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Crank, no start! Spark and fuel in the bowls, Whats next?!

Started by Heinrich535i, June 29, 2017, 09:28:08 PM

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ribbert

Quote from: Heinrich535i on July 06, 2017, 07:16:24 PM
Well, compression results are in. Things aren't looking good for me.

Cylinder #1 - 120psi
Cylinder #2 - 100psi
Cylinder #3 - 120psi
Cylinder #4 - 140psi

I think this means an engine swap is in order.  :dash2:

Any suggestions before I start tearing stuff apart?


Yes, don't! (start tearing stuff apart)

Cold compressions readings with that sort of variance mean nothing.
A compression test without checking the valves have clearance first means nothing.

I wouldn't be surprised if my engine gave similar readings cold (and 60,000km since the last valve check)

Even the 100psi under the conditions you tested is likely to rise to within serviceable limits. If it doesn't it's likely a valve which is just a head off job, not an engine swap.

From my experience, the numbers you quote under the conditions you tested would be reasonable for a serviceable motor.

Don't jump the gun. As Pat says, check the valve clearances, get it hot and re do the compression test while its hot.

IMO

Noel


"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

Heinrich535i

Thanks for the advice.

Popped the valve cover off and everything is very clean underneath! Totally different story for the parts bike, its black underneath the valve cover.

Bike I'm working on has 38k on it.
Parts bike has a mere 24k on it, weird.

Also I torqued the head bolts to spec and the camshaft cap bolts. I noticed the very top right bolt for the camshaft wouldn't fully tighten. It will tighten all the way down however it wont fully seat and lock to torque, it just wants to spin.

I'll include pictures of the tops of the cylinder heads and the conditions.
First three photos are of the bike I'm trying to get running and the last one is the parts bike.


balky1

Quote from: ribbert on July 06, 2017, 08:23:32 PM
Quote from: Heinrich535i on July 06, 2017, 07:16:24 PM
Well, compression results are in. Things aren't looking good for me.

Cylinder #1 - 120psi
Cylinder #2 - 100psi
Cylinder #3 - 120psi
Cylinder #4 - 140psi

I think this means an engine swap is in order.  :dash2:

Any suggestions before I start tearing stuff apart?

Yeah, those are pretty much the numbers I got from my engine when cold, with 33k kms on it, but running perfectly. Like most said here, don't rush for engine swap.


Yes, don't! (start tearing stuff apart)

Cold compressions readings with that sort of variance mean nothing.
A compression test without checking the valves have clearance first means nothing.

I wouldn't be surprised if my engine gave similar readings cold (and 60,000km since the last valve check)

Even the 100psi under the conditions you tested is likely to rise to within serviceable limits. If it doesn't it's likely a valve which is just a head off job, not an engine swap.

From my experience, the numbers you quote under the conditions you tested would be reasonable for a serviceable motor.

Don't jump the gun. As Pat says, check the valve clearances, get it hot and re do the compression test while its hot.

IMO

Noel





FJ 1100, 1985, sold
FJR 1300, 2009

FJ_Hooligan

Quote from: Heinrich535i on July 06, 2017, 09:19:26 PM

Also I torqued the head bolts to spec and the camshaft cap bolts. I noticed the very top right bolt for the camshaft wouldn't fully tighten. It will tighten all the way down however it wont fully seat and lock to torque, it just wants to spin.


Uh, you might want to consider fixing this before starting it.
DavidR.

Heinrich535i

I'm not able to get enough light in there to see down the hole but it feels like whatever that camshaft cap bolt is supposed to be threading into is either missing or fell down, and I'm not trying to cause internal destruction in my engine when I finally get it running. I also torqued the camshaft cap bolts all the way around on the parts bike and they all seemed snug and locked down just fine.

Here is a flipped and edited version of the first photo. Red circle points to the problem bolt.

Does anyone know what this bolts thread into before I take off the cylinder head?

FJ_Hooligan

It screws into threads in the ALUMINUM head. Threads which I assume are stripped out.

Time for a Heli-Coil
DavidR.

Heinrich535i

FJ_Hooligan,

I must say I'm pretty glad I caught this early, would've been utter destruction if I didn't. This is the first bike I've ever owned and it's slowly becoming more of a project than I realized, I've never taken an engine apart this far. I think I might leave this up to the guys at my local motorcycle shop as I've already got an appointment for a valve adjustment on Tuesday.

The price of me buying the valve adjustment tool and the shim kit are more expensive than what they quoted me for the job and I think I'd rather have a professional fix it right the first time, nor have I ever attempted a Heli-Coil. I plan on buying the kit and tool down the road and learning after I get the bike running, I've done valve adjustments on my 1987 BMW 535i before however I was able to make my own tool for that.