Compression revisited

[mikenixon]

A comment. Boring Wing cylinders is not an impossible solution. It's more work and trickier than other 70s Japanese cylinders (requiring a special cutter designed for blind holes) but the technique is well known. And although Honda does not have pistons any longer, aftermarket suppliers do, including CMSNL. Just a reminder.

[flyday58]

Some forums welcome noobs with an invitation to read their respective "info for noobs" section to avoid asking questions that have long since been answered. I vote your initial post here for that section.

[mikenixon]

Thank you, Richard!

[mikenixon]

another good read !

i am but a humble back-yarder, nevertheless it seems that whenever i suggest on an internet forum that a compression test might be in order, i am met with the on-line equivalent of a blank stare. compression ? pshaw ! nothing wrong with MY engine ! (other than the fact that it won't start ).

A little late to the party, sorry. But I would say your described response to the cylinder compression ethic is the one I get most often as well. It seems somewhere along the way folks have associated compression with a ride in an ambulance. In other words, they have relegated it to something done only on an engine found in a salvage yard, not their regular rider.

[BurnsYoFace34]

So quick question I have the carbs off my bike an did a compression test all 4 cyclinders read 75 psi but thats without the carbs on the bike is this good or should i wait till i have the carbs back on the bike I have checked the valve lash an there all set to .004 in. Currently taking the carbs off to replace a carb body the float post broke on one waiting for new one to come lol its a 77 gl1000

[gltriker]

So quick question I have the carbs off my bike an did a compression test all 4 cyclinders read 75 psi but thats without the carbs on the bike is this good or should i wait till i have the carbs back on the bike I have checked the valve lash an there all set to .004 in. Currently taking the carbs off to replace a carb body the float post broke on one waiting for new one to come lol its a 77 gl1000

Carburetors removed is fine, because a properly performed cylinder compression test requires the throttle to held wide open.
The author of this Topic also advises to set the intake and exhaust valve cold engine lash clearance at 0.006 inch.

[pidjones]

So quick question I have the carbs off my bike an did a compression test all 4 cyclinders read 75 psi but thats without the carbs on the bike is this good or should i wait till i have the carbs back on the bike I have checked the valve lash an there all set to .004 in. Currently taking the carbs off to replace a carb body the float post broke on one waiting for new one to come lol its a 77 gl1000

https://www.randakks.com/float-pivot-po ... r-kit.html

[BurnsYoFace34]

So set the valve lash to .006 if its cold then recheck compression?

[gltriker]

Sorry I didn't respond sooner

Yes adjust intake and exhaust valve cold lash clearance at 0.006 inch.

Retest for individual cylinder compression readings.
Depending upon the sealing integrity of the cylinders' internals, very likely you may see an increase in cranking compression test reading numbers..
Possibly 10psi

Ýes, before you ask the inevitable.......

Permanently leave all inlet and exhaust valves lash set at 0.006 inch.
.

[BurnsYoFace34]

So having the low compression like that is that ok I havent reset the cold lash yet an re checked it

[Track T 2411]

75 PSI is low. As you've given no history on the bike, any number of issues could be the cause of such low readings, even the type of compression tester used. Just saying...

[BurnsYoFace34]

Well I know the bike sat for yrs before before I got ahold of it I took it apart all the way down the the frame cleaned it up I never touched the motor at all how ever when I first got it i did put a battery in the bike an sprayed pb blaster inside the spark plug holes an it cranked over I did that several times to try an loosin the rings up the bike was so outa time that after I finally put new plugs an new dyna ignition on that an retimed it the plug wires were on backwards like literally it was cycl 1 was using #2 plug wire stupid didnt realize that till after the fact cuz i had pics showing how I took them off before I put them back on the person before me reversed them idiots I also found out it had a broken drive shaft so replaced that the carbs I took apart an cleaned but didnt replace any jets. But for some reason now when it gets started the idle just jumps up to like 4k rpm an just stays there it'll rev up but back down to 4 k rpm

[MikeNTexas]

If you're thinking of buying a compression tester, good for you! That's something everyone needs to do. But try to spend more than $49 on one. Compression testers having screw-on adapters are a joke; like carb rebuild kits and chicken McNuggets-- worthless.

If not this kind of tester what kind do you recommend. Hopefully not the kind that you simply push into the plug hole. There are lots of applications where they simply wont reach the plug hole. The kind with the hose and adapters at least free up both hands to operate the throttle and start switch at the same time.

[gltriker]

Well I know the bike sat for yrs before before I got ahold of it I took it apart all the way down the the frame cleaned it up I never touched the motor at all how ever when I first got it i did put a battery in the bike an sprayed pb blaster inside the spark plug holes an it cranked over I did that several times to try an loosin the rings up the bike was so outa time that after I finally put new plugs an new dyna ignition on that an retimed it the plug wires were on backwards like literally it was cycl 1 was using #2 plug wire stupid didnt realize that till after the fact cuz i had pics showing how I took them off before I put them back on the person before me reversed them idiots I also found out it had a broken drive shaft so replaced that the carbs I took apart an cleaned but didnt replace any jets. But for some reason now when it gets started the idle just jumps up to like 4k rpm an just stays there it'll rev up but back down to 4 k rpm

Ŕesume your engine speed control concerns in your other Topic:?
https://www.ngwclub.com/forum/search.ph ... =firstpost