. Posted September 16, 2007 Report Posted September 16, 2007 Dont know what I should do, I was going to go with a stroker long rod, but dont think I'm going to need that much power, and I think I might starve the engine a little bit on fuel trying to conserve for really long riding conditions. So I've decided to go with a stock stroke long rod, I'll get an increase in torque and an increase in longevity correct? Right now I've got a top end that has a woods port with a little pull added on the top end, and it was bored to match the wiseco pro lites that I have with it. Here's the situation, to get away from using cut domes, I could use 795 series pistons correct? But boring is done to the thousandths and wiseco only measures to the hundredths. How close do you think the bore would be if I just ordered the same size 795 series pistons? Or do you think it would just be cheaper to go with some cut domes? I have a noss head with 17cc and 19cc domes, can I just get them sent out to get cut?, or do I have to get different domes altogether? Gonna start this build from the ground up soon, and want to have everything situated before I dive in. Quote
RadarRacing Posted September 16, 2007 Report Posted September 16, 2007 You'll get no torque advantage being stock stroke. Having new domes made for $75 to $100 is nothing and you can sell yours for say $40 or have yours recut if they can be made to work with your new combo. I'd get the motor combo that will work best for you powerwise(crank,stroke,porting) and for fuel type you wanna run and think about the dome situation last. It's not that big of a deal.. Quote
Bansh-eman Posted September 16, 2007 Report Posted September 16, 2007 to have the domes makeup for the long rod they will need to have 5mm cut out. im pretty sure almost every builder has domes that are precut laying on the shelf for strokers but not to be used to take up the rod length. they will probly charge you extra to recut them again... the 795s will take up that space and then you can run the same domes you have right now, how ever you should never have your jugs done without having the pistons there with them so you can gt the correct tolerances. as far as extra torque , your not going to have any diferant power by dropping a stock stroke long rod in the motor. your simply goig to relieve some stress on the motor. you ,ight try selling your jugs and buying a set with a little more aggressive port on them. Depending on how much was taken off of your first port to make it a "woods" could effect what othr type of porting you are able to get.... Quote
RZBansheeMan Posted September 16, 2007 Report Posted September 16, 2007 What bore do you happen to be on now ? Wiseco's chart shows their stock rod pistons going in increments of .025" of an inch up to 66 mm .050" and their "795" pistons increments of .050 mm up to 66 mm. They don't measure to the hundredths, but .050 mm ~ .020", so if you go with the 795 you will need to go the next size over that you are on right now, *Unless you are on stock bore*. Mike Quote
blowit Posted September 18, 2007 Report Posted September 18, 2007 Dont know what I should do, I was going to go with a stroker long rod, but dont think I'm going to need that much power, and I think I might starve the engine a little bit on fuel trying to conserve for really long riding conditions. So I've decided to go with a stock stroke long rod, I'll get an increase in torque and an increase in longevity correct? Right now I've got a top end that has a woods port with a little pull added on the top end, and it was bored to match the wiseco pro lites that I have with it. Here's the situation, to get away from using cut domes, I could use 795 series pistons correct? But boring is done to the thousandths and wiseco only measures to the hundredths. How close do you think the bore would be if I just ordered the same size 795 series pistons? Or do you think it would just be cheaper to go with some cut domes? I have a noss head with 17cc and 19cc domes, can I just get them sent out to get cut?, or do I have to get different domes altogether? Gonna start this build from the ground up soon, and want to have everything situated before I dive in. I think you have the stroker and longrod setups confused. You can not use stock pistons with an RD400 rod (115mm). You must either use the blaster pistons or 795 pistons and will return you near to stock porting. By using stock pistons, your piston would come out of the hole 5mm, which is tooo much and would have your port timing off by more than even I can correct. You should simply install the longrod crank and supplement with 795 pistons and hit the trail. There is a small rod angularity change that will affect port timing but not enough to worry about on a trail tuned motor. DO not expect big torque changes with this setup. They do run better but you will not have any benefit in the trails. Simply put, the reduction of rod angle allows for more rpms and a bit more HP on the top. Brandon Quote
Ducman Posted September 18, 2007 Report Posted September 18, 2007 Like blowit said you must use either blaster pistons (big bore) or 795 series pistons with the +5mm long rod. I'd just stick with a stock rod crank unless you want to do some insane stock stroke long rod drag motor. When I went to a 4mm stroker I lost a lot of mileage in the dunes but on the trails it wasn't that awfully bad. On my cub motor I have now its even a little worse MPG wise in the sand but I still was able to go 56+ miles on mountain logging roads, 2nd - 4th gear, and not hit the reserve. Quote
. Posted September 19, 2007 Author Report Posted September 19, 2007 thanks for all the help guys, it got me thinking about it more and everything is making sense now. I believe the bore on those cylinders is a .03 overbore, but not positive on it. I was all backwards on the longrod/stroke/what you have to do to make it work. I was to busy thinking of what to do to not have to change the portwork on the cylinders, and realize the rod will effect where it is in the cylinder as well. Still dont know what I'm gonna do yet, as far as the 795's or just run it with a stock rod crank. I've got a month to think about it Quote
RNBRAD Posted September 19, 2007 Report Posted September 19, 2007 If your going through that kind of trouble, I would go the 4mil and get a bigger tank or get a 6 pack rack and take some gas with you. Quote
. Posted September 20, 2007 Author Report Posted September 20, 2007 See, I've talked to some people that have had 4mill's that ride a lot of tight technical trails (red ore) for one I believe, and the 4mill just got to be to much in the woods. Kind of like that 520 they built for supermoto that was in dirtwheels was to much. I mean, I could probably get away with 30mm carbs on the 4 mill, but I dont want to go any bigger than that. I have a 5.5 gallon tank already, and their has been days where I've carried 2 extra gallons on my back and have needed it. We ride down at Hatfield-McCoy with a bunch of 4 strokes with IMS tanks, and they carry extra gas as well and we'll go out all day. The one system has a gas station at the trailhead opposite of the one we park, but other systems have one trailhead, and to get all the way out and all the way back, takes me more than 5 gallons. Quote
RNBRAD Posted September 20, 2007 Report Posted September 20, 2007 They must be set up wrong. A 4mil with a 2:1 or 28mm carbs, midrange pipe set-up and some timing advance should be better on the technical stuff than a stock stroke could ever achieve. But don't talk to people, go ride one and feel the difference, I think you will be surprised at how much more low end they have for the tight stuff. Quote
dajogejr Posted September 20, 2007 Report Posted September 20, 2007 Oh...just buy a four stroke...LOL. JUST KIDDING... I think a 4 mil setup, long rod...and a 1 into 2 33PWK setup would be a GREAT trail bike.... And blowit is correct...get the right pistons, don't cut the head.... Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.