Checked my compression

robfromga · Post by **robfromga** » January 11th, 2011, 1:18 pm

Faack! 100-105psi

Bike runs fine

Time for a topend? Unknown hours on the motor

Tharrell · Post by **Tharrell** » January 11th, 2011, 1:28 pm

Throttle wide open while kicking?
Makes a big difference.

robfromga · Post by **robfromga** » January 11th, 2011, 1:33 pm

Tharrell wrote:Throttle wide open while kicking?
Makes a big difference.

Yep...wide open, thumb on the kill switch. Kicked the piss out of it maybe 10 times. I dont want to believe it, but I dont wanna go pull all that crap off again

lewisclan · Post by **lewisclan** » January 11th, 2011, 1:39 pm

if its a trail bike Id run it, it can stay right there for years

britincali · Post by **britincali** » January 11th, 2011, 1:43 pm

+1 My AF has shit compression and runs awsome, just means its easier to kick

robfromga · Post by **robfromga** » January 11th, 2011, 1:46 pm

Really? Some Im not facked?

Im not getting at all full power am I? Not that I can handle full power...ya know what I be saying. I just have this thing about things running right.

Post by **AlisoBob** » January 11th, 2011, 1:50 pm

Look down its throat ( reed block out) and up its ass ( pipe flange) and if nothing is scored or cracked, follow Jays advice.

south central hoon · January 11th, 2011, 1:53 pm

just ride it.

anything below 100 start looking at a rebuild. jay lewis is right they'll run for a long time right around 100psi.

also, what is your elevation? temperature? these things will affect the reading as well.

robfromga · Post by **robfromga** » January 11th, 2011, 2:50 pm

south central hoon wrote:just ride it.

anything below 100 start looking at a rebuild. jay lewis is right they'll run for a long time right around 100psi.

also, what is your elevation? temperature? these things will affect the reading as well.

Im at about 300-400' it was very humid,id guess atleast 70%-80% temp was no more than 40f maybe even 35

Bob, I posted some pics in another thread, the intake is clean. I put a pipe on it a few weeks back, thought the exhaust was clean too. I need to reaseal the flange ill check it, but again I thought it was clean.

Im just kinda bummed, I want all my bikes to be at a certain level of repair and didn't want to break this one open yet.

robfromga · Post by **robfromga** » January 11th, 2011, 4:19 pm

intake

see that scratch at 11 oclock?

Post by **AlisoBob** » January 11th, 2011, 4:46 pm

Looks fine to me, check it in another 50 gallons of gas.

Run some 927' @ 32:1

That will help seal things up....

south central hoon · January 11th, 2011, 4:55 pm

just ride it!

lewisclan · Post by **lewisclan** » January 11th, 2011, 4:59 pm

south central hoon wrote:just ride it!

x2

robfromga · Post by **robfromga** » January 11th, 2011, 5:02 pm

Bob, Ive been running Honda HP2 at 40:1 Ive got a couple cr125's and a 250 and they all get the same mix.... I cant tell if your pulling my leg about "tighting things up"?

What I dont wanna do is screw the bottom end, as in crack the piston, piston bits into the case....

south central hoon · January 11th, 2011, 5:05 pm

JUST RIDE IT!

927 @ 32:1 PERIOD.

robfromga · Post by **robfromga** » January 11th, 2011, 5:42 pm

south central hoon wrote:JUST RIDE IT!

927 @ 32:1 PERIOD.

OK!

thanks

Kuma · Post by **Kuma** » January 11th, 2011, 10:52 pm

How do the scallips effect a compression check? don't they act like a compression release at slow kick start speeds and then don't play as much a role in the higher rpms?
if two equal motors, in port timing and calculated compression, what would the measured difference be between a scalliped motor and one without?
What are the advantages of running without scalliped bore?

Post by **AlisoBob** » January 11th, 2011, 11:06 pm

Kuma wrote:What are the advantages of running without scalliped bore?

robfromga · Post by **robfromga** » January 31st, 2011, 7:40 pm

All this still has me thinking of a top end. Im gunna pull off the pipe and cycle it through to check the bore, is there anything stopping me from just ordering a flex hone? It looks pretty simple?

Ehhh?

nmdesertrider · Post by **nmdesertrider** » February 1st, 2011, 12:34 pm

Mine was 2 over and had a crack completely through one side of the liner on the intake side- if I didn't take the head off and check it I could have blown the motor- piston looked fine.
I think 'it depends'

robfromga · Post by **robfromga** » February 1st, 2011, 7:04 pm

I pulled the pipe of tonight and checked out the cylinder, as best as possible through the exhaust. Looks good, no grooves on the exhaust side of the piston or no groves in the bore.

I did notices some lines running up and down in the cylinder, but the were smooth when I got my finger in there.... so am I cool? Can I flex hone it?

100hp honda · Post by **100hp honda** » February 1st, 2011, 8:35 pm

i been lost from the beggining. your concearned with compression so you want to run a ball hone through it ? what good will that do if your planing to re-use the old piston

. if your that concearned just take the jug off and measure what you got. put it back together if everything specs ok. if not then put pc9 on there, its only $60. or get bore job and all new piston. 100psi aint ideal but the bike will still run fine and if the piston aint slopping then who gives a shit. like i said im pretty lost what your trying to do

mr500 · Post by **mr500** » February 1st, 2011, 9:40 pm

The only thing you can't check by looking in the exhaust port is if the bridge is pinching/scoring the piston.Every 500 that I'v pulled the cylinder off that has been worked on by someone else, has not had the bridge relieved.
Lots of bike shops don't even know that 500 cylinders need this mod.
Pull off the cylinder and measure everything so you know where your at.

Tharrell · Post by **Tharrell** » February 2nd, 2011, 4:45 am

Pull the topend.
Check your ring end gap.
It may be that simple.
They're supposed to wear.

robfromga · Post by **robfromga** » February 2nd, 2011, 4:46 am

100hp honda wrote:i been lost from the beggining. your concearned with compression so you want to run a ball hone through it ? what good will that do if your planing to re-use the old piston . if your that concearned just take the jug off and measure what you got. put it back together if everything specs ok. if not then put pc9 on there, its only $60. or get bore job and all new piston. 100psi aint ideal but the bike will still run fine and if the piston aint slopping then who gives a shit. like i said im pretty lost what your trying to do

I never said a thing about reusing anything. Im just trying to redo the topend with out sending the jug out and missing a weekend of riding. I don't trust any of the local shops. So if the bore was clean, ie not scoredy plan was to pull the head on sunday, order a new piston rings gaskets etc, have that stuff Wednesday, hone it and pop it all back together.

Im slightly concerned with the 100 psi, id rather rebuild it and know what's what. The bike has a unknown history. I've rebuilt several topends but always sent away the jug, for nearly the cost of shipping I can get a 50 flex hone. My question was if that's kosher, not if I can reuse the stuff, im cheap ....but im not britt

BannedCR500Riders.com

Checked my compression

Checked my compression