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Crayvex posted:I did 100+ miles on my 77 CB750K on Sunday and I loved every minute of it. I'm noticing that it is missing occasionally at idle. The plug wires and caps could really stand to be replaced. Should I start with the plug wires or should I try something else? How badly is it missing? Like a little stumble or near stalling? I'd only look into it if its the latter. One thing I've learned from my two old bikes is that there are a lot of little things that you just have to let slide because fixing to problem may either be impossible or require a million hours of labour and fabrication. Once you accept that these are inexact machines using inexact technology its a lot easier to maintain them. My 77' KZ650 is grumpy as gently caress starting from cold. Even with lots of choke I still have to flood the carbs with the prime setting to get any kind of action. Then it sits there sounding like a rock tumbler for a minute or two. I'm sure there is a problem there but I've already replaced the obvious parts and it runs perfectly when warm. Its been 10,000 miles like that and I've filed the problem under "bike is old".
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| # ? Sep 13, 2010 13:32 |
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| # ? May 24, 2013 14:37 |
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Crayvex posted:I did 100+ miles on my 77 CB750K on Sunday and I loved every minute of it. I'm noticing that it is missing occasionally at idle. The plug wires and caps could really stand to be replaced. Should I start with the plug wires or should I try something else? Most common cause of misfires at idle on an old CB750K is carburetor related and usually a sticky float (replace needle valve(s)). If it's ignition related spark wires is not a bad bet, but condensers are more likely. They're about $15. A intermittent failing ignition coil wouldn't surprise me either. To help me diagnose your problem some pictures would be of great assistance. What I'd like to see is pictures of your spark plugs, pictures of the closing surfaces of your ignition contact points and pictures of the closing surfaces of your float valve needles.
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| # ? Sep 13, 2010 14:11 |
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Blaster of Justice posted:Most common cause of misfires at idle on an old CB750K is carburetor related and usually a sticky float (replace needle valve(s)). If it's ignition related spark wires is not a bad bet, but condensers are more likely. They're about $15. A intermittent failing ignition coil wouldn't surprise me either. Just installed new points, condensers, and new plugs. I'll pop the plugs and take some pics. Edit for more info: Bike used to be super cold blooded until I did a valve adjustment. Now it fires up immediately but I have to ride it a few miles at 1/2 choke before I can get it to idle without stalling. The bike bogs terribly on initial acceleration. I suspect the accelerator pump is clogged. It's not stalling or anything, it's just missing here and there at idle and low RPM's. Crayvex fucked around with this message at Sep 13, 2010 around 16:48 |
| # ? Sep 13, 2010 16:42 |
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I've been riding my XL350 without any problems except a ton of noise coming from the bottom end but there was no problem with the performance. However, I decided to take a closer look today and found that 2 bolts holding the engine in the frame were loose and just spinning around. Got out the loctite and tightened everything up. No more noise and my engine sounds even smoother than before. So make sure you check any and all bolts before you start taking apart a bike to find that tiny little noise.
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| # ? Sep 13, 2010 22:43 |
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PROTIP: if you snap a clutch cable at the lever all you need to keep on going are some vice grips and duct tape. (Or at least snap it uphill from a garage you can roll into that will give or sell you such tools)
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| # ? Sep 13, 2010 23:16 |
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cheesebot posted:PROTIP: if you snap a clutch cable at the lever all you need to keep on going are some vice grips and duct tape. Outstanding. 
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| # ? Sep 14, 2010 02:37 |
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There are a few reasons that there's a pair of vice grips in my tankbag... And this is one of about ten.
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| # ? Sep 14, 2010 14:17 |
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So I was riding my 74 GT550 the other day and I noticed that at cruising speeds when I'm not giving the bike throttle, it tugs or hesitates a little bit. When it got dark I noticed the headlight would dim a little bit when the bike would tug and you could also hear it a bit in the motor. When you pull the clutch in the hesitation stops. I was told earlier in the day that one of my clutch plates might be sticking? If that even makes sense? The guy told me to ride it a bunch and it should unstick itself. He said stalling out would might help it break it loose? Anyway, I rode it about 50 miles that day and it rode fine for the most part besides that problem. The next day I took it out for about a 5 mile ride. I noticed that it didn't want to idle and I assumed it was because the engine was cold. Around the 5th mile while cruising at around 35 the bike dies and I pull over. The lights were still on and the electronic start was still working but the bike wouldn't actually start up. Pretty much acted like it was out of gas but it had gas in it. I kickstarted it and it started right back up. It still wouldn't idle but I was able to get it home. Any suggestions on what might be going on with either problem? Thanks. Clinton
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| # ? Sep 22, 2010 19:51 |
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Sounds like a charging system issue or a bad battery. Get the battery tested first and we can go from there.
