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Big Bore Kit

Posted: Fri Jun 13, 2014 7:49 am
by Sunnyday
Anybody fitted the 444 kit and with what results its something me n me pal are thinking about i guess the best results would be gained with a free flowing exhaust and a rejet - for the road i might add not the track.

anybody done it ?

Re: Big Bore Kit

Posted: Sat Jun 14, 2014 9:02 am
by JZH
Yes, but I've neither dyno'd it nor have really noticed much of a difference. My personal view is that the handful of extra ccs is not significant enough for a street bike. I did it only because I could. What would make a difference would be a full engine-swap, but that's a bit extreme.

Ciao,

Re: Big Bore Kit

Posted: Sat Jun 14, 2014 7:00 pm
by Sunnyday
I imagine it would have a stronger mid range - what do you mean about an engine swop ?

Re: Big Bore Kit

Posted: Sat Jun 14, 2014 9:27 pm
by JZH
I was referring to putting a VFR750 engine in an NC30 (I think someone managed that feat at least once). That would be a good 40hp upgrade, but it's not straightforward and probably has loads of compromises. The 900RR engine in the NC23/29 has always intrigued me, though. The last version put out 151hp...

Ciao,

Re: Big Bore Kit

Posted: Sat Jun 14, 2014 10:25 pm
by CRM
I just sold a 440 TTS kitted bike.
full system. total loss system making a healthy 72 at the wheel.
plenty more to come but reliability was the name of the game. the torque curve was linear and it really was a grunty bike - perfect for the road.
just need to treat with care, warm up is essential or the knock the tops if the pistons about and slap when cold.

Re: Big Bore Kit

Posted: Sat Jul 26, 2014 2:08 pm
by RickOliver
I`m with Paul on this one - my 444 engine also makes around 70bhp but the point of the exercise with a big bore kit is that it moves the entire dyno curve up the chart by between 5 and 10 bhp which equals much better midrange and tractability.

Warm up carefully and don`t over rev (I`ve reset the rev limiter on mine to 13,750 from the stock 14,500) otherwise the extra reciprocating mass of the bigger pistons will significantly compromise the service life of your crank and rods.

Rick

Re: Big Bore Kit

Posted: Sun Aug 24, 2014 7:22 pm
by JZH
Maybe I should ride it more, LOL...

Ciao,

Re: Big Bore Kit

Posted: Tue Aug 26, 2014 7:17 am
by Sunnyday
Ok sounds like a diet might be the answer.