I don't think it is the compression release, because I get no compression even with all the valves closed(valve shafts are in the valve cover, I removed the valve cover.) Would'nt I get incredible compression while kicking over, spark plug in, all valves closed? I never did an actual compression check, But my other bike (same thing) is hard to kick , on the compression stroke. I want to make sure theres not something im overlooking before I pull the head off. Thank you for your answers.
2007-09-26 04:53:50 · 6 answers · asked by Anonymous in Cars & Transportation ➔ Motorcycles
yep, the automatic compression release on the early-mid 80s XR500/600 were notorious for the symptoms of low compression (not sure if the 350 had this or not?? on right side of cylinder jug). dissassemble and clean thoroughly, maybe even replace the coil spring might not be fully closing off the valve completely.
once you have gone thru that, if that doesn't fix it, run a compression check / leak down check... one of those should find your problem.
2007-09-26 12:37:04 · answer #1 · answered by pmk 6 · 1⤊ 0⤋
A 350 is not such a large motor to generate an incredible amount of compression.
The first thing I would check is the cable and arm for the compression release.
And just to be sure you are aware, the compression release does function automatically.
Honda makes a pretty solid engine ,but that is not to say they never wear out.
Before pulling the cylinder off, get the specs. from Honda and do a compression test, or even better have a shop do a compression and leak down, these tests will tell you if you even need to pull the top end.
The fact that your XR is easier to kick than another bike is not reason enough to take the motor apart.
Is it lacking power?, is it burning oil? smoking? These are more the types of things to be concerned about.
2007-09-26 05:42:36 · answer #2 · answered by Anonymous · 1⤊ 1⤋
The valves "could" be bent and not sealing. I'm not saying that's your problem. But that would be another cause of zero compression.
With the valve cover off - check for excess valve clearance.
OR
Bring the piston to TDC of the compression stroke (valves closed).
With an air blow gun, blow into the spark plug hole and listen at the air box and muffler.
Any hissing noise and there is a bent/leaking valve.
2007-09-26 09:04:53 · answer #3 · answered by guardrailjim 7 · 0⤊ 0⤋
on most (if not all) of the bigger XRs in the mid 80s, they had both a manual compression release on the left handlebar and an automatic one that released on the first part of the stroke of the kick starter (to make it easier to start).
when starting, the technique was to press down slowly on the kick starter until the automatic compression release clicked, then return to top of the kick starter stroke and kick thru ... the first 1 to 2 inches of the kick stroke, the compression release was open (to give you momentum in kicking it), but closed automatically at that point, allowing compression to build inside the cylinder (and therefore start, hopefully) ...
more than likely something to do with the automatic compression release, maybe even something simple like the spring is broken... I would start off by disassembling that...
2007-09-26 12:32:35 · answer #4 · answered by KelleyXR 2 · 1⤊ 0⤋
use some WD40 on the comp relase lever just to make sure it's actually releasing... a 350 is an older model so things can sludge up. You can also borrower a compression check tool from most parts stores for a few bucks. kick it over a few times till it builds up pressure and watch the guage for leakdown. I will bet it's just stuck
2007-09-26 06:25:42 · answer #5 · answered by ? 3 · 0⤊ 0⤋
Use a flashlight look inside the cylinder with the plug out.
Slowly kick the bike with your hand and look at the top of the piston - you may have a hole in it.
Put your finger over the hole and see if it pushes your finger off.
2007-09-26 05:14:11 · answer #6 · answered by cgriffin1972 6 · 2⤊ 1⤋