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CVO Technical => Twin Cam => Topic started by: Slopokes72 on June 09, 2014, 02:17:45 PM
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I am in the process of having some motor work done to my '13 CVO Ultra and was able to get a couple pics of my pistons while the jugs and heads are off. My question is what is "normal" carbon build up on top of pistons. My motor has 15K miles and a mild cam installed and SERT tune. I was just curiuos and looking for feedback from someone other than the HD dealer mechanics. Please look at the pics and give your opinion. Thanks
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here is a closer pic
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Probably oil coming in thru the emmission-breathers if at all oily, if dry/soot then a rich/overfueled condition.
Scott
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More interested in the blow by on the side of the piston and around the rings. In the firs pick looks like the skirt is gouged badly. If there is lots blow by, its a condition that needs to be rectified.
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Yes there is blow by. The piston shows signs
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A leakdown test prior to teardown would have given a heads-up.
Scott
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Those were my pistons at 30,000 miles- it's a wonder the bike even ran as good as it did.
My builder blames full synthetic oil being used from day 1- it will get into the combustion chambers with the high heat and out of round cylinders. He only recommends dino or semi-synthetic, which is what I'm now running.
Not anecdotal or internet info here- he has built over 30 110's, and all had some excessive carbon build up, but apparently I won the prize for the worst he's seen.
:vrolijk_11:
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Ok how is that fixed and should I be looking at cylinder walls as well. My cylinders are getting diamond cut out of state. Heads are getting port and polish work. New high compression pistons are going back in when reassembled.
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My pistons at 11000 miles. '12 CVO SG. Burned a lot of oil. North Star, another member here (Vanamal) had pistons that looked worse, IMHO. Harley should be ashamed of their poor quality.
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I had the same problem, happend after the recal for the 2007 cvo's. In few hondred km it burned all the oil in the carter. The Moco refused to fix it even though it was still on waranty. They blamed it on the Thundermax I had on it, had to pay 1400 €.
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Not taking any sides but the 110 is a pressure cooker, by design. The pistons and cylinders are very high quality. Lean mixtures, heat, retarded spark, high cylinder pressure, and high ambient temperatures all add up to an imminent failure.
I have used the Mahle pistons both in 110 and 113 .060 os twin cams with success but those were properly broken in and tuned. Overly rich is just as bad as lean whatever the tuning device is.
I have attached a 113 for reference, conservative compression optimized for touring 10.4:1 tman 577 cams.
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My pistons at 11000 miles. '12 CVO SG. Burned a lot of oil. North Star, another member here (Vanamal) had pistons that looked worse, IMHO. Harley should be ashamed of their poor quality.
I'd suspect that piston pic showns signs of oil being baked on via mist thru the breathers.
Scott
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I must have been very clouded in my motor, cause it baked alot of it on the pistons and heads.
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They do.
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thanks for all the input. I will ask about this issue when i go back to mechanic. :)
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Northstar pic is a ring issue you can see where gas's have gone past the 2nd ring .. Splattering on the dome is ign ping. ( for what ever reason) you can see where it is pitting in a few areas. High heat some detonation that will knock it loose in certain areas. Air cleaners that introduce mist back into the engine can be the issue. However with 90+% of all air cleaners doing that very same thing the odds would have to be that all pistons would like like that. That is however not the case. With poor ring seal you have increased crank case pressure which will increase the amount of oil carry over = more oil mist going through the system into the engine
What we see is that many of the cylinders are less than round & straight and outside n spec though out the entire area the piston is traveling. Rings have a hard time controlling oil when that occurs. Simple bore and hone will solve the issue. I have countless photo and measurements of 110 cylinders. As well many that thought the air cleaner was the main issue and routed the breathers to the ground. Oil still was baked to the piston dome. Not to say that is always the issue.
We have also found that just about all will mist pretty good with 5000+ rpm ranges in stock form. Bore and hone and the crank case pressure is reduced and no more oil mist issue's that end up on piston domes. :2vrolijk_21: Damage to the piston skirt as pointed out is another piece of info that points towards improper ring seal. More info nothing more, being you are going to bore and hone with the new pistons your issue there should be solved.
