Jump to content
Sign in to follow this  

'87 XR600R request for help

Recommended Posts

OK, I've gained so much valuable information from lurking over the past year, but my '87 is driving me CRAZY, :thumbsup: so I have to reach out for help.

To begin: Starting is difficult. It's a '87 dual carb, no surprises there. I've cleaned the carbs carefully and blown them out thoroughly several times. Odd jetting - the pilot is a 45, the two mains are 110. I've cleaned the air cleaner carefully. The snorkel is OUT of the airbox. I've checked the valve clearances on the intake and exhaust valves, and they're set per the manual.

Electrical seems within spec. I've checked the coil and the stator resistances, and both seem correct. Now, I've read conflicting information regarding the stator, so perhaps someone can correct me. I've read specs for the stator resistance of 230 - 440 ohms. I'm measuring 420 ohms cold, which is high but within spec. That sound right to everyone? I get spark when I do a spark check, and it seems a bit on the weak side, but its clearly visible and sparks on every kick.

The bike acts as if the jetting is too rich. After 5-7 kicks, she starts spitting gas out of the overflow tubes from the carbs, and occasionally will let out an almighty backfire. I've checked and set the float levels several times, and they're per the manual. The float needles look OK, but perhaps they aren't sealing properly. The needle is set at 1 3/8 - 1 1/2 turns out. The main jets seem outrageously lean, at 110's when the stock jetting is supposed to be 122, but the bike runs fine once it gets started. It seems like all my problems would be with the pilot jet, but the pilot is the stock size!

I'm pulling my hair out because the bike won't start consistently. As I've said, it acts like it's too rich, but it should be just fine. The main jets should only affect how she runs, but when it fires off, it idles nicely and pulls like a tractor when I ride it.

I've checked spark, fuel, and air, and all seem good. Anyone think I should ditch the stator and get a new one? Help!

Share this post


Link to post
Share on other sites

What happens if you turn the fuel on and just leave it sitting for 2,3,4 whatever minutes..Does fuel start coming out the overflow. If it does then it has a stuffed needle jet..(above the float) and it either needs cleaning or replacing if the clean doesn't work. They have a tiny spring inside them then the pin which acts on the float tang. If the pin jams gas continues to flow thus flooding the engine and thus leading to massive backfires as the cylinders flooded with juice..Fix it and see how you go.. Also that pilot seems way to small,,that's a stock 86 XR600 size..an 87 XL is supposed to have a 62 or 65 in it..,,those mains are also kinda small..Is the bike modified at all exhaust wise or is it all stock??

Whoops,,,misread..XR,,same stands for the flooding but as you say smallish Pilot even if it's stock..I'm as large as I can go in my 86 XR with the pilot which is a 65,,Thats an XL Pilot ,,you won't find it in an XR fiche,,I run both 125's as mains but I run a CRF450 exhaust on it..,,anyway,,check that needle jet regards the flooding and if you ever do the Tappet gaps don't set them to tight as that'll also lead to massive kickback and backfires..better a tiny bit loose than to tight in there..it's a very fine line between easier starting and a real pig to start with Tappet gaps..

Edited by Horri

Share this post


Link to post
Share on other sites
OK, I've gained so much valuable information from lurking over the past year, but my '87 is driving me CRAZY, :thumbsup: so I have to reach out for help.

To begin: Starting is difficult. It's a '87 dual carb, no surprises there. I've cleaned the carbs carefully and blown them out thoroughly several times. Odd jetting - the pilot is a 45, the two mains are 110. I've cleaned the air cleaner carefully. The snorkel is OUT of the airbox. I've checked the valve clearances on the intake and exhaust valves, and they're set per the manual.

Electrical seems within spec. I've checked the coil and the stator resistances, and both seem correct. Now, I've read conflicting information regarding the stator, so perhaps someone can correct me. I've read specs for the stator resistance of 230 - 440 ohms. I'm measuring 420 ohms cold, which is high but within spec. That sound right to everyone? I get spark when I do a spark check, and it seems a bit on the weak side, but its clearly visible and sparks on every kick.

