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tim512

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Everything posted by tim512

  1. Intro A lot of the time on these forums the topic of timing is thrown around: “My bike won’t start?” – “check your timing”. “How do I detune my YZ250’s hit?” – “retard your timing” “I’ve got detonation problems!” – “retard your timing”. “I’m looking for more performance and am willing to run race gas” – “advance your timing”. “I’ve just bought an aftermarket crank” – “make sure you check your timing as mine was 6 degrees retarded” When should I test/change my timing, common reasons: - To make sure it is set correctly because its easy to do - You bought an aftermarket crank (set it back to zero degrees or otherwise) - De-tune the hit when you get on the pipe (1 or 2 degrees retarded) - To combat detonation problems (1 or 2 degrees retarded) - You're playing with your squish/shaved down your cylinder head (only because this can cause detonation problems) - Looking for minor performance gains and are willing to run race gas (1 degree advanced +) note: I am no expert on this, you should do your own research before considering advancing your timing. - You can also use the process to check if your crank rod and main bearings are in spec. In theory, if there is any delay/free play in movement of the dial gauge when you rotate the flywheel then one of those is out is out of spec. In this thread I intend to - Explain how to put together a tool to check your timing using a dial gauge of FeeBay and an old spark plug - Brief pictorial guide on how to test your timing - What timing is Build the tool As you can see, its simply a dial gauge and an old spark plug I’ve chopped up and put on it. Works perfectly! What you’ll need: 1. A dial gauge. I got mine for about $15 of FeeBay. No doubt its Chinese. Some people will tell you to stay away from Chinese and get a better quality one, that’s up to you. 2. An old spark plug. 3. A grinder or dremel to grind the metal lip off the spark plug ceramic. Pictures of this below. 4. A hammer and screwdriver. 5. A drill Steps: (pictures of each below) 1. Grind the metal lip off the spark plug. This is what holds the ceramic part in. 2. Grind off the arm on the bottom of the spark plug. 3. Place the plug into something such that you can knock out the ceramic with the screwdriver and hammer. 4. You’ve now got your thread! The next steps vary depending on the dial gauge you bought. 5. On mine I needed to drill out the hole a bit as it was too narrow to fit my dial gauge in. See picture. 6. I also needed to shorten it slightly as my dial gauge was not long enough. See picture. edit: somewhere in this process you should consider adding a vent hole such that the compression when the piston is at TDC does not affect your reading. See Mark6299's post Clarification: Shortened it slightly as described above in step 6 How to test your timing Note, the Yamaha service manual has a section on how to test and set your timing to zero degrees. I highly recommend you refer to this, it’s better than my guide below. Steps: (pictures of each below) 1. Remove your fuel tank. Drain your radiator fluid and then remove the hose that attaches to your cylinder head. 2. Screw in your new tool!. 3. Remove your flywheel cover. 4. Rotate your flywheel counter-clockwise, and while doing this pay attention to your dial gauge. 5. At a certain point your piston will reach Top Dead Center (TDC). At this point your dial gauge will stop and start turning the other way. Set this point on your dial gauge to zero degrees by unscrewing the set screw and rotating the face. 6. On a 2000 YZ125 my timing needs to be set 0.02”/0.52mm below TDC. Refer to your service manual for your number (I think YZ250s are 0.007"?). To do this rotate the flywheel clockwise (ie the other way to the way you were turning it before) until it gets to 0.02”/0.52mm (depending on your dial gauge). Note my bike was very slightly advanced. 7. Look at the notch on your flywheel. Is it perfectly aligned with the mark on your stator? If not, loosen the stator screws and align them. 8. You have now set your timing to zero degrees! Yes I know my bike is pretty dirty, but I’ve spent heaps of $$$$$ time and effort on it to make sure it runs great! And yes the engine mount is broken lol What timing is: The Wikipedia article below explains it better than I can. At its simplest – timing refers to at what point the spark plug fires. So by setting my timing to 0.02”/0.52mm Below TDC, that means that when the piston is 0.02”/0.52mm below the top most point of its cycle, the spark plug fires. What a minute, wouldn’t it make more sense for the spark plug to fire when it is at absolute TDC? No – to quote Wikipedia: “The need for timing the spark is because fuel does not completely burn the instant the spark fires, the combustion gasses take a period of time to expand” Changing your timing such that the spark plug fires further from TDC (ie advance the timing) or closer to TDC (ie retard the timing) has various implications. I won’t discuss those here, nor am I an expert on them all. Note that aftermarket cranks are notorious for being set several degrees retarded from the factory and so you should always test your timing if you buy an aftermarket crank. Credit: Mostly, the TT community. I've learnt so so much on here and saved so many $$$ by learning how to do things myself. Carver's original YZ250 timing thread Wikipedia Pete's bike blog Mark6299's post regarding a vent hole
  2. Hey guys I’ve learnt a lot from reading these forums (going from almost zero knowledge to having a good basic understanding about 2 strokes now) however I have now run into a problem I’d like to get help with! I have searched the forums. Basically, while riding my 2001 125 last week 2nd gear was quickly (but not instantly) degrading, like it would slip a bit and by the end of the day it didn’t work at all – it would make the bike just jump around and stuff and the engine really didn’t like it. All other gears were fine so I was just riding by going straight from 1st to 3rd. So I’m going to attempt my first crankcase split, I’m going to buy some tools of rocky mountain (since his videos were really good) to help. Basically because I live in Australia things take a million years to get here and I don’t want to split my cases then leave them for a few weeks waiting for parts, do you think if I order 2nd gear pinion and wheel parts (ie 2nd gear on main and counter shaft) I should be right? Or is it likely other nearby gears are broken too? Or maybe only one part the gear is broken and I’m wasting money getting both? Also, any other tips for a guy about to split his cases for the first time? Or tips for working with the transmission?
  3. tim512