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| # ? Sep 22, 2010 20:16 |
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clinto posted:I was told earlier in the day that one of my clutch plates might be sticking? If that even makes sense? The guy told me to ride it a bunch and it should unstick itself. He said stalling out would might help it break it loose? halfway down: http://www.ozebook.com/compendium/suzi/bully1.htm This group of GT riders suggests neutral + a few kicks to loosen it up when cold, plus some tribal knowledge re: the pushrod adjuster. This is in addition to Z3n's suggestion above. And if you read the thread in its entirety, you soon find that the owner poured some STP wonder fluid into the case, thereby creating the sticky mess. DON'T BE THAT GUY
Marv Hushman fucked around with this message at Sep 22, 2010 around 20:59 |
| # ? Sep 22, 2010 20:52 |
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It is really hard to miss a sticky clutch if you know what to look for. Does the bike surge forward when you put it into first gear from neutral with the engine running despite you having the clutch lever fully pulled in? If so then you either need to adjust the clutch (at the lever and/or engine) or you have a sticky clutch plate.
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| # ? Sep 22, 2010 20:56 |
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Marv Hushman posted:This group of GT riders suggests neutral + a few kicks to loosen it up when cold, plus some tribal knowledge re: the pushrod adjuster. This is in addition to Z3n's suggestion above. Thanks for the link, any other GT related links would be useful because I can't seem to find much of anything on them. Also, you'll have to excuse me because I'm really not at all knowledgeable about bikes in general. When I was with my friend, I sat on the bike and felt the vibrations of the motor, then pulled in the clutch and the vibrations were a lot smoother and the "off" vibrations went away. That's when we decided it was a sticky clutch plate. I then rode it for over an hour averaging 45-50mph so it seems like any type of sticky clutch plates should have been loosened up by then? Also, the bike doesn't surge forward when I'm in first and have the clutch in at all, that I've ever noticed. As far as the battery goes, I had just charged it because it was completely dead. Although, I didn't charge it all the way, just about for an hour until it was charged enough to get the bike running. Bad idea? Sounds to me like it would be something other than the battery because when the bike died, the lights stayed on and electric starter would still turn but not actually fire the engine. But then again, what do I know. I will recharge the battery and let it charge all the way and see how it acts. clinto fucked around with this message at Sep 22, 2010 around 22:07 |
| # ? Sep 22, 2010 22:03 |
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You can get all kinds of weird behavior with a battery that's low or failing, that's why it's so important to test it and make sure it's good before you move on to anything else. The rattling that goes away when you pull in the clutch sounds like a worn clutch basket or bearing. Once you load it up it stops rattling. If your battery was dead after a long ride, chances are you have a problem with the charging system. Get the battery fully charged, and then tell us the voltage at the battery when you start it and rev it to 3k or 1/3rd of total RPM, whatever is higher.
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| # ? Sep 22, 2010 22:12 |
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Before I forget to post it again.. I put those other shocks on my CX500 and they don't fit the top posts all the way to the frame as the stock ones do due to the wide tophat. So, here's a picture of how they sit.. And yes, I'm rockin them hard. Is this okay? 
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| # ? Sep 24, 2010 00:03 |
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SaNChEzZ posted:Before I forget to post it again.. I put those other shocks on my CX500 and they don't fit the top posts all the way to the frame as the stock ones do due to the wide tophat. I think this is the reason Honda ditched the covers on the original. You really don't want partially secured shocks, nor do you want the covers even close to rubbing against the frame. I think you'll be fine if you add some spacers or a series of thick washers between the shock and frame to fill that gap. Buy longer bolts if you have to. Hardware's cheap. Having one of these work loose and head down the highway won't be.
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| # ? Sep 24, 2010 01:10 |
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Marv Hushman posted:I think this is the reason Honda ditched the covers on the original. You really don't want partially secured shocks, nor do you want the covers even close to rubbing against the frame. I think you'll be fine if you add some spacers or a series of thick washers between the shock and frame to fill that gap. Buy longer bolts if you have to. Hardware's cheap. Having one of these work loose and head down the highway won't be. There's no bolts, the threads are on the end of the shaft there and it's just a nut/washer that secures them. I tightened them as much as I could and even added an extra washer to the outside to snug the nut down further.  Should I still add washers to the inside? They're not going any further in, believe me lol.
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| # ? Sep 24, 2010 19:44 |
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SaNChEzZ posted:There's no bolts, the threads are on the end of the shaft there and it's just a nut/washer that secures them. I tightened them as much as I could and even added an extra washer to the outside to snug the nut down further. I see. Scratch my comment then, as long as there's no play. Keep an eye on them, just as you would after introducing any other new component.
