Planet Minis

Kurlon · 10-10-2008, 08:54 PM

Anyone played with their 8mm lift unit for Honda 12v/Lifan 120 BVH? Just curious if it really has anything over a Honda TB 300a. Target build is 60mm x 59mm, using a 28/24 Lifan BVH. Assuming my head is viable... still haven't inspected it post valve springs loosing their temper on the track...

Cycle, any input on how to estimate if I'm over-camming? Looking at estimated intake velocity based on lift and valve size I'm pushing my peak HP out to around 10.5k RPM if the 8mm lift estimate is to be believed.

Are Kibblewhite CRF450 outer springs still the suggested setup for heavy ass Akunar valves and a TB300a or more aggressive cam?

BlackBeard · 10-10-2008, 08:56 PM

whats the tb300a cam lift, same as z40 correct?

Kurlon · 10-10-2008, 09:00 PM

Quote:

Originally Posted by BlackBeard

whats the tb300a cam lift, same as z40 correct?

Yeah, about 7mm, approximately 230deg of duration. The 'Z40' is about the same just timed slightly differently, I've been told.

HACKMUNCH · 10-11-2008, 07:10 AM

dont worry about the lift, in my klx build i have 9.3mm of lift and it work fine. with that much lift and accel pump carb will be a must.

Kurlon · 10-11-2008, 07:16 AM

I've never tuned an accel pump carb, do you defeat the pump, tune as normal, and then start bringing the pump into play, how's that work? (Oh gawd, ANOTHER 28mm carb to get... :P )

HACKMUNCH · 10-11-2008, 07:21 AM

on most carbs you cant adjust the pump. you just run much leaner pilots and much leaner needles because the pump spray raw fuel in as you turn the throttle. very simple design and turns a 4 stroke engine into a monster.

daimojay · 10-12-2008, 01:19 AM

+1 for turning them into a monster.

just be careful when cracking the throttle open once its tuned

insta-power glore, even just looking at the throttle >.>

They work great for such a simple setup .

Kurlon · 10-12-2008, 08:29 AM

Oh tay, so sounds like the cam is worth trying, and a TM28 pumper is the suggested carb, so far so good. That leaves me with valve springs to source, CRF450R outers from Kiblewhite?

HACKMUNCH · 10-12-2008, 08:56 AM

Correct.

fatcaaat · 10-12-2008, 08:58 AM

Will the TB60mm kit work with a 59mm stroke? Howe far on the stroke do you think you can go?

EastCountyPride · 10-12-2008, 11:04 AM

I think they are TRX450 not CRF

Kurlon · 10-12-2008, 09:00 PM

I've got (78 - 59) 19mm of room below the top of the piston, and the Akunar I'm thinking of using is 13.75mm from the top of the wrist pin to the dome. The skirt doesn't protrude past the top of the pin other than on the top and bottom of the piston. (12o'clock and 6o'clock) So I should only have to machine the bore in the cases on the top and bottom to accommodate those portions of the piston, leaving plenty of meat around the studs.

This is of course assuming the 150's pin height is around 13mm from the top of the pin. If it's less, then I run the risk of the pin going more than half way below the deck, at which point bad bad things happen... So before I get too excited I need to measure the actual piston dimensions. If that is the case, I could swap on a longer rod from either a 57.5mm or 55.5mm crank and play with spacer plates, etc. Dunno if I'm game for that. I'm also toying with an alternate setup using TB's new cylinder, but I have to get some more measurements first. : )

Kurlon · 10-12-2008, 09:41 PM

I get the impression that Akunar's website is more of a 'theory' of what they have than anything resembling authoritative... If they still have the cam, great, if not, maybe I'll be numb and grind down the back side of the lobes on a TB300a and see how long it lasts. :P

10-10-2008, 08:54 PM	#1 (permalink)
Kurlon Baron Von BanHammer Join Date: Feb 2005 Location: Windham, ME Posts: 7,857	Akunar cams Anyone played with their 8mm lift unit for Honda 12v/Lifan 120 BVH? Just curious if it really has anything over a Honda TB 300a. Target build is 60mm x 59mm, using a 28/24 Lifan BVH. Assuming my head is viable... still haven't inspected it post valve springs loosing their temper on the track... Cycle, any input on how to estimate if I'm over-camming? Looking at estimated intake velocity based on lift and valve size I'm pushing my peak HP out to around 10.5k RPM if the 8mm lift estimate is to be believed. Are Kibblewhite CRF450 outer springs still the suggested setup for heavy ass Akunar valves and a TB300a or more aggressive cam? __________________ http://www.x386.net/TTR 2004 ST3 - 'Duckie'?!?! 2005 CRF70RR - MiniGP Weapon 2005 CRF70 - Dirt Donk 2008 Pitster Pro X4 Motard 1991 GS500E - LRRS/CCS #771

10-10-2008, 08:56 PM	#2 (permalink)
BlackBeard "ZBBT" Join Date: Oct 2007 Location: 50 riders Posts: 1,772	Re: Akunar cams whats the tb300a cam lift, same as z40 correct?

