Planet Minis

HACKMUNCH · 10-05-2007, 01:32 PM

Well The Engine Is Here And Doug And I Are Going To Get To The Bottom Of What We Can Do With This Engine To Turn It Into A Fire Breathing Monster. At 1st Glance You Can Tell This Thing Is Beefy, Look At The Engine Mount Casting. We Have A 57mm Jialing Crank So Doug Is Talking About Swapping Cranks Right Away But 1st We Are Going To Do Some Measuring Up To See If The New 178cc Takegawa Scut Deal Will Work. To Do This We Will Have To Measure How Much Heigth Above The Gpx 150 Casting The Wrist Pin Is At Bdc. I Know For The Budget Minded You Can Buy A 61mm Akunar Piston And Bore The Cylinder To Get You To 155cc And Up Compression To 12:1. Should Be A Good Upgrade For $60 Or So. Initally Doug Wanted To Go 57mm Stroke By 64mm Bore But Once We Get More Into It We Will See. Doug Is Having A Hard Time Loging In To Planetminis But Should Be Back Up And Running Soon With A Ton Of Pics Of The Engine Torn Down To The Bare Bones.

Kurlon · 10-05-2007, 07:25 PM

So, the rod length and pin height work out such that Jialing 125/Lifan 120 cranks will swap in?

HACKMUNCH · 10-05-2007, 07:35 PM

sure with the right piston.

firepower354 · 10-05-2007, 07:51 PM

Will that require, or allow rather, swapping to a normal 25 timing chain?

HACKMUNCH · 10-05-2007, 07:58 PM

this engine uses a #25 chain but the klx style hd chain.

Z50King · 10-05-2007, 08:34 PM

looks like a pain in the ass to get the rockers in. is it?

what are the valve specs? im guessing bigger than a BVH?

i heard these things do not match up with 125 cranks, but maybe i heard wrong

Kurlon · 10-05-2007, 08:47 PM

Quote:

Originally Posted by Z50King

i heard these things do not match up with 125 cranks, but maybe i heard wrong

Well, thats the million dollar question... It looks like a standard 125 crank would drop in, the question then becomes what's the resulting pin height, and will the cam sprocket line up (and is it the right number of teeth). It may just be a matter of running spacer plates to get the right deck height, or sourcing custom pistons.

Z50King · 10-05-2007, 08:49 PM

ok, thats what i heard, but i guess who i heard it from didnt say it hasnt been tried yet

HACKMUNCH · 10-06-2007, 06:25 AM

well from what doug said the jialing crank will work but you must change out the end bearings. not sure if it is worth all the hassle for the 4mm of extra stroke. the head on the gpx 150 looks identical to the tb klx110 head. 28/23 valves but they use 5.5mm stems. the cam looks decent, 7mm of lift but not much duration. Akunar has just come out with some cams for the klx 110 so that might be a decent upgrade. still think with a 61mm piston this engine stock could make 12hp.

firepower354 · 10-06-2007, 07:25 AM

How much room inside the cases to swing a big arm?

HACKMUNCH · 10-06-2007, 09:18 PM

why stroke it when you can go 65.5mm bore? 180cc with stock crank is very do able.

millbillyfiddy · 10-06-2007, 09:23 PM

Quote:

Originally Posted by HACKMUNCH

why stroke it when you can go 65.5mm bore? 180cc with stock crank is very do able.

I agree

Kurlon · 10-06-2007, 09:23 PM

Hack, it was already dynoing in the low 11s stock, 12s should just be a good port job away. :P

If it's just an issue of swapping bearings on the crank, stuff an Akunar reworked Honda Nice crank in there, 66.5mm would be worth the effort to me. With a conservative 64mm bore, you're at 213cc. 224cc at 65.5mm bore.

Pitster · 10-06-2007, 10:08 PM

Hmm, you guys are getting crazy!! I like it!!

