| Author | Message | ||
     Aesquire |
I mean "panic 2 -3 gear downshifts, not "normal" engine braking as being evil. | ||
| Aesquire |
Keep talking, I'm taking notes:  | ||
| Rick_A |
I've tried the technique of pulling in the clutch and downshifting X# of times while decelerating...half the time X wasn't what it shoulda been. So, I continue to blip as I go. When downshifting from a slightly reduced speed I like to keep the throttle constant and quickly work the clutch while I shift. It takes a lot less time and concentration then slowly letting the clutch out and waiting for the engine/tranny to synchronize. I like letting the front end dive into corners...and to raise coming out. Feels to me like the weight is transferring where you'd want it. Everyone has their style  I use the rear brake only in the dirt/wet, any time the front tire is nearing the limit of adhesion...or when doing tight parking lot maneuvers...I've been through two front rotors and my rear still has many years of life left on it. I've tried some of the other techniques above, but I feel most comfortable with mine. About the overfilling oil issue...I remember reading someone's account of overfilling their oil to the point that their tank cap popped off. It would appear to me that if you filled it to the point of completely covering the return hose that that would surely raise the pressure and leave more oil in the motor. | ||
| Spiderman |
EB = Engine Braking EB = Erik Buell The China Town connection, News at 11  Sorry had to break the tension this thread was getting to serious. | ||
| Bluzm2 |
Hoot, Yes they bolt right on. But,,, the rear one needed to have the vent hole machined as it's on the wrong side. You then have the original hole that needs to be plugged with a 1" rubber plug. The "land" is already cast in, just need to do a couple of passes with a mill cutter on the inide and outside. Then bore a 1" hole for the PVC valve and grommet. I did the whole thing on my drill press. No real precesion needed. Just a flat surface and a hole. I think the XB9x covers are the same as the Blast. If that is the case, you just pick up a front and rear. I picked up the covers, the grommets, gaskets and the vent valves for less than $75.00. Be warned however, the are really rough castings. If you have polished rockers, they are going to take a bit of work to look decent. BTW, you get rid of the top and middle rocker box covers. One less "O" ring gasket to leak. Brad | ||
| Hootowl |
Notsip, I am eagerly awaiting the fix for the puking issue, however, your ball and string analogy is seriously flawed. | ||
| Bomber |
not that another data point is needed, but here comes one anyhow . . . .. .my internally-stock Y2K M2 spews a little from time to time . . . . no relation to street vs trackday time, definate corelation to overfilling the oil bag, seems to spew less with Mobile 1 than withi HD Dino oil . . . spewage is worse on cold, humid days with short rides . . . although I can see the logic behind much of your postings, Notsip, the emperical evidence I've seen doesn't support you statements . . . yet. I realize you stated that there was much more to say, and I, like most everyone else here, it would seem, eagerly look forward to reading more . . . . btw, I DO engine brake a fair amount (having grown up when engine braking represented a fair percentage of your available speed-shedding tactics) . . . although I've not had the heads off, the engine seems to be fine (good compressions, havn't done a leakdown), and I'm pretty darned sure (90-95%) that I've not come too close to the redline while down so, which may mitigate the situation some . . .. keep it coming, please | ||
| Mikej |
Notsip, something to chew on: Two summer ago I rode my M2 from Milwaukee to Seattle in July. Basically rode the flow of traffic (55mph-95mph +/-) when on the multi-lane freeways. Me, camping gear, some tools, some water, all snugged down nice and tight on the bike, loaded but proably not near to exceeding the load limits of the bike. One day I ran over 500 miles, and lost over a half-quart of oil. One day I ran over 600 miles, and didn't loose a drop that I could measure with the dip stick. One day I ran over 600 miles, and lost almost a quart of oil. One day I ran over 500 miles, and lost maybe 3-4 ounces of oil. When I check the oil, as a point of reference, I checked it shortly after turning off the bike, and tried to keep the oil near the middle between the full/low marks. I'd always check the oil level at night, and usually in the morning as a feel-good check, and sometimes I'd check it mid-day on the long ride. (Doing so required removing the luggage/saddlebags/dufflebag, so I didn't like to check it mid-day unless I noticed spray on the shock side.) Riding style was brisk at times, maintained speeds, little to no engine braking, rolling