Lifan 140cc piston diameter??

[damann33]

well I think I wont buy the h/c piston ill stick to the stock. The engine I have will still be better then the way it was stock. I will have the original head with the race cam, and all new internals to suite the cam. I will have a new stock piston to install, just need to hone the cylinder. Thats it, I dont want to buy the shorter cylinder, then have to add different thickness gaskets, shorten cam chain and all that. I will just mod the head, to get a little more performance, thats all.

 

[ixlr8]

What engine have you got ? Lifan "138" aka 127 with BVH ? If so any of the long 73 mm chinese cams and Honda cams will fit ..... As Mack has stated ... the main problem with every aftermarket cam is that they have no decompressor mechs on 'em like the stock cams have ......... so people fit them along with hi comp pistons then wonder why their kick starter mech claps out on 'em ......

For the 127 the TB cam would seem a good choice ... but for longer stroke 140's you want to run a longer duration cam to get them to rev up top ......

The yanks reckon Akunar cams aren't too fantastic .... but they say the dratv BCI cam which is a Z-40 grind is OK ......... the trouble is he won't ship to OZ ...... the only alternative is big50.com who want over $250 for the same cam ...........then there's Ivan Tighe cams in Queensland ....

I haven't actually gotten into trying different cams yet but I'd try an Akunar purely because (like a sleazy HO) they're cheap and available ... LOL .... although my instincts tell me to consult with Mack and get stock cams reground to his recommendations ......... regardless of the higher cost ......

From this week, DrATV now ships internationally, incl to Oz. Maybe I should post this as a new topic.

 

[ixlr8]

What engine have you got ? Lifan "138" aka 127 with BVH ? If so any of the long 73 mm chinese cams and Honda cams will fit ..... As Mack has stated ... the main problem with every aftermarket cam is that they have no decompressor mechs on 'em like the stock cams have ......... so people fit them along with hi comp pistons then wonder why their kick starter mech claps out on 'em ......

For the 127 the TB cam would seem a good choice ... but for longer stroke 140's you want to run a longer duration cam to get them to rev up top ......

The yanks reckon Akunar cams aren't too fantastic .... but they say the dratv BCI cam which is a Z-40 grind is OK ......... the trouble is he won't ship to OZ ...... the only alternative is big50.com who want over $250 for the same cam ...........then there's Ivan Tighe cams in Queensland ....

I haven't actually gotten into trying different cams yet but I'd try an Akunar purely because (like a sleazy HO) they're cheap and available ... LOL .... although my instincts tell me to consult with Mack and get stock cams reground to his recommendations ......... regardless of the higher cost ......

From this week, DrATV now ships internationally, incl to Oz. Maybe I should post this as a new topic.

 

[Cactus Jack]

Smart move .... it's about time .... I've always shown people that he's got a heap of interesting parts and info ....... I'd have bought stacks off him by now ... and I'm positive that there's a lot of other people who will as well .....

 

[damann33]

damn, the cam I bought for 70 bucks is only $40 from that guy

 

[themountain]

Smart move .... it's about time .... I've always shown people that he's got a heap of interesting parts and info ....... I'd have bought stacks off him by now ... and I'm positive that there's a lot of other people who will as well .....

Careful!! they really suck to work with

that from their website:
WE ARE GOING TO TRY TO SEE IF BY USING UPS'S
"UPS Worldwide Expedited"
OR "INTERNATIONAL POSTAL -_- HAVE JACK FIGURE AIR MAIL AND EMAIL ME A TOTAL (I TRUST HIM)"
OUR SITE WILL AT LEAST LET YOU PLACE AN ORDER ONLINE WITH A TOTAL, NO MATTER HOW WE SHIP IT.
NOW, WHEN PLACING YOUR ORDER,
IF YOU WANT US TO SEND THE ORDER VIA THE POSTAL SYSTEM? BE SURE TO PUT THAT INFO AND ANY SPECIAL INSTRUCTIONS IN THE COMMENT SECTION WHEN CHECKING OUT
SORRY, OUR SITE WON'T ACCEPT YOUR INTERNATIONAL PAYPAL OR CREDIT CARDS,, BUT I HAVE AN OPTION TO (WIRE_THE_MONEY)/ SEND_A_T/T, BUT YOU MUST ADD USD25.00 TO THE TOTAL FOR INCOMING BANKING FEES.


and at DAMANN...if you want to use a 57mm piston you can bore your barrel....no problem its iron

 

[prox666]

a quick question for mack or cactus jack i wanted to no if either of u2 could tell me wat this motor is it has 138cc on the head and the only numbers on it r on a white sticker and they are dj156fmi it is oil cooled with the conections going on the head not on the case any idea wat brand it is and is it good or **** thanks if anyone has a clue let me no

 

[Cactus Jack]

Sounds like it's a Ducar ........ Where did you get it from ?????

