spurdy Posted September 15, 2007 Report Share Posted September 15, 2007 You still have to have the domes cut, the 795 pistons were designed for stock stroke with the 115mm long rods. Once upon a time the long rod setup utilized rods from a Yamaha RD 400 bike engine and using the blaster pistons for the 5mm higher pin height, the problem with running blaster pistons was having to bore the cylinders all the way out to fit them, and having to rachamber the head to match the dome of the piston. This was such a popular mod that wiseco made the 795's with the stock dome and starting at std. Banshee bore. They are used on the 4mm long rod stroker (on a 4mm stroker the crank pin is offset by 2mm resulting in the piston traveling 2mm higher in the cylinder and 2mm lower) , but the piston crown will stick out the top of the cylinder 2mm, therefore the domes need to be recessed accordingly. OK. Now I am getting a little concerned :ermm: . I am in the middle of a rebuild. Cases sprung an air leak and ran lean damaging the pistons and requiring bored and honed. I took it to a local shop that has done decent cylinder work for me before. I was discussing with them going to a 4mm stroker crank (my current crank is in good shape just showing some small end play close to service limits and is trued and welded). The jugs are already ported and we discussed the spacer plate and no spacer plate. We decided Hot Rods H129 crank with 795 pistons. He talked like this would be drop in and go. He didn't say anything about changing the porting or machine work to the domes (I am running a Pro Design Cool Head with 17cc domes). If they don't know what they are talking about I think I'll just take my parts and run. I trust them to do the bore and hone but, I am a little worried that this stroker might be over their head. Strange, because they have a really good rep around here. So, adding the +4mm crank to an already ported jug is going to require what? How do you recess the dome in the head? Remove material from the back side of the flange of the dome or remove material from the mount surface of the head? Any comments are appreciated. Thanks! Quote Link to comment Share on other sites More sharing options...
RZBansheeMan Posted September 15, 2007 Report Share Posted September 15, 2007 (edited) Call Jeff @ F.A.S.T. racing, When going to a 4mm stroker You need to have stroker porting done to your cylinder or you could end up having an engine running worse than your present set up. The domes need to be turned on the squish band side (the side that faces the piston). On a two stroke engine as simple as it is, there are fewer parts (obviously), yet that have more working responsiblities. The cylinder serves for both the combustion and the ports are like a cam in a 4 cycle. The piston is serves as delivering the power and acting like the valves in a 4 cycle. So throwing in a longer stroke crank throws all the timing off in the 2 cycle, it would be similar to mis aligning the timing set on a 4 cycle engine, causing poor performance. The 4 cycle has separate components for all these job duties. You can probably purchase domes that are already cut for a 4mm stroker. You also could probably have them do your bottom end, but send the jugs out for 4mm porting and get the proper domes and then have them assemble it. Mike Edited September 15, 2007 by RZBansheeMan Quote Link to comment Share on other sites More sharing options...
spurdy Posted September 15, 2007 Report Share Posted September 15, 2007 Call Jeff @ F.A.S.T. racing, When going to a 4mm stroker You need to have stroker porting done to your cylinder or you could end up having an engine running worse than your present set up. The domes need to be turned on the squish band side (the side that faces the piston). On a two stroke engine as simple as it is, there are fewer parts (obviously), yet that have more working responsiblities. The cylinder serves for both the combustion and the ports are like a cam in a 4 cycle. The piston is serves as delivering the power and acting like the valves in a 4 cycle. So throwing in a longer stroke crank throws all the timing off in the 2 cycle, it would be similar to mis aligning the timing set on a 4 cycle engine, causing poor performance. The 4 cycle has separate components for all these job duties. You can probably purchase domes that are already cut for a 4mm stroker. You also could probably have them do your bottom end, but send the jugs out for 4mm porting and get the proper domes and then have them assemble it. Mike Thanks! I just got off the phone with the local shop. They haven't ordered anything yet. I am picking my stuff back up from them and going another direction. I just tried to call Jeff and their shop is closed this weekend. I checked out his web site and his prices seem really reasonable! I don't mind spending the money as long as I get what I pay for. I suppose he will just have to look at my jugs and see if they can be reused for a stroker crank. I have a buddy that has a virgin set that I could pick up at a good price if I need them. A new set of stroker domes probably would be the way to go. I was surprised to hear that the work is done on the squish side! I figured the dome would just be recessed in the head farther. You mentioned having the bottom end done. I thought the only time the bottom end needed work was with a 10mm stroker? I've just split the cases and have them ready to go to the paint shop. If there is work to be done to them I don't want them painted first! Thanks for the input! Quote Link to comment Share on other sites More sharing options...
