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Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
My top end has been clacking like crazy. Certain RPM sounds like rod knock. Decided to give those rocker lockers a try. Start with the rear, pulled the rocker assembly out and upon removal of one of the primary side bolts I find the threads from the head on the bolt. That sucks because this one is under the frame. Can't thread repair without pulling the head. Sucks but **** happens. Guess I have to pull the head. Meanwhile I decided might as well finish the what I started and put the lockers in. One of the bolts that hold the plate had a big gouge in it. The shaft that holds the rocker (exhaust side) had shifted and smacked the bolt. Another easy fix, stuck it in the press and got everything lined back up, then got the rocker lockers installed.
I've had a oil seepage on the rear cylinder base for quite some time. Enough that after 2 weeks of not washing the bike puddles start forming (on the primary, never on the ground). Since I gotta pull the head and half the motor is apart, might as well replace the o-rings on the cylinders. If i'm doing one, might as well do both right? So I decide to start ripping apart the front and here is where it gets fun.
After pulling the front head I do a quick inspection. There is some shmoo build up on the backside of the intake valve. Its hard and sticky. Kinda weird but I guess I can clean that up. This prompted me to check out the intake manifold where I found oil residue. Not a lot however this was surprising to me, because my heads are 100% vented to a catch can. Meaning that oil in the intake + what I'm guessing is a mixture of oil/carbon on the back of the intake valve has to be coming up past the rings. Inspection of the front cylinder shows some vertical scoring. Not enough to catch a finger nail but you can visually see it. (see the pics below)
Build Details:
Tuner: Thundermax
Cam: Redshift 577
Heads: Revolution Performance Stage 2
P/C: Axtell cylinders / CP Pistons - 107"
Intake: SE 50mm TB, DVR ported to 54mm
Exhaust: D&D Fatcat
Compression: 11:1
Bottom End: Stock. Runout last measured .0065
Last CCP test: Front 210psi / Rear 207psi (within the last 10k miles)
Motor made 115tq and 105hp SAE on a 4th gear pull BEFORE i had DVR re-work the TB. Bike is an '09 Dyna. I ride it hard and push it every chance I get. Motor has ~ 64k miles and build I did (107") has about 40k. I put about 70 miles a day on it 5 days a week and cruise at 3400RPM. Really curious how much longer it will last if I do nothing and just button it back up. The HG I ordered are .040 (was running .030) which should lower my comp to ~ 10.8:1. Not sure yet what i'm gonna do....
Oil Seepage on rear cylinder Front cylinder scoring Some of the shmoo from the guide Close up shot of the intake guide Build up on backside of the intake guide
Should done a compression and leak down test before the tear down but it is what it is. Axtell cylinders and cylinder scoring brings back nightmarish memories of my experience with Axtel cylinder in an all bore 107" motor I built a few years back. I will bet a six pack that if you check the bore of the offending cylinder (check them both) you will find that the cylinder bore is not true. I will also tell you that when I encountered that same problem, I had the cylinders bored .010" over to true them up and they went south a second time. I replaced the cylinders with a set of MTC cylinders and problem solved. Put about 35K miles on that top end with no issues.
Of course, I could be totally wrong but still think the cylinder bores should be checked for true. In my case, the problem presented in the first 2000 miles of the build and rebuild so, like I said, I could be wrong about the source of the scoring but................................
Should done a compression and leak down test before the tear down but it is what it is. Axtell cylinders and cylinder scoring brings back nightmarish memories of my experience with Axtel cylinder in an all bore 107" motor I built a few years back. I will bet a six pack that if you check the bore of the offending cylinder (check them both) you will find that the cylinder bore is not true. I will also tell you that when I encountered that same problem, I had the cylinders bored .010" over to true them up and they went south a second time. I replaced the cylinders with a set of MTC cylinders and problem solved. Put about 35K miles on that top end with no issues.
Of course, I could be totally wrong but still think the cylinder bores should be checked for true. In my case, the problem presented in the first 2000 miles of the build and rebuild so, like I said, I could be wrong about the source of the scoring but................................
Yeah i was thinking to myself after the fact I wish i had a bore gauge to check if they are true. Unfortunately the issue was uncovered while working another problem so the thought of a compression/leak down never crossed my mind. I did however just realize that I have my old original 96" cylinders, never sent them back for the core exchange. I figured for the $65 bucks they were going to refund me I might as well keep them, for a just in case moment. Glad I did now. I'll be reaching out to a few shops to either send mine in and have them opened up OR if anyone has any on their shelf do an exchange. Re-ring the pistons, set the gaps, should be good to go. That is my current hope anyway.
