700cc motors

[RAin geAR]

i was wondering how many people are actually running 700cc motors, who did the work, how reliable are they on the street, and how reliable are they on the track.

[blue88]

Not to jack you thread, but... I have searched 700cc motors as well and I cant seem to find a general idea of what it might cost to put one together. Any ideas on the $$$ aspect

[MasterBates]

www.hordpower.com ?

[jaysun0ne]

i remeber JD saying something like he can build a motor for has cheap as 2k or has much has 5k all depending on what you want and how much you want to spend.

[Rich G]

JD is putting together a 700cc stock valve size ported head street cammed engine for about $1600 including dyno time...
Take a look at the dyno sheets on his website

[blue88]

I was thinking about pulling the thing apart myself, ordering the parts I need and having a machine shop overbore the cylinders. Stock heads, cams, rods, and crank. I have 20k on my stock bottom end, and this would be street use only. I am not sure what this might cost.

So...

Pistons - $335 (Hord)

Bearings - ?

Gaskets - ?

Machine shop time - ?

Did I miss anything? Would the stock bottom end handle this for a reasonable period of time (35-45kk miles after build) ?

[RAin geAR]

hmmm... i'm getting a feeling (from the responses discussion i see so far) that no one really runs these 700cc motors to know how reliable they are track or street wise...

[Dash]

I`d like to vistit Hord if I could, but the US is not exactly across the street for me

it`s a shame that all this tuning stuff is so expensive. reliablity wise I don`t have a clue. the stock Hawk motor is extremely reliable, but when you start changing stuff in the motor...

I dunno. I `don`t know anyone with a modifief Hawk.

[joel]

hmmm... i'm getting a feeling (from the responses discussion i see so far) that no one really runs these 700cc motors to know how reliable they are track or street wise...

Your feeling would be wrong. I have ~50k on a homebuilt 696 + 153 cams,which is what I would recommend and I dunno,15k+ on one with good heads and 174X8's-both have stock bottom ends.

Stock Hawks have broken cranks,others like mine have kept on goin' and goin'...for a streetbike that sees occasional track use,don't worry about it.

Hawks are VERY easy motors to work on- trust me,if _I_ can do it,you can too.Get the pistons from Hord,get a local shop to bore it out and there ya go.Or send it to Hord and know it's all done right...

Back in the old,old,old days of the list one of the best Hawk tuners used to say if you're on a budget,go for more cc's rather than a full exhaust...

[MrDude_1]

hmmm... i'm getting a feeling (from the responses discussion i see so far) that no one really runs these 700cc motors to know how reliable they are track or street wise...

i dont see a overbore only effecting reliability at all.


but once you do that.. and cams... and other work.. etc.. well.. you end up with a more high strung race motor.

but just throwing a 700cc kit shouldn't effect reliability. you're not increasing power to the breaking point or anything....

[Ribbit2]

The old 10hp per 100cc 'rule of thumb' as a line in the sand for decent reliability, is probably as good as anything to go by.

That'd put the aim for a street 700cc at under 70bhp, 650cc at under 65bhp.

It's why I did that '60 - 65hp project' thread so people could see what was practical and achievable for a street motor, and what was needed to go about getting it done.

To get maximum life out of the cylinders of my engine, my first step will be a JD lightened 663cc kit, Megacycle Cams 153x1 street grind, Factory 3 jets, Unipod filters, and a better exhaust system. That should put it the right side of 60bhp. I'd like to get the heads done to Stage 1 with JD too (may have to ship the cylinders, heads, and cams over to him at some point).

Once I've worn that out (and with my mileage, I will), I'll go 700cc.

ETA: If you pay attention to those outstanding Dyno charts on JD's site, you won't go far wrong imo.

[RAin geAR]

I have ~50k on a homebuilt 696 + 153 cams,which is what I would recommend and I dunno,15k+ on one with good heads and 174X8's-both have stock bottom ends.

nice... thanks for the feedback on your builds. how much power

Stock Hawks have broken cranks,others like mine have kept on goin' and goin'...for a streetbike that sees occasional track use,don't worry about it.

hmmm... this i don't understand. how is that possible?

Back in the old,old,old days of the list one of the best Hawk tuners used to say if you're on a budget,go for more cc's rather than a full exhaust...

does this mean that for the same $$$ on a full exhaust, it can be used on a big bore? how much power will more cc's generate without a new exhaust?


... and thanks everyone! i appreciate the great feedback!

[MrDude_1]

hmmm... this i don't understand. how is that possible?

high RPMs put more stress on the crank then more power does... but you're still going to be limited by the crank no matter what.


the key is to go for the most power over the longest duration before max RPM

[RAin geAR]

ok... i understand that high rpm puts a lot more stress on the engine and twins are more reliable because they are not high revving motors. so the 700cc motors run at lower rpms that stock?

sorry to be asking trivial questions and i really appreciate everyone's patience in getting back to me.

however, i'm still under the impression that big bore kits have bigger pistons. bigger = heavier and that more power means more force. bigger and heavier pistons with more force sounds to me like there will be more stress on the crank and rods. or are the new pistons lighter? even so, more power still equates to more stress than stock.

were the stock components designed with more power in mind? what sort of R&D did the big bore kits go through? did they have racers in mind (which means they can rebuild the engine more often)? did they go through a lot of R&D to accommodate reliability?

thanks again!

[dagus]

I have ~50k on a homebuilt 696 + 153 cams,which is what I would recommend

Joel, what exactly is involved in doing this? Is it really as simple as "buy cams, get it bored"? Because then I'd try it... and I always have Lenac nearby help if I need it.

Crap. I have another winter project now.