How to increase compression ratio in motorcycle

How to increase compression ratio in motorcycle. The equation for the volume of a cylinder is (i. 5 to 1 with a removal 10cc. Oct 18, 2021 · Controlling these variables allows for a better driving experience. To increase engine compression, you can install steel shim gaskets in place of the existing head gaskets, which can raise the compression ratio slightly and decrease quench clearance by approximately. 5:1 compression ratio, you get about 139 PSI pressure at TDC when the engine ignites without boost (14. The compression ratio is the ratio between the volume of the cylinder and volume of the combustion chamber. First number each cable with a bit of masking tape so you can replace them in the proper order. Cylinder Head Gasket Volume. Roughly 1cc equals 1/10 of a ratio, if you make the chamber 10 cc smaller you will end up with an extra whole number of compression ratio, i. Boost + increased compression ratio is a bad, BAD thing. as for determining a high or low compression engine lets look at some gas & diesel engines for examples, the highest compression ratio for a gasoline engine is 14:1 for normally aspirated racing engines which will require the use of ultra high octane race fuel, for This lowers the compression ratio because you have more clearance volume above the piston. The more preload you wind in, the fewer rings are left showing. Depends on what skimming the head does. To understand how much more can be had, let’s look at the effect the cam has on the situation. 080 down the bore at TDC. Extend the fork completely by getting the bike off the ground and measure from the wiper (the dust seal atop the slider) to the bottom of the triple clamp (or lower fork casting on inverted forks; Figure 2). 12. regarding my inquiry on 750 twin pistons--TR7RVMan has helped me out with a measurement on a 8. May 6, 2016 · In short, higher compression makes an engine more efficient. Fuel of that rating will give the best performance and economy at the lowest price. Last edited: May 27, 2013. 030 inch to 4. Oct 22, 2007 · An engine's compression ratio is the ratio of the volume of gas in the cylinder when the piston is at the top of its stroke (top dead centre, or TDC) to the volume of gas when the piston's at the bottom of its stroke (bottom dead centre or BDC). Jun 30, 2020 · Turn the engine off. Types of Compression ratio. In most cases a rebore will increase the compression ratio of your engine. This will also increase the combustion chamber temperature, which can lead to pre-ignition and detonation issues. Sep 12, 2023 · Motorcycle engine compression is essentially the act of air and fuel being tightly packed within the engine's cylinders. The Absolute Compression ratio is calculated from the point of volume where all valves are closed (because the engine is only making compression when all valves and/or . 040" and it took about 4cc out of the chamber, which will bump compression ratio by a half point. Test each cylinder at least twice. If you take a standard 4. Write this number down and don’t lose it. com Nov 1, 2000 · Let's take a look at how all these volumes interact by detailing the simple math that's used to determine compression ratio. He swears that the 9. An engine's compression ratio is the ratio of the volume of gas in the cylinder when the piston is at the top of its stroke (top dead centre, or TDC) to the volume of gas when the piston's at the bottom of its stroke (bottom dead centre or BDC). There are a number of Feb 14, 2012 · In every motorcycle brochure and every engine specifications we see specified the 'Compression Ratio', but what is that number. It helps when the overlap is hurting performance The compression ratio (CR) is defined as the ratio of the volume of the cylinder and its head space (including the pre-combustion chamber, if present) when the piston is at the bottom of its stroke to the volume of the head space when the piston is at the top of its travel (‘top dead centre’, tdc). Jun 21, 2021 · However, high-octane gas alone does not yield more power, unless it’s preventing detonation, which is also known as engine pinging or knock. Working on a full frame up resto-mod. There will be one preload adjuster on each leg and they need to be adjusted Dec 7, 2004 · Around these parts, with a steel head engine, about the maximum anyone is running with any big blocks (427 and up) is about 10-10. 5% in ratio, increases efficiency by 4. g. 5%, but only increases efficiency by 3. 0:1. In order to ensure that the mixture is still compressed sufficiently over the reduced effective compression stroke it is necessary to increase the static compression ratio. 2) Mill the cylinder head to reduce volume. It's the same thing with compression ratios. 6mm stroke, this creates a cylinder with a volume of 249cc’s. 010-inch bore, a 4. – Create poor rear wheel traction. 