The bike acts as if the jetting is too rich. After 5-7 kicks, she starts spitting gas out of the overflow tubes from the carbs, and occasionally will let out an almighty backfire. I've checked and set the float levels several times, and they're per the manual. The float needles look OK, but perhaps they aren't sealing properly. The needle is set at 1 3/8 - 1 1/2 turns out. The main jets seem outrageously lean, at 110's when the stock jetting is supposed to be 122, but the bike runs fine once it gets started. It seems like all my problems would be with the pilot jet, but the pilot is the stock size!

I'm pulling my hair out because the bike won't start consistently. As I've said, it acts like it's too rich, but it should be just fine. The main jets should only affect how she runs, but when it fires off, it idles nicely and pulls like a tractor when I ride it.

I've checked spark, fuel, and air, and all seem good. Anyone think I should ditch the stator and get a new one? Help!

My stator seemed to be ok on my 85 xl,but thay are know to be a problem with starting.I bought a new ricky stator and it seemed to help.

I allso had trouble seting my float.Thay are not brass and I cant help but think thay may get fuel loged?But I have never seen any one talk about the weight of the float.But I have seen holley carbs books that say to weight the float and replace it at a point of weight.Look at your needles close if their Is a ring on the rubber buy new one.If you even think maby you might need new ones, get new ones.Or think of it this way, rubber gets hard after a while so it may not seal as well as new soft rubber IMO. The float can get bent easy,are thay the same hight?

Another thing that helped me to set the float was to use clear tubeing on the bottem of the bowl drain. open the drain valve and hold the tubing next to the bowl so you can see how much fuel is in the bowl.

Share this post


Link to post
Share on other sites

I have XR carbs on my 87 XL. I found 42 pilot to be the best starting aid I ever did,(other than learning "the drill"). 122 mains. Stock foam air filter, supertapp with 12 disks, 2.5 wisco overbore.

I did have a stator failure over time that had me suspecting carb problems until it finally died altogether.

Share this post


Link to post
Share on other sites

Thanks so much to all. . . this forum is such a great resource.

I'm sorry, I forgot to mention: stock exhaust, stock air filter.

I'm going to try changing to a 42 pilot, and see what that does. Floats seem OK. I did the "wait test" as suggested above by opening the petcock and lettting the bike sit level for 10 - 15 min., and no leakage. So I'm guessing the float needles are sealing adequately. I will triple-check the float height, and make absolutely sure they're set correctly per the manual.

Will change pilot jets, and see where that gets me. Any opinions on the stator? Ricky Stator gives a value of 110 ohms (!) for their replacement stators, and that's way over what I'm measuring at 420. But 420 is within tolerance according to the book. Very odd. . .

Thanks all.

Share this post


Link to post
Share on other sites

I didn't measure my ricky when I put it in, but I did notice and like the fact that they split the ignition coil into two smaller ones, and added a designated ground wire that you fasten to the frame.

Maybe the two smaller coils decrease the resistance?

Share this post


Link to post
Share on other sites

This is weird. I got the #42 pilot after waiting for it to be special ordered. Installed the pilot, double-checked the floats while I was in there, sprayed everything out well, etc. Then, checked the valve settings again. Pulled the plug and checked it. Then put it all back together, and got ready to try.

One fairly slow kick to fill the float bowls again, then she turned over nicely on the 2nd kick! Good, right?! But that's all she'll do. It'll turn over easily, chatch for about 3 revolutions or so, and die! I've tried adjusting the main screw slowly in both directions in 1/4 turn increments, making sure I wasn't flooded before every attempt. Nothing except an attempt to run, but no sustained running! Very odd. It happens quickly enough that I can't crack open the throttle a little and try to nurse it along.

