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excessive piston to head clearance is of no value as you only increase the chance for deto with stagnent fuel sitting at the outer edge of the head. problem is since parts grow with heat and rods stretch at high rpm it can be tricky to find the point just before the piston contacts the head

if you watch his banshee port videos alot of guys do the same things he does. or maybe he does the same thing other people do im not sure. but there seems to be a connection there. just sayin

Good to know. That seems to suggest the pipe does very little until it has hot gas in it . ie engine running

So you want to know the cylinder pressure of a running engine at a given engine speed then figure out the required fuelair mixture to achieve said pressure. Probly need a scientist like larry said haha. Check blairs book. Might be something in there

i think whats happeneing here is somethings getting lost in translation along the way. were trying to figure out what static pressure has to do with fuel. tricked has seen a pile of similar engines with similar cylinder pressures, need similar fuels. ok but that doesnt answer the question of what non-running cylinder pressure has to do with a fuel. for a while ive tried and been unsucessful to determine any correlation between this pressure and such and such fuel.

for a minute there i thought you might be contributing somehow. just a big let down again

if you see similar stuff day in and day out, 12ish:1, 150 typically. its the same ol fuel. ya i get all that. but uncle larry wants you to look at his triple port stocker with mikes pipes and franks head. static pressure isnt what you would think. now what ? ive always figured even a pipe change would alter kicking comp but never cared enough to do the test. anybody got a spare set of pipes and a half hour ? check pressure then swap a pipe and check again. just for the hell of it i wouldnt mind knowing

between the grime and jb its hard to tell if the crack has traveled beyond the plug boss. if not i would just V the crack, spray some brakecleen in there and hit it with a mini SS wire wheel then weld it. if the crack has migrated to the case floor youll probly want to take cases apart and reasess the situation based on what you see

if everybody is just copying the next guys port job and using the same domes then there must be alot of cloned engines out there that would indeed have a common comp ratio and static cylinder pressure and thus all needing the same fuel. surely there must be some diversity or no ?

CRANKING COMPRESSION VS OCTANE REQUIREMENT Generally, when you increase compression past a certain level, you need to increase the fuel octane requirement in order to combat detonation. Detonation occurs when the cylinder pressure is high enough to ignite the end gases without the aid of the spark plug. This usually occurs in the combustion chamber end zones (near the bore edge of the dome). This ignition of the end zone gases will create a shock wave that will travel and collide with the on-coming flame front. It is this collision that will do the damage to your engine. So, think about it..if you increase the fuel's resistance to auto ignition by raising its octane level then it MAY not self ignite before the flame front reaches it. So, what does this have to do with compression? It stands to reason that higher compression RATIOS will yield higher cylinder pressures (given that nothing else has changed before the compression ratio was raised) Well.. we just determined that the higher pressures are a major player in causing the fuel to auto ignite (not good) hence, the need for higher octane with higher compression RATIOS. OK, we have been talking about compression ratios NOT cranking compression. What about the cylinder's cranking compression? Continuing along the above lines: What about cranking PSI vs Octane requirements?? My opinion is that they are not very closely related. In other words.. knowing what PSI your engine "cranks" out will NOT tell you whether or not you need a higher octane fuel, unless, of course, the PSI number is extremely large (like 200). Then, it may carry more weight and tell you , "yes", you do need some high octane fuel BUT it will NOT tell you which octane you need. OK, "WHY?" Let's do some deductive reasoning here: Take an engine with an exhaust duration of 182 degrees ATDC and install some domes (any domes) that yield.. say 170 PSI cranking compression. OK, take another engine, exactly the same, except the exhaust duration is at 198 degrees ATDC (ie higher exhaust port) Now, install the SAME domes that the other engines has. Now, the cranking compression reads only 150 PSI. Hmmm.... so does this engine require a different octane of fuel than the other one? Probably, but not what you think.. It , most likely, requires, a HIGHER octane fuel NOT a lower octane. I know that the general conception among riders is that the higher the PSI .. the higher the octane needed.. Well, I just told you completely the opposite. With the general consensus.. it would stand to reason that when ever you raise the exhaust port... you need to run a lower octane fuel because the cranking compression will, indeed, get lower with higher exhaust heights. Does this seem right?? What if you lowered the exhaust height? Would you then need a higher octane fuel because the cranking PSI would surely go UP? Let's look a few of the determining factors behind the above statements: Please realize that I will be over simplifying the processes but it should get the point across. 1: With an increase in exhaust height or area.. the probability of having more escaped fuel/air charge "stuffed" back into the cylinder just prior to exhaust port closing increases. This will raise your dynamic cylinder pressures and combustion temps. 2: Along those same lines... during the peak scavenging phase the larger exhaust CAN effectively pull more F/A charge in the cylinder and out the exhaust which then leads us back to #1. 3: Crown temps are higher with a raised exhaust. Anytime you have elevated crown temps, you increase your chances for detonation. IMHO, there is no direct relation between cranking PSI and octane required. I wish there were. For example.. one of my race engines (snowmobile) cranks only 140 PSI but I know that if I don't run at least 110 octane , the engine will not live for very long. As we are beginning to realize... these PSI charts really give no relative information unless your engine is stock ported (and even then, I find that they are not useful) This all relates to information needed when choosing a dome for your engine. I know that when you call up the head shop or go to the counter and ask the parts guy the conversation goes something like this: YOU: "So, if I want to stay with premium pump gas, which size domes should I purchase?" THEM: "Well, if you want to stay with premium fuel your cranking compression needs to stay below 160 PSI. These XXcc domes will put you right at that correct PSI for premium fuel" I DO NOT AGREE WITH THIS LINE OF REASONING! We see that the porting arrangement plays a MAJOR role in the resultant cranking compression. It is NOT only about the head!!! Then.. You factor in the bore size in the equation and you REALLY can get into a pickle!! So, you have to be very careful in choosing domes for your engine. The head (dome) design itself, plays a large role in determining octane requirements of an engine. If the dome is not correct for the engine, you could be forced to run race fuel in order to avoid engine failure. OR on the other extreme, you may THINK your engine requires race fuel, when, in fact, it would live just fine on pump fuel. So, you could be throwing money and convenience right out the window. © Copyright 2006. 2StrokeHeads.com Disclaimer Website updated by Urban Plains Web Design