8 5. See All 4 Photos The total volume includes the swept volume (bore x stroke) and the clearance volume (piston dish/dome, deck, head Jan 27, 2008 · 160 is about right for a stock TC88 but 120, not so much. One further recommendation would be to add a set of mid-length headers to the engine. 1968-1969 should be about 125 PSI, 1970 and later should be about 110 PSI. And consider how much heat energy is lost to the atmosphere that does nothing for power. Spec calls for 8. The "more control" comes from a few things: When you use less travel on big compressions, the geometry does not change as much, keeping the bike feeling more consistent and predictable. Raising an engine’s compression ratio is key to getting the most bang for your buck. Feb 1, 2022 · Compression damping is used to help keep your fork or shock from blowing through quite as much of its travel, giving you more control of your bike. High-compression pistons are a common upgrade for dirt bikes and other motorcycles, but bumping compression isn’t always beneficial. The whole process has some similarities with car ac compressor testing, because two system works with compression system. Click ahead to discover what compression ratio is and how an Mar 12, 2011 · Shaving head will reduce combustion chamber size, therefore increasing compression ratio. Now that you know the swept volume and clearance volume, simply insert those numbers into the formula and solve it. Apr 6, 2020 · To find out which it is, take the tops of the carburetors off, pull the slides, and change the position of the needle retaining clips to raise or lower the needles. The type of compression ratio we've just learned about is what's known as a static compression ratio. This will do more to add power than any other thing you can do. Sep 11, 2014 · Depends on the year as the compression ratio changed. Too hard spring ratio: – Gives easy turning into corners. The manual says the piston size is 95mm and the compression ratio is 8. The compression ratio is calculated in the following two different methods: Static compression ratio; Dynamic compression ratio; 1) Static Jan 16, 2015 · Based solely on our thermal efficiency formula, raising the compression to 12:1 should bump that figure to 397 ft-lbs. Think of it as the engine taking a deep breath, holding it in, and then forcefully exhaling. I got it home tonight and did a compression test. BTW, I would seriously consider replacing the Clymer manual with the Harley manual. Oct 26, 2021 · Calif-- Santa Barbara. #6. '77 D-150 Custom with the original 440. 0:1, there will most likely be options of 13. Though, typically, the high-speed adjusters are only found on the Jul 12, 2017 · The actual compression ratio will be less, depending on how easily the fuel/air mix can get in and out of the cylinder. A useful rule of thumb is that raising the compression ratio one point (i. Stiffer shock rates slow spring movements, while a softer shock rate allows the spring to move faster. 300 on the odometer is correct. It's easy to find what octane rating a gas has: Stations are required to post them on bright yellow stickers on each pump. Flow through the carburettor and inlet ports, the shape and lift of the valves, the relation between inlet and exhaust lift of the camshaft and the design of the exhaust system are all factors. Apr 17, 2019 · When this happens an engine is said to have "come on the cam". 5 to 1 engine would jump to roughly 9. 030-inch, this increases the static compression ratio to 10. So motorcycles need to have desired Jun 30, 2020 · Turn the engine off. 060-. Remove the spark plug cables from the plugs. from 10:1 to 11:1) increases power by about 3%. The Rule of Thumb is to throw out the high and the low reading, and This restricts the oil flow and adds more damping. If you have compression ratio of 10. 0-1 raised to 9. 5:l without serious consequences, using a non-squish cylinder head, but that is very near the limit. You can also think of compression ratio as the engine’s “expansion ratio” – as the combustion gases Feb 1, 2024 · The compression ratio is calculated as: Compression Ratio (rc) = (Vd + Vc) / Vc. Higher compression allows the engine to produce more power with each combustion cycle, resulting in improved overall performance. Posts. Consider the power lost to internal friction, components that consume untold amounts of power just to move them. One of the effective ways to increase power in your Honda Rancher 420 is by increasing the compression ratio of the engine. jpcycles. The fuel will start burning spontaneously (before the spark plug ignites) and Feb 23, 2024 · If an engine’s stock compression ratio is 13. At 9. To see what the effect of boost pressure and altitude is on your static compression ratio, s imply enter the three variables and the calculator will display the results in a new pop-up window. Feb 21, 2024 · The compression ratio is a measure of the volume of the combustion chamber when the piston is at the bottom of its stroke compared to the volume of the combustion chamber when the piston is at the top of its stroke. 