KFunk

Hey Andrew (I'm over in Athens, by the way).. I'm still betting you've got carb problems. My bike strangely seems to idle and rev fine on only my right cylinder when its cold... still haven't pinpointed that problem yet, but there's no on-throttle dying even if I pull the plug and everything for my left cylinder. Anyways, I'm new at this... but the pilot jets control only the idle, right? Seems like those might be OK for you. But worth looking at and cleaning if you take the carbs apart. The round slide, followed by the needle, needle jet, and then main jet will control fuel when you rev it. The round slide seems pretty stout, but the diaphragm that controls its operation could get a tear in it and cause it not to operate right. There are lots of pinholes in the needle jet that clog up easily. The main jet is a pretty big hole that wouldn't clog too easily, and mainly just limits the flow at full WOT. Anyways, I'd first look at the fuel level to double check that first, plus its easy to check without disassembly. You could just be trickling just enough fuel in there to idle and draining the bowl instantly as soon as you rev it. I'd just hook a piece of tubing to the bowl drain, and string it up the side, open the drain, and watch the fuel level in the tube to make sure it stays at a decent level. (as was recommended in my last thread)

I don't have a broom, or a drill... but I figured out how to do it with a 3/8" ratchet, 1/4" adapter, and 1/4" drive socket: I went ahead and changed the oil in both. The right side was really rusty and the metal plug wouldnt come out even with circlip removed. I ended up bouncing on the front of the bike and shot myself in the groin area with the fork spring/plug.

Ah, yes I made an attempt myself earlier. Soaked it in PB Blaster and gave a few whacks and moved it, but couldn't hold it down well enough to remove circlip, and I quickly gave up. No wife here. Would it be wrong to ask the new g/f to help?

I'm in the same boat, and can't figure out what you mean Jim. There's a rubber plug at the very top thats easy to access on my bike (somewhere above part 28 in this pic), but theres nothing underneath that but an immovable piece of metal. It looks like you mean part 20, but that must be hidden by the chrome covers, i.e. parts 33 and 34. Am I gonna have to disassemble a good bit of the front end to get those out of there and access the cover you speak of? Anyways.. it appears my left front fork seal is leaking bad, and it bottomed out on a bump while pulling into a parking lot yesterday. Besides the seals, I think I need to change the inner fork tubes... theres some bad pitting on the left one and some pitting on the right one. I'm shopping ebay for better ones, or may try to get some at a bike salvage yard here. Until I get that stuff, I just wanted to top off the oil and keep the bike somewhat safe for riding around town.... unless you guys think i should park it until its done... Yes, I rode it 110 miles yesterday.

Just an update: I placed that order on Thursday night (from AZ), and received the tires here in Ohio on Tuesday. I found a friend that owns a motorcycle shop and he mounted them for $15 each. I've been takin it easy on them since you're supposed to give them 100 miles to get broken in. But its been 50 miles yesterday and they seem fine. I didn't like a strange little seamline protrusion down the center of the front tire, but thats wearing off quickly. I really can't compare these tires to anything so I'm not a good judge. But they seem to fit fine.

Still been starting really hard in the morning. But when it got goin yesterday, the left exhaust pipe warmed right up, so it must be workin now. I think those rings just needed some stretching. So it was warm yesterday and I had my fresh tires on, so I put some miles on it. I went about 50 miles of backroads and had a great time. I think its up to 2075 miles now. : When I had the wheels at the bike shop to get the tires mounted, the shop owner said the sprocket looked brand new and the tires had full tread depth (they were just old and cracked and couldn't hold air). So yep, thats the real mileage. I actually got it up to 70 or so on the 4-lane highway back home. It seemed like I was fighting the wind the whole time, but I'm not used to goin that fast on bikes. My friend on his V-Star 650 said he was fightin the wind too yesterday, so I guess its not just me.

Yeah, I checked the rocker clearances not too long ago, and that seemed fine. It appeared they were opening and closing just fine, but I didn't investigate extremely well. Perhaps worth another look. Yeah... I figure if its warmed up really well I'm sure to get good comp, but should prolly double-check. Just too cold to take it out right now to warm it up right. At least it can't be too hard at all to change the rings on this thing. Before I go that far though, I'll try to run the crap out of it to see if I can get 'em loosened up. After all, this thing is 27 years old, and quite possibly has only 2000 miles on it... perhaps the lil expander that goes under the ring isn't expanding as quickly as it should (if it even has that, like my RX50 has).