I have no clue what to start looking for anymore! The only think I could find obviously wrong was that the regulator strap underneath the regulator was cracked. I used electrical tape to temporarily hold the two ends together and bolted it back down, just in case there was a short of some kind occurring. That didn't seem to affect anything, but I'm going to try and track down a new strap, just in cast.

I can't believe the carb settings are off enough to not allow it to run, but I have no clue anymore. I know the smaller jet will create a leaner condition on start, so I would guess that would mean a richer setting on the main screw. But frankly, it doesn't seem to make any difference. I'm still getting a spark, so that doesn't seem to be the issue.

I'm at a loss here. Not sure what to check next! Anybody have a similar experience? Thoughts on where to look next?

Share this post


Link to post
Share on other sites

Stator gets my vote. Possible CDI unit. There has been discussion of solder joint issues with CDI's. I don't think carb jetting is the main problem, you have not changed it enough to affect running, besides the pilot jet only affects idle anyway. Also try setting the idle speed up just a smidge in case it is too low. Do not give it throttle while trying to start if you value your foot.

You might try a new spark plug just for kicks, once fouled they never return 100%.

Share this post


Link to post
Share on other sites

Perplexing alright..Go with the new plug as Davek suggests..Make sure the gaps correct.. They run like pigs if it's wrong. Also check the tops of the carbs are screwed on properly..Checked mine a while back and found them to be rather loose. Can't aid running having air coming in there. Can we also assume the gas pouring out problem has ceased or is it still doing it.,,??

I wonder if the CamChain hasn't maybe jumped one of the sprockets and put the Valve timing out.. Wouldn't really want to waste your time if it's ok but sometimes the only way to know is to go in with the scalpel..Would require a removal of the Tappet cover to check,,..not fun when the engines in the bike., though I'm sure someone will tell you how easy it is to do with the engine in..

Edited by Horri

Share this post


Link to post
Share on other sites

:ride:

SUCCESS!!!

Thanks much, Davek, and everyone else, for that matter! I changed to a fresh plug, turned up the idle adjustment screw a touch, and she fired right off on the second kick! Quickly shut 'er down, and repeated. BOOM! Away we went again! I don't have it exactly dialed in yet, because there's a slight backfire on ignition, so the idle screw is in a bit too much, but MAN is this a great feeling after so much screwing around!

I appreciate all of your suggestions so much. I strongly suspect a fresh stator will just improve things, but it is great to have the old gal starting (semi) reliably now! I need to do some fine adjustments now to the idle, and probably need to look at the air screw a bit, too.

Can't say thanks enough to the ThumperTalk community. . . ya'll are great!

Share this post


Link to post
Share on other sites

Get it warm and idling, set your idle speed more or less to spec. Slowly, like half a turn every ten seconds or so, turn your mixture screw in till the idle slows a little. Repeat going out till the idle falters again. Turn it back in until you get the best and fastest idle, and then you are there.

That will get your idle mixture about right, all other adjustments if needed will be jetting and/or needle changes.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

  • Similar Content

    • By TheLastByte
      Contemplating picking up a BRP in the near future and looking for some perspective.The current owner claims that the bike has about six hundred hours on it, but there's no way for me to confirm as the odo's not accurate.
       
      I know brp's have a reputation for running forever on stock top ends, but they must eventually have an expiration date. What should I look for on a high mileage bike like this to make sure I'm not setting myself up for disappointment? Also, What are some non engine/transmission related issues I should look for?
    • By TanSnowman51
      Guys, 
      Have been riding my 650L for over a year and a half and have been loving every second! In August I moved back to Reno after finishing up my masters at Arizona State. I have been spending most of my time riding around verdi to stampede and the Dog Valley road area. Always looking for riding buddies. 
      Was curious what everyone was doing as far as Daves mods or jet kit for the upper elevations 4,000 to 8,000 feet?
      FMF Q4 exhaust, smog delete done so far!
       
      Thanks!
    • By Alexandre Askmo
      Hey dear folk!
       
      I need your help.
       