7 PSI x 9. RSR Compression Ratio Calculator. All of this assumes that your engine is stock, and many of them are not. Squirt some oil, maybe a teaspoon's worth, into the cylinder through the spark plug hole. au. Use (-) for Dome and (+) for Dish. Fig. But we're Those Dyno Guys. 25:1-compression ratio street machines with standard-size carbs, aftermarket intakes, headers, and recurved ignitions, like cams with 0. en. So 10:1 for a stock Shop Now | Tusk Compression Tester https://www. 7:1 ratio. 0:1 CR. Write down the results, release the gauge pressure and repeat. This is Most gas stations offer three grades of octane, with regular rated typically at 87, mid-grade at 89 and premium at 92 or 93 [source: Federal Trade Commission ]. 5:1. Boost Pressure in PSI : Static Compression Ratio : (:1) Target Altitude : (Feet) RSR. On the other hand, 300hp is possible from a 2 liter N/A engine. This method, which is also used to correct warped or imperfect deck surfaces, allows you to control the size of the chamber so you can get the volume needed to achieve a desired compression ratio. , 8. Spring ratio Rear . 050-inch durations in the 215 With a 4. The long answer, of course, is the same as my answer for most motorcycle Dec 18, 2014 · This is also what the S54 engine with a 11. On RD's and RZ's skimming the head brings the squish to a point where it actually works properly, the increase in compression ratio is minimal. Another thing you can do is to have a thicker gasket. Has anyone replaced the pistons to increase Sep 19, 2022 · Since motorcycles use gasoline engines in them, the optimum compression ratio is between 8:1 to 13:1. Apr 11, 2018 · That’s all the air and fuel getting compressed in the cylinder. That’s because the higher ratio allows for an engine to extract more energy from the combustion process due to better thermal efficiency. Jun 11, 2021 · The compression ratio for any engine or individual cylinder is defined as the ratio between the swept volume of the cylinder with the piston at bottom dead center (BDC) and the volume with the piston at top dead center (TDC). 1:1. Sep 22, 2022 · The Big Squeeze. If a shock is too stiff, it can cause the tire contact patch to bounce Dec 1, 1998 · Typical daily driven, under-10. Jul 20, 2020 · See more tips and how to's on Countersteer : https://www. 688 inches from center of wrist pin to top of crown--- can anyone confirm that a 7. 5:1 compression achieves at this rpm. At highest Adding 1 point of compression; e. The oil will hold compression for several turns of the engine. 015 head gasket, which will push the compression up to 9. 000 inch bore (small block) and overbore it by 0. 497. The short answer is, “Use whatever the manufacturer of your engine recommends. Reboring the engine. Typically, petrol engines have a CR of 8 Nov 11, 2019 · The chassis and rider will absorb the impact of the bump instead of the spring. See full list on motortrend. Then, divide the result by the cylinder volume to find the compression ratio. 030 inch, compression will increase by a fraction of a compression ratio point. 4%. May 22, 2019 · In the following section, it will be shown that the compression ratio determines the thermal efficiency of used thermodynamic cycle of the combustion engine. Found-bonus power. Then, if we change to a block with a larger 4. For example, let assume an Otto cycle with compression ratio of Mar 14, 2023 · Grab some G54 merch here - https://www. Sep 2, 2021 · Suppose you want to lower your engine’s compression ratio. As you do so, you can equally increase both volumes. That leads to a longer expansion cycle, more May 25, 2006 · Shovelhead compression test question (s) I just picked up a 1978 Lowrider and the owner has had it since new. 5mm off is roughly equal to a 2cc reduction in combustion chamber volume at this size and a 1 point increase in compression so 9 to 1 would become around 10 to 1. Coincidentally, that compression ratio (5. If your retest with oil gives higher compression, you will know the rings are worn. rockymountainatvmc. Shorter rods, revised shorter stroke crank = lower compression. A high-compression piston Solution: Decrease compression until harshness is gone. Compression is king! By Kevin Cameron. I can't tell you how much to shave, or if you will have valve to piston clearance issues. Symptoms of Low Compression May 19, 2024 · Using Summit’s free online compression ratio calculator, the program gives us a compression ratio of 10. Ideally, I’d like to keep the bike as a 111 and enjoy the drivability of the bike without changing the dynamics to a BBK. By keeping the explosion in a smaller space, more of its power can be harnessed. 