IamKazam Posted December 4, 2005 Report Share Posted December 4, 2005 I know that these questions may have been answered another time, but I have searched with no results. My first question is if a upgraded clutch will be able to handle a 68mm bore cub with a 4mm stroker crank or will I have to purchase a clutch lockout kit and where/what price can I get one (maybe GRR)? Will the cubs accept the noss head, and what size domes will I have to run (not wanting to run race gas) at 1200ft above sea level? What gearing would you guy's suggest I run with this setup(I ride 75% dunes and the other 25 is wide open fields/roads)? Cpi bigbore inframes a good choice for pipes and what about 35mm pwk's as for carbs? Will I have to purchase a bigger intake or will v-force 3 reeds do? I'm looking to just get a little clean up port as I don't want to mess up the Nikasil coating that the cylinders have. Any advice on this winter build would be greatly apreciated. Sorry for all the questions, but I just want to make sure that I have covered everything. Thanks. Quote Link to comment Share on other sites More sharing options...
reded Posted December 5, 2005 Report Share Posted December 5, 2005 You are definitely on the right track . I'm using a FAST Racing clutch in my 421 and it has held up so far. It could go south tomorrow but it is currently holding. I'm goin to a lock up for next yr so I wont have to worry about it. The Noss head will work but you'll hafta have big bore domes. As far as what cc, you'll prolly hafta talk to David in order to work something out for pump fuel. I'm running 20cc domes and have to run race fuel. I use mine strictly for drag and am running 14/41 gearing. You may hafta experiment some with gearing in order to find out what works best for your application, but the stock gearing is a good starting point. Pipes is a whole new can of worms. You can ask 10 different people and get 10 different answers. I run Shearer inframe small bores and it pulls like hell on top but is a lil weak on the very bottom. My brother runs SB CPI's and his seems to have more low end, just doesn't pull quite as hard or as far on top. The BB CPI's are kinda iffy as most people say that 420 is the dividing line between SB/BB. The BB's will work good but I'm not sure if they work as well as SB's. 35 mm PWK's will be an excellent carb choice and now that a lotta people have these motors, you should be able to get good advice on baseline for jetting. VForce 3's will work great. Good luck with the project and make sure you do as much research and talk to as many engine builders as possible before deciding on the porting. There is a shitload of info available for these motors. Try Planet Sand for a lot of valuable info as well. Quote Link to comment Share on other sites More sharing options...
banshee x Posted December 5, 2005 Report Share Posted December 5, 2005 Good write up reded! I pretty much have the same setup as reded,However i have a lock-up on the way.I have 35 mm a/s carbs but am switching to 39mm's.As for gearing i am a big boy and I'm using 14/42 gearing.Tha boss intake will work w/ your v-force 3's and is probably the intake of choice for Hq members-Jim at Passion can hook you up with that.As for not running race fuel I'm not sure if you want to do that with a cub cylinder.The cub runs top notch and i don't think I would want to loose a couple hp from a lower octane fuel.I also run a Noss head and it works great as for domes mine were designed by my builder and built by Dave at noss.Good luck with your build and I'm sure many more will chime in and answer some other quetions you might have Later.......Adam Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted December 5, 2005 Report Share Posted December 5, 2005 You are definitely on the right track . I'm using a FAST Racing clutch in my 421 and it has held up so far. It could go south tomorrow but it is currently holding. I'm goin to a lock up for next yr so I wont have to worry about it. The Noss head will work but you'll hafta have big bore domes. As far as what cc, you'll prolly hafta talk to David in order to work something out for pump fuel. I'm running 20cc domes and have to run race fuel. I use mine strictly for drag and am running 14/41 gearing. You may hafta experiment some with gearing in order to find out what works best for your application, but the stock gearing is a good starting point. Pipes is a whole new can of worms. You can ask 10 different people and get 10 different answers. I run Shearer inframe small bores and it pulls like hell on top but is a lil weak on the very bottom. My brother runs SB CPI's and his seems to have more low end, just doesn't pull quite as hard or as far on top. The BB CPI's are kinda iffy as most people say that 420 is the dividing line between SB/BB. The BB's will work good but I'm not sure if they work as well as SB's. 35 mm PWK's will be an excellent carb choice and now that a lotta people have these motors, you should be able to get good advice on baseline for jetting. VForce 3's will work great. Good luck with the project and make sure you do as much research and talk to as many engine builders as possible before deciding on the porting. There is a shitload of info available for these motors. Try Planet Sand for a lot of valuable info as well. 445035[/snapback] id say that pretty much sums it up... only thing i can think of is if u are not in a huge hurry, go ahead and have your cases port matched to the cub cylinders. usually only costs about 100 bucks and will give you a few extra horsepower. theres at least 6 ppl on this site who have nearly identical setups with the exception of pipes so u should be able to get any kinda jetting help here. Quote Link to comment Share on other sites More sharing options...
IamKazam Posted December 5, 2005 Author Report Share Posted December 5, 2005 Thanks for all the help guys, would it be possible to run a 50/50 mix of race gas and premium with the right size domes/compression? Will I have to port the cases in order for this setup to work?. Thanks Quote Link to comment Share on other sites More sharing options...
reded Posted December 5, 2005 Report Share Posted December 5, 2005 You don't have to port the cases, but it helps when trying to extract every last ounce of hp. It's also easier to do when you're replacing the crank, since the motor is already torn apart. Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted December 5, 2005 Report Share Posted December 5, 2005 Thanks for all the help guys, would it be possible to run a 50/50 mix of race gas and premium with the right size domes/compression? Will I have to port the cases in order for this setup to work?. Thanks 445180[/snapback] yea u can run 50/50..ur builder can get uthe correct domes for your altitude, and type of fuel u wanna run..u dont have to port the cases, but those extra few hp for 100 bucks is worth it. like reded said its easier just to go ahead and do it while u have the motor apart.. Quote Link to comment Share on other sites More sharing options...
banshee x Posted December 5, 2005 Report Share Posted December 5, 2005 Agreed! Quote Link to comment Share on other sites More sharing options...
RNBRAD Posted December 5, 2005 Report Share Posted December 5, 2005 If you have a dremmel you can port the cases yourself with a little instruction. I think for pump gas you will be around 22cc domes, 21 use a 50/50 mix and anything lower you will need 100% race fuel. I would defintly check your compression when it's built just to double check your compression and go with the octane accordingly. I use the FAST clutch as well and have not had a problem with it on the 421 cub. Quote Link to comment Share on other sites More sharing options...
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