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| # ? Sep 24, 2010 20:15 |
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Marv Hushman posted:I see. Scratch my comment then, as long as there's no play. Keep an eye on them, just as you would after introducing any other new component. I've only taken it for a couple short rides (>5miles) so I haven't had a chance to really test it, but from what I have felt it's a night and day difference. When sitting on the bike (all 260lbs of me) the rear used to drop 3-4 inches, almost to the point where the wheel was tucked in the fender, now it barely moves an inch. I really like how the lowering f/r and new shocks has changed the geometry, feels like a completely different bike. Now for a seat so I don't look so funny with low bars and a touring throne
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| # ? Sep 24, 2010 21:11 |
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New Bantam triples finally back from the machinist! It's taken him forever because he's constantly busy with much more lucrative jobs but I won't trust my designs to anyone else. Edit: Realised as soon as I fitted the forks; The centre stand is next to useless now thanks to the increased clearance. Mocked up (still waiting on the new axle)  
ReelBigLizard fucked around with this message at Sep 27, 2010 around 18:24 |
| # ? Sep 27, 2010 12:35 |
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Yesterday my friend and I brought the BSA back to my house after a few months of tinkering at his house. It kinda runs... http://www.youtube.com/watch?v=UbEnWZAb6ns Now heres the best part... When I got it home from my buddies house, we pulled it out of the truck and he told me that no matter how much he kicked it, he couldent get it to pop. I got on it and 3 kicks later it came to life and idled like a champ. I used to have it in the garage but my bicycle collection has grown in the months it has been gone but its sitting beside the garage now.  So today I go squeeze in there give it a kick and it fires right up. I shut it off, wheel it outside on flats and call my other friends to come over and check it out. they get there, check it out, i go to kick it and the bike wont start. my friend tinkers away and we finally got it to pop over but now it hardly runs! oh well - still looks great...   at the moment its pissing out of all the ring seals and there is oil that sprays just about everywhere - I have to pull off all the covers and check it out.... back to square 1.... LobsterboyX fucked around with this message at Oct 4, 2010 around 06:15 |
| # ? Oct 4, 2010 06:11 |
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So I bought new front pads and a master cylinder rebuild kit for my CX500. Any advice for this weekend to save me some bloodied knuckles?
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| # ? Oct 26, 2010 22:19 |
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SaNChEzZ posted:So I bought new front pads and a master cylinder rebuild kit for my CX500. Any advice for this weekend to save me some bloodied knuckles? I suggest double checking the caliper pistons and piston seals. When I pulled mine apart I found rusty pistons and shot seals, and it was three kinds of bitch getting it all cleaned out and put back together again, but braking improved noticeably.
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| # ? Oct 27, 2010 01:22 |
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benwards posted:I suggest double checking the caliper pistons and piston seals. When I pulled mine apart I found rusty pistons and shot seals, and it was three kinds of bitch getting it all cleaned out and put back together again, but braking improved noticeably. Will do. I still have my SV to ride, so if it's sitting in shambles for 2 weeks while I wait for parts it's no biggy.
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| # ? Oct 27, 2010 20:01 |
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I found a solution to the problem of philips head screwdrivers stripping the JIS standard carb screws on our old UJMs. Read on... I was idly browsing around my local Orchard Supply Hardware and saw that they had Pozidriv bits for $1.50 each. I know these because they are used to secure ski bindings and I tune my own skis, so I figured "why not?". When I later did some reading, I found that Pozidriv and JIS drivers are designed not to cam out, and they are compatible. I tried them out on the turn signal switch assembly of my Seca and they seemed to fit perfectly. For local availability in the rest of the US, I confirmed that Home Depot has a Black and Decker set for $10 that includes Pozidriv bits. Usually JIS sets go for > $30. No more stripped carb screws for me!
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| # ? Nov 13, 2010 20:58 |
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 Just picked up a 1973 Honda CL125 Scrambler off CL for $1100. It's in great condition and pretty much restored. The only thing that might need looking at are the valves but otherwise, it runs like a top. Even came with a second set of brand new tires and a box of all the stock parts which were replaced with NOS pieces as well as tons of spare parts. Only 8000 miles on it but it's my backup bike and my girlfriend's primary.
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| # ? Nov 15, 2010 04:32 |
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Nice looking Scrambler!
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| # ? Nov 16, 2010 03:31 |
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Ok, got a question for you folks... On my CB550 i'm getting a fast ticking noise coming from the top of the engine. Still makes it whether it's warmed up or not. I'm thinking it might be the cam chain needing to be tightened, so i tried that but it just seemed to get worse. I just ran it, so I'll check the tappet clearances (says the bike has to be cold when you check them) in a bit and see how/if they're off? If i still have the noise, could it be that the chain tensioner needs to be replaced?
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| # ? Dec 2, 2010 19:41 |
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clicky noise follows rpm? doesn't go away above idle? rockers or cam chain, yeah. rockers and chain tension worth checking. if it can't be fixed that way, it could need a new tensioner or a new chain, but generally speaking those engines make a lot of clicky noises, especially if they're high miles, and it's not a problem. it's just the way they're built. it would have to be a really pronounced clicky noise to demand attention. they're not supposed to be quiet like a modern i4 car.
