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arc2arc

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About arc2arc

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    TT Member

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  • Gender
    Male
  • Location
    New Mexico
  • Interests
    Deep dirt and high water with a few trees thrown in for fun!

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  1. arc2arc

    CRF150R loud ticking noise

    I agree with a previous post. Double check your timing and valve clearance. If the piston and valve train could be easily moved prior to installing the timing chain its probable that you are compressing air when you try and kick it over. Remove the spark plug and try to turn the piston with the Kickstarter. If it is easier your valves are working against you. What did you do to the engine during the rebuild?
  2. arc2arc

    How often to tighten chain?

    I agree with your label on the right side of the sprocket tooth as that is the side of the tooth that carries the load, CCW rotation. However your arrow on the left points to a part of the tooth that seldom sees load and has little wear. This may look like wear because the 2 sides are now uneven but the wear has occurred on the right side. Look at how the straight line from the tooth tip to where the line intersects the curve of the tooth. In your picture, wear has caused the intersection to move down the tooth closer to the tip. The left side is in near original condition and the intersection is much higher on the tooth. Anyway this sprocket is in a condition where I would be actively considering the purchase of a new chain, sprocket, and chainring. I ride a 500 EXC and now have 310 hrs on the bike. I just installed my 4th chain so I agree with the previous comment of expecting about 100 hrs for the useful life of a chain. I ride o-ring chains and do not lubricate them except with wax which I use if my next ride is expected to have lots of water crossings. I check the tension of my chain before every ride.
  3. arc2arc

    Polished Combustion Chamber/Head. Good Idea?

    While not confirming your number I note that to those with an absolute need for speed 2% is worth pursuit. Advances in understanding are always obtained at the edge of what's known. The exhaust gases are much hotter than on the intake side so the volume and thus velocity are higher. That might lend credence to polishing the exhaust side as a priority. I point out that the properties of gas flow is not a linear phenomenon so be careful when reaching for conclusions. Without the proper instrumentation to test the results polishing the ports can be a feel-good exercise based on what your mentor has passed down to you. Most riders will improve their performance by a larger amount if they get well-fitted underwear! If you are interested in this topic, I suggest you look up gas flow through an orifice as a function of the radius at the edge of the opening. Small differences can make for very large swings in flow rates.
  4. It doesn't matter if you have done a hundred of the taps jobs or if I have. The question is does Atolduso feel comfortable doing the operation. Since he needs help knowing what to do I believe he has not been busy tapping blocks in his spare time. His was not the type of question you would ask if you don't have the experience.
  5. arc2arc

    Polished Combustion Chamber/Head. Good Idea?

    If you are chasing performance polish the intake and exhaust porting. Be sure to round any corners that are not a mating surface. You want laminar flow and sharp corners promote turbulence. The inside surface of the head, and sometimes the top of the piston, will build a layer of carbon deposits that will quickly eliminate any gain you received from the polish.
  6. This should be at the very bottom of the possible solutions. Risk of damage due to chips or a broken tap is just not worth the risk since a simpler solution must exist. If the bike was together when you got it follows that something you have done has caused the incorrect fit. Find it! I would take all the bolts out and then set them back in the holes with zero engagement of the threads. The distance from the mating surface to the bottom of the flange on the bolt should be equal for all the bolts. Play mix and match to get the bolts into the correct holes.
  7. arc2arc

    500exc Speedo parts?

