Piston modifications?

GoldenMotor.com

YesImLDS

Member
Jun 29, 2013
960
12
18
Columbia, Missouri
I don't understand anything you just said. Also Dave I just polished it shortly with a wire brush grinder. Wanted to polish it up but didn't have the materials at the time.
 

YesImLDS

Member
Jun 29, 2013
960
12
18
Columbia, Missouri
ha hsjahhaaaha. laff
notch that sucka good! :D

BIGGER OPENING MEANS MORE POWER!!! laff

So clueless, there is no mention of what piston they took a chunk out of?

That's how they get ya. Those flashy words! What I don't get is why people do a half moon when they could cut across? It'd still open at the same time, but with a little less weight.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
Not buy'n it , this here's BOY GO FAST. Look ma no brakes remember ?, Like I said to to the basics ain't to become like this here OK ? Now you take one more guess. If you are building a mouse trap then fine. Otherwise,you will need to remove the studs on the intake and exhaust ports and double up the width on each without interfering with the height of them so's not to disturb the timing.Once completed you now must weld in the replacements and grind off the weld or pool a weld large enough to grind flat and drill and trap the studs back in place your choice OK ? I'm serious some of you kids have mice.
BGF, I know what you're saying here and honestly, you're absolutely clueless.

The exhaust port can be widened quite a bit, since the piston ring retaining pins are on the intake side of piston, but you cant "double" the width of any of the ports on one of these engines period end of story....

On the intake side you can widen the port some but you have to be carefu not to go to far are you will expose the ring gap and retaining pin and bingo....you just ruined the jug.

Yeah, will the skill needed and a good A/C tig capable of welding aluminum a person could add some extra material to each side of the exhaust port, machine it down and then drill and tap for a wider bolt pattern exhaust flange, but as long as you dont widen the port beyond the inside width of the stock studs it would be easy to build an adapter plate that would allow for a wider exhaust flange bolt pattern.

Im trying to be nice here BGF since I really cant figure you out completely, but you really come up with some far out in left field ways of thinking that is leaving many of us scratching our head trying to figure out what the deal is with many or most of your comments and then you just show up in threads or on chat without a single thing to say and post a youtube link that may or may not work and if it does it has absolutely nothing to do with the topic or topics being discussed.... but hey I guess your having fun stirring the pot and getting a giggle from some of our reactions.....lol

carry on, ride safe and get your facts on things together before making yourself look un-edjamakated on these discussions.....lol..!!!!
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
That's how they get ya. Those flashy words! What I don't get is why people do a half moon when they could cut across? It'd still open at the same time, but with a little less weight.
best thing to do is find a type jug that allows the least amount of the piston skirt to be seen @ TDC, several different jugs out there and they're not all created equal.

You will also find that if you have a 40mm stroke engine you'll have much less port timing issues with the right jug, so far all the jugs I have dont set up ideally on either of the 38mm stroke configurations.
 
Last edited:

YesImLDS

Member
Jun 29, 2013
960
12
18
Columbia, Missouri
best thing to do is find a type jug that allows the least amount of the piston skiry to be seen @ TDC, several different jugs out there and they're not all created equal.

You will also find that if you have a 40mm stroke engine you'll have much less tport timing issues with the right jug, so far all the jugs I have dont set up ideally on either of the 38mm stroke configurations.
True that. Problem with these motors is you have to treat all of them as one of a kind because the configurations on these will never be the exact same as any others! Too many manufacturers and too many different parts being forced to work!
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
True that. Problem with these motors is you have to treat all of them as one of a kind because the configurations on these will never be the exact same as any others! Too many manufacturers and too many different parts being forced to work!
This is sorta true, the key is to find a vendor who sells a jug that works best for the type of performance you trying to achieve with your China Girl build.

Some of the jugs will be better suited for a build that gives good down low to midrange power, lower exhaust port, lower transfer openings, higher intake port and the opposite is going to apply when you want better high rpm potential, athe higher rpm potential has to also have overall balance of engine considered also since to much vibration will limit engines ability to rev into the higher rpms, even if you get a badly balanced engine to rev high, it will die young since it will beat the bearings to death.

40mm stroke engineshave a clear advantage from what Im seeing with all my engines and jugs that I have on hand, multiple jugs have ports timed as if they're made specifically for the 40mm stroke engines, even the jugs that are claimed to be specific for GT5 or the half breed engines dont have the ports placed in an ideal location for those engines.

