Boring Cylinders

[dgyver]

Anyone know of a place to have GS cylinders bored in the southeast? I got a price of $60/cylinder. $120 seems a little high. I know race cars are around $30/cylinder.

[Reknelb]

prices around here are usually around 30-40 per hole. Thats usually for a 1mm-2mm over bore and hone.

[dgyver]

I am needing a 5mm overbore for 79mm pistons from a stock 74mm cylinder.

[Reknelb]

Can you go that big on stock sleeves? If someone is charging you 60 per hole to  re-sleeve, bore and hone then thats not bad.

[dgyver]

That is the largest bore you can go on stock sleeves. They don't need to replace the sleeves, just bore them. I was told $120 just to bore the 2 cylinder holes to 79mm, resleeving is even more.

I have one cylinder that has been bored to 79mm (thanks KevinC) but I am concerned about their reliability since there is a chip in one of the sleeves. I don't think the piston reaches that part of the sleeve but I still need to verify this.

[KevinC]

I ran those cylinders with the chip, and didn't have any problems until a piston scuffed - not sure if it was the same side or no. The piston doesn't go down that far. Won two races with the cylinder chipped like that!

I think you have to be very careful to run rich with the sleeves bored out to 79 mm. With the cast iron that thin, I think it is really easy to get a hot spot. And of course it is really easy to chip the lower edge!

[GRU]

i just calculated that 39.5 Pi x^2 * 56.6 * 2 = 558 cc

so you increase your power for a little more then 1/10
whouldn't that increase the power to about 60 HP at the crank?
if so, that is a very good mod on our bike...

[dgyver]

I ran those cylinders with the chip, and didn't have any problems until the piston scuffed. The pistom doesn't go down that far.

I think you have to be very careful to run rich with the sleeves bored out to 79 mm. With the cast iron that thin, I think it is really easy to get a hot spot. And of course it is really easy to chip the lower edge!

Thanks for reassuring me about that you did run it with the chip.

Are you saying to run rich? As running leaner creates a hotter engine, correct?

GRU...I would not say that this a "very good" mod for the bike. Yes it will increase HP and torque but the realiability of the engine comes into play. Just for grins, I do plan on putting it on a dyno to see what kind of HP it is putting out.

[KevinC]

I was getting about 53 hp with a 555 engine, 36 mm GSXR carbs, Yosh or Hindle exhaust, pods. Until the balance shaft bearings went.

[GRU]

I was getting about 53 hp with a 555 engine, 36 mm GSXR carbs, Yosh or Hindle exhaust, pods. Until the balance shaft bearings went.

to the rear wheel or?

i quess it's a good mod if you're racing, but not for street and race....

i'm looking for some mods to do to get about 60 hp at the crank so i'm interesed in a best way to spend my money  

[KevinC]

Yeah, lean is hotter, but more power to a point. I was fooling with the jetting while racing. I knew I was on the lean side and was working towards rich - I know you should start rich and work leaner, but circumstances and not wanting to mess up a winning bike...

Anyway, the balance shaft bearings went, then the piston scuffed, then the crank bearings, then... I ended up wasting the rest of the season with broken engines. Hence the SV this year!

[Reknelb]

I was getting about 53 hp with a 555 engine, 36 mm GSXR carbs, Yosh or Hindle exhaust, pods. Until the balance shaft bearings went.

Just out of curiousity, did you have the head ported and/or milled? We were getting the same hp with stock pistons, stock headers with a slip-on, 36mm gsxr carbs with velocity stacks, ported and milled head, degreed stock cams, and the ign. advanced.
BTW we confirmed that the ign. andvance did give a couple HP at the top end from stock.

[Blueknyt]

Wow, all you guys sound high, the 2 places i checked into were 8 and 12$ a hole.

[KevinC]

Our dyno reads a fair bit lower than others in town. Our local track is at 3,300', but of course they correct the dyno reading for sea level.

The head was ported, dual plugs, ignition advaced, degreed high lift cams. The 53 hp was with the jetting off quite a lot - unfortunately the CB shaft bearings went before I had a chance to get it back on the dyno.

[The Buddha]

I was getting about 53 hp with a 555 engine, 36 mm GSXR carbs, Yosh or Hindle exhaust, pods. Until the balance shaft bearings went.

to the rear wheel or?

i quess it's a good mod if you're racing, but not for street and race....

i'm looking for some mods to do to get about 60 hp at the crank so i'm interesed in a best way to spend my money  

Yes wheel , cos there is no other way to measure it really, ok fine you could fit it on a crank dyno and try it, however crank dyno's outside of the manufacturer factory are rather un common...
Cool.
Srinath.

[octane]

A shifter kart racer I know turned me on to this little contraption - not sure if it would work for the bike. If so, I'd love to know though!

www.ezbore.net

[Blueknyt]

seems to be designed for certain bore .010- .180   i have built 1 high performace B&S engine in my time, kicked ass for about 20 min, then went the way of all rockets, er... bottle rockets that is.