dozer Posted July 29, 2012 Report Share Posted July 29, 2012 i bought everything to build a 421 serval last week and finally got all together and ridden yesterday. the combo is a hotrods 4 mil crank, 68mm serval cylinders, cool head with 24cc domes,upp intakes, v force 3 reeds, 35mm pwk carbs and the exhaust is fmf sst. the cylinders were clean up ported by jeff at f.a.s.t. then i gasket matched the cylinders and cases. i also sharpened the divider in the intake and sharpened the dividers in transfers. i did not raise or lower any timing or drastically reshape anything. i know the sst pipes are killing it . i plan on getting better pipes but the injection pump went out in my diesel so it may take a week or two. this thing is freakin fun to ride. its not lazy down low like my 358cc was. i switched from a 13/41 gearing to 15/41 gearing and the engine still doesnt bog down . in the trails im not down shifting near as much just roll into the throttle and hold on. out in the open it starts to pull really hard then kinda lays over up top, i believe because of the pipes. as soon as i get some decent pipes on it were gona head to sandtrax in tulsa for a dyno tune then ill post up the graph. im pretty excited with how its running but then again who isnt when they build a new engine. Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted July 29, 2012 Report Share Posted July 29, 2012 You should be fine but do not sharpen dividers on the intake. A sharp edge has more of a tendency to crack later and sharpening it will not make it any faster. Not being a smart butt at all but it would be nice to see guys not wanting sharp bridges thinking it will be faster. Quote Link to comment Share on other sites More sharing options...
dozer Posted July 29, 2012 Author Report Share Posted July 29, 2012 You should be fine but do not sharpen dividers on the intake. A sharp edge has more of a tendency to crack later and sharpening it will not make it any faster. Not being a smart butt at all but it would be nice to see guys not wanting sharp bridges thinking it will be faster. thanks for the info, i did not sharpen it to a knife edge. i didnt narrow the divider were the piston rubs the cylinder wall at all . im no pro at porting but i do understand some of the basics and im always open to learning more Quote Link to comment Share on other sites More sharing options...
rjdgriff Posted July 29, 2012 Report Share Posted July 29, 2012 That's basically identical to my motor only different pipes I had T5s on mine and when I switched to the rockets it made a major difference up top Quote Link to comment Share on other sites More sharing options...
dozer Posted July 29, 2012 Author Report Share Posted July 29, 2012 That's basically identical to my motor only different pipes I had T5s on mine and when I switched to the rockets it made a major difference up top did you lose much bottom end when you switched? i cant make up my mind on wether i want to get pro circuts or shaerer pipes. looking at the dyno room threads the pro circuts look like they would be a great overall match. Quote Link to comment Share on other sites More sharing options...
rjdgriff Posted July 29, 2012 Report Share Posted July 29, 2012 I lost some bottom end but it wasn't enough to bother me, especially considering the top end gains. With the t5s I could damn near be at a stop and still instantly hit the power again in 3rd gear, now it has a cpl second delay in 3rd and its back in the power Quote Link to comment Share on other sites More sharing options...
lms1977 Posted July 29, 2012 Report Share Posted July 29, 2012 Cool glad you are liking the serval I have a 10mil serval and really like it as well. I would put the shearer pipes on it this way if you ever want to do more to it with porting you will be set..!! I have been playing with my setup and I have the shearers on it again drive it to day it is insane on the hills. I used to think the cpi's had more down low but my big problem was my reeds I have rad valves in it. Which was killing my low end reeds were way to stiff.. I have been constantly changing stuff and it keeps getting better. Glad you are liking your new motor Quote Link to comment Share on other sites More sharing options...
guns4children Posted July 30, 2012 Report Share Posted July 30, 2012 Cool glad you are liking the serval I have a 10mil serval and really like it as well. I would put the shearer pipes on it this way if you ever want to do more to it with porting you will be set..!! I have been playing with my setup and I have the shearers on it again drive it to day it is insane on the hills. I used to think the cpi's had more down low but my big problem was my reeds I have rad valves in it. Which was killing my low end reeds were way to stiff.. I have been constantly changing stuff and it keeps getting better. Glad you are liking your new motor It might run as good as the 421 1/2 smerv one day. Haha Quote Link to comment Share on other sites More sharing options...