10-11-2008, 07:10 AM	#4 (permalink)
HACKMUNCH 3rd Gear Member Join Date: Apr 2006 Location: BRUNSWICK OHIO Posts: 4,859	Re: Akunar cams dont worry about the lift, in my klx build i have 9.3mm of lift and it work fine. with that much lift and accel pump carb will be a must.

10-11-2008, 07:16 AM	#5 (permalink)
Kurlon Baron Von BanHammer Join Date: Feb 2005 Location: Windham, ME Posts: 7,857	Re: Akunar cams I've never tuned an accel pump carb, do you defeat the pump, tune as normal, and then start bringing the pump into play, how's that work? (Oh gawd, ANOTHER 28mm carb to get... :P ) __________________ http://www.x386.net/TTR 2004 ST3 - 'Duckie'?!?! 2005 CRF70RR - MiniGP Weapon 2005 CRF70 - Dirt Donk 2008 Pitster Pro X4 Motard 1991 GS500E - LRRS/CCS #771

10-11-2008, 07:21 AM	#6 (permalink)
HACKMUNCH 3rd Gear Member Join Date: Apr 2006 Location: BRUNSWICK OHIO Posts: 4,859	Re: Akunar cams on most carbs you cant adjust the pump. you just run much leaner pilots and much leaner needles because the pump spray raw fuel in as you turn the throttle. very simple design and turns a 4 stroke engine into a monster.

10-12-2008, 01:19 AM	#7 (permalink)
daimojay 1st Gear Member Join Date: Apr 2008 Location: australia Posts: 219	Re: Akunar cams +1 for turning them into a monster. just be careful when cracking the throttle open once its tuned insta-power glore, even just looking at the throttle >.> They work great for such a simple setup .

10-12-2008, 08:29 AM	#8 (permalink)
Kurlon Baron Von BanHammer Join Date: Feb 2005 Location: Windham, ME Posts: 7,857	Re: Akunar cams Oh tay, so sounds like the cam is worth trying, and a TM28 pumper is the suggested carb, so far so good. That leaves me with valve springs to source, CRF450R outers from Kiblewhite? __________________ http://www.x386.net/TTR 2004 ST3 - 'Duckie'?!?! 2005 CRF70RR - MiniGP Weapon 2005 CRF70 - Dirt Donk 2008 Pitster Pro X4 Motard 1991 GS500E - LRRS/CCS #771

10-12-2008, 08:56 AM	#9 (permalink)
HACKMUNCH 3rd Gear Member Join Date: Apr 2006 Location: BRUNSWICK OHIO Posts: 4,859	Re: Akunar cams Correct.

10-12-2008, 08:58 AM	#10 (permalink)
fatcaaat 3rd Gear Member Join Date: Sep 2004 Location: Arlington, VA Posts: 2,970	Re: Akunar cams Will the TB60mm kit work with a 59mm stroke? Howe far on the stroke do you think you can go?

10-12-2008, 11:04 AM	#11 (permalink)
EastCountyPride PM Newbie Join Date: Mar 2007 Location: East County San Diego Posts: 48	Re: Akunar cams I think they are TRX450 not CRF

10-12-2008, 09:00 PM	#12 (permalink)
Kurlon Baron Von BanHammer Join Date: Feb 2005 Location: Windham, ME Posts: 7,857	Re: Akunar cams I've got (78 - 59) 19mm of room below the top of the piston, and the Akunar I'm thinking of using is 13.75mm from the top of the wrist pin to the dome. The skirt doesn't protrude past the top of the pin other than on the top and bottom of the piston. (12o'clock and 6o'clock) So I should only have to machine the bore in the cases on the top and bottom to accommodate those portions of the piston, leaving plenty of meat around the studs. This is of course assuming the 150's pin height is around 13mm from the top of the pin. If it's less, then I run the risk of the pin going more than half way below the deck, at which point bad bad things happen... So before I get too excited I need to measure the actual piston dimensions. If that is the case, I could swap on a longer rod from either a 57.5mm or 55.5mm crank and play with spacer plates, etc. Dunno if I'm game for that. I'm also toying with an alternate setup using TB's new cylinder, but I have to get some more measurements first. : ) __________________ http://www.x386.net/TTR 2004 ST3 - 'Duckie'?!?! 2005 CRF70RR - MiniGP Weapon 2005 CRF70 - Dirt Donk 2008 Pitster Pro X4 Motard 1991 GS500E - LRRS/CCS #771

10-12-2008, 09:41 PM	#13 (permalink)
Kurlon Baron Von BanHammer Join Date: Feb 2005 Location: Windham, ME Posts: 7,857	Re: Akunar cams I get the impression that Akunar's website is more of a 'theory' of what they have than anything resembling authoritative... If they still have the cam, great, if not, maybe I'll be numb and grind down the back side of the lobes on a TB300a and see how long it lasts. :P __________________ http://www.x386.net/TTR 2004 ST3 - 'Duckie'?!?! 2005 CRF70RR - MiniGP Weapon 2005 CRF70 - Dirt Donk 2008 Pitster Pro X4 Motard 1991 GS500E - LRRS/CCS #771

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