At my wits end on project 500X....

[Billy Golightly]

As some of you may, or may not know, I've had a pretty shitty run of luck lately between alot of things going on here. So I decided I'd pull the ole 500X out from the back of the barn and start working on it again and bit to see if I could get it running enough to atleast putter around on, something to make me feel like I was accomplishing something on it other then it just sitting in the shop collecting dust. So, I'll give everyone a brief as I can be (Still probably not so breif) history of the 500X motor and how it is.


After it was fully assembled (New piston, borejob, new rings, valve job, new reeds {Yes, I know 4 strokes aren't suppose to have reeds. Yes, I'm sure it has them. No, I haven't been smoking dope} New timing chain, chain adjuster, valve guide seals, and I can't even remember what all else. My dad built an engine stand for it out of 1 inch steel plate, and we mounted it on there so I could crank it up and run it some without having to get it all back in my frame and something not be right. Then I had to start working on my wiring harness, from scratch. So I spent a day or two studying the wiring diagram in t he Clymer manual I have and got it all figured out. I ended up wiring it direct (Without a killswitch) for now just so I could hear it run and stuff. I pulled the plug, kicked it over a few times while it was on the stand, and I got good fire. We hooked up a small gas tank to the carb made out of a Laquer Thinner can, after a few minutes of kicking, it cranked up, and damn did it sound good. However, it seemed to breakup in the midrange, and evened back out in the topend. So I suspected perhaps a timing problem, going by that I pulled off my rocker cover and checked to make sure the cam was installed correctly, and it was. So at the time I figured I might have just got a bath of bad gas or had a smaller carb related problem and didn'treally worry about it.

Fast forward about 5 monthes to now, motor is in the frame, gas tank is on, everything is pretty much together, but I don't have a good spark. So I change various componets since I had a few at my disposal. I changed the coil, no difference, I changed the coil wire, no difference, changed the spark plug boot, no difference, changed the pulse generator (AKA CDI pickup) and it got better, put the coil back on it and it was firing good, good enough to make me not want to hold the end of it while kicking it over. Everything gets put back together, carb spends 2 nights in a 5 gallon bucket of carb cleaner, fresh gas is bought, petcock on the fuel tank is cleaned, all my cables get routed. Give the carb fuel, checked the bowl to see if its getting fuel, it is, good there. So I then I start to kick it for 10-15 minues and I get nothing, not even a back fire. So I decided we should maybe try hooking it up to our tractor and pull it around some. pulled and pulled and pulled and pulled, never even one fart. So we go back by the shop, I grab some starting fluid, and take my seat and fenders off so I can see the back of the carb. We get moving again and with a little clutch work I get the wheels turning (instead of sliding) in 1st gear. I open the throttle slide and give it a big shot of fluid, nothing happens. Keep giving it to it, I get 1 normal pop. Give it some more, POW, backfire out the exhaust 2 inches from where I was spraying ether (Was a little more cautios after that) and then I gave it a few more squirts and I got a huge back fire out the back of the carb.

Bring it back to the shop, take all my electrical componets off (Except for the stator) and test them with the ohm meter, everything checks fine. Later that night I do a firing test by clamping the plug on the side of the cylinder with vise grips. I'm getting fairly decent spark (Not a big huge fat blue spark, but it is blue). It has more then enough compression, everytime I've pulled the plug it has had a fuel smell (Must be getting gas). I've got the 3 componets for an engine to run, and it won't, and its really pissing me off. The timing setup on it is very similar to a 350X, as its not really adjustable. Both the clymer and my Honda manual state that if you suspect timing as a problem then to check and replace electrical parts such as the CDI or the pulse generator, both of which checkout fine on my ohm meter...So here I set with another "Demon infested trike". Don't feel bad John Swinehart...I know how you feel....I know exactly how you feel.

[hrc200x]

That sure sounds like timing. but since your 110% sure its right it must be. I recently fired up my 350x motor. I kicked and kicked, you could kinda hear a pop, but it was very quiet. I bet it was kicked over 50 times before it fired up. It never once backfired. You said you had a backfire out the exghaust, do you have a full exghaust on it, or just the head pipes? Are they by chance plugged or the muffer plugged?

How fast would you say the tractor was pulling it?

[Billy Golightly]

Only the headpipe is on it, I doubt its clogged because when the tractor is pulling it and turning it over, you can feel air coming out of it (Already had a similar thought, from when I seen the picture of the guy that had the collapsed exhaust {sorry, forgot your name}). The tractor was probably going near 10mph, maybe a little faster. It was moving pretty well.

[Rocketman250r]

I know you say you have checked the timing, but that sure sounds like what it is. You sure your cam is not off by 180 degrees?

[Billy Golightly]

I've had it apart and checked once and it was right...I guess I could do it again though since thats what everything points to.

[hrc200x]

I vote to pull it behind the TRX 250r, get the R into about 3rd gear and see what happens.

[lushatc200x]

its those damned muffler bearings hondaatc. i told you i dont know how many times to replace them but i see you havent so.