ROBINSONDB22 · 10-06-2007, 10:11 PM

i wanna buy the motor... where do i find a pipe to fit it!!!!!!!

HACKMUNCH · 10-07-2007, 06:59 AM

ok somemore good news, i think the scut 178cc takegawa kit might fit, it would be real close. this would put us near 190cc. i need dimentions of the scut piston to make sure but from the pics of the piston it looks like it would be real close to working. i am going to try and head over sam's and look in his klx graveyard and see if i can scrape up some dimentions with the stock klx crank. Doug,John and I have came to some conclusions on this 1st build. doug wants to go 65.5mm bore by 53mm stroke putting him at 179cc with the new takegawa +r head. here are some pics via Doug. doug has add new pics click here ----> Putfile - Uploaded Picture

firepower354 · 10-07-2007, 07:03 AM

Quote:

Originally Posted by HACKMUNCH

why stroke it when you can go 65.5mm bore? 180cc with stock crank is very do able.

I thought..... (says it all).

HACKMUNCH · 10-07-2007, 07:18 AM

dude we race these things not scoot around the neighborhood. we do not want crazy crank angles. these things have to live 2 motos and be able to be started.

micro75 · 10-07-2007, 07:58 AM

On the pipe I think we will have a fix for the x4 pipe with out bending it buy just adding a piece This is what I wanted to do before I bent my pipe but got impatient. I will post pics and a how to as soon as completed

themountain · 10-07-2007, 08:09 AM

Isn't there a 185cc regulation at max??

10-05-2007, 07:25 PM	#2 (permalink)
Kurlon Baron Von BanHammer Join Date: Feb 2005 Location: Windham, ME Posts: 7,857	Re: The Gpx 150cc Yx Build Thread!! So, the rod length and pin height work out such that Jialing 125/Lifan 120 cranks will swap in? __________________ 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

10-05-2007, 07:35 PM	#3 (permalink)
HACKMUNCH 3rd Gear Member Join Date: Apr 2006 Location: BRUNSWICK OHIO Posts: 4,859	Re: The Gpx 150cc Yx Build Thread!! sure with the right piston.

10-05-2007, 07:51 PM	#4 (permalink)
firepower354 3rd Gear Member Join Date: Oct 2006 Location: Flint MI Posts: 6,260	Re: The Gpx 150cc Yx Build Thread!! Will that require, or allow rather, swapping to a normal 25 timing chain?

10-05-2007, 07:58 PM	#5 (permalink)
HACKMUNCH 3rd Gear Member Join Date: Apr 2006 Location: BRUNSWICK OHIO Posts: 4,859	Re: The Gpx 150cc Yx Build Thread!! this engine uses a #25 chain but the klx style hd chain.

10-05-2007, 08:34 PM	#6 (permalink)
Z50King Almost Banned Join Date: Sep 2004 Location: Upland, Ca MSAC Posts: 6,642	Re: The Gpx 150cc Yx Build Thread!! looks like a pain in the ass to get the rockers in. is it? what are the valve specs? im guessing bigger than a BVH? i heard these things do not match up with 125 cranks, but maybe i heard wrong

10-05-2007, 08:49 PM	#8 (permalink)
Z50King Almost Banned Join Date: Sep 2004 Location: Upland, Ca MSAC Posts: 6,642	Re: The Gpx 150cc Yx Build Thread!! ok, thats what i heard, but i guess who i heard it from didnt say it hasnt been tried yet

10-06-2007, 06:25 AM	#9 (permalink)
HACKMUNCH 3rd Gear Member Join Date: Apr 2006 Location: BRUNSWICK OHIO Posts: 4,859	Re: The Gpx 150cc Yx Build Thread!! well from what doug said the jialing crank will work but you must change out the end bearings. not sure if it is worth all the hassle for the 4mm of extra stroke. the head on the gpx 150 looks identical to the tb klx110 head. 28/23 valves but they use 5.5mm stems. the cam looks decent, 7mm of lift but not much duration. Akunar has just come out with some cams for the klx 110 so that might be a decent upgrade. still think with a 61mm piston this engine stock could make 12hp.

