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Post by pete130 on Dec 10, 2017 22:56:15 GMT -5
Hi im setting up my stroker bigbore and my piston is ending up about 2mm below port bottom is this a bad thing i know level is good and above is bad i can change head hight easy im worried about piston going to far past bottom of ports any ideas please or can i leave and just make sure timing is ok and squash is good thanks
i have a 100cc aerox motor with a 57mm barrel thats 5mm longer than stock and thicker webing for porting alloy of course now my problem is ive fitted dummy bearings and no gaskets to get port timing i was hoping with the stroker crank 52mm it would end up needing a spacer at most kit came with .5 .4 .3 .2 alloy gaskets its a KN 9 port kit for bws 100cc ment to be 16hp out of box come with a recessed race head to compensate the barrel 5mm longer i have put togeather and see that the piston is 1 to 1.5mm below port bottoms i know piston should sit at edge of bottom of port i have 2mm head spacer made like a head fin matches head fin size looks good and head seems to fit great but havent done squash gap yet im thinking it i get barrel mechened bace to get piston to sit at bottom of ports the timing numbers im getting are very poor from what ive read i have all the porting tools to do whats needed and great softwere to make up port templets im intrested i anyone opion on if im going down the right track or leading my self up the garden path. Im thinking when barrell is done i can use other race head i have 9.2cc same as 4mm recesed head have rear mont carb setup 28-30mm and 15/42 gears with polini variator belt stage6 112mm full adjustable clutc my go with polini 2g 2 shoe good lanch prodigy torque pully race well street race everything more to the race side have a nice hydroformed turbokit pipe 220mm 4pot breaks polini digital rota but only good on race days but have digital race cdi for aerox 100cc very hard to find and expencive lol
Pete130
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Piston
Dec 10, 2017 22:59:03 GMT -5
Post by pete130 on Dec 10, 2017 22:59:03 GMT -5
piston 1-1.5m past bottom of ports and is same amount from top of barrel i should get barrel machined to get piston to sit at edge of port bottoms getting very bad timing numbers if i leave lol realy bad lol please help dont want to use spacers unless i realy have to have some but want some one option on what to do thanks to all who read
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Piston
Dec 10, 2017 23:30:17 GMT -5
via mobile
Post by jdl357 on Dec 10, 2017 23:30:17 GMT -5
I'm about to do the same with a stroker 90cc I have. If being level is the goal, you might have to machine off some of the base of your cylinder. I'll be watching what you do, might be of help when I do my stroker.
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Post by oldgeek on Dec 11, 2017 0:45:58 GMT -5
So what does TDC look like? Possibly you got too much stroke? A picture of TDC will tell us more. Damm I wish we could get that Aerox 100 stuff here easily!
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Post by oldgeek on Dec 11, 2017 4:33:07 GMT -5
Stop making new threads! Only one thread is needed for you to get help.
What are the timing numbers you are getting? What are the timing numbers you would like?
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Post by moofus02 on Dec 11, 2017 9:16:33 GMT -5
Guess we really need to know where your timings are as mocked up to give good advice. Would be interested in pics of the heads you have
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Post by 90GTVert on Dec 11, 2017 17:35:13 GMT -5
I have done some moving and combining about 5 threads into just this 1. Creating more than 1 thread for the same issue just confuses the people that may try to help you. Please keep this issue to this thread from now on so all details are in one spot.
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Piston
Dec 11, 2017 22:55:43 GMT -5
via mobile
Post by pete130 on Dec 11, 2017 22:55:43 GMT -5
Hi hope i have right place piston bdc is 1.5mm below ports can have barrel machined it is 4mm longer than stock for port work has that lol got what seema to be a great bbk but used a stroker crank as well so timing is out of course should i keep going sown to way im going or am i realy wrong i have 2 heads one is a 4mm recesed head and i have spacers to get squash right plan on .8 piston doesnt have windows like stock but shirt doesnt seem to block intake much at all a 5mm at most if u need pics to see can upload just dont want to muck this up first 2stroke rebuild done everything else lol its looking like 190-194° exhaust and 132-136° intake didnt cheack blow down but u could work out easy anyway thanks for reading
Pete130
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Post by 190mech on Dec 12, 2017 14:37:46 GMT -5
I saw your port layout in the Port Map section,it looks like the cylinder is designed for a 52mm stroke as thats the distance from the top of the bore to the port floors..If you have a 54mm stroke,it'll drive the transfer port durations way up..Then you'll have to figure out how to take care of the squish as the piston will be 2mm above the cylinder deck...