 

[prox666]

the guy at atomik sent itto me when i did the kick star gear in my prox its a 1down 3up its got atomik on the side cover thats it i complaned that he sent me a diffrent motor so he sent ma a lifan ip55fmj but i still got the outher one just wanted to no wat it is and is it anygood thanks as u seam to no what u r talking about

 

[Cactus Jack]

I'd say it's actually a 127 cc motor .... 54 mm bore x 55.5 mm stroke if it's start in gear or EVEN a 124 cc .... 54 mm bore x 54 mm stroke if it doesn't start in gear ...

But nobody can really know for certain unless they pull the head off and measure the bore x stroke ..... there was a run of motors that had 138 on the cylinder but they were proven by many people from all over the world to be 127's when they measured them .....

The Lifan 140 will have a lot more bottom end grunt but won't rev as hard up top ....

Do you have to send the old motor back ?????

It seems that Atomik DOES have decent after sales service after all ..........

 

[Cactus Jack]

Careful!! they really suck to work with

Yeah you're dead right mountain ........ UPS sucks .... (higher prices than USPS) ...... they don't take Paypal or credit cards and want $25 US in bank fees .... WTF !!!!! Wayyyy too risky All designed to jack the price sky high and make it not worthwhile ...... ........ WOFTAM ........

 

[prox666]

i have all the motors still hear they do have good customer service at atomik i dont have to send that one back one more thing i read the unlock the the box in 50brotherhood mag n spoke the guy that built it n he said that the lifan 1p55fmj 1down3up star in anygear motor thats in my bike is to week or sumthing along thoes lines wats your opponion on building it up also i have put a irk in my 1p55fmj but have not put the new oilslinger i got in yet do u think i will notice any diffrence once i change that thank u for all your help

 

[Cactus Jack]

The 1 down 3 up trannies are supposed to have shifting problems and people reckon the kick starter gears can break in the 1P55FMJ's if you don't kick start them properly once you fit a high comp piston and performance cam that has no anti kick back mech on it .......

Also most people just slap IRK's on without checking the timing with a timing light and degree wheel and wonder why the engine grenades due to detonation or breaks the kick start mech due to kick back .....

If the ignition is advanced too far , the result will be severe engine damage ....... it makes me wonder just how many of the people building these engines up actually know what they're doing .....

Also people just swap flywheels and slingers over WITHOUT having them checked for balance .... when you build up a race car engine you get the entire crank , piston , rod and flywheel assembly precision rebalanced ...... if you fit a piston that's heavier than stock in a single cylinder engine , you need to get the balance "factor" redone by someone who specialises in the field ......

 

[themountain]

i have all the motors still they do have good service i dont have to send that one one more thing i read the unlock the the box in 50brotherhood mag n spoke the guy that built it n he said that the lifan 1p55fmj 1down3up star in anygear motor thats in my bike is to week or sumthing along thoes lines wats your opponion on building it up also i have put a irk in my 1p55fmj but have not put the new oilslinger i got in yet do u think i will notice any diffrence once i change that thank u for al your help

...and you should work on the way you write your posts

thats worse than chinese

 

[prox666]

how hard is it to check the timing do i just need one of them timing lights also please explane degree wheel

 

[cass38a]

Full stop . Comma , Question mark ? CAPITAL LETTERS

It really would help everyone if you used a few of them

 

[Cactus Jack]

how hard is it to check the timing do i just need one of them timing lights also please explane degree wheel

First off , you need to have an accurately incremented timing mark ("T" mark) on your flywheel that shows where true top dead centre is (most IRK rotors DON'T have any marks) ........ then you need to know where the best timing settings are right throughout the rev range and the ONLY way you can know the best settings are thru years of seat of the pants experience with your chosen engine OR by using a dynomometer and timing light ....... the BEST settings are one's with the least amount of advance required to make the best power at any given rpm ...... and even then , a general purpose engine should have the advance backed off slightly to allow for extreme engine temperatures , varying loads encountered during different types of riding conditions , carbon build up etc ......... the longer the stroke ....... the greater the safety margin needs to be ....

Anyone who alters an engine in any way , shape or form and breaks a crank is a fool if they blame the breakage on the engine brand or type ..... detonation from over advance can bust even the best crank shafts in the world plus other engine components within seconds .........

Back to timing an engine ...... Once you accurately know where TTDC is a degree wheel or timing tape is used to tell you where it's best to have the engine firing at during various engine revs ...... the timing curve should be worked out with the engine under load to simulate REAL life usage and a dyno is closest to that ........ short of actually riding the bike and using trial and error testing .......

A degree wheel is merely a circular "disc" like a round protractor that shows degrees incremented around the circumference .......... you could use a degree'd tape or make your own marks on your flywheel ....... they are simply reference points so that you can accurately know where the engine is firing at during various rpms ...

I use an advance curve checking power timing light with inductive pickup that tells me the degrees that the ignition is firing at over various rpm ...... without the need for a degreed flywheel , timing tape OR degree wheel .......

 

[prox666]

my stock flywheel did have a letter t and sum lines in it and a letter f on the side but the irk kit hade no letters or lines to find tdc but the sharft that it goes on has a grove so it only goes on when u line up the grove is that to keep it in the rite place

 

[Cactus Jack]

The keyway simply stops the rotor from turning on the shaft ... it doesn't get the timing lined up .........