6 to 1 compression ratio piston--- 1. Can I just mill the heads? If so, how much without going to adjustable overhead? What about just changing the pistons? I am looking for about 10:1 at the end. 91:l) is very nearly all a non-squish combustion chamber will permit in an otherwise fully-developed two-stroke engine. For example, if the maximum volume of the cylinder is 500 cubic centimeters (cc) and the minimum volume is 50 cc, the compression ratio would be: rc = (500 cc + 50 cc) / 50 cc = 11:1. With too much damping the rebound will be too slow. Decrease compression until sliding stops and traction is regained. the cylinder's displacement in cubic centimeters or cc) and C the total combustion chamber volume Crop an image by enclosing a rectangular area with a custom or predefined aspect ratio. 00 inch stroke, 70cc chamber, 0. Calculations. In practice that number is usually exceeded and the bigger the cam, the bigger the gain. A comparison based on a specific compression ratio increment Jul 31, 2019 · To measure this, put the bike in a chock or have a mate hold it steady. com Sep 22, 2022 · The Big Squeeze. Increase Compression Ratio. This is just the cylinder itself. With a 77mm bore and a 53. Mar 18, 2005 · One of the easiest ways to get a harder hit and better low-to-mid power is to increase the compression ratio. (Which can be further improved upon by using a thinner head gasket. 005-inch below the deck computes out to 11. At 12. During this inhalation phase, the air-fuel mixture is squeezed into a tiny space. This is why high performance engines with aggressive camshafts also tend to have high static compression ratios. 0-1 raised to 13. If the compression ratio is lower than optimum, there will be trouble in fuel combustion. 5:1 on my 95VT1100C. Jan 12, 2023 · January 12, 2023 JE Powersports - Blog. . Sep 15, 2022 · Turn over the engine at least 4 or 5 full cycles. This means that the fuel-air mixture in the cylinder is compressed by a factor of With a proper set of chambers the rpm goes up 1,500 rpm or so. The next factor in compression ratio is cylinder head gasket volume, which contributes to clearance volume above the piston. ) I also take it that the cylinder heads may also need to be decked as well so they don't smash into the valves. Similarly, if the compression ratio is too much, like that of diesel engines, then there will be engine knocking. If you recall from high school geometry, Volume of Cylinder = Pi x radius squared x height (in this case, stroke). A higher compression ratio means more power output, but also requires higher octane fuel. Apr 8, 2009 · Anyone know what it is roughly, it's a truck motor if that changes anything. Fork preload adjusters live at the top of the fork legs and generally require a 14 or 17mm spanner. e. May 16, 2006 · The formula for the CR is (V+C)/C. You will need a fully charged battery capable of easily turning over the engine. Squirt some motor oil in that hole, run the piston through a couple of cycles and re-test. Benefits. That's why there is an S54 engine for that application. I'm considering ebaying a 96mm Wiseco piston kit for this engine to save money, but it says the compression ratio is 11. So I have to disagree with your blanket statement. To understand what detonation is and why you want to avoid it, let’s talk about the combustion process for a moment. Static and dynamic (or corrected and uncorrected) as well as effective (boost) compression ratios are explained for both two-stroke and four-stroke engines. 5-1, also +12. If an engine has a high compression ratio, it means that a given volume of air and fuel in the cylinder is being squeezed into a Dec 14, 2011 · Newark, OH, / Concord, NC. Rebound damping settles the bike back into place after a bump and helps maintain the wheel’s contact with the road. The spark plug then ignites this compressed Mar 6, 2019 · Step 1: Extend the suspension completely and measure. Mar 16, 2024 · 3. You really need to cc the head and do the cylinder volume calcs to get an exact figure. Further to this basic damping adjustment, more and more bikes are now coming with high-speed damping adjusters. And on most road motorcycles there is a power increase to be had by increasing this ratio. Now run the test again. 051 gasket, a pure flat top piston, and a piston 0. If, for example, the relationship of the BDC volume is 13 times larger than the volume at TDC, then the compression Higher compression is normally achieved in a few ways: 1. Apr 22, 2023 · There are a few ways to increase compression ratio: 1) Use a higher compression ratio piston. Every 0. 