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Piston
Dec 13, 2017 1:13:17 GMT -5
Post by pete130 on Dec 13, 2017 1:13:17 GMT -5
Hi sorry didnt relise about posts well the crank is a 52mm as you said about barreli havebpics ill post im getting 200ex and 140trans but thats not right as i think 30°is the 1.5 mill the barrel needs to be milled and should be good i wanted opion in should i just do that and gi feim there or I want to do wright first time i have resesed head 4mm and spacers to do squash gap to .8 i want sorry to sak so much at once realy want to build and run.my plan was after seeing piston 1.5mm past port was to mill and be donw with it instead of trying to make work i know i have to look at skirt civering exhaust port think thats ok but will cheack i was looking at around 192ex and 134trans around that have pipe ment to be goos for 11500 but still a street bike lol im lucky sea level not a hill for miles and im 60kg si bike should hall ass im hoping am i going the right way thanks all there is a 2mm spacer on barrel in pic
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Piston
Dec 13, 2017 1:13:53 GMT -5
Post by pete130 on Dec 13, 2017 1:13:53 GMT -5
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Post by pete130 on Dec 13, 2017 1:21:41 GMT -5
I know what your saying 52mm should be so close not funny buy its way out barrel is the 4mm longer and my crank is 4.4mm stroked so by rights i should have to use the .4mm gasket that came with kit wow am i stupid its not taque down at all would that bring barrel down that much and only have one dummy bearing in to look at and im thinking your all going to say no wonder where do these people come from feel stupid but im happy to be wrong as long as im shown whats right lol give me good news and it will help if i at least add right bearing and tarque barrel didnt want to do bearings till have to got hybrid ceramic expencice thats all
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Piston
Dec 13, 2017 2:24:55 GMT -5
Post by pete130 on Dec 13, 2017 2:24:55 GMT -5
I have look at again if im right its 6.9230° per mm of piston travel on paper from what i worked out 52mm crank should be .4mm short of deck hight as starnd is 48.6mm crank is 4.4mm longer ment to be i did look at it and it seems to travel the 52mm so i dont know whats going on the barrel is 4mm longer than standard but thats where the crank should be filling does the barrel compress that much when taque down if so im amazed at that ? And sorry again for being so wanting being trying to sort out and build for 4 months now and money as we all do heres a pic of barrel with stats on paper thanks
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Piston
Dec 13, 2017 4:51:10 GMT -5
Post by 190mech on Dec 13, 2017 4:51:10 GMT -5
Installing a taller piston or longer connecting rod would get the same results,the 52mm BWS100 crank Ive got has a 90mm rod..A piston swap would be the cheapest option if one can be found..Do your best to get the piston aligned with the bottom edge of the transfer port at BDC as this greatly aids in piston cooling...
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Post by pete130 on Dec 13, 2017 5:21:55 GMT -5
Thats was my goal as i said all the parts are ment to line up 52mm stroker thats 4.4mm over stock barrel 4mm longer and i used digtal calapers all works out so i should only have to make up the .4mm top and bottom to have ports and deak line up but as you said piston may be to short the crank is ment to have stock forged rod pitty buy numbers it should line up close and it wouldnt have the port timing im getting its to high and i do ive read a lot about it all and know the theory but never done lol would it realy put lining up if only have sanded bearing that drops in no play but not tight at all and barrel not taque down at all would it realy be over a 1mm if so ill put bearings in and tarque to see what i get your a very smart person you know a lot about 2strokes and scooters thanks for taking the time yiu must get a lot asking a lot ill try do a full pic rebuild with this may help others thanks
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