Help reading Squish Clearance

[granddad]

I am checking the squish clearance on my sons spree & this is what I came up with
http://s1289.photobucket.com/user/grand ... a.jpg.html

I hope it's visible lol, this is new to me. If not, the mic is reading 1.18mm at the tip of the solder. I have been reading every post I can find but I am dumbfounded & cannot figure out how to read this micrometer. I bought a complete rebuild on ebay (jug, piston, rings, gaskets) & I am only getting 100 psi comp. If anyone can tell me if this is in spec I will surely appreciate it. Thank you, Tony.

[swimmingfree]

100 psi is the low end of things but it will run ... put some oil down the spark plug hole then try getting it running .. if that dont work set the plug at 0.025 and put some gas oil mix down the hole just a fue drops ...
ps did you cleand the carb ???is it fresh gas ??? do you have spark??? if not chack the kill switch !!!
swimmingfree

[granddad]

The bike runs, starts easy & has a little hesitation mid throttle but runs decent. I have seen that min. comp is 114 & this is at 100 with a recent rebuild. From reading through the numerous post this spree should have more compression after a rebuild. Visually the crank seals & case seals are not leaking & I have not done a leak down test to be certain everything is proper. I also sprayed starting fluid around all seals & no change in rpm, it runs smooth. I just can't figure why I would have such low compression & that led me to try checking the squish clearance. I just can't comprehend reading the micrometer to see if it is in spec. It's a 1984 Iowa in great condition. I actually ride it more than my son, it's great scooting around town here in Algonac Mi.
http://s1289.photobucket.com/user/grand ... c.jpg.html

They're not spree graphics but they're Honda graphics & my son thinks it makes it look newer.
Thanks again for replying.

[bakaracer]

that is a bit much. you want it more around .8 for stock. how thick is the base gasket? how many head gaskets are you using?

[dun rite]

when doing a compression test you need to hold the throttle wide open. Also the length of the hose on the tester has some to do with lower readings. the longer the hose the less accurate it is. The new rings may need some time to seat properly also. Breaking the engine in slowly by heat cycling and light ridding helps.

[patthesoundguy]

Those digital calipers are pretty slick, I have a set, can't live with out them. Just make sure you close them up and zero them then measure and they will always be accurate measurements. Otherwise you are reading them correctly. And heat cycling the new parts is very important to do before trying to rev it up. And make sure to follow break in procedure, so no wot for the first while, and vary the throttle a bunch while riding.

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[devenex]

Not sure what compression should be like before the rings seat, but it will go up as the rebuilt top end breaks in. You can also add a little oil and see if that increases your reading.

Did you hone the cylinder when replacing the rings?

[granddad]

Today I tore the bike down & pulled the head. It looks like a leaking head gasket. in the pic there is carbon build up in one spot & if you look close you can see where oil was seeping to the left of the build up on the flat surface.
If anyone wants to elaborate Please do so.
http://s1289.photobucket.com/user/grand ... sort=3&o=0
Thanks again, Tony.

[bakaracer]

use a metal straight edge and check for warpage. refer to the service manual for service limit. you need feeler gauges to check that. if within spec then get a new head gasket and tighten in criss cross pattern and tighten a little at a time. less chance of squishing tge head gasket to much on one corner and warping the head.

[granddad]

Thanks!!!
As I now recall opening the small box that the kit came packaged in, the head gasket was was crimped from bending it into the small box. I was upset at the time but it was ebay & you get what you pay for & sometimes it's not packaged good. I used it hoping it would be OK. I'll go to the Honda dealer & order one. As for the head I'll drop that off on the way & have them resurface it. Thanks Everyone, I'll get back & let ya know how everything works out.

[Pete M]

Are you sure your guage is accurate?

[patthesoundguy]

Your hesitation may be caused by the cylinder base gasket not be right in the kit, I have the same kit most likley and look what I found.
http://www.hondaspree.net/phpBB3/viewtopic.php?t=26503
Ebay spree stock cylinder kit update and heads up
I'd try the old head gasket if its not all bent up see if that gets more compression. Remember the head bolts only take 8 or 10 ft pounds that ain't a lot. And pull the cylinder and check the base gasket to make sure the gasket is right if you diddnt cut it when you installed it. If its like mine and not cut out for the ports cut it and soak it well with two stroke oil when you install it so it will come off next time you need to service it.


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[granddad]

Quick Update. I purchased an OEM complete gasket kit. I'm also having the head milled, still waiting.
But as I'm waiting & wondering why the compression would be so low with a complete rebuild I thought back about the installation.
When I got the kit I removed the head, jug, piston & rings & threw them in the trash. I never looked at the manual or took the rings off the old piston, thinking the kit was everything I needed. When I looked in the manual I saw the expansion ring for the lower ring. If my memory serves me right the kit did not have that ring included & so it was not installed. To me that would explain the lack of higher compression. The plug is dry & a dark tan so what I am asking is, is the expansion ring supposed to be used with the complete rebuild kit.
I'll tear it apart tonight & take a look. Thanks again for the suggestions & help. I will also make sure the base gasket is cut to size this time around.

[patthesoundguy]

I wouldnt worry about the ring expander, some high end big bore kits only have one ring on the piston. Just a thought... is the piston pointing the right way round. If the exhaust port side of the piston was facing the wrong way maybe a ring gap is lined up with a port.

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[paulpauly7]

i fitted a kitaco 44.5 mm piston to my old se50 it was a single ring piston the bike now has over 2000kms on it and still running strong compression still at 125psi