the throttle with no wrist snapping (it would have been a looooooong walk home). Mostly rode between 9:30am-10:00pm. The back to back days were similar temps and mostly similar road conditons. Earlier that summer, in late May, I rode from Milwaukee to Superior,WI. Country two-lane freeway, followed by super-slab, followed by a straight-shot north bound freeway. Lost nearly a quart of oil. Next day I rode into Duluth, met up with BluzM2, rode down to Minneapolis, then continued on my own to RedWing, MN, then on to LaCrosse, and then back home north of Milwaukee. More miles than the previous day, but no noticible oil loss. My M2's breather setup, both vents T'd together, then one hose drops down and snakes infront of the front pulley and ends with a vent filter hanging below the bike. Any vent spray covers the shock and right side of the swingarm. I'll probably be rerouting the venting system this year to something different. My point is that there is no identifiable reason why one day the bike will vent more than the next with similar riding conditions and style. My assumption is it has something to do with atmospheric pressure and dew point and relative humidity. Comments? I should add that the majority of the above riding was between 3,000-4,500rpm continuous. Didn't hold above 4,500 for long unless I was cranking up a hill and smiling around the corners. There were a few times like that, but mostly on the low spewage days. Maybe I just need more mountains to cure the oil pukage.  | ||
| Mikej |
I should add, after reading Bomber's post, that one of the lowest oil loss days started out leaving Custer WY in a light mist/rain, then cleared up and got hot, and included a spirited hop over the BigHorn mountains, and ended west of Cody WY. If high humidity or heavy moisture in the air lead to higher oil loss then that day should have done it. I also had a few meandering detour wanders that added a hundred miles or more. | ||
| Littledog1 |
Mike J, This is a little off thread, but did you take the road from Dayton to Graybull, 14 or 14i(I think), through the BigHorns? Last year, I drove from Cody to Sheridan, via Graybull and Dayton, and that drive through across Big Horns was spectacular! It would have been even more stimulating on the Buell. Mickey | ||
| Mikej |
Mickey, On the bike I took hwy-16 between Buffalo and Ten Sleep. Light traffic and open clear road, very nice on the bike. This last summer I drove in a car and took 14 (not 14 alternate). Tighter turns than 16 and more traffic. If I get out that way on a bike again I'll go the alternate 14. area in question(if the nasty-long link works.) | ||
| Jim_Witt |
Mikej/Mickey One of the most beautiful places I visited too. I made a circle going east on 14 and back on ALT 14 to Cody. Also went north on 296 to Tower Junction (into Yellowstone), down to Fishing Bridge and "back (out of Yellowstone) towards Cody. Stayed at cool campground on the lake near the Buffalo Bill Dam and also north at Bear Tooth Pass. I'll have to admit I was scared as hell (of bears) while camping in certain areas especially with all the bear warning signs. Cheers, -JW:> | ||
| Mikej |
Jim, I found the campground on the river a little less crowded than the one on the lake near Buffalo Bill. And a slight breeze kept the flying biters away. I figured that as long as the trash cans didn't have the bear-proof lids then I'd probably be somewhat safe. Kept my | ||
| Sarodude |
Blake- I'm not really defending the point but I have heard some people mention issues with rod stretch on decel. I don't know if what's at stake is a more severe condition OR a condition the engine / driveline may not be optimized to handle. As a silly, anecdotal example, my SO's Saturn model has a history of destroying something they refer to as a Quill Bearing. Something to do with engine braking - according to the dealer techs. In that instance, I MIGHT guess that the helical gears put a thrust on a shaft opposite of what the supporting bearings / seals / case halves might be optimized to handle. I don't really know. -Saro | ||
| Bomber |
XB9 . . .. if I read (and re-read, and re-read again) you correctly, you're advocating coasting through the first part of a corner? hmmmmm . . .. .make me feel a little uneasy just to think on it | ||
| M2me |
Also, how does engine braking affect breather spewage (if it does at all)? I can see where it might but I can't explain it with my limited mechanical knowledge. | ||
| Mikej |
It used to be said that one way to check for worn rings in a car was to accelerate hard, then decelerate with engine braking hard, then hit the gas and look in the mirror for blue smoke. Smoke caused by engine braking sucking in oil through the worn rings and worn valve guides and then burning it off. I'm still just wondering why my bike is variable in it's oil pukage or spewage. If it were consistent then I could track down some possibilities. Maybe it's just got one of them magic valves that pukes when it wants to. Is Notsip still here or lurking????? | ||
