Planet Minis

Pat Farsole · 08-09-2007, 08:16 PM

Since they are off a 110 which normally have the stock Honda cylinder stud spacings ........do they have the same stud spacing as a BVH ???????

Kurlon · 08-09-2007, 08:20 PM

There are a few out there that use Lifan 120/Jialing 125 stud spacing, most however are off Lifan 3v 107s from SDGs, those run larger studs on a unique stud pattern.

700'sDAD · 08-09-2007, 08:22 PM

Quote:

Originally Posted by Kurlon

Says the math. 2 19mm intake valves should flow equivalent to a single 29mm intake, with better low lift flow.

I have had both Heads on the flowbench and the 3 valve did have better low lift flow and stayed consistent all the way through to high lift.

700'sDAD · 08-09-2007, 08:23 PM

Hey Josh pull up the post of Matts 146 3 valve.

Kurlon · 08-09-2007, 08:26 PM

http://www.planetminis.com/f21/youve...ike-60320.html

Pat Farsole · 08-09-2007, 09:41 PM

Quote:

Originally Posted by Kurlon

There are a few out there that use Lifan 120/Jialing 125 stud spacing, most however are off Lifan 3v 107s from SDGs, those run larger studs on a unique stud pattern.

Point taken (107's are wrongly referred to as 110's over here) . The three valve heads sound like a good idea bar the claim of cracking between valves .

x6rs · 08-10-2007, 01:32 AM

have you heard of many guys that have had problem with cracks between the valves??

Pat Farsole · 08-10-2007, 02:22 AM

NO , only from what you said ! I can't see why they'd crack unless the inlet valves weren't seating properly and the engine was running too lean - allowing between the seats to get too hot and crack from the intermittent heating and cooling .

I've seen plenty of alloy car and diesel truck heads cracked between the valve seats and combustion chambers though .

MPE · 08-10-2007, 08:04 AM

Air cooled multi valve cylinder heads suffer from excessive heat build up between the valve seats.
Does anyone remember the Honda XR250 motors back in the 80's,they used to suffer badly with cracking between the valve seats to the extent valve seats would fall out of the head!.
I TIG welded and repaired quite a few allow Honda cyl heads back in the day.
Hondas quick fix was using an oil cooler in the following models to drop the temperature a little giving a better cylinder head life.
Porsche even gave up on the concept of Air cooled 4 valve cylinder heads due to similar heat build up issues.One of the main reasons they were forced to go the way of watercooling to stop cylinder head cracking between the valve seats.Perhaps with the relatively the small cc and output of Chinese 50 motors heat build/Failures wont be such an issue.
I wonder how long before the inscrutable Chinese come up with a Water cooled 4 valve Lifan motor !!??

Brian

x6rs · 08-10-2007, 11:45 AM

Quote:

Originally Posted by MPE

Air cooled multi valve cylinder heads suffer from excessive heat build up between the valve seats.
Does anyone remember the Honda XR250 motors back in the 80's,they used to suffer badly with cracking between the valve seats to the extent valve seats would fall out of the head!.
I TIG welded and repaired quite a few allow Honda cyl heads back in the day.
Hondas quick fix was using an oil cooler in the following models to drop the temperature a little giving a better cylinder head life.
Porsche even gave up on the concept of Air cooled 4 valve cylinder heads due to similar heat build up issues.One of the main reasons they were forced to go the way of watercooling to stop cylinder head cracking between the valve seats.Perhaps with the relatively the small cc and output of Chinese 50 motors heat build/Failures wont be such an issue.
I wonder how long before the inscrutable Chinese come up with a Water cooled 4 valve Lifan motor !!??

Brian

theres a aircooled 4 valve doch engine available in sweden, but i costs alot,
checkout Pitbike - Home

do you think that i can use a 3 valve head on my lifan 140 engine if i use an oilcooler? got a "real" oilcooler(not the chinese cnc-crap) on it now.

Kurlon · 08-10-2007, 01:06 PM

I have yet to hear of a 3v or DOHC head failing from cracks in the head between the valves. Run it.

micro75 · 08-10-2007, 01:22 PM

Here is another way to flow 29 mm intake and probaly have a lot better cam selection this is the stock seat with a cut down 30 mm Akunar valve

Kurlon · 08-10-2007, 02:48 PM

You're going to need to go bigger than 29mm to beat a 2 x 19mm valve setup across the board, the 2 x 19mm setup has you at low openings, aka critical time.

x6rs · 08-11-2007, 08:21 AM

Quote:

Originally Posted by Kurlon

You're going to need to go bigger than 29mm to beat a 2 x 19mm valve setup across the board, the 2 x 19mm setup has you at low openings, aka critical time.

im going to test port my 2 valve head with plastic, and if i get hold of a 3 valve head test that one, i live in sweden and cant find anyone who sell them anymore....

smartt yamaha127 · 08-11-2007, 08:28 AM

I Have A New 3 Valve Head I Could Ship.

x6rs · 08-11-2007, 02:06 PM

Quote:

Originally Posted by smartt yamaha127

I Have A New 3 Valve Head I Could Ship.

ok, whats the price? how big valves? cam?

x6rs · 08-11-2007, 02:09 PM

Quote:

Originally Posted by themountain

Here , Mate...its in Germany

Monkey Shop Raubling - Zylinderkopf mit 3 Ventilen als Umbau-Set 3V_head

thanks for the tip, but thats sounds kind of expensive... 149 euro i get a brand new engine for 250...

x6rs · 08-13-2007, 01:27 AM

Quote:

Originally Posted by themountain

I NEVER SAID ITS CHEAP...ITS A PLACE TO GET THEM

and they are to put directly on to your GPX/LIFAN engine

ok, the "standard" 3v heads are not bolt on?