0:1, so that you can make an informed decision on how much compression will benefit you based Mar 24, 2017 · The easiest way to improve compression is with a set of 64cc chamber cylinder iron Vortec heads and that 0. In other words, it's the ratio of compressed to uncompressed gas, or how tightly the incoming fuel The head thickness required to achieve a given volume is based on new valves and seats and a stock combustion chamber. You can adjust the damping force or rate of your shock when it tries to compress and when it rebounds. Resize an image online to a specific size in pixels. In this article, we’ll walk you through the basics of how to diagnose and repair low compression on your bike. Less than 100 440 half tons built for '77. – Makes the rear feel harsh. Put simply, it’s a measure of how much air and fuel a cylinder in an engine can squeeze. Compute Jul 7, 2022 · Increase Thunderstroke 111 Compression Ratio. In this formula, V is the swept volume of the cylinder (i. Apr 20, 2018 · The ratio of the two different volumes is the compression ratio. 1417) / 4 x Bore The compression ratio of the petrol engine typically falls between 10:1 and 14:1, whereas the compression ratio of the diesel engine typically falls between 18:1 and 23:1. In other words, it's the ratio of compressed to uncompressed gas, or how tightly the incoming Oct 9, 2010 · 1000cc SV (swept volume) + 100cc CV (chamber volume) / 100cc CV = 11. 0:1, compression will increase by less than a point with a 0. Now turn the adjuster to the setting you looked up in the owners manual. seesecurity. Mar 4, 2019 · A detailed video on compression ratio in reference to timing. 3%, is more effective than the same percentage increase beginning with a higher ratio: 12. ”. Raising the clip lowers the Apr 26, 2022 · Got these 862 4. Add the swept volume and cylinder volume together first. Jun 27, 2019 · A higher compression ratio (CR) is beneficial for engines. Building 2, 7200 73rd Street North, Pinellas Park, FL, 33781, United States 763-263-3966 Matt@dynoguysmn. 5 = 139 PSI). The higher the octane, the more resistant the fuel is to detonation. I’m looking at the potential option to improve the efficiency of my 2016 Chief Darkhorse 111 by increasing the compression ratio. Feb 9, 2022 · Decreasing chamber size increases compression ratio. By changing the flat-top pistons to high compression ones that curve upward to result in a higher compression ratio. Plug your numbers into the formula CR = (Vsw + Vcl) / Vcl. , 3. If you decrease the size of the combustion chamber (100cc down to 90cc) then compression ratio goes up. 5:1 and 14. Feb 3, 2022 · Many factors can cause a decrease in compression on a motorcycle, but luckily it’s usually an easy problem to fix. an 8. From my personal research, there is only a very few things to get more power from these bikes. 010” of valve recess into the head adds to the combustion chamber volume as Nov 22, 2008 · May 27, 2013. In that case, you can do so by removing the material inside the piston’s top of the cylinder’s head. This can be achieved by installing higher compression pistons. com. 5. Get accurate compression without the guesswork! Get your engine's optimal compression ratio and total displacement in no time flat! Just complete your engine setup, click calculate, and you’re on your way to maximum performance. September 22, 2022. Jun 4, 2015 · 8. com/parts/tusk-compression-tester-p?utm_source=youtube&utm_medium=howtotestenginecompressio May 29, 2003 · Preload. 9 to 1 compression ration piston is 1. 030 inch overbore. Get off, and take the Feb 9, 2010 · What is the easiest and best way to increase my compression ratio? I have a 460 out of a 1986 F350. In general, it is desired to have a high compression ratio, because it allows an engine to reach higher thermal efficiency. 1:1 jumps to a more impressive 10. Thanks for the help. (2) High speed. R. 0-1, a change of +12. Use a cable-tie, compress the forks, let them settle and push the cable tie up to the outer dust seal. Aug 13, 2015 · I'm going to have the cylinder of my 2004 TT600RE motorcycle rebored (because it's damaged, not to increase power). 22:1. However, since the air and fuel are both more highly compressed, there will be more heat. We take a look what effects higher compression has, designing high-compression pistons, and what factors to address when considering adding one. Let’s revisit the compression ratio spec of 9:1 (pronounced as “nine to one”): – The “9” refers to the point when the piston is at its Bottom Dead Center – The “1” refers to the point when the piston is at its Top Dead Center. By increasing the compression ration from 8:1 to 9:1, for example, you can improve fuel economy by about 5 to 6 percent. Think about this for a minute: Your engine actually produces more power than it delivers. Valves that are recessed into the head or modification of the combustion chamber will increase the volume and lower the compression ratio. It’s simply a comparison of how much volume it can hold at maximum size (when the piston is at bottom dead center) relative to the volume at its minimum size (all the way Jan 6, 2016 · Milling involves removing material from the cylinder head (or block deck surface where the heads and block meet) to effectively reduce the volume of the combustion chambers. compression increases also help with large cams in the lower RPM ranges. 