rjdgriff Posted July 30, 2012 Report Share Posted July 30, 2012 Cool glad you are liking the serval I have a 10mil serval and really like it as well. I would put the shearer pipes on it this way if you ever want to do more to it with porting you will be set..!! I have been playing with my setup and I have the shearers on it again drive it to day it is insane on the hills. I used to think the cpi's had more down low but my big problem was my reeds I have rad valves in it. Which was killing my low end reeds were way to stiff.. I have been constantly changing stuff and it keeps getting better. Glad you are liking your new motor I want a 10 mil sooooo frickin bad!!! Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted July 30, 2012 Report Share Posted July 30, 2012 I lost some bottom end but it wasn't enough to bother me, especially considering the top end gains. With the t5s I could damn near be at a stop and still instantly hit the power again in 3rd gear, now it has a cpl second delay in 3rd and its back in the power That is the classic ol' rocket pipe! Mostly due to the large chamber volume. I remedy that with timing and compression. Not sure if either are good for the serval though as not much info is out like that for them. Pretty kick ass how they sing to ya when just cruising at low throttle. It's like they come on really fast for a second then flatten out then just explode! Nearly unnoticeable on my new passion Ice/TT motor though. Quote Link to comment Share on other sites More sharing options...
rjdgriff Posted July 31, 2012 Report Share Posted July 31, 2012 That is the classic ol' rocket pipe! Mostly due to the large chamber volume. I remedy that with timing and compression. Not sure if either are good for the serval though as not much info is out like that for them. Pretty kick ass how they sing to ya when just cruising at low throttle. It's like they come on really fast for a second then flatten out then just explode! Nearly unnoticeable on my new passion Ice/TT motor though. They do sing a very pretty tune that is for sure. I have learned exactly where to cruz so all I have to do is goose is and away I go Quote Link to comment Share on other sites More sharing options...
FASTOYS Posted August 3, 2012 Report Share Posted August 3, 2012 Dozer, glad you like the combo.. They are super fun to ride lil motors! FYI to anyone else wanting to sharpen edges on ports.... It can actually hurt the performance in some instances and like Radar said can cause breakage. Quote Link to comment Share on other sites More sharing options...
dozer Posted August 3, 2012 Author Report Share Posted August 3, 2012 (edited) Dozer, glad you like the combo.. They are super fun to ride lil motors! FYI to anyone else wanting to sharpen edges on ports.... It can actually hurt the performance in some instances and like Radar said can cause breakage. thanks jeff the motor has been everything you said it would be. everything arrived quickly and was easy assemble, although i did have a yamaha mechanic helping me... if i end up doing a cub this winter ill give ya another call. everyone else, jeff was awesome to work with and very friendly. i just realized i didnt post it at first but this entire package came from f.a.s.t. , i apologize for not mentioning that earlier on the sharpening of the edges, ive seen inside some of your porting and hjr porting. i tried to mimick just a little of what you guys do without moving things around near as much. i only went about an 1/8 into the cylinder toward the piston. on the cases i just matched the gasket .i was kinda surprised how inconsistent the widths of the dividers were in the cylinders. with that being said i am by no means a pro porter. ive also seen guys with carbide bits and cartridge rolls really screw things up by making things way to big or so thin it cracked quickly. the bigger is better mentality has really got some guys in trouble. i wasnt goin in thinking im billy bad ass on a high price set of cylinders. last of all, it will be headed to sandtrax dyno in tulsa soon with a set of shearer pipes. ill post the graph in the dyno section when it happens. Edited August 3, 2012 by dozer Quote Link to comment Share on other sites More sharing options...
theneil Posted August 3, 2012 Report Share Posted August 3, 2012 I just got a 68/58 serval from jeff about 2-3 weeks ago, awesome service and a great motor. I got t5s, 35 pwk air strikers with v force2s and some timing on it... doing the wide open 1-6 for a plug chop the first few times out was nuts, i damn near flipped it 2 times in a row. ] Quote Link to comment Share on other sites More sharing options...
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