks for the info. Is there any certain year CB750 to get pistons from?

It needs to be for the early single valve CB750. Honda CB750K-K6 (1969-76)

[HondaRidr]

Awesome build. Those old racers are so cool!

Sent from my SM-G930T using Tapatalk

[Ghostv2]

So are those Douglas 8x8 wheels with the turf tamers squeezed on? I wanna try and run along the same tire setup with mine. I'm not sure how jumping will go on a solid frame with those kinda tires though. I mean it's not like you're getting huge air anyways. But still. I need to find or make some cleated pegs though. But I'd like to find similar ones to yours. The bar and mount looks way more solid.

Also how's your speed with the 32T sprocket and the smaller tires? I'm sure power and acceleration is amazing, but I'm not sure how it would match in speed. Is the sprocket NOS aftermarket or did you have it made? You can only get like 48-51T available new anymore.

Hope you don't mind all the random questions lol. Just trying to get my build done right the first time. Gotta ask all the questions I can to a person who knows about the 90/110s the most while I have your attention lol. Like you, these are my favorite builds for all the same reasons. There was so much you could do to these and so much available. Too bad nobody puts time into repop'ing these old race parts like they do with the 250r's.

[90crazy]

Awesome job! Museum quality for sure.

[ironchop]

Awesome build....Id love to hang out in y`alls garage over a weekend.

[Ghostv2]

Awesome build....Id love to hang out in y`alls garage over a weekend.

I second that. I'll put my sleeping bag right next to the 90's.

[Joseph Farrow]

So are those Douglas 8x8 wheels with the turf tamers squeezed on? I wanna try and run along the same tire setup with mine. I'm not sure how jumping will go on a solid frame with those kinda tires though. I mean it's not like you're getting huge air anyways. But still. I need to find or make some cleated pegs though. But I'd like to find similar ones to yours. The bar and mount looks way more solid.

Also how's your speed with the 32T sprocket and the smaller tires? I'm sure power and acceleration is amazing, but I'm not sure how it would match in speed. Is the sprocket NOS aftermarket or did you have it made? You can only get like 48-51T available new anymore.

Hope you don't mind all the random questions lol. Just trying to get my build done right the first time. Gotta ask all the questions I can to a person who knows about the 90/110s the most while I have your attention lol. Like you, these are my favorite builds for all the same reasons. There was so much you could do to these and so much available. Too bad nobody puts time into repop'ing these old race parts like they do with the 250r's.

Yes those are Douglas 8x8 wheels. The tires work excellent for most tracks. We ran them on flat track, TT and MX. As far as jumping, it's like jumping on anyother hard tail. Kind of like riding a bicycle. You can jump things for example a double and as long as you land on the down slope you're good. lol

When Judson broke in the bike he had a 11-49 sprocket combo. With the smaller diameter tires it was all low end with no top end. He switched out to a 12-32 and it made all the difference in the world. It still has enough torque to wheelie in every gear and will pull way out for speed. The 32 tooth rear sprocket was special order. A friend had a batch made and we grabbed a few. As far as the cleated foot pegs you can probably find a set without much trouble.

[Joseph Farrow]

Here is some 90-110 Race Action. Sorry for such a short vid. My phone would only let me do so much.....
In this vid I pull the hole shot and Jud is in Second. I think he gets by before the end of the race. In the main I pull the hole shot and end up winning. Jud gets tangled up with some other riders at the beginning and has to make his way through the pack. He ends up second.

[Ghostv2]

Those things look like 200x's scootin' around the track. That's crazy!