      A bit of background info, I’m a complete noob when it comes to holding a wrench and doing anything more than filling up the bike. I have however had an interest for as long as I’ve had a bike to make it mine, and that’s why I’m writing to you now. I just bought a donor bike, a Honda NX650 which a friend of mine is helping me fix up and then modify to my liking (I’m hoping to end up with a gorgeous scrambler in about 9 months).
       
      We found a hairline scratch in the cylinder and need to bore it. This leads me to my question.
       
      Should I get a 1st overbore performance piston or keep the compression ratio as is? If so is there anything in particular I will need to modify to tolerate the high compression piston?
       
      If I do get the performance piston, should I also get a new carburetor, hot cam, and new exhausts? I am planning on new exhausts anyway (2-1 from an XRL) and I’m planning on removing the airbox and getting a K/N pod air filter.
       
      Again, keep in mind I know nothing, my friend has however fixed up a bunch of XRLs and cars but never really used performance parts. Help me out with the decision please, I would also like to keep the whole build to a reasonable cost (I know this is a very relative number).
       
      I should also add that I want to keep the DNA of the bike, for example keeping the fuel tank instead of switching to a smaller rounder one as one usually sees in most custom builds. The aim of the whole build is to have an insanely fun bike to ride, both in the city and off-road, as well as giving it a bunch of my personality 😊
       
      Thanks a lot for any help!
       
      Best,
       
      Alex
    • By MrCitizen
      I've been rebuilding/restoring an XR650R for some years now (after toasting the motor in 2013). Sent the motor off to be rebuilt, had a local shop rebuild my forks and shock, and took care of most everything else myself.
      As of a couple months ago I had almost everything assembled and ready to run.

       
      As a final check before adding fluids to the bike, I decided to stick my boroscope into cylinder and take a look. The results were concerning.

       
      These boroscope pics looked so gnarly that I pulled the head off the motor to get a more thorough look.

       
      To say that I'm concerned is an understatement. I have pics of the motor internals pre-rebuild, and can confirm that this is definitely a new piston and replated cylinder. I also have all the old parts from the motor, so it does have a new cam, connecting rod, valves, and basically everything else I expected to have replaced.
      The builder "ran the motor briefly to confirm everything ran alright" and then shipped it back to me. I reached out to him with these pics and he said,
      The piston looks like this because he had it machined from 12:1 to 11:1 compression. The streaks on the cylinder wall are normal for one that isn't broken in yet. Regarding the valve impacts in the piston head: "My concern is that something may have passed through the cylinder. How does it run?" I've never run this motor. I can feel these streaks in the cylinder wall with my fingernail. Did he re-use a piston from some other motor?
      Is this dude jerking my chain or is this motor fine to run?
      He's a fairly well-known builder in the XR community and was recommended to me by guys in the (now-gone) XR650R forum.
    • By Jonas Reppe
      I got my XR600r dirt bike giving me a carb issue that I just can not get worked out. It starts first kick and idles well, throttle cracks off nice and crisp when you whack it, but if you ease into the throttle to just above idle it's a spit and sputter pile of shit! Lol. I can turn the idle speed adjustment up to a fast idle and it starts spitting and studdering just the same. Done a lot of research and it points to the pilot circuit. I put a rebuild kit in it and have taken it apart and cleaned it seriously 12 times now. I'm at the point of looking for a different carb body to try. They're about $100 though. A new keihn carb is $250 on eBay. Any thoughts? That pilot adjust screw doesn't seem to adjust anything until it's fully seated or falling out. It has ran ok in that idle to 1/4 throttle circuit before but it don't now. The last 6 removal/cleanings haven't made any changes, previous ones did improve the throttle snap when you whack it.
      The main needle clip is on the middle groove.
      I checked for air leak with some starting fluid when it was idling and seen no change to the way it ran, indicating no leaks. 
      Bike has stock jet sizes, foam filter, stock exhaust. 1,830' elevation here in South Dakota. 
      I'm baffled..
×