Low Compression in three cylinders.
#1
Low Compression in three cylinders.
Edit: I guess I have low compression in all cyclinders. 1 & 4 had 125LBS and 2&3 had < 50LBS
So I took my bike into the shop. Last time I rode it was in the rain, and then next day it wouldn't start.
Took it to Honda. They tell me compression is bad.
I don't see how this happens overnight.
Then they call me back and tell me there is sand in the motor.......quick conclusion.......after an hour
****ing previous owner.....
Now they want to do a leak down test to figure out where **** is going wrong.....I really hope I don't need a new motor.......
So do I trust the dealer? Get a second opinion?.....advice/comments/halp......thanks
How much does an F4i motor cost?
Update: They did a leak down test and they said its coming from the head and not the pistons.
So I took my bike into the shop. Last time I rode it was in the rain, and then next day it wouldn't start.
Took it to Honda. They tell me compression is bad.
I don't see how this happens overnight.
Then they call me back and tell me there is sand in the motor.......quick conclusion.......after an hour
****ing previous owner.....
Now they want to do a leak down test to figure out where **** is going wrong.....I really hope I don't need a new motor.......
So do I trust the dealer? Get a second opinion?.....advice/comments/halp......thanks
How much does an F4i motor cost?
Update: They did a leak down test and they said its coming from the head and not the pistons.
#2
RE: Low Compression in three cylinders.
Hmmm...if you took it to a Authorized Honda Repair center, they are probably right. Sand in the engine, if someone was riding by a beach or in a sandy area and the sand got into the air intake it would be stopped mostly by the air filter, but some could get into the engine. Ask for a quote of how much to repair it before you look at buying a new engine. btw you can get used motors on ebay for around 900.
#4
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#6
RE: Low Compression in three cylinders.
Now they did the leak down test and its coming from the head and not the pistons.....hmmm. I definitely think they are jumping to conclusions without having taking the motor apart. Considering I have rode this bike for three months with out any problems as the sand definitely didn't come from me. I can get a used pistons and rods for $50 on ebay right now. Should I take the chance and get them and risk it not being the pistons?
#7
RE: Low Compression in three cylinders.
A leak down test is not jumping to conclusions. If they said it was coming from the head, maybe it is leaking through the valves. It is possible that it may need the shims adjusted and the valves are slightly open when the engine is cold. This is the part where they are going to have to start charging you for a tear down and inspection. If it were mine, I would do, or ask for a valve clearance check. If the valves are fine, then I would take it home and put some Rislone in each cylinder and let it sit overnight. Rislone is supposed to free up stuck cylinder rings, and I have seen it work on an old bike with a lot of mileage that lost compression. It wouldn't hurt to put that in and let it sit for longer than one day. Just some suggestions for you.
#8
RE: Low Compression in three cylinders.
From:
http://www.mobiloil.com/USA-English/...Test.aspx?pg=2
Hearing Problems
Beyond getting an overall picture of engine condition, the leakdown test is an excellent way to pinpoint where engine problems are before tearing down the engine. Listening for where the air is escaping by ear can isolate the problem.
[blockquote]Intake Valve: Air whistling out of the intake, carburetor, or throttle body indicates leak at the intake valve.[/blockquote]
[blockquote]Exhaust Valve: Air heard hissing out of the tailpipe, turbocharger, or exhaust manifold means an exhaust valve leak.[/blockquote]
[blockquote]Piston Rings: Whistling or hissing out of the PCV valve, oil filler cap hole, or dipstick tube means the air is pushing past the rings. Suspect ring or cylinder wall wear.[/blockquote]
[blockquote]Head Gasket: Air bubbles in engine coolant seen at the radiator filler cap could mean air escaping into the coolant past the head gasket.[/blockquote]
[blockquote]Cracked Cylinder Head: Bubbles in coolant or coolant being pushed up out of the radiator neck can also indicate cracks in the cylinder head or cylinder walls.[/blockquote]
http://www.mobiloil.com/USA-English/...Test.aspx?pg=2
Hearing Problems
Beyond getting an overall picture of engine condition, the leakdown test is an excellent way to pinpoint where engine problems are before tearing down the engine. Listening for where the air is escaping by ear can isolate the problem.
[blockquote]Intake Valve: Air whistling out of the intake, carburetor, or throttle body indicates leak at the intake valve.[/blockquote]
[blockquote]Exhaust Valve: Air heard hissing out of the tailpipe, turbocharger, or exhaust manifold means an exhaust valve leak.[/blockquote]
[blockquote]Piston Rings: Whistling or hissing out of the PCV valve, oil filler cap hole, or dipstick tube means the air is pushing past the rings. Suspect ring or cylinder wall wear.[/blockquote]
[blockquote]Head Gasket: Air bubbles in engine coolant seen at the radiator filler cap could mean air escaping into the coolant past the head gasket.[/blockquote]
[blockquote]Cracked Cylinder Head: Bubbles in coolant or coolant being pushed up out of the radiator neck can also indicate cracks in the cylinder head or cylinder walls.[/blockquote]
#9
RE: Low Compression in three cylinders.
ORIGINAL: Aweasel
I don't see how sand would cause blowby. Sand would likely fawk up the bearings but not cause ring failure or a blown head gasket
I don't see how sand would cause blowby. Sand would likely fawk up the bearings but not cause ring failure or a blown head gasket
Sand could definitely affect ring seal, however, by accelerating ring wear to the bore surface. More noteably, however, it would cause premature wear at the valve seats.
Having the shop simply check your valve clearance won't necessarily solve the problem. Chances are your motor needed the shims adjusted anyways.The proper and most cautious approach (and this will probably we what your $dealer recommend$) is a head rebuild. Inspection of valve guides for wear, but more importantly, a valve seat job. Then of course shimming things back out once that job is done. (Cutting the valve seats will change your valve clearance / shim height)
good luck,
the blonde weasel