Don't worry about the shmoo in the the ports, It's simply the place where the injectors can't wash off the port.
You scuffed a piston and it go into the rings. Probably the source of you rattle. Not sure the cylinder is out of round as the hone marks still look pretty even. Might have been fit too tight and too hard of break in. Could also simply be too much fuel and timing.
The rear cylinder leak is likely from poor case mating. Cometic gaskets cannot handle a step. Use case sealer or black small tube RTV.
Don't know how long it will last as is. Need to look at the piston skirt / check clearances.
Don't worry about the shmoo in the the ports, It's simply the place where the injectors can't wash off the port.
You scuffed a piston and it go into the rings. Probably the source of you rattle. Not sure the cylinder is out of round as the hone marks still look pretty even. Might have been fit too tight and too hard of break in. Could also simply be too much fuel and timing.
The rear cylinder leak is likely from poor case mating. Cometic gaskets cannot handle a step. Use case sealer or black small tube RTV.
Don't know how long it will last as is. Need to look at the piston skirt / check clearances.
Understandable the fuel wouldn't wash this portion but issue is where did it come from and why is the rear head not gunked up. Having the heads breathe externally to a catch can there should be no oil entering the intake side. Ring gaps were pre-set. When I received everything I pulled it all apart and double checked that they were correct. Can't remember what they were set to as this was a while ago. Break in was done in stages. I.E. Run for 10 seconds, let it cool. Run for 30 seconds let it cool, etc, etc...Followed by under 3k RPM for first 500, under 4k for the 500 after. OIl changes between at 250, 500, 1k then every 5k after that.
If too much timing could do this, that is where i'm betting the issue is. With the t-max tuner I always felt like I was chasing the timing. Bike was never tuned on a Dyno. I loaded the map then tuned the timing by feel which was if it was pinging i'd pull timing and update the tune. Not even close to ideal, I'm well aware. Nearest tuner is over 3 hours away and 99% of them don't want anything to do with a t-max. Based on these events though, might be time to bite the bullet and just drop her off somewhere (once fixed) to have a proper tune done.
Fuel "shouldn't" be an issue with the autotune but I suppose anything is possible. I'm gonna pull the cylinders off tonight, i'll post some pics if I find anything else of interest. Appreciate the ideas of potential causes though, its been very helpful.
Understandable the fuel wouldn't wash this portion but issue is where did it come from and why is the rear head not gunked up. Having the heads breathe externally to a catch can there should be no oil entering the intake side. Ring gaps were pre-set. When I received everything I pulled it all apart and double checked that they were correct. Can't remember what they were set to as this was a while ago. Break in was done in stages. I.E. Run for 10 seconds, let it cool. Run for 30 seconds let it cool, etc, etc...Followed by under 3k RPM for first 500, under 4k for the 500 after. OIl changes between at 250, 500, 1k then every 5k after that.
If too much timing could do this, that is where i'm betting the issue is. With the t-max tuner I always felt like I was chasing the timing. Bike was never tuned on a Dyno. I loaded the map then tuned the timing by feel which was if it was pinging i'd pull timing and update the tune. Not even close to ideal, I'm well aware. Nearest tuner is over 3 hours away and 99% of them don't want anything to do with a t-max. Based on these events though, might be time to bite the bullet and just drop her off somewhere (once fixed) to have a proper tune done.
Fuel "shouldn't" be an issue with the autotune but I suppose anything is possible. I'm gonna pull the cylinders off tonight, i'll post some pics if I find anything else of interest. Appreciate the ideas of potential causes though, its been very helpful.
Understandable the fuel wouldn't wash this portion
I assume that you really mean "Understandable the fuel could wash this portion "
IMO you brake-in might have been a little light. No one knows if the clearances were too tight but if snug, and out of tune, things could stick.
Timing on Tmax is critical. It will affect the AFR. IMO too much timing makes the sensor think the mixture is lean. At 11 to 1 ,all bore, with that cam, you won't need much timing. Maybe 24-26 degrees max and you'll be pulling timing out of partial throttle also.
I assume that you really mean "Understandable the fuel could wash this portion "
IMO you brake-in might have been a little light. No one knows if the clearances were too tight but if snug, and out of tune, things could stick.
Timing on Tmax is critical. It will affect the AFR. IMO too much timing makes the sensor think the mixture is lean. At 11 to 1 ,all bore, with that cam, you won't need much timing. Maybe 24-26 degrees max and you'll be pulling timing out of partial throttle also.
This is the exact battle I've had, pulling timing at part throttle. Always seemed like it was getting better but never 100%.
