Planet Minis

john3219 · 12-02-2009, 06:50 AM

i have a lifan 125 motor. and im only 15 and im not stupid im very into all these honda motors i know them inside and out. but i have the lifan 125 with the 54bore and 54stroke and i believe the big valve head. can any one tell me if these heads have the large dome combustion chamber like the old atc70 heads and the tb race heads. im building my little brother a race trx 90 and the atc70 head just isnt cutting it let me know. thanks, john

john3219 · 12-02-2009, 06:57 AM

anyone?

firepower354 · 12-02-2009, 08:37 PM

The dome is even bigger than the ATC head, and has larger valves at a different angle. Plus the bolt pattern is slightly different. The TB head is like a "modern" 12v 70 chamber and uses a smaller dome.

The new TB piston for the 30/23.5 head is about as close as you can get off-the-rack. You'll still have to shorten the jug slightly to get the quench and compression up. There are 54mm Akunar pistons with the pin height closer, but they're 2 weeks out.

john3219 · 12-03-2009, 06:34 AM

thanks for the info. im using a 12:1 hc piston of dratv. and if i deck the head about half a millimter on the lifan will it still work?

dax · 12-03-2009, 12:36 PM

I think the Lifan head needs deep valve reliefs close to outer edges of piston top. And that dratv's hc piston has the top piston ring groove so close to the piston top it's impossible to cut big enough reliefs.

john3219 · 12-03-2009, 12:50 PM

so what would my options be? not deck the head and get a lesser compression piston

firepower354 · 12-03-2009, 01:13 PM

What sort of clearance do you have now?

This Akunar is made for the Lifan chamber and valve location, gives BIG compression. I can get one for you on next week's order.

john3219 · 12-03-2009, 05:13 PM

i dont know the clearences. but tht looks way different from the piston i have.. how much would that run me with piston/rings/clips/and pin?

doopsx3 · 12-03-2009, 05:18 PM

Quote:

Originally Posted by firepower354

What sort of clearance do you have now?

This Akunar is made for the Lifan chamber and valve location, gives BIG compression. I can get one for you on next week's order.

I remember that picture.....BIG COMPRESSION is actually an understatement...lol

john3219 · 12-03-2009, 05:22 PM

whys that?

doopsx3 · 12-03-2009, 05:37 PM

Just that I think that pic is one of a piston Terry got for me and yes it will give you a boost in the compression ratio for sure...more than most IMO....not a bad thing

TRT · 12-03-2009, 06:08 PM

How much asked the boy?

john3219 · 12-03-2009, 06:15 PM

sweet, with that much compression did the clutch slip when you kicked it? and what octan gas did you use?

firepower354 · 12-03-2009, 07:35 PM

The pistons are $70. Clutch should be fine, if it was fine to start with.

12-02-2009, 06:50 AM	#1 (permalink)
john3219 PM Newbie Join Date: Dec 2009 Posts: 82 My Mood:	lifan 125 head? i have a lifan 125 motor. and im only 15 and im not stupid im very into all these honda motors i know them inside and out. but i have the lifan 125 with the 54bore and 54stroke and i believe the big valve head. can any one tell me if these heads have the large dome combustion chamber like the old atc70 heads and the tb race heads. im building my little brother a race trx 90 and the atc70 head just isnt cutting it let me know. thanks, john

12-02-2009, 06:57 AM	#2 (permalink)
john3219 PM Newbie Join Date: Dec 2009 Posts: 82 My Mood:	Re: lifan 125 head? anyone?

12-02-2009, 08:37 PM	#3 (permalink)
firepower354 Advertiser Join Date: Oct 2006 Location: Flint MI Posts: 12,325 My Mood:	Re: lifan 125 head? The dome is even bigger than the ATC head, and has larger valves at a different angle. Plus the bolt pattern is slightly different. The TB head is like a "modern" 12v 70 chamber and uses a smaller dome. The new TB piston for the 30/23.5 head is about as close as you can get off-the-rack. You'll still have to shorten the jug slightly to get the quench and compression up. There are 54mm Akunar pistons with the pin height closer, but they're 2 weeks out. __________________ If it has my name on it I did it;) FirepowerMinis.com 810-237-9537 M-F 9-6 Custom FPM parts and engines. Parts and service for all makes. Honda Trail Bikes parts and accessories. Piranha/Medina/Thumpstar bikes, parts, engines and accessories.

12-03-2009, 06:34 AM	#4 (permalink)
john3219 PM Newbie Join Date: Dec 2009 Posts: 82 My Mood:	Re: lifan 125 head? thanks for the info. im using a 12:1 hc piston of dratv. and if i deck the head about half a millimter on the lifan will it still work?

12-03-2009, 12:36 PM	#5 (permalink)
dax 1st Gear Member Join Date: Jun 2006 Posts: 164	Re: lifan 125 head? I think the Lifan head needs deep valve reliefs close to outer edges of piston top. And that dratv's hc piston has the top piston ring groove so close to the piston top it's impossible to cut big enough reliefs.

12-03-2009, 12:50 PM	#6 (permalink)
john3219 PM Newbie Join Date: Dec 2009 Posts: 82 My Mood:	Re: lifan 125 head? so what would my options be? not deck the head and get a lesser compression piston

12-03-2009, 01:13 PM	#7 (permalink)
firepower354 Advertiser Join Date: Oct 2006 Location: Flint MI Posts: 12,325 My Mood:	Re: lifan 125 head? What sort of clearance do you have now? This Akunar is made for the Lifan chamber and valve location, gives BIG compression. I can get one for you on next week's order. __________________ If it has my name on it I did it;) FirepowerMinis.com 810-237-9537 M-F 9-6 Custom FPM parts and engines. Parts and service for all makes. Honda Trail Bikes parts and accessories. Piranha/Medina/Thumpstar bikes, parts, engines and accessories.

12-03-2009, 05:13 PM	#8 (permalink)
john3219 PM Newbie Join Date: Dec 2009 Posts: 82 My Mood:	Re: lifan 125 head? i dont know the clearences. but tht looks way different from the piston i have.. how much would that run me with piston/rings/clips/and pin?

12-03-2009, 05:22 PM	#10 (permalink)
john3219 PM Newbie Join Date: Dec 2009 Posts: 82 My Mood:	Re: lifan 125 head? whys that?

12-03-2009, 05:37 PM	#11 (permalink)
doopsx3 3rd Gear Member Join Date: Aug 2008 Location: San Diego Posts: 5,018 My Mood:	Re: lifan 125 head? Just that I think that pic is one of a piston Terry got for me and yes it will give you a boost in the compression ratio for sure...more than most IMO....not a bad thing

12-03-2009, 06:08 PM	#12 (permalink)
TRT 3rd Gear Member Join Date: Nov 2005 Location: Earth Posts: 2,220 My Mood:	Re: lifan 125 head? How much asked the boy?

12-03-2009, 06:15 PM	#13 (permalink)
john3219 PM Newbie Join Date: Dec 2009 Posts: 82 My Mood:	Re: lifan 125 head? sweet, with that much compression did the clutch slip when you kicked it? and what octan gas did you use?

12-03-2009, 07:35 PM	#14 (permalink)
firepower354 Advertiser Join Date: Oct 2006 Location: Flint MI Posts: 12,325 My Mood:	Re: lifan 125 head? The pistons are $70. Clutch should be fine, if it was fine to start with. __________________ If it has my name on it I did it;) FirepowerMinis.com 810-237-9537 M-F 9-6 Custom FPM parts and engines. Parts and service for all makes. Honda Trail Bikes parts and accessories. Piranha/Medina/Thumpstar bikes, parts, engines and accessories.

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