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Re: Sym dd50 build!!
Posted: Mon May 14, 2012 2:22 am
by bakaracer
Madman wrote:Ok my mistake It was 7.9 : 1 When I rechecked them tonight!
Can I get away with this ratio?
yeah thats perfect gearing. you can get to your target speed no problem.
Re: Sym dd50 build!!
Posted: Mon May 14, 2012 2:23 am
by bakaracer
how much you paid for that bad boy(temp gauge)?
Re: Sym dd50 build!!
Posted: Mon May 14, 2012 2:25 am
by Trafficjamz
nice paint video
very nice
Sym dd50 build!!
Posted: Mon May 14, 2012 4:00 am
by Madman
bakaracer wrote:how much you paid for that bad boy(temp gauge)?
bought the k-type CHT thermocouple and meter separate! They were12$and 6$ each + shipping from china! Surprised with the quality I will provide the links!
Sym dd50 build!!
Posted: Mon May 14, 2012 4:07 am
by Madman
Here are the links:
http://www.aliexpress.com/snapshot/106561543.html
http://www.aliexpress.com/snapshot/106556201.html
Just did some modifying and it fit right on the meter will shorten the cable when I put it on the bike.
Re: Sym dd50 build!!
Posted: Mon May 14, 2012 9:33 pm
by bakaracer
you can use that meter for egt readings too. you will need to weld a bung to put the egt sensor in on the header j 6in from the piston.
Sym dd50 build!!
Posted: Tue May 15, 2012 12:37 pm
by Madman
Just bought a piston kit and a whole new 50mm bore kit from Tiada. Should arrive in a couple of days and I can start putting the engine back together and do a dam pressure test!
Sym dd50 build!!
Posted: Fri May 25, 2012 4:31 am
by Madman
Ok so pressure tested the motor today, found some leaks and fixed them mainly around the base of the ct intake so I doubled the gaskets there and came up good, was also leaking around the spark plug so swapped it out and came up good there too!!

Re: Sym dd50 build!!
Posted: Sun May 27, 2012 7:00 pm
by bakaracer
now take a compression test. remember that kit your using is a 12.5to-14to1 compression ratio kit. if the compression is higher than 125psi, add a head gasket maybe 2 if need to. adding the head gasket adds volume to the top half to lower the compression ratio for you to be able to run that motor on pump gas without it running hot, seizing or blowing a hole in the piston.
Re: Sym dd50 build!!
Posted: Sat Jun 30, 2012 2:41 am
by kauaianman
bakaracer wrote:now take a compression test. remember that kit your using is a 12.5to-14to1 compression ratio kit. if the compression is higher than 125psi, add a head gasket maybe 2 if need to. adding the head gasket adds volume to the top half to lower the compression ratio for you to be able to run that motor on pump gas without it running hot, seizing or blowing a hole in the piston.
so compression must be below 125 for pump gas?
Re: Sym dd50 build!!
Posted: Sat Jun 30, 2012 9:22 pm
by kingkamehameha
Yup! Many people make the mistake of installing a expensive race bore and running it on ethanol free with only the o-ring head gasket. I used a brand new stock headgasket from honda and opened it up with a dremel
Re: Sym dd50 build!!
Posted: Mon Jul 02, 2012 10:52 pm
by kauaianman
so 135 too high for pump gas.
thats probablly why i'm heating up.
I have the corsa on with 1 extra head gasket (addition to the O-ring) and i get about 135ish compression.
you think if i drop compression to 120 or below i should take car of the heat problem?
is it OK to use multiple head gaskets (2-3) i'm thinking i may need 3 to get it below 120? any good way to keep them lined up and from leaking?
Re: Sym dd50 build!!
Posted: Tue Jul 03, 2012 12:55 am
by kauaianman
lowered the compression to 118 (3 head gaskets)
still running hot...
no leaks everything checked.
i have the same setup with the ministroke and the 50mm taiwan.
the piston is perfecly flush with the bottom of the exhaust port on BDC.
pretty sure its the 50mm made for the ministroke cause i just used the base gasket that came with the kit and the exhaust lined up perfect.
could running too big of a jet cause heat problems??
running the 30oko with this setup 58p 150m
runs good with good throttle response. put on center stand from idle to full WOT no bogging just clean rev up and back down to idle.
Re: Sym dd50 build!!
Posted: Tue Jul 03, 2012 4:38 am
by kingkamehameha
Did you do a leakdown with the temp gauge attached? How hot is your bike getting? What is your needle at? Did you port match the boost? 150 is a huge jet size for a ministroker. You need to learn how to do a proper plug chop. You should be in the 132-138 main jet range with a oko 28. Get rid of the 30 its gonna be a pain to tune that is wayyyy too much carb. Call me up tommorow 345 3596
Re: Sym dd50 build!!
Posted: Wed Jul 04, 2012 3:25 am
by kauaianman
kingkamehameha wrote:Did you do a leakdown with the temp gauge attached? How hot is your bike getting? What is your needle at? Did you port match the boost? 150 is a huge jet size for a ministroker. You need to learn how to do a proper plug chop. You should be in the 132-138 main jet range with a oko 28. Get rid of the 30 its gonna be a pain to tune that is wayyyy too much carb. Call me up tommorow 345 3596
ok i'll try the 28 with that jet settings.
yup i did match the boost port for the 50mm all the way down. like in this thread.
i call u up.