locogato11283 Posted July 22, 2005 Report Share Posted July 22, 2005 you can get the 4mm cubs in either 65mm or 68mm(big bore). most people seem to go with the big bore whcih puts your displacement right at 421cc. you can either run a big bore pipe or something like a small bore cpi, shearer or rockets. for dragging this setup will kick some ass. wide open roads i think youll be fine as well. as forthe trails i dont think itll be all that great there, but you said you dont ride them that much. the cubs were designedto use all stock parts. so if u have shit thatll fit stock cylinders, itll fit the cubs. call jeff @ FAST racing. he should be able to get you cubs..1-785-364-5325 Quote Link to comment Share on other sites More sharing options...
J-Madd Posted July 22, 2005 Report Share Posted July 22, 2005 keep the 4mm crank and sell the stock crank and stock cylinders put that money towards the cub all you will need is the cylinder pistons and domes. It will be worth it and you should only be out 500 or so dollars out of your pocket. 395802[/snapback] Cylinders: 875 w/out port job (250 more for port work) Pistons: 175 Big Bore Domes (if you go with the 68mm bore): 20 bucks I'm doing the same thing now. I've already paid for my 68 mm cubs and full drag port, domes, etc. I didn't stroke it b/c didn't want to buy a crank yet. I'm trying to sell my extra stuff now, without much luck. Its over $1300 when you look at it like that for some cubs. NOT $875. That shit adds up quick And I don't have the carbs and pipes that I really want yet. But It'll be worth it if they ever come in. (Is there a shortage/delay of production in cubs?) I agree the keep the crank and sell the stock parts, but you'll probably be out a little more the $500 extra IMO. Quote Link to comment Share on other sites More sharing options...
chapmanmd Posted July 22, 2005 Author Report Share Posted July 22, 2005 Will my small bore CPI inframes be ok with the 421? Think the 33PWK's will be enough carb? Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted July 22, 2005 Report Share Posted July 22, 2005 Will my small bore CPI inframes be ok with the 421? Think the 33PWK's will be enough carb? 395820[/snapback] yea you should be fine. 33s will work also but 35s would be better. im runnin 35mm pwk, rockets, vf2, 21 cc dome and its runs like a striped ass ape...well u may have seen the hillclimb videos. Quote Link to comment Share on other sites More sharing options...
Big Blue Posted July 22, 2005 Report Share Posted July 22, 2005 Cylinders: 875 w/out port job (250 more for port work)Pistons: 175 Big Bore Domes (if you go with the 68mm bore): 20 bucks I agree the keep the crank and sell the stock parts, but you'll probably be out a little more the $500 extra IMO. 395818[/snapback] Price what it would cost to do the stock cylinders, it doesnt take much to get over 700 just in the topend on stock cylinders when all he will need is cylinders, pistons and domes. Also where did you get domes for $20? and where are you getting your cub from. Quote Link to comment Share on other sites More sharing options...
eehsnab2 Posted July 22, 2005 Report Share Posted July 22, 2005 id save up and sell your cylinders and buy the 4mm cubs...wasting time and money with boring, porting and pistons on stock shit. for what you have in just that plus selling your cylinders you could buy cubs.. 395792[/snapback] Couldnt agreee more... Best money spent so far! Quote Link to comment Share on other sites More sharing options...
fixitrod Posted July 23, 2005 Report Share Posted July 23, 2005 Will my small bore CPI inframes be ok with the 421? Think the 33PWK's will be enough carb? 395820[/snapback] Kinda like putting stock pipes on a stroker isn't it. Maybe not quit that drastic but cpi doesn't make a big bore pipe for the hell of it. Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted July 23, 2005 Report Share Posted July 23, 2005 Kinda like putting stock pipes on a stroker isn't it. Maybe not quit that drastic but cpi doesn't make a big bore pipe for the hell of it. 395908[/snapback] i wouldnt think quite that drastic. im runnin the rockets on my 421 cub and it runs real fuckin good. im wondering if they are considered small bore or big bore and what determines this?? Quote Link to comment Share on other sites More sharing options...
chapmanmd Posted July 24, 2005 Author Report Share Posted July 24, 2005 Does anyone know what the companies mean by small bore and big bore on the pipes? Thanks for the input. Quote Link to comment Share on other sites More sharing options...
trex banshee Posted July 24, 2005 Report Share Posted July 24, 2005 the difference between cpi small bores and cpi big bores is the diameter of piping from the end of the expansion chamber to the silencer and exit hole. if you ever have a set of each setting side by side look at the very end of the silencer where the exhaust comes out it will be bigger. Quote Link to comment Share on other sites More sharing options...
alcoholbanshee Posted July 24, 2005 Report Share Posted July 24, 2005 Use the 4mm LR crank, buy a 68mm cub top end and some PD big bore domes. On 100 octane gas with CPI's you should easily see 85+horsepower. The cylinders should cost around $1100.00 with cleanup porting, the domes 75.00, and the pistons 140.00. So for less than 1400.00 you have a damn hard running motor.And if you buy unported cubs it would be less than 1200.00! Quote Link to comment Share on other sites More sharing options...
switchblade Posted July 24, 2005 Report Share Posted July 24, 2005 I no that the shearer sb and bb pipes are to totally differant pipes, but Im' not sure about the other companys. On a motor that size I'm sure you could get away with either a small or large bore pipe. Quote Link to comment Share on other sites More sharing options...
ScrewMachine Posted July 25, 2005 Report Share Posted July 25, 2005 Ok, I'm jackin' this thread. A&S built me a 7mm cub a few months back and supposed to send me a set of CPI big bore inframes...well, I got small bores. I'd already used 'em after I figured this out, so can't return 'em. Figure I can prolly sell the small bores and buy some big bores, but dunno if it's really worth the ass pain...anybody know what kind of gains we'd be looking at going from a small bore to a big bore?? Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted July 25, 2005 Report Share Posted July 25, 2005 Ok, I'm jackin' this thread. A&S built me a 7mm cub a few months back and supposed to send me a set of CPI big bore inframes...well, I got small bores. I'd already used 'em after I figured this out, so can't return 'em. Figure I can prolly sell the small bores and buy some big bores, but dunno if it's really worth the ass pain...anybody know what kind of gains we'd be looking at going from a small bore to a big bore?? 396959[/snapback] whats ur cc size?? i would think with any 7mm big bore would be the way to go.. Quote Link to comment Share on other sites More sharing options...
ScrewMachine Posted July 25, 2005 Report Share Posted July 25, 2005 It's a 443cc. I know what you're saying about big bore pipes bein' the right choice, I was just wondering if anyone had any numbers, i.e. dyno runs, to prove how much more power a big bore pipe would make over a small bore pipe. I mean, if I'm only lookin' at another 2-3 hp, why do it...but if we're talking 5-10 hp hell ya I'm down! I'd call the builder, but he's too damn difficult to get a hold of. Anyways....I'll prolly be sellin' these small bores and gettin some big uns. Was just hopin' to get some info from y'all.... Quote Link to comment Share on other sites More sharing options...
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