| Blake |
If interested... there is a new "Fastest Way Through a Turn" discussion topic. | ||
| Mikej |
Awwww maaaaaaaaaaaaaaaaaan, guess we lost the thread to the reason some of our bikes spooge. bummer. back to the bottle idea next i guess. | ||
| Blake |
Understatement of the year?  | ||
| Notsip |
Sorry for getting off topic, must be my A.D.D. acting up again. Just trying to make a suggestion about cornering. One analogy always comes to mind when I think about cornering. "IF IN DOUBT, GAS IT!!!!" Usually worked for me. Will have more on the spewage shortly. | ||
| M2me |
Great. Looking forward to it Notsip. Breather spewage or puking always seems to be a big topic with both Sportster and Buell owners. I think we all agree on overfilling the tank as a big cause but sometimes, like Mikej says, it'll just come and go with no rhyme or reason.  | ||
| Notsip |
After reviewing Blake's diagram of the engine and swing arm I see a couple of things missing. Excellent diagram!!! 1) Front motor mount attached to the front cylinder head and attached to the frame. 2) The middle motor mount that attaches the front cylinder head and the rear cylinder head together and then is attached to the frame. Now you have the engine securely mounted in the chassis. Going back to the swing arm action. When the motorcycle is under acceleration the rear of the swing arm raises upward thus pulling backwards on the shock absorber that is mounted to the bottom of the engine. When this happens it is trying to pull the front of the engine towards the back of the motorcycle. The amount of this force is variable due to the set up of the compression pressure of the shock. The higher the compression setting the more force that is being excerted on the shock mount that is mounted on the bottom of the engine. When the motorcycle is in a decceleration state the swing arm is now moving downward thus pushing forwards on the shock mount on that is mounted on the front of the engine. When this happens it is trying to shove the shock mount forwards towards the front of the motorcycle. The amount of this force is determined by the amount of rebound that is dialed into the shock. The higher the rebound setting the more force that is going to be excerted on the shock mount that is mounted on the bottom of the engine. The setting will vary from rider to rider determining the riders weight and riding style. The heavier the rider the stiffer the spring, compression and rebound must be set thus applying more excertion on the bottom of the engine. The next thing that needs to be looked at is how the engine is used as a stress member as there is no sub frame to absorb the forward and backwards action of the shock mount that is mounted on the bottom of the engine. The top motor mounts are attached in two locations. Front cylinder head and on the front and rear cylinder head heads. At this point the engine is suspended by the motor mounts on the cylinder heads and at the rear of the engine cases thus making the engine act as a sub frame. Now lets think about how much stress that is repeatedly applied to the engine by just the shock alone. When the swing arm raises up it is trying to pull the bottom of the engine backwards thus trying to pull the engine down from the front and top motor mounts. Then when the swing arm is lowered it is applying pressure to the front of the engine thus trying to shove the engine upwards towards the front and top motor mounts. With all of this action of pushing and pulling on the engine it will eventually take it toll on the performance of the engine. Let me explain how it affects the engine. The engine cases have four(4) 3/8" cylinder studs per cylinder screwed into them, then you have a base gasket then a thru-stud cylinder a head gasket and the cylinder head. Every time that the swing arm moves, the shock is either going forwards or backwards thus pushing up or down on the engine and it's components causing a stretching and compression on theses components. Now lets add some cold cylinder head torque (clamping) pressure to the cylinders. This would be a static pressure of 5,250# per cylinder stud +/-500# per stud, (this could vary depending on the torque sequence, base gaskets, heads gaskets, squareness of the cylinders, cylinder heads and the content of the materials used to manufacture them)now lets multiply this times four (4), this equals somewhere between 19,400# to 23,000# of clamping pressure on each cylinder. The ideal torque would be an equal 5,250# per stud or 21,000# per cylinder but this is not obtainable that is why there is a +/- 500# per stud. Now the engine is started and brought to temperature. As the engine reaches an operating temperature of 175 deg. oil temperature and 325 deg. of cylinder head temperature things start to expand. With the cylinder limited in the amount it can grow in height because of the approx. 