Lifan 124cc (1P52FMI) in pursuit of more power

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DarkRayne

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Hey guys I have a lifan 124cc engine that I'm looking at getting more power out of, I've already got a pitster pro race exhaust and 26mm mikuni carb on it that i got from DHZ and I have ordered a TB 411 race cam from tbolt usa for it, and was wondering what the next step would be. I was thinking of getting a port and polish and high compression piston in it, would this be the way to go?

Also guys I'm new to bikes and am not to keen on fitting pistons and cams or porting and polishing my engine, so if anyone knows a place that would fit these mods and do a port and polish for me I'd be very greatful. I live Qld, Gold Coast area, thanks guys.
 
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if you have decent funds go for a takegawa head

or pay somone to work the head (larger valves porting and polishing) and then put your cam in there...

wait till you wear out your current piston imo before you worry about installing a new one...
if you got the cam and it is a higher lift than yours you may need what they call "hd valve springs" (its just to make sure the valve does not bounce and follows the cam correctly)
 
Im on abit of a budget because of christmas but I could afford to lay down up to $500 on the engine... This is the cam I recently ordered, its not to aggressive and says it works well with the stock valve springs.

TB 411 Race Cam GPX Pitster YX Piranha Lifan - Pit Bike Engine Parts - CHINA 50-110 PERFORMANCE - TBW0411 - TBolt USA, LLC

I have had my bike for bout a year and a half now so thats why I thought it might be a good idea to start doing some work to it... What change would I have left from $500 if I got a professional port and polish?
And what would you recommend with the remaining money?
TB sells a 146cc big bore kit, including high comp piston for $130

http://tboltusa.com/store/tb-141cc-big-bore-kit-br14mm-pin-p-855.html

Pretty much just looking to get the bike as quick as possible for under $500 (I want to beat my mates lifan 140 lol, theres always a reason for everything)

I appreciate the input thanks heeps!
 
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professionals charge too much, i hear there are many mechanics in qld on this forum that may do a good port and polish...
if i was do do it i would only charge about $150 but i am in Victoria
remember when you add alot of power you will probably be struggling with the clutch and getting it to bite (slipping with the extra power) so you may want to factor in stronger springs for the clutch.... (if need be try mods without and see how it holds)
bigbore you will get good power out of, a little cc goes a long way remember it adds stress to your crank and conrod but if tb sells a kit for it then it should be fine...

haha it does suck being behind your mates in the power department, but its fun when you get better at cornering and end up upp there ass all the time

the mods are not really hard to do... like new camshaft thats pretty easy (many tutorials out there) and also piston and rings will be approx 10 minutes more work than pulling the head off for the port and polish job

after you put all your new parts in you will need to re-jet the carby that takes time (for newbies) and patience, if you crack it and dont want to do it a shop can do it for you

i find sending it into a shop is losing a challenge, so i never send it in :p even if it means hours of frustration.
 
Ok I'll prob just go with a port and polish and cam for now just so I don't loose to much reliability and get really frustrated lol.. Hopefully those mods together will be enough to at least keep up with the guy, if not might have to take more drastic actions like bore kit etc lol.

If anyone is interested in doing a port and polish and fitting a cam for me I will pay u well. I live Gold Coast 10min from Robina town centre.

Thanks heeps for the help zwebx
 
Seriously mate if you want to beat your mates 140 and you have a little coin to throw at it i would go for this,
New 2012 GPX 125CC RACE ENGINE This engine is the best china 125 on the market and it hauls ass, read the stats on it, the high comp piston and 13'000 rev range makes this donk awesome, you are also leaving behind the weak clutch and the gpx doesnt run the clutch on the crank, and is a start in any gear engine as opposed to start in neutral only. I dont want to sound negative at all but dont waste the funds on bombing up a lifan 125 with the crappy 52mm piston(not even a 54), id sell the cam on miniriders and purchase a GPX 125 now, young motovert24(harry) equalled his gpx125 to a yx160 and he is a Miniriders sponsored rider and his advice is good enough for me, but if you chose to do the lifan by all means we will still give advice and help where possible buddy.
 
yeah i actually +1 the gpx they scream...
and if you go for new cam sometimes it needs a re-jetting (as i found out)
more air = needs more fuel simple
 
Im also a gpx/jialing fan i have the older engine branded motovert(no oil filter)
to make real power with a gpx
Lifan BVH(tb race cam kit,port&polish)or tb racehead
tb 146 high comp bbk
hd clutch springs
32mm exhaust
and a 26mm flatslide oko or genuine vm26

that would make a nice engine but it will cost a pretty penny to build properly..
 
This would do the job lol:

TB125.jpg


TB125.jpg


TB125.jpg


New 2012 GPX 125CC RACE ENGINE
 
Wow that's a serious looking engine!
I thought these gpx engines come stock with race cam, high comp piston, big valve head, heavy duty clutch springs etc, didn't think there was much to do apart from bore her out. Does tb just have a more aggressive cam setup and even more heavy duty springs?
Also there's a 131cc bore kit and a 146cc bore kit for this engine, would the 131 be stronger cause its not bored out as far?
And the vm26 vs oko26 flatside verse round slide right? Flatside got more top end round slide more overall torque, smoother power curve is that correct?
Sorry for all the questions but I'm getting a gpx probably in the next week or so and long term I would definitely like to mod it up, cheers
 
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Wow that's a serious looking engine!
I thought these gpx engines come stock with race cam, high comp piston, big valve head, heavy duty clutch springs etc, didn't think there was much to do apart from bore her out. Does tb just have a more aggressive cam setup and even more heavy duty springs?
Also there's a 131cc bore kit and a 146cc bore kit for this engine, would the 131 be stronger cause its not bored out as far?
And the vm26 vs oko26 flatside verse round slide right? Flatside got more top end round slide more overall torque, smoother power curve is that correct?
Sorry for all the questions but I'm getting a gpx probably in the next week or so and long term I would definitely like to mod it up, cheers

your correct about the carbies...