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| # ? Dec 2, 2010 19:57 |
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Well I screwed around with it for a bit and have it running a little less noisily now. The worst of the tick goes away now above about 2000 rpm, so I don't think it's anything too serious, and it's not even that bad now. The odometer says 8800, but i'm not sure if the engine is that old or not.... it's in almost too nice a shape for it to be completely original. Is replacing the tensioner a big job? I'm still sorta new with the "working on stuff" thing. Don't have feeler gauges small enough for the clearance though, so I'm still not sure what the rockers are like. I took it for a quick zip around and it revs pretty happily and all so who knows.
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| # ? Dec 3, 2010 00:52 |
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tensioner is in the cylinder block so replacing that means a top end teardown. thats a big job if you're new to working on engines. 8800 miles seems rather low for a 70s cb to me, those things are usually beaten on and parts replaced and etc. including odometer. i'd get some feeler gauges of the right size and check the rocker clearance more carefully. it's not too hard and it's a good job to do for learning about engines. i'm gonna make up a rule of thumb and say if the clicking is difficult to hear above like 3k rpm, your engine is fine. unless you have straight pipes. so change the oil every now and then and it'll last forever. fyi, there is another similar noise common to these engines, though louder and uneven and more like a clunk, which is heard mostly at idle. it is some slap (looseness) in the primary chain (chain between engine and transmission) and it is not fixable without a total rebuild, but is also ignorable unless it's really loud.
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| # ? Dec 3, 2010 03:15 |
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Ok that sounds good. Yeah i think there must be a bit of slack in the primary chain because there is a bit of noise coming from that area, but it goes away if any throttle is applied so I'm not gonna worry about it. Thanks!
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| # ? Dec 3, 2010 13:06 |
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Don't forget that many of these older bikes have tons of clutch rattle. My 77 CB750 sounds like a box of rocks until I put it in first gear.
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| # ? Dec 3, 2010 15:25 |
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Crayvex posted:Don't forget that many of these older bikes have tons of clutch rattle. My 77 CB750 sounds like a box of rocks until I put it in first gear. My KZ650 makes awesome noises when its cold and in neutral. Its like the clutch basket is trying to pound its way through the case. I thought this was an issue but the guys at kz650.info say no big deal if it goes away when its warm. Its a spectacular array of noises when I haven't tensioned the cam chain as well after a lot of miles.
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| # ? Dec 3, 2010 15:38 |
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Took it in to work to get some properly sized gauges, most of the tappets were pretty loose. Set the tension on the cam chain after that and all of the noise from the top is now pretty much gone. The noise from the primary is still there (only at or around idle and still not even all the time) and some of the old guys were freaking out about it, but it's nothing crazy and i don't feel like completely tearing down the engine this winter! Definitely is going to need some carb cleaning/syncing though.
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| # ? Dec 3, 2010 18:23 |
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Carbonate posted:carb cleaning/syncing this will help the primary chain slap noise too
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| # ? Dec 3, 2010 19:48 |
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Rode 50miles from San Francisco to Milpitas on my girlfriend's 74 CL125 at 4AM going 55mph the entire way. Getting passed by everything sucks and makes me wish I had my 82 CB750F running proper. Does anybody have any recommendations for good dual-sport tires that will fit a 78 XL350? I was just thinking about running trials tires as I live in the city.
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| # ? Dec 5, 2010 05:36 |
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i dunno about dual sport tires but there's a guy on a moto-guzzi forum i know who seems like a pretty hardcore rider in that he rides year round, and he runs cheng shin trials tires the whole time. i thought that was insane and the knobs would just pop off or something but he swears it works great. and works in snow too. but that is a guzzi owner so take it with a grain of salt.
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| # ? Dec 5, 2010 07:50 |
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EvilCrayon posted:Does anybody have any recommendations for good dual-sport tires that will fit a 78 XL350? I was just thinking about running trials tires as I live in the city. This doesn't make sense. Anyway, Metzeler makes some pretty awesome tires for your bike.
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| # ? Dec 5, 2010 14:04 |
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I can also vouch for the CS trials tires. They wear relatively quickly but they are cheap as hell and sticky enough that I could drag pegs on my friends klx650 on the road. Edit: They're on the cb200 in my avatar too. Z3n fucked around with this message at Dec 5, 2010 around 18:15 |
| # ? Dec 5, 2010 18:11 |
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| # ? May 24, 2013 14:37 |
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Z3n posted:Edit: They're on the cb200 in my avatar too. I'd like to see the un-cropped version of that picture sometime...
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| # ? Dec 5, 2010 19:20 |
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