Yes they will all work as far as the engine being able to run and perform ok up to a certain point, but when you're trying to push the performance above average the 40mm stroke engine with the right jug is the clear winner from what Im seeing.

But who knows, maybe there are some things I haven't encountered yet since I only have about 6 different jugs so far.
 

MadMaxed

New Member
Feb 15, 2015
117
0
0
31
Florida
This is sorta true, the key is to find a vendor who sells a jug that works best for the type of performance you trying to achieve with your China Girl build.

Some of the jugs will be better suited for a build that gives good down low to midrange power, lower exhaust port, lower transfer openings, higher intake port and the opposite is going to apply when you want better high rpm potential, athe higher rpm potential has to also have overall balance of engine considered also since to much vibration will limit engines ability to rev into the higher rpms, even if you get a badly balanced engine to rev high, it will die young since it will beat the bearings to death.

40mm stroke engineshave a clear advantage from what Im seeing with all my engines and jugs that I have on hand, multiple jugs have ports timed as if they're made specifically for the 40mm stroke engines, even the jugs that are claimed to be specific for GT5 or the half breed engines dont have the ports placed in an ideal location for those engines.

Yes they will all work as far as the engine being able to run and perform ok up to a certain point, but when you're trying to push the performance above average the 40mm stroke engine with the right jug is the clear winner from what Im seeing.

But who knows, maybe there are some things I haven't encountered yet since I only have about 6 different jugs so far.
Do you know if the Dax Gen IV F80 a 40mm or a 38mm?
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
Do you know if the Dax Gen IV F80 a 40mm or a 38mm?
the newest ones are GT5 geometry engines which are 38mm stroke.

these are still good engines and will give good performance, the 40mm stroke ones he used to sell are the ones I think I like the best, but I also have two of the new lowers still in the box Im planning to build up as soon as I have time, I have one GT5 38mm stroke hoing on a bike now and it really is a screaming engine, 40+mph with a 41T sprocket on 26" bike.

I put a Fred piston in it from CRmachine which has some ramps machined at transfers, this does help with flow into cylinder and helps it perform better in the mid to upper rpms.

If you're considering the dax engine, its a good choice in my opinion.

the lower is a good foundation to build on since they have a better balanced crank assembly.

If you are looking for really good performance and dont have the tools to do port work and such, get a upper engine cylinder kit from crmachine . com, Fred has done the work to improve timing issues and all the basic needed port work to get it breathing good has been done also, yeah it isnt cheap and some of us do the work ourselves, butnot everyone can so Freds cylinder kits are a great choice for those who need more of a plug anday set up.

Again dax current engines are 38mm stroke, but I dont think you can go wrong with them.
 

MadMaxed

New Member
Feb 15, 2015
117
0
0
31
Florida
the newest ones are GT5 geometry engines which are 38mm stroke.

these are still good engines and will give good performance, the 40mm stroke ones he used to sell are the ones I think I like the best, but I also have two of the new lowers still in the box Im planning to build up as soon as I have time, I have one GT5 38mm stroke hoing on a bike now and it really is a screaming engine, 40+mph with a 41T sprocket on 26" bike.

I put a Fred piston in it from CRmachine which has some ramps machined at transfers, this does help with flow into cylinder and helps it perform better in the mid to upper rpms.

If you're considering the dax engine, its a good choice in my opinion.

the lower is a good foundation to build on since they have a better balanced crank assembly.

If you are looking for really good performance and dont have the tools to do port work and such, get a upper engine cylinder kit from crmachine . com, Fred has done the work to improve timing issues and all the basic needed port work to get it breathing good has been done also, yeah it isnt cheap and some of us do the work ourselves, butnot everyone can so Freds cylinder kits are a great choice for those who need more of a plug anday set up.

Again dax current engines are 38mm stroke, but I dont think you can go wrong with them.
I bought a dax complete engine. It runs really smooth still breaking it in. I'm about to skirt and rap the piston on it. All in a really good engine to buy for sure
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
I bought a dax complete engine. It runs really smooth still breaking it in. I'm about to skirt and rap the piston on it. All in a really good engine to buy for sure
I agree, Duane makes sure he has a good product to offer, the engines I've built up from dax have been the strongest and overall best running engines I've had.