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If the pressure cooker is not fixed those spanky straight cylinders will become distorted again. Fuel, air,timing and proper compression for the octane. I speculate the stock 110 would live a lot longer at a half point less compression and a valve spring change done plus a good tune.
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If the pressure cooker is not fixed those spanky straight cylinders will become distorted again. Fuel, air,timing and proper compression for the octane. I speculate the stock 110 would live a lot longer at a half point less compression and a valve spring change done plus a good tune.
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:2vrolijk_21:
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If the pressure cooker is not fixed those spanky straight cylinders will become distorted again. Fuel, air,timing and proper compression for the octane. I speculate the stock 110 would live a lot longer at a half point less compression and a valve spring change done plus a good tune.
The reason the ccp is up so high is for the Moco to squeeeeeeeeeeeeeze through EPA on that size production engine,(including the 6 speed to lower engine rpm at testing speeds) and no doubt that a tune is always good.
Springs on the other hand, in spite of the seat/nose pressure that some suspect is an issue. I am not sold on that.
Metric ton of 180-200 psi seat-pressure Bob Wood spring-equipped engines out there w/o issues.
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EPA oh come now.
NOx emission load increases as the compression is raised. Remember model year 1970 to 1971? Compression lowered by car manufacturers across the board and retrofit timing retarding devices to lower NOx on older cars.
Consider the "Useful Life" provision of the clean air act that manufacturers must comply with also.
And regarding springs by design there are some that introduce harmonics that present as valve train noise. And only enough pressure to control the valve with a safety margin is needed. I tested a tw6h equipped bike with 1.9 and 1.61 valves and got down to 130# seat before experiencing lofting. Not a suggestion just my observation. Excessive pressure is a parasite, raises heat, contributes to premature part failures (such as lifters), and takes away power. I know you disagree so no need to argue this on an open forum again.
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Spring pressure has been long proven not to be parasitic.
Only time is upon start up.
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Spring pressure has been long proven not to be parasitic.
Only time is upon start up.
Not trying to start a pissing contest.. However ,, where is this information coming from??. As you cannot re write the laws of physics,. I know for a fact that Pac spring manufacture will state the opposite of this .
Again looking for real data , and not bashing you, or your shop or your methods etc..
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Not trying to start a pissing contest.. However ,, where is this information coming from??. As you cannot re write the laws of physics,. I know for a fact that Pac spring manufacture will state the opposite of this .
Again looking for real data , and not bashing you, or your shop or your methods etc..
While better to err on the side of a bit too much spring pressure than not enough,saying that spring pressure isn't included in the laundry list of parasitic
losses in an engine is not true at all.
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I pulled my pistons at 4k miles and they looked like this.
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Not trying to start a pissing contest.. However ,, where is this information coming from??. As you cannot re write the laws of physics,. I know for a fact that Pac spring manufacture will state the opposite of this .
Again looking for real data , and not bashing you, or your shop or your methods etc..
Contact Bob Wood............ ;)
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No thanks ,... I am working with PAC on some things at this present time. They will tell you that what you posted is incorrect. But they are just the spring manufacture. What do they know. Simms tester will also prove that springs in fact a parasitic item the entire time
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Hey there, my builder has a machine that plugs in to the bikes fuel system and then you run the bike ( in one spot, not riding it ) and this supposed to de carbon the combustion chamber. After thats done change the oil and filter.
I dont know it this works? Have you guy's ever heard of such a method and device?
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OK so if the chamber is cleaned the problem is still there
When pistons present as those did there is a ring issue
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Yeah, plus if the combustion chamber cleaning works, and bits or chunks of carbon are dislodged, they more than likely will get dragged around and damage the rings and sides of the pistons like what happened to me.
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Contact Bob Wood............ ;)
ie: GOD (LOL)
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ie: GOD (LOL)
Not at all.........pm sent. ;)
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Let's just use a little common sense about this spring contest. Take one in your hand and squeeze it......... it takes energy to compress it! The stiffer it is the more energy is used and you must supply it over and over again each time it is squeezed. That energy comes from the crankshaft via the camshafts turning. It is and will always be a parasitic loss at some level.
