XR650R Thread!

Discussion in 'Thumpers' started by JustinT, Nov 24, 2008.

  1. Jayrod1318

    Jayrod1318 Poster

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    You say it back fired a few times?

    Sounds like maybe you are 180degrees off on your cam.

    turn the gas off, unplug spark plug and ground it.....Have someone kick it over a bunch of times while putting your hand over the end of your exhaust. (gloved). is it blowing air out or is it sucking it in?

    Like wise you can see if you are blowing air out the carb instead of sucking in.

    Humor me?
  2. BuRPsa

    BuRPsa Finally growing up..

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    Ist,

    Did you ever check if the valves actually seal - like by pouring in meth in the intake & exhaust ports, with the head in your hands or on a bench? A very mild seepage may be acceptable but not clear sweating, never mind leaking.
    In any case I would increase the valve clearance now, goto 0.3 & 0.4mm, and try again, just to get it to run. Also, some 4% 2T premix (yes, oil-rich!) may help in valve-sealing just to get it to run, and obviously this is a temporary makeshift measure.
    When it starts set the carb there where it idles best (only the idling, fork the rest), then go back to proper valve settings, fuel etc, and take it from there.
    With the std camshaft I doubt if one can set the cam 180-deg off, unless you have a non-std flywheel that is. But, this is darn easy to check: take rocker covers off, turn engine until both valves "rock", then check if the piston is in the top of stroke if not TDC. If so all's fine. Mind though, I think valves will hit the crown with a cam 180 degs off so you would have noticed this already, especially seeing you've tkaen the top off already.

    1 thing: the camshaft is stock innit? Not reground or modded in some way?
    Another thing worth checking (dunno what a 'spark tester is, sorry, Thick here :wink:) is the spark. Take a normal 4-hole button. Rig a ground wire through 1 of the holes, and rig the HT through the diagonally opposite hole. Kick the bugger over and you should see & hear the spark, pulling a generous distance. If this works your spark quality is fine.. but maybe this is what that tester does?
  3. BuRPsa

    BuRPsa Finally growing up..

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    Ist,

    one more thing: on the flywheel there's a rectangular piece of metal spotwelded, it is the trigger for the ignition. Is this bit in good nick, the edges not damaged in some way?
  4. slickwill

    slickwill Exhiled

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    If I read your last post correctly you said it was running at some point after the rebuild then stopped? If so then I don't think the theory about the cam being off 180 could be right. After building my engine twice I also feel like you really have to screw something up to end up with it off by 180. The cam installation process is pretty fool proof.

    The fact that it intermittently fires up for a couple revolutions would seem indicate that you have spark. A five dollar spark tester could confirm easy enough that you have spark at all times. As long as that checks out you are left with a fuel issue. This could be as simple as a new plug and some new fuel. I'd also recommend pulling your carb and shooting compressed air through every opening you can find. It should always have a clear path to somewhere else on the carb. You can also run a guitar string through all of the small ports to verify that it is clean.

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  5. galland1

    galland1 n00b

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    Mine acted exactly the same when I had the idle set too low.

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  6. RideFreak

    RideFreak Torque Junkie

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    "Originally Posted by lstzephyr
    Alright I'm bumping this back up with new components and even less of a guess. I've got an entire new electrical system because I thought it might have incorrect spark timing. I replaced the woodruff key thinking that might contribute to missed timing. No change."

    Like I said long ago, I'd have hooked that thing up to something and give it a good pull, enough to turn the motor over consistantly. You're going to wear out the kickstarter and your wallet :D

    Yeah it should start by kicking it but I've had bikes that didn't want to start, pulled them and was able to tell much better what was wrong when they were forced to run as opposed to relying on the kickstarter and having the motor fire intermittently. Also had them fire up, them motor clear out and they run fine. 2 weeks ago we were in Moab and one of the riders showed up on an XR650R to ride with us, his bike hadn't been started all winter. He kicked and kicked, nothing, nada, didn't even fire. He was all ready to pack it up, I tied off to it with my 300 (should have gotten a pic) and gave it a good pull, it turned over for about 50' before it started firing, missed, sputtered and finally cleared out, the bike ran fine the rest of the day. I'd never rely on the kick starter 100%.
  7. nanisx

    nanisx Been here awhile

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    I know works connection discontinued making them.... Just wondering if there is any other company that makes some nice frame guards for the xr650R
  8. Sean-0

    Sean-0 straya carnt

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    http://www.bboffroad.com.au/xr_650r.htm
  9. slickwill

    slickwill Exhiled

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    I meant to make that same statement in my long winded post.