THE TRUTH ABOUT COMPRESSION TESTING by Mull Engineering We would like to take the chance to answer some general questions and myths about compression testing an engine. Compression testing is a method of using a pressure testing device to measure the “cranking” pressure developed in the combustion chamber during cranking speeds of kick or electric starting. These engine speeds are generally between 100 and 400 rpm. This is usually accomplished by removing the spark plug and installing a pressure tester in place of the park plug and cranking the engine over. This pressure can be somewhat indicative of the condition of an engine and is often used to trouble shoot an engine. We get a lot of questions about what the pressure should be for a given engine and especially, what is safe for certain fuels. Well, hate to break the news but if you are going to rely on compression testing to determine your fuel selection, you are asking for trouble. The reason is that cranking compression numbers can vary greatly from actual running compression due to many variables such as volumetric efficiency or air fill into the cylinder at cranking speeds, and the wet fuel that is added by the carburetor as rpms come up to operating speeds which does not compress as easily as air. These do not even consider the high pressures of burning fuel in the combustion chamber. The only way to correctly determine the right fuel for an engine is by comparing the swept volumes of an engine when the piston is at top dead center and bottom dead center. This is expressed as the compression ratio or CR. There are also other considerations like head design, piston design, squish clearance, etc, but we will keep it simple for this discussion. Checking compression is a great way to check the condition of an engine and determine if an engine is in need of service providing additional tests are performed. This is only applicable if there is a base line measurement to refer to, either from a manual, or from testing a given engine when it is new and considered a valid value. Regarding four strokes, this form of testing is also a great way to determine if valves are seating properly and at the right time. This form of testing, however, may not give accurate data as to the piston ring seal, wear on the piston rings, or piston condition itself. Bottom line is that many other things can be going wrong in the engine and the compression test will not show it! This is why experienced technicians use this form of testing only as a guide and usually along with other tests. This testing might be compared to testing a child’s temperature to determine illness, it is simply not enough data to give the full picture. However, by compression testing, one can easily determine, if an engine has lost substantial compression and if an engine is in need of service. Many people will look to perform a compression test at home and this can be done with just as much accuracy as any service shop, given the right equipment and knowledge. Contrary to popular myth, an actual pressure gauge bought about anywhere, can be rather accurate. This, however, is only looking at the dial gauge portion though. There is also a hose extension and the adaptor component that will screw into the head in place of the spark plug. One of the most common mistakes is selecting a tester in which the head adaptor does not screw into the cylinder head with the same amount of thread as the spark plug that came out. This lack of thread can be compared directly to adding extra volume in the cylinder head and will not represent the same pressure numbers as if the spark plug were reinstalled. Obviously selecting a tester with the correct length of threads will eliminate this problem. You must also be careful not to use too long of an adaptor as well because of the opposite effects as well as potentially causing internal engine damage from mechanical contact from moving parts in the engine and the tester adaptor. The next and most common problem we see is when a tester is selected, it should have a “Schrader valve” in the very tip of each adaptor. A Schrader valve is the same valve used in the valve stem of a tire and is a one way or check valve device. What this does is isolate the volume in the cylinder head from the volume in the tester adaptor and extension hose. Without this valve in place at the very tip of the adapter, the extra volumes in the hose and adaptor will act to increase the cylinder head volume and give a false (low) reading. The Schrader valve must be in good condition and work correctly and it is common to replace them regularly. The method for compression testing an engine is rather elementary but certain things must be considered. First, you want to turn the ignition switch off so you don’t get surprised. Install the tester adaptor in place of the spark plug and either hold the throttle wide open to allow the most air to the engine or you can simply remove the carburetor entirely. Then either kick or electrically crank the engine over until the compression gauge will not go any higher. This process generally takes around 50-200 revolutions of the engine to complete the test. Excessive cranking while the gauge is still climbing is sign of leakage somewhere in the engine. When the test is complete, the gauge should hold the tested pressure at the gauge indefinitely. If not, there is certain leakage of the tester, either the mentioned Schrader valve, or other unions should be inspected. It is NOT a requirement to purchase an expensive compression tester but one should certainly be selected of decent quality and include the considerations listed above. Regarding four strokes, it should be mentioned many engines use a form of compression release to lower cranking compression to make an engine easier to turn over and start. This compression release is usually turned of by mechanical means right after starting. This mechanism will directly affect accurate compression testing. You may need to refer to your manual for an estimated compression value with the compression release in use, or you may need to render the release mechanism ineffective for testing. If the engine uses electric start, it may be impossible to turn over without the compression release so derated numbers from a service manual will be required.

