Who wants to see the inside of my engine ? (56k think twice)

[md86]

Alright , took my head off because the shop said my exhaust valves weren't holding pressure during a leakdown test . Figured I'd snap some pics to see what some of you think . LOTS of carbon in there , eh ?
#1 piston

#1 valves

Head


Didn't see anything scratched-up or obviously damaged , but LOTS of carbon .. Still gotta take a close look at the head to find out where the problem lies exactly . Thoughts , opinions , helpful tips welcome .

[KatDan]

sounds like you might be due for a valve job, my friend. carbon build up between the valve faces and the seats in the head, so it won't close tight no matter what. if there is no damage, you can buy a valve grinding tool and some valve lapping compound, disassemble the head and do it yourself. you will have to re adjust the valves afterwards, too. or you could take it to a machine shop and have them do it for you.

[KnightRider]

Yeah,. what he said.

LOTS O CARBON! I'd say the carbon build up on the valve seats is causing the leak, thus lost compression.

I'd do it yourself, you seem mechanically inclined enough to drop the motor, remove the valve cover and head....so I think some small valve lapping would be cake fo ya.

Have fun, take pics. -Eric

[sexwax]

I was hoping to see something else. Like, something for me to stick my crankshaft into.

[Micdalen]

Juding from the cylinders, and the valves, tends to point to leaky valve seals, and dire need of a valve job.

Oil leaking down the valves will shroud them on the combustion stroke.

Looks like a misfire or incomplete burn in cylinder one. One possibility is worn rings also.

Hard to see the cylinder walls. Any scoring or discoloration on them?

Was cylinder one and four the worst on compression test?

Good point least not a dropped valve or burned piston.

[Trigger]

Doesn't anyone believe in Techron or Racing Fuel(1 tankful every 6 fillups)???
This makes the third engine I've seen this way and most of the fouling (Carbon Buildup) could have been prevented.

[sexwax]

md86 doesn't believe in Techron because he believes the Chevron company is a product of a capitalist society which burns rainforests, chokes baby seals with spilt oil, and is destroying the Ozone layer. Man.

[md86]

Hey , know what ? I've used PLENTY of Techron , and Seafoam , and Berryman's , and Blue Star .... So I don't think that stuff's all it's cracked-up to be when your jetting is off .
So , the engine is still in the bike , I just slipped the head off (with lots of grunting and swearing) . Anyway , I started de-carbonizing the head today . My hair is black now , and so is my carpet . Wore my wire wheel down to the nub . Looks like I'll be lapping a couple of valves . We'll see how that goes . Hopefully that'll solve the problem . If not , it'll be time for another head I guess .

[Dan Dubeau]

If not , it'll be time for another head I guess .

Can never get too much head

[md86]

Update:
Did some lapping of those exhaust valves today . Took it to my uncle (pro mechanic) for his inspection , and he says it looks like I done ok , and to do the water test (fill the chamber with water , see if it leaks out) . So it's re-assmbled , awaiting the results of said test . If it goes well , and my new head gasket gets here tomorrow like it SHOULD (BETTER , I paid $20 extra to 2-day it ) , I outta be about ready to put Humpty back together again . If not , I may be waiting a while , as it's supposed to rain pretty much continuosly for the next WEEK .
:edit:
And hour and a half later and the water level is still pretty high . There's a bubble by the sparkplug , but the water isn't down much at all .

[freight dog]

Great news! So for a few bucks and a lot of personal effort, hopefully you've got it running better than ever. Good for you.

[md86]

Alright , I've scraped off tons of carbon , and once my gasket gets here (Bike Bandit SUCKS , BTW ) , I'll hopefully be ready to re-assemble in the next couple of days . Lots of rain in the forecast the next several days . Need to take the thing outside and hose it off good with brake cleaner , too . Anyway , think I need the molybdenium grease like the book says for the cam journals , or would soaking everything with engine oil be cool .

[Ritchey79]

You can soak them in engine oil or automatic transmission fluid and they'll be fine. I've been building race engines for everything from dirtbikes to ARCA stock cars for years and I always pre soak my parts in tranny fluid for 24hrs. Tranny fluid penetrates the metal more than oil.

[Prozak]

does the black deposit on cylinder head could really come from oil leak !? Not only carbon bluid up ??

Md86, how did you proceed to clean valve guides and seats ? Risky job ?!

thanks

[Range]

You can soak them in engine oil or automatic transmission fluid and they'll be fine. I've been building race engines for everything from dirtbikes to ARCA stock cars for years and I always pre soak my parts in tranny fluid for 24hrs. Tranny fluid penetrates the metal more than oil.

never trust a guy whos avatar is a girl on a bike with fur!

...but in this case...yeah....I would question the use of water for the leak test....wouldn't it be better to use a light oil, such as mineral spirits?

while the head is off and the valves are out....redo the seals and guides and get the springs checked (that could also cause the leak)