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  10. FlyGuy

    FlyGuy MachineHead

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    Alright gents I need a couple extra opinions on my current situation. I can't get my bike to start again after it died the other day. It was running fine on a new engine rebuild until I turned into the bar and it sputtered and died. I figured it was low on fuel and didn't bother with it. When I went to leave I couldn't get it to start. It hasn't started since.

    I have:
    New fuel
    new petcock
    new fuel line
    new spark plug
    new coil
    new wiring harness
    new stator
    new coil pickup
    new woodruff key on crankshaft
    Checked for spark(has spark on spark tester and when holding plug to head)
    Top end is fresh(new piston/rings/valves/seals/tensioner/cam chain etc less than 8 engine hours ago)
    Checked cam chain, cam timing, valve clearance(all in spec)
    Cleaned the carb thoroughly ( tore it down completely and had it dunked over the weekend by the local machine shop)
    Attempted bump starting (the bike only locks the back tire, I need a bigger hill)
    pulled cylinder off and checked valves/piston. Everything looks fine.
    Swapped cdi with ebay xr400 cdi that was stated as pulled from running bike
    I'm working in a 70 degree shop so temp is not an issue.

    After the carb cleaning it would periodically fire 3-4 revolutions then die. Barely more than the spin of the kick. Starting fluid has no effect other than raising the amount of backfires.

    I swapped on my recently rebuilt HS40 Carb (mikuni tm40) to see if it was still a plugged pilot circuit. No change except it will fire 3-4 revolutions every other kick now. I think that is because the accelerator pump allows me to toss fuel in. I didn't want to add another variable(new carb) but I wanted to rule out the stock carb as the issue.

    So my thinking is that it could be one of a few things:

    Unlikely:
    Loss of compression(it is still more difficult to kick than before rebuilt so it appears to have compression)
    CDI(only failure symptoms I can find say that there is no spark with a dead cdi, I have spark so probably not cdi)
    Plugged pilot circuit in both carbs (I checked both thoroughly, especially the hs40)

    Where do you live? I may open a Honda dealer next to ya

    Wow that's a lot of parts and work for no result

    In hind sight a timing light would have answered allot of questions about Ignition timing and ignition performance before the parts replacing started.

    The manual has a section on what to look for where you use a timing light pointed at the crankshaft where you should see a (F) on the flywheel when the timing light strobes.

    But To push start the 650r should be easy, But you might not know?

    Start in neutral and pull in the compression release
    have someone push you Or better yet use a steep hill (I try to stop on downhills when I can)
    Don"t stop at the bars anymore unless they run to a fairly steep downhill OK
    Once up to peak momentum jam it in to second and wait for the engine to build a bit of momentum then let out the compression release.

    OK from here go to a hill with 200 foot or more of rapid decent and get the thing to spin over if on a steep hill you can bring on the throttle (good).
    Now bring a plug wrench with ya and if it don"t start buy the time you are at bottom of the incline, pull the plug and see if it has a wet appearance?
    if yes then look at spark timing and cam timing.

    You say its harder to kick ? that may be because you set the cam to the (f) mark on the flywheel instead of the (T) mark?

    On the spark timing I would invest in a cheap timing light.

    And if the plug is dry and you cant smell fuel Look at carb again

    Also you cite a series of parts and things you have done but no results, So as a result we don't know if you have added a new problem with the things have been done, as they have not proven themselves in actual service;

    Anyway hope the best and if ya get it going? let us know
  11. crypto666

    crypto666 Long timer

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    Did Istzephyr say what happened when he hit it with ether (starting fluid)?

    That is usually a good indicator of carb problems.
  12. Cpt. Ron

    Cpt. Ron Advrider #128

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    I too vote for a pull start. Last weekend I changed carburetors. Couldn't start it for the life those who tried (I can't as of yet during my ACL rehab). Regardless, three different people tried and couldn't. Granted, they aren't BRP experts, but still adults willing to take my advice. It finally started with a pull start. After that, kick starting it was a snap.
  13. lstzephyr

    lstzephyr Solo con rambo

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    Thanks for the advice guys. I am quite fond of this bike so I am unwilling to give up on it. I tried all the basic normal diagnostic things first. The collection of parts got thrown at it over time. Some were spares, some are now spares but it has helped rule things out. I didn't resort to buying things until months and quite a few hours of messing with it. It stopped running at the bar back in September.

    Camshaft is stock. The flywheel appears normal.

    Spark is present on spark tester but I thought it might be out of time which was the rational for the new components.

