Re: [2cylinderhondas] Re: Please share your experience with getting

friend · Post by **friend** » Fri Apr 20, 2007 12:13 am

Miles E.
Look at a regrind on your cam, then use lash caps on the valves (they will have to be made). And the volume of air fuel mixture is enough with the later carb, just need to open the jets and move the pin up on the accelerator pump shaft. When boring for new pistons, keep the cylinders as straight as possible and as for rings,
go to the next size up and grind to the closest gap without touching. Never had a stock set of rings come close to what's necessary. Then torque the head to to 45 pounds feet. And, retorque after the first warm-up. Don't forget to change out the cam chain, you know what they say about the weakest link.
Oh yea, use an oil cooler and remote filter.
Bill

> -----Original Message-----
> From:
> 2cylinderhondas@yahoogroups.com [mailto:2cylinderhondas@yahoogroups.com] > On > Behalf Of > wanna600 > Sent:
> Wednesday, April 18, 2007 3:00
> PM
> To:
> 2cylinderhondas@yahoogroups.com
> Subject:
> [2cylinderhondas] Re: Please share your experience with getting more horses > out of the 600.
> I've managed to squeeze a little more power out of my 600.
> Here's a
> rough outline
> 1. Homemade equal length (26"? x 1.25 Dia) headers going to a > mandrel > bent 1.5" exhaust - required removing the vertical hood latch > support > bar thingy for clearance, which in turn required hoodpins.
> 2.
> Mike in NC sells oversized pistons- they bump you up to a huge > 640cc if I > remember right. They're also lighter.
> 3. Mild port job on the head... I
> paid somebody with more experience
> than I to do that.
> 4. Stock cam
> 5.
> Carefull assembly (selection of the base gasket thickness)to > set > piston/head clearance as low as you dare to go (I'm at .032"), > to > increase compression.
> 6. Loose pistons and rings to reduce
> friction.
> 7. 39mm Keihin FCR-MX Carb. This is huge. I haven't finished > the > airbox/cold air intake for it yet, so it's not fully dialed in, but > it > is night and day more powerful and responsive than it was with the > old > CV carb.
> I don't know how much power I had before/after doing
> this work, but
> after installing the carb, I accidentally found myself at
> 70mph in a
> 40 zone while tuning the A/F ratio. I had never had speed sneak > up on > me in the honda before.
> -Miles E.
> --- In
> 2cylinderhondas@ yahoogroups. com
> ,
> "misterpoopoohead"
> wrote:
> Hi Gang,
> > I thought I'd start another thread!
> Have any of you rebuilt the 600 engines with the specific intent of
> pumping out more horses than the 35 or so that they normally get?

friend · Post by **friend** » Sat Apr 21, 2007 3:04 am

I agree there are lots of bigger, better and higher performing carbs on the shelf, but the intake is only so large. So unless you are going to a larger intake manifold and widening the head intake along with larger valves or cutting your cam, a larger carb is defeating the purpose. This is why I say, work on the jets, the original carb has a variable venturie allowing the same capabilities as a two barrel carb. The function is there. I always look at an engine like a pump. intake equals exhaust for efficient running. Open your intake and exhaust with an equal cut and you will increase output. Otherwise you will be starving the intake or choking the exhaust.
Bill C

> -----Original Message-----
> From:
> 2cylinderhondas@yahoogroups.com [mailto:2cylinderhondas@yahoogroups.com] > On > Behalf Of > wanna600 > Sent:
> Friday, April 20, 2007 12:12
> PM
> To:
> 2cylinderhondas@yahoogroups.com
> Subject:
> [2cylinderhondas] Re: Please share your experience with getting more horses > out of the 600.
> Bill-
> Thanks for your thoughts. The cam is stock, so no lash caps > necessary.
> The Keihin FCR-MX carb is a far more advanced design than even > the > later stock carb. It does a better job of atomizing fuel and > flowing > air than a CV carb ever could. My old Mikuni 38mm CV carb held a > near > perfect AF ratio and had a bigger throat than the old early > stock > carb, but this new FCR-MX just blows it away. It's using 25 years > of > carb design evolution to your advantage! This design of carb is > used > on almost every racing 4 stroke motorcycle engine except the > fuel > injected ones.
> The downside is that it's a pain to set up,
> machining is necessary.
> Miles E.
> --- In
> 2cylinderhondas@ yahoogroups. com
> ,
> wrote:
> > Miles E.
> > Look at a
> regrind on your cam, then use lash caps on the valves
> (they
> > will
> have to be made). And the volume of air fuel mixture is enough > with
> the later carb, just need to open the jets and move the pin up on the
> accelerator pump shaft. When boring for new pistons, keep the > cylinders > as > > straight as possible and as for rings, go to the next size up > and > grind to > > the closest gap without touching. Never had a stock > set of rings > come close > > to what's necessary. Then torque the head > to to 45 pounds feet. And, > > retorque after the first warm-up. Don't > forget to change out the > cam chain, > > you know what they say about > the weakest link. Oh yea, use an oil > cooler > > and remote > filter.
> > Bill
> > -----Original
> Message-----
> > From:
> 2cylinderhondas@ yahoogroups. com
> [mailto:
> 2cylinderhondas@ yahoogroups. com
> ]On
> Behalf Of wanna600
> > Sent: Wednesday, April 18, 2007 3:00 PM
> > To:
> 2cylinderhondas@ yahoogroups. com
> Subject: [2cylinderhondas] Re: Please share your experience > with > getting > > more horses out of the 600.
> I've managed to squeeze a little more power out of my 600.
> Here's a rough outline
> > 1. Homemade equal length (26"? x 1.25 Dia)
> headers going to a mandrel
> > bent 1.5" exhaust - required removing the
> vertical hood latch support
> > bar thingy for clearance, which in turn
> required hoodpins.
> > 2. Mike in NC sells oversized pistons- they bump
> you up to a huge
> > 640cc if I remember right. They're also
> lighter.
> > 3. Mild port job on the head... I paid somebody with more > experience > > than I to do that.
> > 4. Stock cam
> > 5. Carefull
> assembly (selection of the base gasket thickness)to set
> > piston/head
> clearance as low as you dare to go (I'm at .032"), to
> > increase
> compression.
> > 6. Loose pistons and rings to reduce friction.
> > 7.
> 39mm Keihin FCR-MX Carb. This is huge. I haven't finished the
> airbox/cold air intake for it yet, so it's not fully dialed in, but it
> is night and day more powerful and responsive than it was with the old
> CV carb.
> > I don't know how much power I had before/after doing
> this work, but
> > after installing the carb, I accidentally found myself
> at 70mph in a
> > 40 zone while tuning the A/F ratio. I had never had
> speed sneak up on
> > me in the honda before.
> > -Miles
> E.
> > --- In
> 2cylinderhondas@ yahoogroups. com
> ,
> "misterpoopoohead"
> > wrote:
> > > Hi Gang,
> > > I thought I'd start
> another thread!
> > > Have any of you rebuilt the 600
> engines with the specific intent of
> > > pumping out more horses than
> the 35 or so that they normally get?