kessig4x4 Posted July 6, 2012 Report Share Posted July 6, 2012 Are there any cons to running a set of 72mm cylinders on a 4 mil short rod engine versus running 68mm cylinders? I mean if there aftermarket cylinders than overheating shouldn't be an issue because the manufacturer should've compensated for the larger bore size correct? Any information would be helpful thankyou Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted July 6, 2012 Report Share Posted July 6, 2012 There is no replacement for displacement. I would certainly not worry about overheating any aftermarket cylinders as long as the cooling system is up to snuff. (water pump, radiator, etc) It probably wouldn't be a good idea to go open dune a big cougar or caracal cylinder for hours on end, but cubs, cheetahs, dm/x's, athenas, wicked sr71, and twister cyls are all up to the task of keeping themselves cool if you know how to tune and have the cooling system needed. I really am surprised I am not seeing more of the super servals as the extra 50 CC's are the same price. However making a stock cylinder capable of big bore is almost a waste now a days and after 68 mm they need ALOT of work to keep them sealed up and become almost unreliable. Dunno if that helps ya or not Quote Link to comment Share on other sites More sharing options...
Trick2stroke Posted July 6, 2012 Report Share Posted July 6, 2012 Aren't pistons more expensive? Would seem to be the only downside to the 72 mm. Quote Link to comment Share on other sites More sharing options...
kessig4x4 Posted July 7, 2012 Author Report Share Posted July 7, 2012 (edited) Cool, yeah i was looking at some cub cylinders but im still shopping around. From what i remember seeing it seems like the pistons are about a hundred bucks more when you buy replacements, but i could live with that. I will probably go with the 72mm bore. Because like you said theres no replacement for displacement. I would probably need to get one of those nice expensive radiators right? Im not sure id be comftorable with one of those 100 dollar ebay ones on it Edited July 7, 2012 by kessig4x4 Quote Link to comment Share on other sites More sharing options...
kessig4x4 Posted July 7, 2012 Author Report Share Posted July 7, 2012 (edited) I just read on the MM atv site that the 72mm requires case boring, which i havent read anywhere else...At that point id might as well bump it up to a 10mil stroker which i dont plan on doing. So i guess thats why you dont here of em as much as a 68 bore. Unless that was only referring to a 10 mil stroke which was unclear because theyre in the same subject area Edited July 7, 2012 by kessig4x4 Quote Link to comment Share on other sites More sharing options...
Rotax Raptor Posted July 7, 2012 Report Share Posted July 7, 2012 Since you've looked at m&m's site now, the best thing to do would just call Andy and get his opinion. He can intelligently explain the pros and cons and give you pricing. 918-333-4341 Quote Link to comment Share on other sites More sharing options...
BANSHEE HP Posted July 7, 2012 Report Share Posted July 7, 2012 there is no 72mm piston for a short rod (110mm). top case boring is required for the 72mm cheetah or supercub. Quote Link to comment Share on other sites More sharing options...
badassbanshee479 Posted July 7, 2012 Report Share Posted July 7, 2012 you have to open up the top of the cases to accept the bigger bore cylinders... what you are thinking of is case trenching.... witch is needed for 7mm and up stroker cranks..... i have a 10 mill super cub with a 72 bore and the thing flat out rips! i love it! also like the fact that its a 521cc where as a 10 cub is only 465cc..... Quote Link to comment Share on other sites More sharing options...
koster88 Posted July 7, 2012 Report Share Posted July 7, 2012 Since you've looked at m&m's site now, the best thing to do would just call Andy and get his opinion. He can intelligently explain the pros and cons and give you pricing. 918-333-4341 I agree, Give Andy a Call. He has helped me so much with one of my builds that he is doing for me. GREAT guy! Quote Link to comment Share on other sites More sharing options...
NickisGod Posted July 7, 2012 Report Share Posted July 7, 2012 As stated. 72mm+ requires upper case boring to fit the sleves. Its like 80$. Also jeff at fast mention this to me. He dosnt like the large bore cylinders because they become weak due to the removing of material for inner cylinder walls. So basically they are thin walled but will work fine but are more proned to fractures Quote Link to comment Share on other sites More sharing options...
Robbizzo Posted July 10, 2012 Report Share Posted July 10, 2012 I just built a 472 super cub. Called Cam at Redline and talk about all the usual stuff. It came down to what you do and how you ride. I play in the tree shots and rip around more then race so I was looking for all around power. I run 35 pwks on 110 with 6 degrees timing, CPI's, stock radiator, ignition etc and it made 92hp. I dont remember the torque but it came on very early. It flat out makes usable power everywhere! With an 8 over and 22" 12 paddles it wheelies on command but is not a light switch, its really smooth. I weigh 235 and it hauls me around great! I ride at coos bay and a lot of my buds have 421's, that rip btw, but I wanted to try a super cub and I love it. Just sharing my experience, call Cam, he knows his cub's. Later Quote Link to comment Share on other sites More sharing options...
robert0762 Posted July 10, 2012 Report Share Posted July 10, 2012 With a 72 mm bore do you have to run trinity's head or are there other companies who make heads and domes for that bore? Quote Link to comment Share on other sites More sharing options...
badassbanshee479 Posted July 11, 2012 Report Share Posted July 11, 2012 With a 72 mm bore do you have to run trinity's head or are there other companies who make heads and domes for that bore? others make a super cub head and domes..... mine has a noss machine head on it..... Quote Link to comment Share on other sites More sharing options...
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