Thumpstar Headkit??

[noidea]

to confirm - ducars do have 14mm gudgeon.

 

[FLICK]

to confirm - ducars do have 14mm gudgeon.

Is that the Ducar DJ154FMI engine? could you also confirm the bore and stroke for me please.... The seller I got mine off claimed they're 52.4mm x 55.5mm (=119cc), (but I don't realy trust ebay sellers)

... Could I assume the Ducar DJ154FMI has the same barrel/head dimensions as the Lifan 1P54FMI, or are the similar model numbers just a coincidence? ...

Thanks

 

[roost]

the 54 in serail number is the bore size = 54mm bore(125) , 52= 52mm(119), 56= 56mm(138) and so on. If your engine is a dj154fmi it is a 54mm bore making it a 125

 

[Mack]

Remember though there are also different stroke measurements. Generally 54mm, 55.5mm and 57mm.

 

[Mack]

Is that the Ducar DJ154FMI engine? could you also confirm the bore and stroke for me please.... The seller I got mine off claimed they're 52.4mm x 55.5mm (=119cc), (but I don't realy trust ebay sellers)

... Could I assume the Ducar DJ154FMI has the same barrel/head dimensions as the Lifan 1P54FMI, or are the similar model numbers just a coincidence? ...

Thanks

If you are considering one of those cylinders for your ducar give us the stud spacing measurements and we can tell you if it will fit. Aside from that you will have to measure the height of the ducar barrel as well cause there are different heights on various engines.

 

[FLICK]

Nah... just sussing out the specs for if I decide to do any work down the track....

Thanks

 

[noidea]

the ducar i have has a 54mm piston... seems like a pretty common engine so i would assume most other ducar 125's would have a 54mm piston.

 

[FLICK]

So I guess the Ducar 124cc must be a 54mm stroke (54x54=123.6cc), rather than 55.5 which would make it 127cc...

Edit: confirming my maths, DrATv have a bore and stroke chart here:
http://www.dratv.com/boxstccclhe.html
The site has lots of info and pics of the Lifan 120 engines..

 

[roost]

correct me if i'm wrong but if you have a Lifan 125 1P54FM1 if it is a 54x54(which my old one was) the 138 kit on ebay is a 56x55.5 if you fitted it to a 125(54x54) and did not change crank and rod you would have a compression issue or more to the point lack of comp.Is this correct, just to clear it up for 125(54x54) owners who want to buy the ebay one(56x55.5), because as far as i know it would be a problem.But i'm a car mechanic not a motor bike mechanic.

 

[cranga]

I just recieved my 138 barrel off ebay, put it on just before, fits fine, same length as the old 125 barrel. i should have measured it just to be sure. but it will be apart again before it is started.

 

[FLICK]

... Not that I was planning to do it anyway... But it looks like the 138cc kits wont go on the Ducar DJ154FMI 124cc engine (54x54?)(which has a 70mm tall barrel) ...

The Lifan 120 (52.4mm x 55.5mm) based engines are 78mm tall (according to http://www.dratv.com/127852cy.html

 

[Mack]

correct me if i'm wrong but if you have a Lifan 125 1P54FM1 if it is a 54x54(which my old one was) the 138 kit on ebay is a 56x55.5 if you fitted it to a 125(54x54) and did not change crank and rod you would have a compression issue or more to the point lack of comp.Is this correct, just to clear it up for 125(54x54) owners who want to buy the ebay one(56x55.5), because as far as i know it would be a problem.But i'm a car mechanic not a motor bike mechanic.

It actually would be the best upgrade for the 54 x 54 Lifan, because the steel cylinders are going to cause overheating problems in the aussie summer. There shouldn't be any loss in compression, a gain if anything. The reason being that both motors use a 78mm barrel but have either different rod lengths or pin to crown heights to bring that piston to correct deck height. So as long as the pin to crown height is the same on the replacement piston it will sit where it did before. C'ept now with a 56mm piston the squish band will actually be increased slightly.

 

[Mack]

Actually this cylinder is perfect for a rad Ducar build if any of you guys are up for it. Just fit an offset crankpin to increase the stroke to whatever tickles your fancy, fit piston of choice then just machine the barrel to the perfect height. Normally when using offset crankpins the cylinder must have a base plate made up. A good combo without case boring would be 56 x 56 or 57 x 57. But if ya want to play around you can go much bigger.

 

[roost]

thanks Mack that clears that up, i did not relise the barrels are the same size but i should of as the crank is the main thing that is changed in a stroker car engine, the barrel hight is not touched(except for a small amout of decking in some cases)

 

[mad man]

Thumpstar englines are chinese GPX motors. Try ebay or a whole saler for info.

 

[LOL]

hey there guys, i'm really curious, i have a loncin 124cc motor (stamped on the cylinder/barrel), however on the engine numbers it says LC52FMI, so i assume that it has a stroke of 52.2mm? which probably means its a 120cc...and not 124cc...however!, i have measured the cylinder length...and it is 78mm...which is very simular to the lifan engines?, i'm not sure what the piston pin size is...but yeah, i will check the stud spacing tommorow!, do you guys think this 138cc kit would work on my motor? thanks!

 

[LOL]

ok guys, great news, i went to measure the stud spacing just now, because i couldn't wait, walked out and fell over in the garage lol! anyway, the stud spacing is very simular to the one in this picture, which is out of a 120cc lifan motor , however one stud is like .5mm off, which shouldn't be a problem, so as i am aware this kit will fit my bike...as long as the piston pins are the same size :S! i will measure this soon too...

 

[Andoru]

okay guys, finally bad news...the gudeon pin on the loncin is 13mm..as i have taken my cylinder appart today to have a look, i am aware that the lifan gudeon is 14mm? so that means that this kit will not fit my loncin...looks like i will have to go for a lifan engine..

 

[Mack]

There are other considerations when looking for a kit. Some motors have shorter or longer rods, so compression will be affected. Also the jailing and mabye the Loncin a 57mm stroke. Can someone check this on a Loncin?

As far as 13mm piston pins go...there are more kits available than for a 14mm. High compression too.

 

[LOL]

sorry guys, andoru, LOL both me..same guy diffrent accounts..sorry!