Broken CCT Diagnosis
Thread Starter
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Squid
Joined: Dec 2009
Posts: 85
Broken CCT Diagnosis
I'm a small time motorcycle tinkerer in florida. I do it as a hobby. I'm looking at a 99 superhawk that doesnt run, and am hesitant to buy it due to all of these CCT posts. The motor will crank, and at least the front cylinder has spark (not sure about the rear).
Anyway, I just wanted some feedback on how to diagnose whether or not there could be a cct failure which has caused huge motor damage.
Anyway, I just wanted some feedback on how to diagnose whether or not there could be a cct failure which has caused huge motor damage.
Out of my mind, back in 5
MotoGP
Joined: Nov 2006
Posts: 6,109
From: Skurup, Sweden
The easy way is to open it up and look at it... The hard way is just about any other combination of diagnostics known to man... If you wheren't there when it went kaputt, there isn't any other way to know for sure...
Thread Starter
Member
Squid
Joined: Dec 2009
Posts: 85
Well, unfortunatly opening it up is not an option until i am already financially invested in the bike. I guess what I meant to ask was...does the ability to crank this bike without hearing bad engine noise mean that the CCT's have not failed? and ... what are other ways for a prospective buyer to check for this problem in a driveway before purchasing?
I am tryin to avoid buying a bike that has bent valves and needs completely torn apart.
I am tryin to avoid buying a bike that has bent valves and needs completely torn apart.
Out of my mind, back in 5
MotoGP
Joined: Nov 2006
Posts: 6,109
From: Skurup, Sweden
Put it on stands, in gear and turn the wheel by hand... Then you should hear if anything inside the engine is FUBAR'ed... As said it's not really a reliable way though, just a hint of what might be or not be wrong...
But considering the frequency of CCT failures I'd say if there is something purely mechanical wrong, ie grinding noises it's most likely a CCT... The odds are in favour of that by miles...
But considering the frequency of CCT failures I'd say if there is something purely mechanical wrong, ie grinding noises it's most likely a CCT... The odds are in favour of that by miles...
evil man of nothing
MotoGP
Joined: Jan 2006
Posts: 4,517
From: Boynton Beach, FL
When it's one of these "as is" deals where you don't know you kinda have to assume that's the problem. Factor in the time/cost to you to repair it or swap engines when agreeing on a price...if it is the problem then you're prepared...if not they you'll be pleasantly surprised. A decent mile '99 in nice shape both mechanically and cosmetically should probably go for between $2500 & $3000. What does this one look like?
BTW where are you located in FL?
BTW where are you located in FL?
Last edited by captainchaos; Dec 29, 2009 at 07:19 PM.
Destructive Tester
Superstock
Joined: Oct 2009
Posts: 263
From: N.E. oHIo
A compression test will tell you if the cylinder has a decent seal, or not.
You will still be in the dark as to the problem if it does not have decent compression.
A leak down test will not only tell you if you have a decent cylinder seal, but it will also tell you what the likely problem is.
Bent valves....air will escape through the carbs or exhaust depending on which valve(s) are not sealing or bent.
Bad rings....air will escape through the crankcase breather.
Holed piston....a chitload of air will escape through the crankcase breather.
If the owner won't let you do some simple diagnostics, either get the bike dirt cheep or walk away.
Rex
You will still be in the dark as to the problem if it does not have decent compression.
A leak down test will not only tell you if you have a decent cylinder seal, but it will also tell you what the likely problem is.
Bent valves....air will escape through the carbs or exhaust depending on which valve(s) are not sealing or bent.
Bad rings....air will escape through the crankcase breather.
Holed piston....a chitload of air will escape through the crankcase breather.
If the owner won't let you do some simple diagnostics, either get the bike dirt cheep or walk away.
Rex
Senior Member
SuperSport
Joined: Nov 2009
Posts: 677
From: Rancho Cordova, California
My experience, (and I experienced a failure) is that the motor can crank and maybe even run with a CCT failure and even a broken valve, though you will hear something if a valve broke for sure! See if he'll let you pull the front cylender head. That can be done with the motor in the bike. From what I've seen here, it's usually the front that goes.
Destructive Tester
Superstock
Joined: Oct 2009
Posts: 263
From: N.E. oHIo
A leak down test takes a bit longer than a cranking compression test.
Here's a link to an article explaining the test:
http://www.automedia.com/Engine_Leak...cr20080301lt/1
Rex
Thread Starter
Member
Squid
Joined: Dec 2009
Posts: 85
Well, I bought it. Unfortunately, it's so cold that its even a pain to get my Buell started. I'll be interested in how much good I can do for this thing in my unheated garage for now.