[plkmonster2]

take off the reeds. it probably takes the gas to long to get to the engine, or it might not get enough because the valves open before the reeds, then the reeds close quikly. when it takes the gas to long to get to the engine, it doesn't pull enough in, or it pulls it in too late, causing it not to fire, and to send it out the exhaust. smell the exhaust, is it gassy?

[G-MAN-1]

well now that you work at the honda shop you should bring it there maybe one of the mechanics can help you out?????????????????

[TimSr]

This may have nothing to do with your problem, but Ill offer up the experience. After rebuilding my Z, its been very easy to start, usually first kick, even cold. Came home from riding parked it in the garage for a week. Went to start it, kicked and kicked - nothing. Plug had great spark, was wet with gas. Tried drying inside of cyclinder with lighter (this is dangerous!), whoosh flame ball shoots out. Turned over with kickstarter, repeated a couple times with a few more fireballs, put plug back in, thought cylinder should be dry, still nothing. Removed exhaust, and as I picked it up, a pint of gas pours out all over my shoes. By this time Ive concluded the floats didnt shut off, and the entire thing was thoroughly flooded, and the crank was probably full of gas too. I didnt want to turn the whole thing upside down, so I took the plug out, left exhaust off, and turned motor to position piston to the top. I off course turned the gas off, and drained float bowl. I let it sit for a couple days open, to dry out, and went back in. First kick, it fired up (exhaust was still off) blew gas all over front wheel from the exhaust port of the cylinder which, of course, ignited and set teh front wheel afire. I sprayed it with the handy water sprayer and put my wheel out. I put the pipe on, fired it up, and let it run for a while as it billowed out plumes of blue smoke for a few minutes until it dried out. After that, back to normal.

[Billy Golightly]

Thanks TimSr...I was actually considering a similar problem. Last night when I started to take my rocker cover off again to re-check the timing, and I took the timing plug out on the left side cover (To align the marks) I thought I might have smelt a little bit of a gas/oil mixture on the back side of the plug. Definetly something I'll check into.

plkmonster2, The reeds were checked right after it was running the first time, as I had thought maybe that was part of the problem too, but they were fine. I just don't get how it ran before and now won't, unless its a problem similar to what TimSr is saying, Or something completely different that just happens out of the blue.

[350Xrider]

The XR500 motor is bullshit all together,I mean it is a strong motor but they did some stupid stuff.I have a 1980 XR500 and it had a broken kicker shaft as did almost every other xr 500 i've seen,and you have to split the cases to do that and to put the countershaft seal in. I can split the cases in next to no time though,I thought a little and worked around taking the top end and the crank off the motor(because of how the cases split horizontally).That motor is a bear to lug around to get on the bench and move around it weighs like 100 lbs. I think mine is out of time,almost every single time you kick it,the kicker comes back up violently,and if your reflexes aren't quick enough you'll loose a leg over it. My counter balancer is off a little,but that shouldn't cause that.And I put a brand new countershaft seal in and wiped the shaft off and put a little grease othe seal and everything and it still leaks around the shaft,and I'm not about to split the cases over it again,I could rig it and fix the problem,but i was hoping it would seat in if I let the bike set and run with a fan in front of it so as not to over heat and I took the chain and sproket off and put it in 5th gear and tried to get the seal to seat in but it still wouldn't. Any suggestions on any of this? Thanks

[86350X]

It deffinantly sounds like timing. I have an 82 500r and The reeds are no problem. You should concentrateon your cam and ignition timing,, but like ou said it ran before, so your cam is probably fine,,, is there any chance you have a valve stuck open? And even though you have good spark, you need to make sure it is at the right time also,,,,, Good luck

[Bill X_R]

[quote="TimSr"]I sprayed it with the handy water sprayer and put my wheel out. quote]

LOL...Hey Tim....Good thing that pint of gas didnt decide to ingnite! Might have made for a good bomb!

[Billy Golightly]

The XR500 motor is bullshit all together,I mean it is a strong motor but they did some stupid stuff.I have a 1980 XR500 and it had a broken kicker shaft as did almost every other xr 500 i've seen,and you have to split the cases to do that and to put the countershaft seal in. I can split the cases in next to no time though,I thought a little and worked around taking the top end and the crank off the motor(because of how the cases split horizontally).That motor is a bear to lug around to get on the bench and move around it weighs like 100 lbs. I think mine is out of time,almost every single time you kick it,the kicker comes back up violently,and if your reflexes aren't quick enough you'll loose a leg over it. My counter balancer is off a little,but that shouldn't cause that.And I put a brand new countershaft seal in and wiped the shaft off and put a little grease othe seal and everything and it still leaks around the shaft,and I'm not about to split the cases over it again,I could rig it and fix the problem,but i was hoping it would seat in if I let the bike set and run with a fan in front of it so as not to over heat and I took the chain and sproket off and put it in 5th gear and tried to get the seal to seat in but it still wouldn't. Any suggestions on any of this? Thanks

The early XR500's are a bit odd...considering they have reeds and how the cases split verticly..About your countershaft seal, if theres ever been any wire or anything of that sort wrapped up around the countershaft, it could have burred the countershaft its self, or gouged out the case enough that the seal would still not seal properly. Oddly enough I have 3 XR500 motors and all of them have the kick starter shafts intact? Maybe I'm not so unlucky after all