Well, I spent a couple days last week riding all around town and out some country roads. :D I had a great time and it felt pretty damn strong, but I don't have much experience with bikes larger than 50cc. I went ahead and synched the carbs using the yard stick/tube/ATF method, and it seemed to run pretty darn smooth after that. But for some reason its a real pain to start if it sits overnight, and then it'll only idle on the right cylinder. Even when revving it in neutral, the left cylinder's exhaust pipe never gets hot. Once the thing gets warmed up after a bit of riding, the left cylinder seems to start doing better, and the idle gets faster and faster and I have to crank down the thumbscrew to keep it from idling too high. I went ahead and swapped the coils between the two sides, and there was no change. Still the left cylinder does nothing at cold idle. I've gotta go ahead with a proper compression test, next? I tried it real quick and got like 100-150 psi out of the left one at first, but then it went to nothing for some odd reason. This is while it was idling on the right cylinder... i know thats not how you're supposed to do it though, and am looking for the proper procedures. With cars, you've got to run it for a while and get it fully warmed up, then pull all plugs and turn it over a few times till you get the highest reading. Same for this bike? In any case... just wondering if the compression rings on the left side are pushing out as much as they should...

hmmm, actually had essentially no spark on the left cylinder! That would explain why the spark plug always looked black there. Exhaust pipe was cold to the touch after some running... engine would die completely after pulling right plug wire, but no change if I pull left wire. It'll arc to the block just fine though, and shock the crap out of me. Tried a couple different plugs, no change. Tried closing the gap some, and then it'd fire and pop at random bad times. Opened the gap up a lot wider, and it seems to run better, and the exhaust pipe will get hot. Also used my hotter plugs I got sittin around. I'm wondering if the coil is just weak. I gotta pick up a decent multimeter and check the resistance on it. At least used coils look cheap on ebay. I'm wondering if it could also be caused by PO's crappy wiring mishaps. Some of the fuses were wrapped in tinfoil.... and they got really hot to the touch before. Wondering if that let too much juice thru and got the coil hot as well (i know my car's coil doesn't like working when its hot). So yeah, I just pitched all of that tinfoil. Ignition didnt want to come on at all at first after removing it, but I wiggled things around and then the lights came on. Supposed to be a warm day tomorrow, might be time for a long ride finally! Oh and I've got my homemade synchrometer all ready to go, and might try it out tomorrow.

There, its purring like a walrus now. It was those pilot jets. Thought I had them cleaned out, but I guess not. I ended up using the bristles on a toothbrush. Figure they can't damage like a wire can. Now I can see light thru them pretty easy. I can't really go for a test ride right now, its 25 degrees and theres snow on the ground. I'm not sure if its revving as smooth as it should yet, though. Seems to want to stumble a bit, then gets stuck at high revs after you let off the throttle. Should probably get building myself a synchrometer...

i think the idle circuit just isn't working. I can get it to stay at a relatively constant 1 to 2K, but only if I apply a little throttle. Cranking in the idle speed screw all the way doesn't help. I think it has to do with that pilot jet I mentioned earlier, and the tip being clogged. The clogged one corresponds to the cylinder that runs lean...Soaking in brake cleaner and blowing with air pump still didnt unclog it. I made another attempt to unclog it, which helped the situation, but didn't solve it. Now I'm gonna try soaking in PB Blaster a while. I don't have a good air gun handy and had been using a 12V tire pump. I'm gonna have to venture somewhere to use a real compressor, maybe. Or maybe I can just use some air from one of my car tires somehow to get a sudden blast.... and yeah, I took the petcock all the way off and went thru it. The diaphragm seems ok in it.

Almost there! I can get it to start with the kick starter alone pretty easy and run for a while, but still doesn't seem to want to idle. I went ahead and took the petcock out and everything looks clean as can be. The fuel level seems to be OK now, but the bike runs way better when its on prime and the fuel level is a little higher. I think I'll try a new hose and clamps on the vacuum line maybe. I took the synch screw out a good bit, too, and that might help. Still seems odd though that right cylinder looks really white/gray no matter how much i richen it, and the left cylinder always looks black no matter how lean I go.

OK, fixed the floats like that, and figured out how to connect the clear tube. Stupidly forgot about the nipple at the bottom of the bowl that is controlled by the phillips screw. But yeah, no real change in running ability of the bike. Seems like the fuel level is pretty good in the tube, almost fills the entire bowl. If I rev the bike a bit it'll take the fuel level down to almost the bottom, it supposed to do that? Anyways problem isnt revving it, its trying to get it to idle. I tried switching to the hotter plugs, and it might run a little easier, but not by much. Either way, the right cylinder always seems to run way way leaner than the left cylinder, maybe the things are way out of sync? I tried to crank up the idle speed with the big knob, but then I noticed it was already cranked in almost all the way.... hmmm, that it explains why it idled really high after getting warmed up before on the few times I had it out riding. I bet the P.O. cranked it that high just to keep it running.... and explains why he got frustrated with it and sold it to me for $150... Oh well, I'll get 'er goin again sometime. I'm thinkin I might have to just wait till a warmer day to get it somewhat running to tune it. It's about 20F here today. I'm in a somewhat warmer attached garage, but I gotta leave the door open when I run it.