    YZ250 (2008 YZ250) FRONT BRAKE INQUIRY

    interesting perspective since the 2008 they swapped to the smaller and better front bake - at least I thought that was general consensus
  4. tim512

    Latest craiglist find

    "runs good" hahahahahahahahahaha
  5. tim512

    APT Smartcarb

    Can't remember the exact dimensions but fit is definitely an issue as the Smart Carb is bigger. Based on Lectron experiences, getting the thing on your bike will be a pain and it will also cause your airboot to be tweaked and rub on your shock spring. How much - well we will have to wait and see once the first cast units start arriving in people's hands. this issue and the carb's dimensions have been discussed if you search either on TT or KTM talk
  6. tim512

    Extra spring?

    Is it a clutch spring?
  7. I just bought a rattle can of black and painted it... Doesn't hold up too bad and it's incredibly easy to take off if I need to refresh it
  8. tim512

    rear shocker

    1. Got to FAQ 2. Download a manual 3. Answer your own question
  9. IMO unless you can honestly say you rarely ever ever ever go above say 50% throttle I would think the 38 is a better option. The 38 should still have a clean bottom but will allow you to ring it out more which is when the smile is really put on your face. More fun IMO if the terrain you're riding allows that
  10. On your 295 what porting did you get? If mid/top - go 38. If low/mid - go 36. The 38 shouldn't take away bottom but should give more on top. The 36 shouldn't take away from top but should give more top. Your decision.
  11. tim512

    2005 kx250f worth it?

    Buy a two stroke
  12. tim512

    APT Smartcarb

    wow so its now November.....
  13. tim512

    Help with some gas mixture math, please!

    For all the guys saying to get 32:1 in metric you simply multiply by 32... Technically that gives you 31:1 FYI
  14. tim512

    anyone ever seen a jack daniels bike?

    Putting Jack Daniels, beam, etc stickers on your bike will make you look like the ultimate goon,... including energy drink stickers why would anyone want that in their bike
  15. tim512

    Kid gets nailed by a dirt bike

    the guy that hit him didn't even stop...
  16. tim512

    yz125 coolant leak

    more detail needed
  17. tim512

    Not progressing lately

    Write it down then?
  18. tim512

    1999 YZ125 overflow, fuel.

    Had the same problem.. I bought a $2 set of o-rings (pack of like 40 various sizes), threw the right size on and it fixed it
  19. tim512

    Who's paying?

    This is a great thread. You should all be proud,and it also it teaches you how to earn and appreciate things. I'm a young adult now who worked hard during my teenage years to earn and achieve things. Those skills have helped me immensely in life generally and I now own my own house, bike, have a good job, girlfriend etc. Keep up the good work.
  20. tim512

    To Part or Repair?

    ^^^ agree. I would add though, my understanding is prices on used bikes drop during winter too due to less demand. So if you can swing it, buy the new bike in the middle of winter if you find a great deal, and part out the 94 during riding season.
  21. tim512

    Neck Brace For Big Shoulders?

    Ring leatt first and see if they can help you with adjustments etc If possible, maybe also try taking your brace to a dealer just so you can try a few helmets on and see if they make any difference
  22. tim512

    2004 yz250 erratic idle

    My bike does exactly the same thing (I think based on your vid). I'm fairly certain with my bike the issue is the float height which at the moment I'm having problems with and trying to fix (likely just a new viton needle and seat and/or floats needed, so fairly simple and cheap) In short, the float height slowly rises during idle, but while riding it seems to be ok (perhaps I'm burning fuel faster than it leaks?) For more info I have a thread here - the issue is not yet resolved but when I get some time to look into it I'll post updates: http://www.thumpertalk.com/topic/1040428-time-to-replace-floats-carburetor/?hl=%2Bnew+%2Bfloats#entry10970096
  23. tim512

    Any mods that are necessary on a YZ125?

    Things you need to do, IMO: - Jetting - Tune your suspension for your weight If you want to do the SSS swap, you just need to buy the parts of ebay and put it all together, there are other threads with the detail on the conversion
  24. tim512

    Looking for WR Gearbox Information

    Just be careful, there is a well respected forum member adam728 I think who said the 3 to 5 swap was a bad move due to odd gear gaps
  25. tim512

    yz 125 rebuild with some pics

    That poor cr!
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