in the real world "race cam" means nothing... its about duration and lift and each play a different factor eg. a high lift shorter duration cam usually gives low down torque whereas the long duration short lift cam is for higher rpm... and probably stronger cam springs, i dont own a gpx 125 so im not sure what they come with (i have a lifan 150) and the "race gpx" as in the tbolt modded one would have the largest valves that they can fit in the head (and thats why they have to run a 57mm piston to fit the valves)
with the bore sizes its pretty amazing how much stress you can put on a crank before you wear them out quick or break them.. in theory a 131 kit bottom end would last longer but that depends on the piston weights and whatnot to see how much stress is being put on the crank...
so... pretty much because the engine has been around for a while look for somone like tb to make a kit for the engine and email him asking questions like how the bottom end stood up and whatnot
also they would of had to install a hd clutch or hd clutch springs and they have roller rockers... you could install them for a little extra $$ they will make a decent bit of difference and will make it respond faster
 
Ok cool thanks for the info... They sell a complete race head with out the bored out cylinder, that prob seems the way to go for overall reliability and performance gain. What kind of horsepower can you expect from a properly tuned 125 engine (15 hp?), would the extra 26cc (146cc race head) be pumping out that much extra ponies considering they using the same piston, cams etc? Just thinking if there not much performance gain with a bore kit, and there's a lot more added stress then whats the point? Cheers
 
Ok cool thanks for the info... They sell a complete race head with out the bored out cylinder, that prob seems the way to go for overall reliability and performance gain. What kind of horsepower can you expect from a properly tuned 125 engine (15 hp?), would the extra 26cc (146cc race head) be pumping out that much extra ponies considering they using the same piston, cams etc? Just thinking if there not much performance gain with a bore kit, and there's a lot more added stress then whats the point? Cheers
a good head is what really makes an engine... alot of people say head/flow makes 70% of hp
increasing the cc will increase the "Punch" or torque and hp expected hp is hard to say but it will feel much better than stock...
1st off get your engine in your bike and get it tuned (jetted) taker her for a break in run and a couple of runs after that and then see if you need more power believe me the gpx will feel much better than the lifan 125

there may be added stress but sometimes it does not decrease reliability too much as in the gains are greater than the risk sometimes...

if you are really keen on just getting raw power and beating your mates i would probably save an extra $100 and wait for a atomik nitrus to pop up on ebay win it for approx 600 (they go for that all the time) get the bike strip the engine carbs and whatnot off (whatever you want) put your old engine in the nitrous and sell that for approx $400 or whatever you can get (clean her up really nice) and save another $100 too cover postage or labour for the work and buy a tb head .TB Race Head V2 Kits GPX Pitster YX Piranha SSR - TB Parts - CHINESE ENGINES - TBW9017 - TBolt USA, LLC

but i guess thats more of a project rather than just buying a gpx 125 (yeah i get carried away sometimes)
 
Ok sweet thanks for all the help, yea I definitely think the gpx 125 engine will be more than enough for a while to come, but I'm definitely going to get that tb race head on it at some stage, looks awesome and its different to the usual path of large displacement.

Man if atmoik nitrous go for that much I might just buy one anyways just to cruise on and be reliable!
Cheers again
 
yea the gpx125 is one hell of an engine for what it is, by far my favorite engine i've owned. perfect gear ratio and snappy power along with the speed to match.
actually rode my friends bike which has the same engine as what my motovert had new (jialing125) and rode the gpx before it. the power difference is massive even with heaps of clutch slip and a couple of issues with the bike. its basically a 125 verison of my lxrs engine just abit more reliable.
i've had 1 issue with it which was only because the sprocket snapped off and made a mess

with the bbk's i reckon dont bother with one unless you have a V2 tb race head. v2 head gives the bike so much more go and revs. v2 head is the better upgrade out of the 2.

if you've brought the gpx 125 and an oko 26 flatslide the jets in mine are 36/100
 
Re: Lifan 124cc (IP52FMI) in pursuit of more power

Tbolt usa does not sell this engine do they ?

Pitster pro USA is selling it as the HP 125 crate engine, it has different valve covers and has pitsterpro logos on it, but it has the Daytona style outer rotor and high comp domed piston and close ratio box, order one mate and you won't look back:)
 
Thats really good to here that its powerful as well as very reliable, exactly what im looking for. Im going to order one next week with a 26mm oko carb, cant wait to vs my friends 140 and win for a change! :first:

Btw with the tb race head (distant future) how will that change the engines reliability, am I going to be rebuilding the thing every 20-30 hours, can you even cruise on it or is going at the same speed/same revs going to be bad for the engine? cheers
 
I have the tb v2 on my 155z with hi comp piston and the jetting has been a bit of a bugger, i actually ditched the oko26 for a mikuni 30mm roundslide as the roundslide is not as aggresive for low and mid revs as i do a lot of trail riding and hillclimbs, but if young harry (motovert24) says hes jetting is 36 and 100 on his oko then you shouldnt have a prob with it, I believe its when you big bore your engine things like reliability and gearbox life is shortened(by shortened i dont mean 30 hrs but more so over the years) but it also comes down to riding, if you thrash it day in day out then like anything you need to maintain it twice as much and change oil regularly(10hrs some do every ride) the v2 if anything will help your engine in the long run and the power gain from it will leave you smiling or screaming in your helmet. But this is just my opinion and welcome other riders to have a say.
 
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