Yamanube · 08-13-2007, 11:48 AM

Use Devcon rather than JBWeld.

x6rs · 08-14-2007, 09:29 AM

devcon? never heard of it, do they sell in europe?

08-09-2007, 08:16 PM	#21 (permalink)
Pat Farsole 2nd Gear Member Join Date: Nov 2006 Posts: 389	Re: portin´ the head Since they are off a 110 which normally have the stock Honda cylinder stud spacings ........do they have the same stud spacing as a BVH ???????

08-09-2007, 08:20 PM	#22 (permalink)
Kurlon Super Moderator Join Date: Feb 2005 Location: Windham, ME Posts: 8,301	Re: portin´ the head There are a few out there that use Lifan 120/Jialing 125 stud spacing, most however are off Lifan 3v 107s from SDGs, those run larger studs on a unique stud pattern.

08-09-2007, 08:23 PM	#24 (permalink)
700'sDAD 2nd Gear Member Join Date: Apr 2006 Location: Oviedo, Florida Posts: 722	Re: portin´ the head Hey Josh pull up the post of Matts 146 3 valve.

08-09-2007, 08:26 PM	#25 (permalink)
Kurlon Super Moderator Join Date: Feb 2005 Location: Windham, ME Posts: 8,301	Re: portin´ the head http://www.planetminis.com/f21/youve...ike-60320.html

08-10-2007, 01:32 AM	#27 (permalink)
x6rs PM Newbie Join Date: Aug 2007 Posts: 49	Re: portin´ the head have you heard of many guys that have had problem with cracks between the valves??

08-10-2007, 02:22 AM	#28 (permalink)
Pat Farsole 2nd Gear Member Join Date: Nov 2006 Posts: 389	Re: portin´ the head NO , only from what you said ! I can't see why they'd crack unless the inlet valves weren't seating properly and the engine was running too lean - allowing between the seats to get too hot and crack from the intermittent heating and cooling . I've seen plenty of alloy car and diesel truck heads cracked between the valve seats and combustion chambers though .

08-10-2007, 08:04 AM	#29 (permalink)
MPE PM Newbie Join Date: Apr 2007 Posts: 6	Re: portin´ the head Air cooled multi valve cylinder heads suffer from excessive heat build up between the valve seats. Does anyone remember the Honda XR250 motors back in the 80's,they used to suffer badly with cracking between the valve seats to the extent valve seats would fall out of the head!. I TIG welded and repaired quite a few allow Honda cyl heads back in the day. Hondas quick fix was using an oil cooler in the following models to drop the temperature a little giving a better cylinder head life. Porsche even gave up on the concept of Air cooled 4 valve cylinder heads due to similar heat build up issues.One of the main reasons they were forced to go the way of watercooling to stop cylinder head cracking between the valve seats.Perhaps with the relatively the small cc and output of Chinese 50 motors heat build/Failures wont be such an issue. I wonder how long before the inscrutable Chinese come up with a Water cooled 4 valve Lifan motor !!?? Brian

08-10-2007, 01:06 PM	#31 (permalink)
Kurlon Super Moderator Join Date: Feb 2005 Location: Windham, ME Posts: 8,301	Re: portin´ the head I have yet to hear of a 3v or DOHC head failing from cracks in the head between the valves. Run it.

08-10-2007, 01:22 PM	#32 (permalink)
micro75 2nd Gear Member Join Date: May 2006 Location: Hermitage, PA Posts: 561	Re: portin´ the head Here is another way to flow 29 mm intake and probaly have a lot better cam selection this is the stock seat with a cut down 30 mm Akunar valve

08-10-2007, 02:48 PM	#33 (permalink)
Kurlon Super Moderator Join Date: Feb 2005 Location: Windham, ME Posts: 8,301	Re: portin´ the head You're going to need to go bigger than 29mm to beat a 2 x 19mm valve setup across the board, the 2 x 19mm setup has you at low openings, aka critical time.

08-11-2007, 08:28 AM	#35 (permalink)
smartt yamaha127 2nd Gear Member Join Date: Jul 2007 Location: Colorado Posts: 367	Re: portin´ the head I Have A New 3 Valve Head I Could Ship.

08-13-2007, 11:48 AM	#39 (permalink)
Yamanube 1st Gear Member Join Date: Apr 2006 Location: Minnesota Posts: 241	Re: portin´ the head Use Devcon rather than JBWeld.

08-14-2007, 09:29 AM	#40 (permalink)
x6rs PM Newbie Join Date: Aug 2007 Posts: 49	Re: portin´ the head devcon? never heard of it, do they sell in europe?

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