21,000# compressing it, the cylinder wall will start to distort. Depending on the aluminum material content, this will be variable and uncrontrollable. With unequal clamping pressure on the cylinder it will cause the cylinder to distort differently at each stud. When this happens a low spot in the cylinder bore will appear at each cylinder stud beacause of the machining required for the stud to pass thru thus creating a weak spot in the sleeve because of lack of support. The weakest area will always give way first and never returns to normal. This is known in the industry as four corner scoring, even though there is no scuff marks. Now let's add in the up and down pulling motion created by the shock and the vibration of the engine when it is running, (this will also be inconsistant as you vary the rpm's. Now let's add some more factors into this. We will start with the piston's material. Is it made from cast aluminum, forged aluminum or hypereutectic material? Each one of these has a different expansion and contraction rate and require different piston to cylinder wall clearance to operate properly. The tighter clearance you run the more friction will occur which will produce more heat and that will be partially tranferred into the cylinder wall. If you increase the piston to cylinder wall clearance you will reduce the amount of friction and less heat will be transferred to the cylinder wall but you will have more piston rock in the cylinder due to the increased clearance. This will cause problems with ring flutter and pulsation as the piston goes up and down in the cylinder. Now for some more factors, let's add in the rod angle into the equation. With the rod angle on a V-Twin the rod and crankshaft is trying to shove the piston thru the thrust side of the cylinder which causes more friction and heat. Now let's add in piston speed and G Forces. At 6,000 rpm's the piston is moving in the cylinder at a speed of 3,816 ft/per second and achieving 2,490 G's. Just think about how much friction is generated with the piston just moving up and down in the cylinder. The total horsepower loss due to friction in a 1200cc engine at 6,000 rpm is 34.50 Hp measured at the crankshaft. Now with the clamping pressure hot, piston to cylinder wall clearance, engine stress due to the rear shock movement, rod angle, piston speed and piston G's this is quite a strain on the cylinder. With all of this going on, the cylinder is going to get very distorted. The more distortion in the cylinder wall creates more high and low spots for the piston rings to travel over, thus causing ring flutter and pulsation and this is what causes failure of ring seal and causes blow-by into the crankcase. The lighter the material that the cylinder is made of, the more distortion will occur. Past experience has taught us that using a cast iron cylinder (Axtell) will help eliminate a very large majority of the problems that occur from the stress that is put on a cylinder. The cylinder is heavier and retains a little more heat, but maintains the best cylinder bore consistancies over all. We will come back to this later. These are only a few of the problems encountered. This will lead us into what happens when the blow-by goes into the crankcase, which will come next. | ||
| Hootowl |
The action of the rear suspension places a load on the engine cases, but not the heads and cylinders. You are forgetting that the load path for the rear suspension does not go through the frame. The swingarm is connected to the engine. The motor mounts do not transfer any suspension loads. Also, the mount in the front and the mount in the middle of the heads only carries lateral loads, not front to back or up and down. Hence the term, "uni-planer isolation". There is stress placed on the front cylinder by the front isolator, which carries the weight of the engine, but that doesn't have anything to do with the action of the rear wheel. The rear portion of the frame doesn't carry the weight of the engine, rather it exerts a downward force on the rear isolators. If you took out the rear isolators the engine wouldn't fall out, rather the frame would drop on the motor. By the way, I do not dispute that iron cylinders may be stronger, and I sincerely appreciate you taking the time and effort to explain your views. It's been a good read so far. | ||
| Blake |