newer hotrods are welded at the factory

the main thing is you want the rods running straight up the bore. use the stud holes as reference ( assuming theyre sqaure to the bore and not offset for some dumb reason but most engines use studs sqaure on the bore) and put a pencil mark on each case at center and align the rods on the mark. if the crank hasent seperated or some dumb hillbilly hasnet taken it apart, then you should be good and that should center up your crank wheels also, because from the pics theyre shifted a mile to the flywheel side. dont worry about the flywheel side bearing. since it doesnt have a dowel or clip, its mostly irrelevant if its on the shaft all the way or not roller bearing inner race shouldnt be putting a bunch of side pressure on the rollers. on the other hand it needs to be inside the bearing far enough that the rollers are making full contact. make sense

Bansheehq=home of the meanest rufest tufest parts changers on da web

If the site vendors wont sell you a piston for $78 and free shipping then dont even bother. Can buy it all day on ebay for that price

Who ever did it looks like they filled up the dowel pin hole and probly half the stud holes then tried to file it down with a cheese grater. Have fun with that mess

Its pretty sad when the best advice you get is someone calling you a retard. Sorry justintoxicated ill have to opologize for these guys. When they dont know the answer to a question (which is most of the time) its easier for them to act like a fool and call you names like alittle kid. This bearing and case stuff is the bare basics. You would think these guys would understand it but I guess not. Pretty clear who the retards are. But if you ask them I guess its me and you are retards lol. Hek theres even a so called engine builder chimed in that offers nothing about how to get the bearing out. For sure im gonna back to the blaster site haha

You can Look up the thermal expansion of any material and that will explain why the oven works even though your heating bearing and case. With the amount of interference honda designed in the bores, its around 250ish where the interference is canceled out and becomes near zero. In lamens terms, the bearing bore and bearing are nearly the same diameter and thus allowing the bearing to be removed easily

Could careless how he does it but ive seen people break cases from hammering bearings out

Im tellin ya the oven is the prefered method but if you dont believe me you can ask on the honda sites and they will say the same thing. Aotopart stores sometimes rent tools. They may have a bb puller

Going back to blaster forum so I have a chance to learn something

theres no useful info around here. go back 10yrs........ still nothing. unless a guys wants to know how to install handlebars ,then it would take 7months to read all them posts

the oven works because the expansion of steel and aluminum is different. trust me ive done a bunch of hondas. after a few you can do em in your sleep. BB pullers aint cheap. especially a high qaulity one. most BB puller sets probly wont have that large of a collet included, so youll have to measure the bearing and buy that collet seperate. for a one time use i would probly contact a legitimate shop and have them pull the bearings out. putting new ones back in you can do yourself, if you use some good judgment

appears someone like you stuck a walmart dremel in the left side then got confused and put it back together. sound about right ?

looks par for the course to me