I've already reached out to a few tuners in CA but just like when I did the build I'm being turned down for the tmax. power vision or tts is what everyone wants. Gonna keep looking tomorrow, gotta be someone in CA that can tune it.
Take a micrometer and measure your piston skirts, you may find it's not right. If it's collapsed or been scrubbed somehow, the clearance could very well be excessive and that will cause piston slap--which sometimes is misinterpreted as a con rod knock,maybe that's what you were hearing. My experience with too little piston clearance,you'd probably have signs of heat, galling or even a seizure. I think that scoring without seizure is more typical of something foreign going through your combustion chamber or maybe a chip from a failed ring or something. Whatever the case, again- I'd mike the pistons and put a dial bore indicator up and down and all around those cylinders to check for correct clearance, taper wear, out of round. You might get away with a de-glaze if everything measures up within tolerable specs. You may even get away with a light hone if you've got a bad piston that needs to be replaced but don't go forward without doing these checks or you could be right back here way sooner that you'd hoped.
Looking at your pic of the score marks on that cyl, I notice there are score marks above the travel of the rings. Makes me more suspicious that it swallowed something. Also the carbon is washed off the immediate top of that piston (right in line with the score marks) like oil had been blowing by, unhappy rings.
This is the exact battle I've had, pulling timing at part throttle. Always seemed like it was getting better but never 100%.
I've already reached out to a few tuners in CA but just like when I did the build I'm being turned down for the tmax. power vision or tts is what everyone wants. Gonna keep looking tomorrow, gotta be someone in CA that can tune it.
Yeah, Tmax needs a bit of work on the higher end of the CR. You can figure out how to tune it or go to another tuner. I've not done 11 to 1 but have done 5 different builds with CR at 10.8 and one at 10.5, also a few at 10.0. It's all about marking the throttle and getting the feel for too much partial.
BTW Here are pics of the shmoo in the manifold and port on a motor with about 60000 miles and external breathers. The crap in the port will get washed off but not in the manifold. It's not oil from the breather but very small amounts of oil making it past the rings and valve guides. Stuff gets blown into the intake at lower speeds when you got a cam with overlap. It take a bunch of miles for it to build up.
Take a micrometer and measure your piston skirts, you may find it's not right. If it's collapsed or been scrubbed somehow, the clearance could very well be excessive and that will cause piston slap--which sometimes is misinterpreted as a con rod knock,maybe that's what you were hearing. My experience with too little piston clearance,you'd probably have signs of heat, galling or even a seizure. I think that scoring without seizure is more typical of something foreign going through your combustion chamber or maybe a chip from a failed ring or something. Whatever the case, again- I'd mike the pistons and put a dial bore indicator up and down and all around those cylinders to check for correct clearance, taper wear, out of round. You might get away with a de-glaze if everything measures up within tolerable specs. You may even get away with a light hone if you've got a bad piston that needs to be replaced but don't go forward without doing these checks or you could be right back here way sooner that you'd hoped.
Looking at your pic of the score marks on that cyl, I notice there are score marks above the travel of the rings. Makes me more suspicious that it swallowed something. Also the carbon is washed off the immediate top of that piston (right in line with the score marks) like oil had been blowing by, unhappy rings.
I don't have the tooling to measure the piston to cylinder clearance. I've got a set of cylinders and new rings on order from FM, probably be here sometime next week. Both pistons visually look fine. No obvious scratches/wear on the skirts that I could see. I did find the rear cylinder suffering from the same score marks. They are much much lighter, one of those you gotta hold it at the right angle under a light to see. Given that, I think Max Headflow has it right with the timing issues and I suspect that is the cause.
Originally Posted by Max Headflow
Yeah, Tmax needs a bit of work on the higher end of the CR. You can figure out how to tune it or go to another tuner. I've not done 11 to 1 but have done 5 different builds with CR at 10.8 and one at 10.5, also a few at 10.0. It's all about marking the throttle and getting the feel for too much partial.
First off, let me just say thank you for the help you have provided so far. Info you've given me I think is spot on and probably the cause of the issues....
Bike has never seen a tuner. I've had to play with the timing extensively. Always lowering it little by little. IIRC the base timing in the upper range i never touched. I remember lowering it on the low end which seemed fine (below 3k under 40%). It was always above there where i could never seem to get it right. I was also mainly pulling timing from the "Timing vs TPS" sections, never really pulled any on the base timing map "Timing vs Engine Speed" (for the upper end, I did pull some here on the low end). You mentioned previously 24-26 degree max, without even looking at the map I can say it was above this.
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Cylinder scoring + gunk on guide