Notsip, I guess I should have better explained the intent of my diagram. It is what is known as a "Free Body Diagram", meaning that we isolate a discreet portion of an assembly/structure, release/free all its constraints, and show all the resulting forces acting externally to the assembly/structure and also those forces acting at its now unconstrained boundaries in order to maintain equilibrium... Maintain equilibrium meaning that if the assembly/structure of interest were floating free in space with all external loads applied as shown, it would remain perfectly still and stationary. The structure/assembly of interest is the engine/tranny/swingarm assembly (ETSA) including the rear shock. I therefore did not depict the frame or the rear wheel or the front end for that matter. You can however see the loads that, for the case shown (no braking or acceleration) represent the forces that the frame and rear wheel would impart to the assembly of interest. Zat make sense?  The leftmost upwards force is the front isolator pushing up on the front cylinder head. Proceeding to the right, the 2nd force, acting downwards, represents the weight of the assembly acting through it's center of mass; the next applied load acting downwards is the force transferred by the rear isolators; the last applied force acting upwards represent the load supported by the rear axle holding up the swingarm. The lengths of the force arrows are roughly representative of their relative magnitudes. You can see that the total upwards force is equal to the total downwards force; that is equilibrium, the sum of all forces equals zero. You might also notice that the sum of all moments about any point due to the forces is also zero, the 2nd condition required for equilibrium. The blue and red internal loads would not normally be shown on a free body diagram as they are not external applied loads or reactions. I sketched those to demonstrate to you how the shock mount loads would not in any way significantly affect the cylinders. I would clarify with Hoot on one point... as shown by the free body diagram, the front motor mount load is sensitive to rear suspension activity. If you encounter a bump in the road as input via rear axle, each of the forces shown in the diagram would increase in magnitude. I chose not to include any braking or acceleration loads since that would impose horizontal loading and the structure is not statically determinant wrt horizontal loading... meaning not easily analyzed without some brave assumptions or advanced methods and lots of pertinent design data. Where is that Abe fella when you need him? The other motor mounts you refer to are out of plane and not pertinent to this discussion, as Hoot already pointed out. The rear shock cannot in reality ever push on the front mount as you contend. It is in a state of perpetual tension, always pulling wanting to retract, never wanting to extend. Again, the loads imparted to the shock mounts will not affect the cylinders. The blue arrows show the load path of that internal reaction to the shock's tensile loading. It is FAR away from and in no danger of affecting cylinder integrity. And also again, I'm not sure it is responsible to suggest that the loads imparted by the stressed engine configuration are in any way deleterious to the integrity of the engine. You would do well to examine the magnitude of those loads and their relative effects on the geometric integrity of the cylinders. Like I said before, we are talking about loads in the mere hundreds versus some pretty beefy structure with strengths in the tens of thousands of PSI and stiffness to match. Since the rear cylinder does not carry any significant externally applied loads, it would seem that if your theory were true wrt to the stressed engine, only the front cylinder would exhibit signs of distortion and then excess blow-by. Since that is not true I think we can logically dispense with the idea that the stressed engine configuration is in any way culpable in contributing to blowby and breather pukage. Do you agree? Now, as to the clamping pressure and thermal distortion... please continue. FYI... 3/8" diameter lubricated cylinder studs under a make up torque (T) of 35 FT*LBs (420 IN*LBs) would produce a theoretical preload (P) of between approximately... and P = T/0.15D = 420/(0.153*3/8) = 7,470 LB with the typical uncertainly of +/- 30% for uncalibrated torque/tension relations. It kind of makes sense that your preload of 5,250 LB per stud is on the low end when you realize that the screw head presents a significantly larger faying diameter surface compared to a normal 3/8" nut for which the above rule-of-thumb equations apply. The larger faying surface in effect increases the moment arm of the resisting force, more moment arm, same preload = higher torque. Interesting. Let's check that versus combustion pressure. If peak combustion pressure (p) is 1,500 psi, the force (F) acting to blow the cylinder head off the cylinder is... If combustion pressure increases to 2,000 psi, the force increases accordingly to 19,200 LB. I don't know what the peak combustion pressure is in a stock engine, but if it is near 2,000 psi, it looks like your measured preload or specified torque may be a bit low; not much margin there in a cold engine scenario. I'd clarify that the 34.5 HP you claim is lost to friction at 6,000 rpm is for the case of WOT, full power output. It obviously would not take a 35 HP motor to simply crank the engine at a rate of 6,000 rpm. Have you tested any Millenium cylinders? This is interesting stuff; more later... | ||
