Carbon??? - Harley Davidson Forums: Harley Davidson Motorcycle Forum
Harley-DavidsonForums.com is an independent enthusiast website owned and operated by VerticalScope Inc. Harley-DavidsonForums.com is not sponsored by or in any way affiliated with Harley-Davidson Inc.. The Harley Davidson names and logos are trademarks owned by Harley-Davidson Inc.

Go Back   Harley Davidson Forums: Harley Davidson Motorcycle Forum > Specific Model Areas > Dyna General Discussions

» Insurance
» Our Partners
»ATV Reviews
»Motorcycle Games
Reply
 
LinkBack Thread Tools Display Modes
Old 11-22-2012, 04:00 PM   #1 (permalink)
Senior Member
 
bikedelic's Avatar
 
Join Date: Oct 2010
Location: Charlotte/Harrisburg NC
Posts: 868
Garage
Carbon???

Took my heads and cylinders off today. There is a large heavy carbon buildup on the front piston and hardly anything on the rear piston. What would cause the front to build up and rear to be almost spotless? 91 Evo, 47k miles.

Also, the rear plug was pretty fouled, the front, fairly normal.
bikedelic is offline   Reply With Quote
Old 11-22-2012, 04:07 PM   #2 (permalink)
Grandstanding Member
 
Dave63's Avatar
 
Join Date: Jun 2008
Location: PA
Posts: 29,788
I'd suspect an intake leak at rear cylinder intake seal. If you were to compensate for the leak, the front would run slightly richer.

As well, I'd be curious as to the compression difference between the front and back, prior to taking it apart.

Why ARE you taking it apart?
__________________
__________________________________________
“When the going gets weird, the weird turn professional....” ~ Hunter S. Thompson~

R.I.P. Rubberdown. 1971-2012
Dave63 is online now   Reply With Quote
Old 11-22-2012, 04:37 PM   #3 (permalink)
Senior Member
 
bikedelic's Avatar
 
Join Date: Oct 2010
Location: Charlotte/Harrisburg NC
Posts: 868
Garage
Quote:
Originally Posted by Dave63 View Post
I'd suspect an intake leak at rear cylinder intake seal. If you were to compensate for the leak, the front would run slightly richer.

As well, I'd be curious as to the compression difference between the front and back, prior to taking it apart.

Why ARE you taking it apart?
The base gaskets were leaking and the paint was flaking pretty bad so while I had the rocker boxes off I thought I would have a look at the pistons and cylinders and replace the base gaskets. I am also installing new pushrods, tappets and an EV27 cam.

I stripped the paint off cylinders today and I will strip heads later this weekend. I am going to leave the heads with the raw aluminum sand finish and redo the black on the jugs.

If you will recall from a previous post, I had a noise I thought was tappets.
bikedelic is offline   Reply With Quote
Old 11-22-2012, 04:57 PM   #4 (permalink)
Grandstanding Member
 
Dave63's Avatar
 
Join Date: Jun 2008
Location: PA
Posts: 29,788
Quote:
Originally Posted by bikedelic View Post
The base gaskets were leaking and the paint was flaking pretty bad so while I had the rocker boxes off I thought I would have a look at the pistons and cylinders and replace the base gaskets. I am also installing new pushrods, tappets and an EV27 cam.

I stripped the paint off cylinders today and I will strip heads later this weekend. I am going to leave the heads with the raw aluminum sand finish and redo the black on the jugs.

If you will recall from a previous post, I had a noise I thought was tappets.
Ahhhhh. I forgot. Check to make sure the valve guids aren't all carboned up and/or worn too.

A chunk of carbon banging around in a cylinder can make a pretty funky noise too.....
__________________
__________________________________________
“When the going gets weird, the weird turn professional....” ~ Hunter S. Thompson~

R.I.P. Rubberdown. 1971-2012
Dave63 is online now   Reply With Quote
Old 11-22-2012, 05:10 PM   #5 (permalink)
Senior Member
 
bikedelic's Avatar
 
Join Date: Oct 2010
Location: Charlotte/Harrisburg NC
Posts: 868
Garage
Thanks Dave, I will check them before I put it all back together. I hope you had a great Thanksgiving.
bikedelic is offline   Reply With Quote
Old 11-22-2012, 10:48 PM   #6 (permalink)
Senior Member
 
tussuck's Avatar
 
Join Date: Jan 2010
Location: Australia
Posts: 429
If you have the jugs off you may want to look at getting them honed and popping in a new set of rings.


