Author Topic: Anyone use the 708cc yet?  (Read 9100 times)

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Offline BPLP

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Anyone use the 708cc yet?
« on: November 11, 2017, 08:09:13 pm »
Hey I'm just getting into the racing mower game and I'm starting off with the classic 12.5hp briggs but I'm just wondering if anyone has used the 708cc v twin from the good ol' harbor freight? There ain't no performance parts for it but that doesn't me no one has tried it yet. I personally have no aspirations to use it because I'm kinda interested in the 14hp boxers but who knows maybe I'll drop one of those in my mower. Anyone?

Offline Mower Maniac

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Re: Anyone use the 708cc yet?
« Reply #1 on: November 11, 2017, 09:21:55 pm »
There are performance parts. Performance670.com
AZLMRA
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Offline BPLP

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Re: Anyone use the 708cc yet?
« Reply #2 on: November 11, 2017, 09:39:57 pm »
But that's for the predator 670 which is a horizontal shaft engine, not for the 708 which is a clone of a different engine and vertical shaft.

Offline Mower Maniac

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Re: Anyone use the 708cc yet?
« Reply #3 on: November 11, 2017, 10:54:58 pm »
Same motor but bigger bore.
AZLMRA
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Offline BPLP

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Re: Anyone use the 708cc yet?
« Reply #4 on: November 11, 2017, 11:28:35 pm »
Are you sure? I think the 670 is cloned from a briggs and the 708 is cloned from a Kawasaki. Also ones a vertical shaft and ones a horizontal shaft. Different resting points on the cam shaft as well. The 670 rests on its side while the vertical shaft 708 rests on its end.


Offline PJG56

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Re: Anyone use the 708cc yet?
« Reply #5 on: November 12, 2017, 07:13:25 am »
The only sanctioned class that motor would be leagal for might be FXT
Paul Guptill  (oppy) #238modX
2012 slmra mowstock champion(builder/owner)

2013 slmra mowdified champion(builder/owner)
2013 ARMA national champion Mod-X(builder/owner)
2014 ARMA national champion Mod-X(builder/owner)
2014 All American Champion Mod-X/CP(builder/owner)
2014All American Champion FXT (engine builder)
2014 All American 2nd place SP(builder/owner)
2015 All American 2nd place BP (builder/owner)
2016 OutlawTriple Crown FXT Champion (engine builder)

Offline BPLP

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Re: Anyone use the 708cc yet?
« Reply #6 on: November 12, 2017, 12:01:42 pm »
Yeah currently I'm not thinking about racing just because I don't have any tracks around me so it would just be to rip up and down the street one then put it away before the cops come.

Offline Mower Maniac

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Re: Anyone use the 708cc yet?
« Reply #7 on: November 12, 2017, 11:27:29 pm »
They are both honda clones
AZLMRA
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Offline BPLP

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Re: Anyone use the 708cc yet?
« Reply #8 on: November 13, 2017, 08:03:37 am »
Is it cloned from the 688cc?

Offline Mower Maniac

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Re: Anyone use the 708cc yet?
« Reply #9 on: November 13, 2017, 08:46:26 am »
Honda gx 620, they made a 640 and 670 too
AZLMRA
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Offline BPLP

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Re: Anyone use the 708cc yet?
« Reply #10 on: November 13, 2017, 09:22:48 am »
Do do you think it matters that one is a vertical shaft and the other is a horizontal shaft?

Offline Mower Maniac

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Re: Anyone use the 708cc yet?
« Reply #11 on: November 13, 2017, 07:09:04 pm »
Not really. Probably slight oiling differences but otherwise bigger bore
AZLMRA
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Offline BPLP

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Re: Anyone use the 708cc yet?
« Reply #12 on: November 13, 2017, 11:20:24 pm »
Yeah I hopped on parts tree and the gxv630 and gx660 camshafts and cranckshafts are the same, as well as the valve train.

Very interesting stuff and I'll be sure to email Performance 670 about our findings.

(I emailed them before about the question and they said they didn't know)

Thanks!