It should be noted that all this was done because someone had messed with/freshened this motor. there were signs of filing on mating surfaces.
When it is reassembled the deck height will have to be determined to make sure all things clear.
What I have learned so far is to choose a machinist that is also a builder and has worked on air cooled engines and roller cranks. I should add that so far I am no where near $$$ what the few N600 guys that build engines are asking.
--- In 2cylinderhondas@yahoogroups.com, wrote:
Hi Lyle,
> > Has to be a shop near you.
Neither the shop nor I are certain about whether we can get away with
0.5mm over pistons, and now I better understand why. I'm liking the
idea of ordering both sizes of piston and letting them sort it out,
but I'm still convinced this engine was already bored to 0.5mm over.
I was told it had a "full topend job 20k miles ago", measurements of
the sleeves are pretty close to 0.5mm over, and pistons are well
larger than spec. So I think whether it's still able to handle 0.5mm
over is a matter of wear and damage.
> >> You said the oil pump failed, how is your crank?
> >> Must start with the crank, rod, bearings and move your way up.
Crank is out of spec at the roller bearings at the ends. I feel a
tiny bit of play up and down where the crank arms connect but I don't
have any way to take the crank arms off to measure inside. Crank and
arms are one piece in Honda's parts diagrams, too. If I were smart,
I'd order a rebuilt engine and call this thing the parts engine.
Interestingly enough, someone claims to have crankshafts new:
http://www.bernardiparts.com/products/1 ... 8-190.aspx
I think I'm going to take my chances with a used one, though, if the
bearing journals are in spec.
The rollers themselves are described as "ROLLER (6X10)" or similar. I
don't see mechanical specs for them.
If I ordered something like
http://www.partzilla.com/parts/detail/k ... -Y006.html, any
guess as to whether it would fit and be correct?
Sorry for all of the questions but the temptation to try to pick your
brain is too great. I've spent days reading about stuff but that can
only general cases.
Cheers,
-scott
> On 9/12/13, Lyle craft59@...
> > wrote:
> > Here is a shop near me in Florida.
> http://precisioncycleinc.com/cylinder_b ... eving.html
> > Use them as a guide.
> > Has to be a shop near you.
> > Lyle
> > --- In
> 2cylinderhondas@yahoogroups.com
> , "Lyle" wrote:
> >> Hi Scott and Dale, I would like to help you, but I don't have the right
> >> machines or boring bars to bore an engine. I can do small Go-Kart engines
> >> that we race, but that's about it.
> >> My website: Tru-Craft.com
> >> Do a google search for motorcycle shops or automotive shops in your area.
> >> Then check out a few, a good shop will be clean and organized. They will
> >> take a couple measurements and let you know what you need. Motorcycle Race
> >> shops would be the best, they usually are more precise and are used to
> >> custom type machining.
> >> You said the oil pump failed, how is your crank?
> >> Must start with the crank, rod, bearings and move your way up.
> >> My 2 cents.
> >> Lyle
> >> --- In
> 2cylinderhondas@yahoogroups.com
> , scott@ wrote:
> >> > Hi Lyle and Dale,
> >> > Dale, not a bad thought!
> >> > Lyle, thank you for the thoughtful walkthrough. Are you interested in
> >> > this
> >> > job?
> >> > I ordered 1mm over pistons but I suppose I could get 0.5mm over too and
> >> > keep one set on the shelf depending on how exact measurements play out.
> >> > Regards,
> >> > -scott
> >> > On 0, goinhm@ wrote:
> >> > > Hi Scott (and Lyle),
> >> > > Scott..... why not send your cylinder barrel to Lyle and let him
> >> > > do the
> >> > > machine work? Then you know it will be done right. And the barrel
> >> > > doesn't weight that much to ship.
> >> > > Some of the people on this post seem to sell pistons and rings.
> >> > > And
> >> > > some have recommended _Hastings_
> >> > > (
> http://www.hastingsmfg.com/?gclid=CMWAt ... Ogod4jsAmw) > for
> >> > > their new rings. Not sure who to recommend for the
> >> > > pistons (maybe Hastings can recommend a vendor or someone on here).
> >> > > good luck,
> >> > > Dale
> >> > > Hi Scott, I am a machinist so I like this stuff:)
> >> > > The 600 motor is a motorcycle engine type, so I would recommend a
> >> > > bike
> >> > > engine machine shop. Search for a good shop in your area.
> >> > > The best tool for measuring a bore is a dial bore gauge, but why buy
> >> > > one?
> >> > > Have a good shop measure it for you.
> >> > > The only measurement you need is the largest bore size, usually at the
> >> > > top
> >> > > where the top rings dig into the bore, from the piston rocking in the
> >> > > bore.
> >> > > The only measurement on a piston needed is 90 degrees to the piston
> >> > > pin on
> >> > > the lowest part of the skirt. Your pistons skirts are damaged so
> >> > > nothing
> >> > > left to measure.
> >> > > Your measurements don't seem correct, a range of 74.42 to 74.72 that
> >> > > is
> >> > > about a 0.012" difference. The max bore size for a 0.50 piston is
> >> > > about
> >> > > 74.52mm or 2.9340". So if your measurements are correct then a 1.0
> >> > > piston is
> >> > > needed.
> >> > > If you go with a 75mm piston(1.00mm oversize).
> >> > > Then the bore should be about 2.9530" and the piston 2.9510".
> >> > > Buy the pistons first, they vary in size and must be matched to each
> >> > > bore
> >> > > and marked! The machinist will mic them at the skirts. Then bore the
> >> > > cylinders to within about (0.001") and "Perpendicular to the base".