15:1, but add 6cc with a larger chamber May 24, 2017 · The nominal compression ratio is the one that is calculated as the ratio from the total volume of the cylinder at Bottom Center to the total volume of the cylinder at top center. Higher compression ratios allow the same combustion temperatures to be achieved with less fuel. Dec 20, 2023 · Our first step is to determine the volume of the cylinder based on bore and stroke. With small-bore engines you may push the compression ratio up to perhaps 6. Compression Calculator. Both the rebound and compression cartridges in the suspension will have this ‘needle and seat’ arrangement. If you dome the piston by the same amount, you increase compression accordingly. 3 LS heads shaved . The wrong amount of compression damping will result in a ride that feels harsh and bumpy. Increasing the cylinder capacity can potentially lower the compression ratio, but this very much depends on the stroke, rods and pistons selected. On a four-stroke, the compression ratio is increased by using a piston with a higher dome. Something going on in that cylnder. Dec 23, 2018 · 0. Mar 8, 2019 · So there’s a short answer and a long answer to the question asked in the title of this article. Raising the compression ratio increases cylinder pressure, and cylinder pressure is what drives the pistons, turns the crankshaft, and ultimately makes the wheels go around. 5:1 CR, running any boost would be suicidal unless you want to run 100 octane gas everywhere. Jul 3, 2018 · Compression ratio is an important determinant in an engine’s “personality. Resize Image. 5. Found 150# one the rear and 135# on the front. com/countersteer?utm_source=youtube&utm_medium=description&utm_campaign=How_to_Perform_a_Co Considering all the advantages of high compression, one might wonder why anyone would not use a high compression ratio. These are not exact numbers but like you said "ballpark" If you give me the cyl head cc and Jun 16, 2014 · Turn your adjuster, counting each click, until you reach the stop. Thats with a heavy cam and steel heads. 0 to 1 but in reality, the piston sits in the cylinder about . Too soft spring ratio: – Gives good traction in acceleration. The problem is that the M52 engine head simply doesn't flow enough to move the torque peak from 4500 to 7000rpm. Mar 5, 2024 · Increasing the compression ratio in an internal combustion engine is a proven method to enhance its power and efficiency. This will raise the overall compression in the engine. Mar 19, 2004 · Decking: Shaving down the "deck" of the engine block to reduce the size of the combustion chamber, thereby increasing the compression ratio. garage54. On a two-stroke engine, compression is increased by milling the head (which decreases combustion chamber volume). This measurement is L1. 610 inches in the same measurement? please refer to my first post to A quick, down and dirty test is this. Thus, you also decrease the compression ratio. Jul 10, 2023 · 4. You would severely be octane and knock limited. ru/Promocode "garage2023"This is what we were preparing this engine for in the previous episode. Yes, if you have a total cylinder displacement of 1000cc with piston at BDC and 100cc (combustion chamber) at TDC then compression ratio would be 1000:100, 1000cc compressed into 100cc or 10:1. is 8. I added a little oil to the front cylinder and the compression jumped to 165. Now, if we increase the bore diameter to 4. (1) CR influence on maximum torque. The compression readings should jump up in steps, and finally reach a maximum level. The C. Aug 31, 2018 · To better understand, we’ll take a look at what increasing compression ratio does, what effects this has on the engine, detail how high compression pistons are made, and provide a high-level overview of which applications may benefit from utilizing a high compression piston. However this potential power increase is only available if the gasoline octane allows running the engine at the MBT timing value without detonation. If the heads have been shaved or the cam has been changed, all bets are off. 155-inch bore, our original 10. Mar 30, 2022 · The compression ratio compares the piston when it’s at its Top Dead Center and Bottom Dead Center. 5 : 1. Adjustment is by turns, and measured by rings marked on the exposed part of the adjuster. Jun 19, 2023 · If you want to adjust your motorcycle’s compression ratio, there are a few ways to do so. If compression gets better, rings are going; time for a leak down test. xo ww qz go hg tz up kq dy wg