    Check the OEM parts list. The larger, on-line stores offer free access, pricing and availability. If forced to instal an entire new unit log the current hours and mileage on your meter at change over into your maintenance log.
  8. I am not a certified technician so I cannot deduce the manufacture's intention of the specification. However some deductive reasoning might help. Remeasure the concentricity and clock the position of the high points on each side. If they align the part is within spec as both side of the crank would move in tandem and you would take the difference of the 2 measurements. If they clock on opposite sides you could be out of spec as the crank would wobble by the sum of the measurements. What the manufacture is attempting to control with this specification is the bending of the crank between the main bearings as it turns and is forced to accommodate the lack of concentricity. The stress will go from max positive to max negative once for each revolution of the crank. The bending from non-concentric centers is additive to the bending from the load induce by the piston. If the 2 bearing surfaces are perfectly concentric the bending stress in the crank under no piston load would be zero.
  9. I have never seen a rim break like what you have shown. Looks like fatigue failure. As the tire hits the dirt there are 2 paths for the load to be distributed. 1st The weight of the the rider and the bike are carried by the spokes at the top of the wheel putting them in tension. 2nd The force of a impact, such as a landing, should be distributed by the tube to the entire inside of the rim. Too big a load or tool of air pressure can allow a point load at the edge of the rim. A snake bite and tube puncture is typically the result. What tire pressure were you riding? Did you check it prior to the session? Did you have any indication of low pressure while riding? When was the last time you checked the tension of your spokes? If your spokes were loose the amount of load carried in tension at the top of the wheel would be reduced and the amount of load and flex demanded of the rim at the contact patch would increase. A combination of loose spokes and too low of inflation on the tube might have allowed the rim to flex in a manner it was not designed to do and eventually the result was metal fatigue. Based on the amount of dirt on the tire it appears the soil was soft and that might have prevented you from feeling the condition. You are one lucky dude that the rim didn't catastrophically fail while at speed! I would not replace that product with another rim from the same manufacture without sufficient explanation. Its your neck. Not theirs!
  10. arc2arc

    Opinions on Handguard Mounts??

    For 5 years I have run a BRP bar mount, with isolation bushings, and have direct mount SICASS wrap arounds. Over the years I have had lots of drops and crashes but have never been let down by the performance of this setup. The mounting is much more secure and in my experience is better at keeping things in alignment when the going gets tough! With my previous conventional setup it used to be common occurrence to have my wrap around get rearranged from a crash or nasty drop. Sometimes to the point of interfering with the clutch or the throttle which required disassembly for realignment while on the trail, much to the dislike of those riding with me. The rigid mount and the beefy structure of the wrap arounds has taken care of that malady. I won't be going back to a traditional setup.
  11. arc2arc

    Rear brake pedal while standing downhill

    The riding in that video series is impressive! Love the "turn left to go right" on the downhill switchback. Never tried that. Now imagine riding those switchbacks with a 25 lb chainsaw on the front fork and a 40 lb pack on you back. If that's not hard enough consider that your authorization to ride the trail is contingent that a person on the trail 1 week out should not be able to tell a moto was on the trail. That means if you skid or roost you have to get your butt off the bike and repair the trail tread. Replace your divots riders! Keep those trails open. I clear trail for the forest service and those are the rules that are defined in my Volunteer Agreement. In return for being considerate with my use of the trail and providing a service to the district ranger, within the forest district I serve, I can ride on any trail I want. It is not easy and it requires compromise but it is a sweet deal for all involved!
  12. arc2arc

    Rear brake pedal while standing downhill

    All of the above suggestions go out the window as soon as you need to brace with your right foot while navigating a tight right hander on the steep. If you really feel the need to use the rear brakes on the downhill (I do) make it simple on yourself and instal a left hand rear brake. Rekluse makes a very nice one that is super simple to instal!
  13. arc2arc

    Big backfire issue and Tail light wiring

    As previously mentioned in the post above backfiring is a good indication of too lean a mixture. Buy a set of jets and have at it! Cool bike.
  14. arc2arc

    Top end rebuild, what happened?

    Anything unusual about when you drove the piston out of the compression sleeve and into the cylinder? Could you have raised a burr on the rings? At this point what has been done has been done. If you can't find anything obvious sitting on the rings you might as well put it back together and run it until more symptoms develop. What have you got to lose? If you want to address it with more certainty you are pulling the piston, resurfacing the cylinder, installing new rings etc. so why not let it run and look at it in a couple of hundred hours or when trouble rears its ugly head.
  15. arc2arc

    Top end rebuild, what happened?

    Anything unusual about when you drove the piston out of the compression sleeve and into the cylinder? Could you have raised a burr on the rings? At this point what has been done has been done. If you can't find anything obvious sitting on the rings you might as well put it back together and run it until more symptoms develop. What have you got to lose? If you want to address it with more certainty you are pulling the piston, resurfacing the cylinder, installing new rings etc. so why not let it run and look at it in a couple of hundred hours or when trouble rears its ugly head.
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