I ran 16/38 and 16/39. . . 16/40 was a bit too much but, that was for Sand Mt., NV.

Good numbers!

Is that an Alum. sleeve in the jug? Where did you get the sleeve?

 

I went through Millennium Technologies, when I started this venture, I bought a Jug with a 105mm steel sleeve in it, after all the hubbub on failed steel sleeves I contacted Kurt at millennium, he said we been doing aluminum sleeves for years with no problems, but we haven't done a DS650 before, where Scooby just went and bored and plated his jug which is what I wanted to do but Kurt at Millennium explained that a sleeved cylinder is actually stronger, sort of if you slide a pipe in a pipe and try to bend it, well this is pressed not slide into the cylinder, also that the sleeve is of the same metal alloy as the original Jug, the sleeve and cylinder expand and contract at the same rate with out worry of slipping or egg shaping, the aluminum sleeve also dissipates heat better than the steel sleeves that expand at a slower rate than the Jug causing the casting to squeeze teh steel cylinder into a egg shape over time is what I been hearing about.
They also plate the aluminum to factory specs also, and there ya go for $400 bucks you have a 720 big bore, Even HPR used them to plate there 730 jugs.

As I written, there has been no problems, runs great, and I will keep posting through Glamis season this winter on this bore.

I believe this is a great setup for the average Joe play duner/trail rider, very easy on the wallet and I am hoping more reliable than the JE steel sleeve version, time and wear and tear will tell.

I think for the all out wild man, hill shooter, 300 ft dragger, 30 plus shot NOS addicts, motor types then the HPR 730 jug cant be beat for that abuse.

 

WOW, Erbe! That's a realistic effort with no smoke & mirrors. Dang nice results most people could afford too.

All it would take is a couple of more nice people like you and a whole bunch of Rotax riders would be riding their thumps daily.

What is there for people not as lucky as you to grab one of those large cylinders, and just have the stock cylinders? Does the size make that much difference or is it mainly in your setup?

Thank you Sir for your kindness and knowledge.

 

So far to date the 720 been running great, no troubles no over heating, second set of cams were the trick, seems the DS likes to breath so longer duration cams help out, I never had a chance to ride with a HPR 730 DS yet with the 3 or 4 cams, im hoping to meet some in Glamis in the next few months, cost wise with out compairing and cost wise I like my build, if any one needs info where to get these items IM me.
Its not about who made what its about having fun riding!

 

Actualy im convinced steel or aluminum if its done properly it cant be beat sleeves do work.and are a economical way to go big. i have two 800 sleeved motors and so far im thrilled about them.[img]i/expressions/face-icon-small-happy.gif[/img]

 

never had a problem with mine. lots of runs and lots of nitrous

 

I would like to here how the DS are running with the 720 kits, they were selling em on E bay for while

 

If your talking about TVI's that is what Sandman430 runs.as far as the one your running your the only one ive heard of but im sure there are others.There was a co. In cave creek az doing them for awhile.And i heard they were having good luck.

 

didn't scooby do the same cylinder as erbed650, the one that didn't work was the samcoe which i don't believe to be around anymore. I've seen some of the problem engines, that had those they were a mess. seems the first stock cylinder bored to 105 were a mess also, who did those. seems pami had ok luck with the 102 bore

 

Scooby was pushen that bored cylinder tp the limit, I think he hooked up through bomber and eric and got a 730 jug, im not sure.
I have a extra cylinder that was done a few months back that I had welded up around the outer cylinder jacket ti the casting walls to match the head gasket, (was $150.00) had this done to add extra support to the cylinder in case of dentanation under High compression or a monster NOS shot, I just havent sent it out yet to be bored and plated ($225.00)yet since the sleeved cylinder is working still.
My build wasnt for racing but for play dunning, im still checking out Flea Bay for an extra motor to try this upgraded cylinder on with more aggressive cams down the road, strocked crank heck maybe a NOS kit, like I said before damn thing is a toy, have fun with a build at your own wallet pace and enjoy!