I'll formally introduce myself later (after I get the new addition out of my pickup and get some pics)
I'll formally introduce myself later (after I get the new addition out of my pickup and get some pics)
Thread Starter
Member
Squid
Joined: Dec 2009
Posts: 85
I got it firing on the front cylinder. Nothing on the back yet except for a backfire that caught the carb on fire for a second from the starter fluid. No compression or leak down test done yet.
I'm getting a good spark when grounding the spark plug, but if not grounded the spark will arc from nearly anywhere on the plug wire. I'm pretty sure that's not supposed to happen but I'm thinking I should still be able to get the cylinder to fire considering its grounded when screwed in. Anyone have any thoughts on this?
Anyway, I'm planning on swapping the plug wires to check if this could be the culprit, doing a compression test on both cylinders, and if still not figured out I'll pull the carbs for a cleaning (I want to check out the jetting anyway).
I'm getting a good spark when grounding the spark plug, but if not grounded the spark will arc from nearly anywhere on the plug wire. I'm pretty sure that's not supposed to happen but I'm thinking I should still be able to get the cylinder to fire considering its grounded when screwed in. Anyone have any thoughts on this?
Anyway, I'm planning on swapping the plug wires to check if this could be the culprit, doing a compression test on both cylinders, and if still not figured out I'll pull the carbs for a cleaning (I want to check out the jetting anyway).
Thread Starter
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Squid
Joined: Dec 2009
Posts: 85
I just did and everything is tight. I lined up the rt mark the fe and fi on the cam sprockets seem to be in the right position... Is there a test I can do specifically for the head gasket? Is there a way for me to tell if a valve is sticking without pulling the head?
Thread Starter
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Squid
Joined: Dec 2009
Posts: 85
Ok...I now notice that the exhaust cam lobes are not staying in contact with the valve lifters. If the cylinder is timed properly what could cause this? at first I was thinking it could be a broken valve spring but since both exhaust lifters are sticking down I'm not to sure.
EDIT: Should this be moved into the tech section?
EDIT: Should this be moved into the tech section?
Last edited by psyclown; Jan 9, 2010 at 10:40 AM.
Member
Squid
Joined: Nov 2007
Posts: 71
From: Glenwood Springs, CO
If you have daylight under the followers the valves could be interfereing with each other and making contact when open. This could have easily been the result of a cct failure causing the engine to jump time. Try turning the engine by hand and having a listen for air excaping, would either be from the carbies or the exhaust. That would confirm the bent valve diagnosis. Bummer dude.
Senior Member
MotoGP
Joined: Mar 2007
Posts: 3,132
From: Phoenix, AZ
Ya, not bad considering. Sometimes a head comes up cheap, so a replace might be cheaper than repair.. (I think front & rear might be interchangeable, but am not positive)
Edit: Either way, this is from Indierocker's shop:
http://cgi.ebay.com/ebaymotors/GOOD-...Q5fAccessories
Edit: Either way, this is from Indierocker's shop:
http://cgi.ebay.com/ebaymotors/GOOD-...Q5fAccessories
Last edited by lazn; Jan 10, 2010 at 10:56 PM.
Member
Squid
Joined: Nov 2007
Posts: 71
From: Glenwood Springs, CO
Maybe easier on the brain and cheaper in the long run to go with an unmolested factory engine? Engine work is difficult, stripped threads, unexpected surprises, and unless you work on engines all the time a huge learning curve. Just ask me how I know. Anyways, you bought the bike right, I bet this engine sells for less than $400 bucks.
JMHO,
joe
http://cgi.ebay.com/ebaymotors/1998-...item33591ed46d
JMHO,
joe
http://cgi.ebay.com/ebaymotors/1998-...item33591ed46d
Member
Squid
Joined: Jul 2009
Posts: 30
From: SF Bay Area
Years ago a friend of mine bought the fastest CB350 around only it was not running. The owner said "It started making a ticking sound while running at 6000 RPM so I hit the kill switch and pushed it home."
We pulled the valve cover and the left cylinder had a broken valve spring. My buddy was pretty happy. Next came the carbs. Not as good, some metal shavings in the intake. When we pulled the head our jaws dropped! No piston! Connecting rod & wrist pin which made ~5mm groves in the cylinder wall. Upon closer inspection we found a golf ball sized chunk of aluminum that had been beaten to roughly spherical shape.
Needless to say, good deal gone bad.
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