> >> > > Hone to
> >> > > finish size to get 0.0015" to 0.0025" clearance. Check ring gap and
> >> > > you have a
> >> > > perfect job.
> >> > > Lyle
> >> > > --- In
> 2cylinderhondas@yahoogroups.com
> , Scott Walters
> >> > > wrote:
> >> > > > Hi Dale,
> >> > > > > Did you take your engine to an automotive machinist?
> >> > > > Just the pistons and the cylinders, but yes. This outfit in town
> >> > > > rebuilds engines and does machine work.
> >> > > > > But do ask him why your measurement is different from his
> >> > > > > measurement?
> >> > > > I did. His response was, "This thing isn't super precise, but it
> >> > > > should clean up just fine."
> >> > > > As you can see, that didn't inspire huge amounts of confidence.
> >> > > > Between that and him wanting me to order and bring in the pistons
> >> > > > before he starts machining it, I'm balking.
> >> > > > > What did you use .... micrometer or caliper?
> >> > > > Digital micrometer. He had a dial micrometer.
> >> > > > I'm tempted to pick up a bore gauge.
> >> > > > > If the 0.5 mm doesn't work out, why do you want to go with 1.0
> >> > > > > mm?
> >> > > > I don't know the ins and outs of different options. How would 0.5
> >> > > > not
> >> > > > work out? Would the machinist call me back and say that he needs
> >> > > > to
> >> > > > go larger to get the scuffing out, or would it just be too
> >> > > > sloppy/loose of a fit against the pistons leading to more scuffing
> >> > > > of
> >> > > > the skirt and blowby?
> >> > > > If I'm going to go with sloppy, it seems like the most logical
> >> > > > thing
> >> > > > to do would be to stick 0.50 over pistons in and skip the
> >> > > > re-boring
> >> > > > and let the minor scuffing work itself out on the piston rings.
> >> > > > > These pistons were also offered in a 0.75 mm oversize.
> >> > > > That seems like the logical choice, but I don't see any of those
> >> > > > currently being sold online. I've found some Honda dealers that
> >> > > > have
> >> > > > online parts finders with the N/Z 600 still listed, but very few
> >> > > > parts
> >> > > > still in stock including no pistons of any size.
> >> > > > The pistons I do see for sale are care of O'Connor's at
> http://honda600shop.com/parts.php?Category=N+%26+Z+600
> and are only
> >> > > > in
> >> > > > 0.50 and 1.00 over.
> >> > > > Have any leads on 0.75 over pistons?
> >> > > > Thanks for your comments.
> >> > > > -scott
> >> > > > On 9/9/13, goinhm@ wrote:
> >> > > > > Hi Scott,
> >> > > > > Did you take your engine to an automotive machinist? Or someone
> >> > > > > who
> >> > > > > regularly works on engines?
> >> > > > > Go back and talk to the machinist and take your pistons. If he
> >> > > > > is
> >> > > > > suggesting to go with 0.5 mm oversize, go with it.
> >> > > > > But do ask him why your measurement is different from his
> >> > > > > measurement?
> >> > > > > What did you use .... micrometer or caliper?
> >> > > > > If the 0.5 mm doesn't work out, why do you want to go with 1.0
> >> > > > > mm?
> >> > > > > These pistons were also offered in a 0.75 mm oversize. After 1.0
> >> > > > > mm,
> >> > > > > then you have to have the cylinders resleeved which can be very
> >> > > expensive.
> >> > > > > good luck,
> >> > > > > Dale
> >> > > > > Hi all,
> >> > > > > Thanks for the advice earlier recommending taking the side off
> >> > > > > and
> >> > > > > looking at the oil pump on the '72 Coupe. Sure enough, the oil
> >> > > > > pump
> >> > > > > had imploded. I don't know if the camshaft started eating itself
> >> > > > > first and the metal clogged the oil pump, or if the oil pump
> >> > > > > imploded
> >> > > > > and oil starved the camshaft. Probably the latter, I guess.
> >> > > > > It looks like it might have 0.5mm oversized pistons in, but
> >> > > > > they're
> >> > > > > badly scuffed from overheating. Measuring front to back, they're
> >> > > > > 74.49mm on one (R) 74.55mm on the other (L). Side to side, where
> >> > > > > they
> >> > > > > aren't scuffed, they're 74.22 and 74.24.
> >> > > > > Measuring the cylinders at the top, I get 74.52 side to side and
> >> > > > > 74.65
> >> > > > > for the left and for the right,74.50 side to side and 74.42 front
> >> > > > > to
> >> > > > > back. The bottom of the cylinders measure about the same but a
> >> > > > > bit
> >> > > > > worse: L front to back is 74.72 and R front to back is 74.64.
> >> > > > > I took the cylinders and pistons in to a machine shop today and
> >> > > > > they
> >> > > > > suggested a 0.5mm overbore after a quick measure of the top. They
> >> > > > > got
> >> > > > > slightly lower numbers than I did and I don't think they heard me
> >> > > > > when
> >> > > > > I mentioned the pistons were maybe already oversized.
> >> > > > > I don't have any experience with engine bores and pistons, so...
> >> > > > > questions:
> >> > > > > Does this sound like this was over bored and had 0.5mm oversized
> >> > > pistons
> >> > > > > put in?
> >> > > > > At this point, would it make sense to go for/stay with 0.5mm
> >> > > > > oversized
> >> > > > > pistons or should I have it rebored for 1mm oversized pistons?
> >> > > > > Thanks for any insights!
> >> > > > > Regards,
> >> > > > > -scott