| Steveshakeshaft |
Interesting stuff indeed. And your analysis is quite some way to explaining why some engines will exhibit leaky base gaskets? I have wondered (but not done yet, since I have good base gaskets!) what the bond strength would be like if you actually used a gasket compound like Loctite 574 to "glue" the cylinders to the crankcases (no gasket ofcourse)? And how much it would add to the structural integrity of that joint, and hence the engine as a stressed member. Practical experience tells me that using 574 on industrial machines not only totally eliminates oil leaks, (given fairly true surfaces ofcourse!) but it pretty much guarantees you have to be pretty darn determined to get that joint apart again! Regards Steve www.ukbeg.com steve_s@ukbeg.com | ||
| Notsip |
On the mounting of the engine Blake speaks about the way it should work. And I agree mostly with what he says. But in real life it doesn't work as well as we think it should. There are to many other flexing factors that comes into play. I didn't mention them because I didn't want Blake to waste his time in figuring them out because what it is designed to do doesn't always work as designed. Save your energy for later. As for the cylinder studs, the number that I used was figured using the actual cylinder stud supplied by H-D. I know that the numbers that Blake and I have are a little different, but if you want the exact clamping pressure take a H-D stud and have it analized then take the results from that and then refigure your loads. You will see why there is a difference. In going with your scenerio with combustion pressure, and this is different depending on what compression is being used, no there is not much margin there. That is why it is imparative that the engine be thoroughly warmed up before applying any loads to it. Blake is correct, the frictional horsepower loss is different at every rpm. I used the 6,000 rpm number because that was the number used to figure piston speed and G's. If you want the losses at different rpm's just let me know and I will give them to you or you can figure them on your own. Yes we have tried the Millenium cylinders. To make it short we have tried probably every cylinder on the market for the past 5 years. The only cylinder that we have found that will withstand all of the rigors that it is put through is the Axtell Cast Iron Cylinder because of it durable strength. Yes it does have some drawbacks but I look at the overall picture. It maintain's it's concentricity better than anything else which gives you more consistant horsepower as heat develops in the engine. Also keeps blow-by at a minimum. My thought process is this. Less weight equal less stability and concentricity which reduces consistant horsepower output, reliability and increases blow-by. More weight equals more stability and concintricity which produces consistant horsepower output, reduces blow-by and increases reliability. This is not a hard one to figure out. | ||
| Mikej |
So, if I understand this right, on the high oil loss days I am getting extra blowby due to how the heat expansion in the cylinders reacted that day. On the low/no oil loss days the cylinders and pistons have reacted in a friendlier way to the heat expansion. In other words, with the stock setup, I'm basically stuck without major work and component swapping. Am I correct in my understanding of your input? Not wanting to cast stones, but I'm curious to what the drawbacks are in your opinion to the Axtell cylinders. There is give and take with any product. Thanks for your time. | ||
| Notsip |
I want to make it clear that I do not have anything against aluminum cylinders, we use them all the time on other engines. But when used is this application they have serious flaws and drawbacks. Blake; It has been brought to my attention from an outside source that your analogy on the swing arm theory is flawed and you may want to rethink it. I am not an engineer so therfore I can only state what past experiences has taught us. Again things don't always work the way that they are designed and intended to. This is probably one of those situations. | ||
| Hootowl |
Blake, I wasn't taking whole motorcycle up-and-down movement into account, only the swingarm movement. This was in response to the assertion that swingarm movement placed loads, conducted through the suspension, on the front head via the uni-planer mounts. |