Crap, I just realized that. I was thinking the other tang off to the side did that. doh.

i'll see what i can do tomorrow... gotta find a drill and such. quick question on the floats: About the center tabs in the middle, where the needle valve actually rests. Should that be straight across, like on the same plane as the bracket of the float? or should it be bent down away from the needle valve slightly? One of mine was one way and one was the other.... I bent the flat one down to match the other, since it seemed to give the float more room to move. Maybe that was the wrong thing....

Yeah, I was thinking about trying that like you said, but I wasn't sure how to connect the tube. I just have phillips head screws at the bottom flush with the surface. It seems like I'd need a nipple with the right threads that would thread in there. Or are you just screwing a soft rubber hose in there thats a close enough fit?

OK, I got a couple ideas. I could switch and put hotter plugs in to make it run easier. I've got NGK BP5ES and BP6ES standing by, since luckily it takes the same plugs as my BMW car. I also might crank the idle speed way up. Whatever it takes to get it to some kinda of idle, even if really high. Then I'll tune the mixture of each carb by ear till its runs the fastest/smoothest, crank down the idle, fine tune it again, and so on till I get it to 1200 rpm idle and I can use the stock BP7ES plugs. The only other thing I could suspect is the float level, since I messed with it a lot. But that seems like a pretty darn simple and reliable way of checking it, drewpy. It should be around 32mm right? Thats whats in my Haynes manual, hope I got that right. I'll give it another shot tonight, and hopefully get it to go good before pissing the neighbors off too much.

This is gettin annoying trying to figure out how to get the thing to idle. I keep goin back and forth on the mixture screws, and checkin the plugs, and can't get it right. Sometimes it'll start up easy, sometimes it requires some starter fluid. It'll rev up pretty damn high for a while, but will stumble and die if I let off the gas. Should be a dark tan on the plugs, right?

Ohhh OK, I figured so. So the older bikes with points didn't have the plug? That saves me some trouble I guess, till the module or whatever dies... I kinda like points tho in their simplicity to see visually and cost of replacing them. I had wondered when the changeover happened, as my '83 rx50 doesn't have point. I'm still running points in my '74 BMW car tho.

and woohooo, it fires up and runs again. Sounds pretty sweet and free revvin with the carbs cleaned out. It takes some starter fluid to get it goin, and it won't idle yet though, gotta find the sweet spot in the mixture screws I think, and find a screwdriver small enough to adjust them with the gas tank still on there.

Thanks again for all the help, you're providing way more info than the manual. It'd take me forever to figure it out without you. I just checked the valve clearances for the heck of it, and all seem ok with no adjustments necessary. Not as easy to check as my old BMW car, but do-able. Next I want to check out the breakers to see 'em, but I can't figure out how to get out the little plug that goes over one of the phillips head screws that holds the breaker cover in. Looks like I'm gonna have to get a drill, but is there something I'm missing? Sorry for all the newbie-ness, but I can't seem to find much of the info I want thru the search.

i'm thinkin i might just have it set a lot leaner than before... and should try richening it up. I stupidly took out the mixture screws all the way without taking note of how many turns out they were. Then I just checked the manual that said 1 to 1 1/4 turns out, and put them both in at about 1 1/8 turns out. I'm thinkin i should take them both out a turn or two, fire it up hopefully, and adjust from there. It's all stock, but the air filters are kinda burnt up and essentially non existent, so that may be giving it too much air. Oh and I might as well check valve clearances for the heck of it.

OK, I went ahead and did it that way... put it back together.. and it still doesn't want to go for some reason. I put it on prime for a bit and cranked and cranked, and nothing. I tried some starting fluid in the right cylinder, and managed to get it to fire a bit but it wouldnt stay running. Tried left, not so much good. Seems to be fuel coming down from the petcock OK. I dunno... I'll try to fiddle with it some tomorrow evening.

OK, I found some compressed air and cleaned out all passages. Is there supposed to be a hole in the tip of the pilot jet? looks like there might be one in one of them, but not the other... Anyways, I'm a little confused on setting the float height. Do you set it at the position where the float bowl would be full or empty? If I just turn the carbs upside down like in the manual, then gravity makes the floats sink all the down well below the specified height, and the adjustment tang wouldn't help the position it since its sticking up vertically. I assume they must mean the other position, as if you're picking up on the floats to their max height, or if the carbs are sitting right side up and hanging down to their resting position. Just wanna double-check before I put 'em back together.

Nevermind, I got 'em out. Just did some lookin and that section was covered earlier in the Haynes manual, but still kinda confusing. I figured out they could only come out thru the carb throat, got brave and gave 'em a few whacks with the hammer and a screwdriver and they broke free. They sure are nasty looking. I'm gonna soak them over night in something, think brake cleaner is OK? Oh, and on the float needles, it appeared the problem was some weird ridges around the edge preventing it from sliding. I filed them down and polished them off with really fine grade steel wool, and they seem to operate smooth. I still gotta find my ruler to set the float height, and she should be running sweet tomorrow evening.