Sent from my iPhone using Motorcycle.com App
__________________
I prefer my engine blown not stroked!
D.L.R.A #1174
tussuck is offline   Reply With Quote
Old 11-23-2012, 04:21 AM   #7 (permalink)
Senior Member
 
Hunt/fish 365's Avatar
 
Join Date: Oct 2012
Location: Turbotville, PA
Posts: 570
Quote:
Originally Posted by tussuck View Post
If you have the jugs off you may want to look at getting them honed and popping in a new set of rings.


Sent from my iPhone using Motorcycle.com App
X2 With 47K and the fact you already have it apart you might as well freshen it up.
Hunt/fish 365 is offline   Reply With Quote
Old 11-23-2012, 06:47 AM   #8 (permalink)
Senior Member
 
bikedelic's Avatar
 
Join Date: Oct 2010
Location: Charlotte/Harrisburg NC
Posts: 868
Garage
Can the jugs be honed (they look pretty good - very faint crosshatching still visable) without needing new/oversized pistons?

I still curious about the lack of carbon buildup on the rear piston too. Also still curious about why my rear plug is fouled and not the front plug.
bikedelic is offline   Reply With Quote
Old 11-23-2012, 07:20 AM   #9 (permalink)
Retired citizen
 
SCHMIDTYS's Avatar
 
Join Date: Jun 2009
Location: Pt. Wash.,WI
Posts: 12,969
The carbon buildup and fouled plug could also be caused from leaking valve seals, common Evo problem. Oil getting past the seal into the combustion chamber.
Installing new rings you'll want to hone the cylinders for a fresh cross hatch, helps the new rings break in. I use B-B hones (ball hones) instead of stone style hones.
__________________
Disclaimer : Don't believe anything I say unless you are absolutely sure that I know what I'm talking about .
SCHMIDTYS is offline   Reply With Quote
Old 11-24-2012, 03:42 AM   #10 (permalink)
Senior Member
 
tussuck's Avatar
 
Join Date: Jan 2010
Location: Australia
Posts: 429
Correct on the honing... All they do is refresh the crosshatch so you can keep the same pistons. Just buy a set of new rings and you will be good to go. Very much worth the effort!


Sent from my iPhone using Motorcycle.com App
__________________
I prefer my engine blown not stroked!
D.L.R.A #1174
tussuck is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 12:28 PM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.
This site is in no way affiliated with Harley-Davidson
Motorcycle News, Videos and Reviews
Honda Grom Forum Harley Davidson Forum Honda 600RR Kawasaki Forum Yamaha R6 Forum Yamaha FZ-09 Forum
1199 Panigale Forum Roadglide Forum Honda CBR1000 Forum Vulcan Forum Yamaha R1 Forum Yamaha R3 Forum
Ducati Monster Forum Harley Forums Honda CBR250R Forum ZX10R Forum Star Raider Forum Yamaha Viking Forum
Suzuki GSXR Forum V-Rod Forums Honda Shadow Forum Kawasaki Motorcycle Forum Star Warrior Forum KTM Duke 390 Forum
SV650 Forum BMW S1000RR Forum Honda Fury Forum Kawasaki Versys Forum Drag Racing Forum Ducati 899 Panigale Forum
Suzuki V-Strom BMW K1600 Triumph Forum Victory Forums Sportbikes BMW NineT Forum
Volusia Forum BMW F800 Forum Triumph 675 Forum MV Agusta Forum HD Street Forum Suzuki GW250 Forum
Yamaha Motorcycles Victory Gunner Forum Honda Vultus Forum HD LiveWire Forum Ninja H2 Forum