With that said, some of the energy is recovered when the spring returns to it normal expanded state but NOT all of it. Some is lost due to friction, more is lost to overcome the mass and friction of the valvetrain it must push back out of the way. So it's not a pure 100% loss but it's still a loss and the stiffer the spring the higher the loss is.
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spring pressure is a nessasary evil,with some cam profiles the pressure the pressure must be increased to prevent any valve float,but its important not to use more pressure than needed,for the parasitic loss & extra strain on the lifters.
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spring pressure is a nessasary evil,with some cam profiles the pressure the pressure must be increased to prevent any valve float,but its important not to use more pressure than needed,for the parasitic loss & extra strain on the lifters.
We have a winner, the trick is to use no more than is necessary for the job at hand. Some setups are going to require more but just to have it, for the sake of it, wears parts out faster and cost larger power losses. As you increase the pressure, the load goes up, so you need to make the proper adjustments to handle it. It's all about being efficient with what your doing that will increase durability of the parts being used.
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so guys.. and sorry to sidetrack your springs conversations; with all this talk of the carbon buildup, and for those that DO NOT want to change pistons, how do you get rid of the buildup without tearing the motor apart again? I'm sure at some point that buildup affects your tune. When I did my heads at 13k miles, I cleaned them up all nice and purty. Less than 300 miles later they looked just like North Star's pic up top again but oily. That's when I said screw it and modified by backplate and blocked off the oil entry back into the throttlebody.
Someone mentioned MMO sprayed into the TB a while back but never got around to doing that as I wasn't 100% comfortable in doing so.
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I thought all that carbon comes from old farts driving bikes too slow and lugging the engines ;D
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Hah. This old fart don't ride like an old fart I assure you
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So, if thick carbon build up takes up room in the combustion chamber. Wouldn't that increase your compression? And as a result increase the power? Now I finally understand how guys on this forum are getting 130/130 from stock engine's with just a pipe install. Its all that carbon build up. :bananarock:
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So, if thick carbon build up takes up room in the combustion chamber. Wouldn't that increase your compression? And as a result increase the power? Now I finally understand how guys on this forum are getting 130/130 from stock engine's with just a pipe install. Its all that carbon build up. :bananarock:
It does decrease chamber volume.
If you tune a fresh engine as tight as you can, say on an Evo style engine, as soon as the client does build carbon(natural occurrence)you'll hear from him that it pings.
Scott
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Scott, no feedback on the MMO sprayed into the air cleaner? I was appalled to see the oily buildup that soon after replacing heads.
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Wonder if its all the crap they put in the gas that collects on the pistons. :huepfenjump3:
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it's that retarded EPA BS of having excess oil flow back into the intake from the top end instead of HD drilling out the damn rocker plates properly to let it go back down to the crank/cam area
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Wonder if its all the crap they put in the gas that collects on the pistons. :huepfenjump3:
Shell coolaid?
When I saw my heads-pistons at 10K I was really surprised at the amount of buildup.
Researched it some and looked into the whole "Tier" rating of gasoline. Figured it all made sense since at the time I was using whatever was the cheapest high test fuel. Typically the WaWa near my house and on the way to work.
After the bent valve repair I switched to Shell premium, based on being a top tier rated and their claims at keeping an engine clean.
When I pulled the engine apart at 56K it looked about the same as it did at 10K.
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it's that retarded EPA BS of having excess oil flow back into the intake from the top end instead of HD drilling out the damn rocker plates properly to let it go back down to the crank/cam area
Fortunately we don't epa BS EGR in our bikes - yet.
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When the motor health is good only a light mist comes out the breathers. The latest breather assemblies work very well at separating oil from air. And regarding EGR well HD actually accomplished compliance but did so without any add-on devices except the cat. They work to meet a bulk load limit of emission content. Cylinder head design and other items including the cat allow them to come in under the threshold. A healthy properly tuned motor will not build a lot of carbon either BTW