    Exhaust blows.:lol3

    Backfires out exhaust with ether. It sounds like a shotgun. It backfires without ether but only after opening the accelerator jet on the carb. Plug isn't soaked but isnt dry either.

    Bump starting was unsuccessful. I have bumpstarted many many vehicles and this bike many times. Something wasn't right.

    Ridefreak: I do need to try pull starting. It has been raining for weeks so I haven't had a chance. It was nice out today and should be this weekend so I will give it a try. It is on the list of things to do.

    The catch is that the compression is 50psi on a compression tester. I tried a compression test early on in this but I thought I had simply done the test wrong afterall it was a new topend. I think that may not be that simple. We re-tested the compression last night after checking to see if the exhaust was in fact still blowing. This time I paid much more attention to the test and I think we may be doing it correct and compression may be wonky. Kicking it feels different than the xr600, which runs, sitting next to it. When kicking it feels like it has compression but at tdc it isn't a sharp kick but more of a slow notchy progression. I'll test more stuff and see what happens.

    Hopefully that answered everyone. Thanks again, and feel free to open a honda dealer next to me and fix this stupid thing already!
  14. Shibby!

    Shibby! Long timer

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    I haven't followed your issues / work so closely but know there was a lot of engine work done.

    Is it possible the rings were installed upside down?
  15. lstzephyr

    lstzephyr Solo con rambo

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    Yeah it has been a long process so I wouldn't expect anyone to have kept up with it all.

    The bike ran for a day or two after the original rebuild though so if they were upside down it probably wouldn't have caused it to stop running. The bike was running fine at 45 mph in 3rd and it sputtered, backfired, surged and died. I doubt a ring, camshaft timing, or something would cause that. Does that make sense?

    It is possible at this point that whatever broke has been fixed and I have introduced a new problem however.
  16. Shibby!

    Shibby! Long timer

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    I'm not sure why rings have an up and down side, but my guess is because it causes them to seat and seal properly.

    Maybe the new rings were sealing well enough (you need compression to make the engine run), but as they wore quickly they suddenly lost enough compression to kill the engine. Now it won't run because you have 50PSI. Have you tried a wet test? (some oil down the spark hole first (tea spoon)).

    If you don't have compression, that's your problem. Valve mating and piston seal.

    Maybe I should go read from your first post. I'll be honest I didn't ready any till I saw the 50 PSI post. haha.

    Dumb question too, but is your decomp functional and not activated?
  17. RideFreak

    RideFreak Torque Junkie

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    I'm wondering if its the auto decomp, again a good pull should get it started if that's the case.
  18. lstzephyr

    lstzephyr Solo con rambo

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    That makes sense about an up and a down side. I hadn't thought about wear and it does have only around 100 miles on it. I guess it is possible.

    I haven't tried a wet test. I pulled the rocker cover tonight to try kicking it over without the cam involved. The kick cycle feels the same, with a lot of compression, and a sort of spongy leaking feeling. Compression may be the culprit.

    We are planning on trying a differential compression test on it. That seems like the next option. If nothing else it will show where the air may be leaking from.

    Ridefreak: Would the pull start overcome the auto decomp? I guess that is speed limited. Its supposed to be nice this weekend so I will give pull starting a try. I'm going to buy you a case of beer if that was the problem all along.:lol3 Unfortunately I think it is more than that.

    Edit: We just put 75 psi of shop air into the cylinder to see where or if it leaked. Its blowing out the crankcase vents so we have a piston/cylinder/ring issue. I'm somewhat annoyed I misdiagnosed it 45 times but I'm also super excited to finally have a symptom that can lead to a resolution of the issue. I guess I'm pulling the engine down again.
  19. RideFreak

    RideFreak Torque Junkie

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    The decomp can stick, had it happen to me. They def have a hard time starting if that's the Case. It is speed related, it should activate at kicking speeds but not at idle speed and above. Obviously it can also cause compression readings to be haywire. I've not tried a compression test on the xrr, not sure if it's even accurate with the ks comp system.
  20. Shibby!

    Shibby! Long timer

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    My money is on rings! Lets hope it didn't wreck your plating or piston.

    Could be a cheap fix if that's it. New head gasket and rings.

    I've had mine stick a few times. I eventually found out that it happens when I stop my bike on my garage pad in gear and let it roll back and stop via the engine compression. It activates the decomp. I then don't ride it for awhile and when I go to kick it, the damn thing won't start. I haven't found out how to disengage it other then kicking it over for 5 minutes. Eventually it fires up.