RZBansheeMan Posted September 15, 2007 Report Share Posted September 15, 2007 Thanks! I just got off the phone with the local shop. They haven't ordered anything yet. I am picking my stuff back up from them and going another direction. I just tried to call Jeff and their shop is closed this weekend. I checked out his web site and his prices seem really reasonable! I don't mind spending the money as long as I get what I pay for. I suppose he will just have to look at my jugs and see if they can be reused for a stroker crank. I have a buddy that has a virgin set that I could pick up at a good price if I need them. A new set of stroker domes probably would be the way to go. I was surprised to hear that the work is done on the squish side! I figured the dome would just be recessed in the head farther. You mentioned having the bottom end done. I thought the only time the bottom end needed work was with a 10mm stroker? I've just split the cases and have them ready to go to the paint shop. If there is work to be done to them I don't want them painted first! Thanks for the input! When I mentioned having the bottom end done I was refering to the shop splitting the cases and installing the new crank and seals, I wasn't sure if you were going to do that yourself or not, No prblem on the input. I am not the most knowledgeable guy on these things, but I do try and share the information that was shared with me and or share any of my experience with others. :beer: Mike Quote Link to comment Share on other sites More sharing options...
spurdy Posted September 15, 2007 Report Share Posted September 15, 2007 When I mentioned having the bottom end done I was refering to the shop splitting the cases and installing the new crank and seals, I wasn't sure if you were going to do that yourself or not, No prblem on the input. I am not the most knowledgeable guy on these things, but I do try and share the information that was shared with me and or share any of my experience with others. :beer: Mike Thanks again! Yeah, cases split, cleaned, sand blasted, cleaned again (boy is it a bitch to get all the sand out!), taped and ready for paint. Just need to figure out if I want the additional headache of the +4mm stroker or go back with stock stroke. I think either way I want to go with a new crank, so I figure might as well stroke it. I am the only one I ride with that runs a banshee and have only dealt with stock strokes up till now. With no one else around that runs one I am left on my own to choose. I guess I'll talk to Jeff and run my set up by him and see what he thinks. Thanks again for the advice! :smile: Quote Link to comment Share on other sites More sharing options...
. Posted September 16, 2007 Report Share Posted September 16, 2007 you could have the cases port matched to your top end if you want to, will give a little cleaner transfer flow. was gonna ask about my situation, but I think I'll start my on post. Good luck with your build man.....I'm starting on mine as soon as my wedding is over (nov 3rd) Quote Link to comment Share on other sites More sharing options...
kawiking Posted October 8, 2007 Report Share Posted October 8, 2007 so a set of ported cyln. would have to be re-ported for a 4-mill crank ??? Quote Link to comment Share on other sites More sharing options...
ZR2Freak Posted October 9, 2007 Report Share Posted October 9, 2007 Not Hi-jacking your thread or anything.. But this is alot of good info.. sure has helped me out in the direction i need to be going with my buildup!.. i too was ona debate whether to run stock stroke.. or stroker.. i now know the answer!... Quote Link to comment Share on other sites More sharing options...
ban02shee Posted October 10, 2007 Author Report Share Posted October 10, 2007 ok well i am close to being done the crank and bottem end is together i got wrong pistons though i ordered them for the cyclinders i had .080 over and received .040 lol but once i get that all set, i need to find out wat size domes to get for the coolhead, thanks in advance also what should i go with for a carb on this bike, 2 into 1 , or keep them seperate i can get a good deal on 2 flatside 35mm keihin Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted October 10, 2007 Report Share Posted October 10, 2007 (edited) To clarify for all on this. A stroker crank and pistons is not a drop in deal. You will either need machinework to the head, or domes, and stroker port work done to the cylinders for the bike to run right. It cant be joe bob in the back of the parts plus doing the machine work either. You need someone experienced with the stroker crank, pistons, gaskets, and cool head you are using. Edited October 10, 2007 by Snopczynski Quote Link to comment Share on other sites More sharing options...
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