10-06-2007, 07:25 AM	#10 (permalink)
firepower354 3rd Gear Member Join Date: Oct 2006 Location: Flint MI Posts: 6,260	Re: The Gpx 150cc Yx Build Thread!! How much room inside the cases to swing a big arm?

10-06-2007, 09:18 PM	#11 (permalink)
HACKMUNCH 3rd Gear Member Join Date: Apr 2006 Location: BRUNSWICK OHIO Posts: 4,859	Re: The Gpx 150cc Yx Build Thread!! why stroke it when you can go 65.5mm bore? 180cc with stock crank is very do able.

10-06-2007, 09:23 PM	#13 (permalink)
Kurlon Baron Von BanHammer Join Date: Feb 2005 Location: Windham, ME Posts: 7,857	Re: The Gpx 150cc Yx Build Thread!! Hack, it was already dynoing in the low 11s stock, 12s should just be a good port job away. :P If it's just an issue of swapping bearings on the crank, stuff an Akunar reworked Honda Nice crank in there, 66.5mm would be worth the effort to me. With a conservative 64mm bore, you're at 213cc. 224cc at 65.5mm bore. __________________ 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

10-06-2007, 10:08 PM	#14 (permalink)
Pitster Advertiser Join Date: Apr 2005 Location: Lindon, Utah Posts: 2,276	Re: The Gpx 150cc Yx Build Thread!! Hmm, you guys are getting crazy!! I like it!!

10-06-2007, 10:11 PM	#15 (permalink)
ROBINSONDB22 3rd Gear Member Join Date: Feb 2007 Location: KILLumbus, Ohio Posts: 2,463	Re: The Gpx 150cc Yx Build Thread!! i wanna buy the motor... where do i find a pipe to fit it!!!!!!!

10-07-2007, 06:59 AM	#16 (permalink)
HACKMUNCH 3rd Gear Member Join Date: Apr 2006 Location: BRUNSWICK OHIO Posts: 4,859	Re: The Gpx 150cc Yx Build Thread!! ok somemore good news, i think the scut 178cc takegawa kit might fit, it would be real close. this would put us near 190cc. i need dimentions of the scut piston to make sure but from the pics of the piston it looks like it would be real close to working. i am going to try and head over sam's and look in his klx graveyard and see if i can scrape up some dimentions with the stock klx crank. Doug,John and I have came to some conclusions on this 1st build. doug wants to go 65.5mm bore by 53mm stroke putting him at 179cc with the new takegawa +r head. here are some pics via Doug. doug has add new pics click here ----> Putfile - Uploaded Picture Last edited by HACKMUNCH; 10-07-2007 at 07:39 AM.

10-07-2007, 07:18 AM	#18 (permalink)
HACKMUNCH 3rd Gear Member Join Date: Apr 2006 Location: BRUNSWICK OHIO Posts: 4,859	Re: The Gpx 150cc Yx Build Thread!! dude we race these things not scoot around the neighborhood. we do not want crazy crank angles. these things have to live 2 motos and be able to be started.

10-07-2007, 07:58 AM	#19 (permalink)
micro75 2nd Gear Member Join Date: May 2006 Location: Hermitage, PA Posts: 519	Re: The Gpx 150cc Yx Build Thread!! On the pipe I think we will have a fix for the x4 pipe with out bending it buy just adding a piece This is what I wanted to do before I bent my pipe but got impatient. I will post pics and a how to as soon as completed

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10-07-2007, 08:09 AM	#20 (permalink)
themountain 3rd Gear Member Join Date: Oct 2006 Location: Pico/ Azores/Portugal Posts: 1,122	Re: The Gpx 150cc Yx Build Thread!! Isn't there a 185cc regulation at max??