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orthod0ks posted:I just took my new (to me) GS750 out for my first ride. There's quite a bit of oil leaking from the exhaust though. What would cause that, and is it any sort of an easy fix for someone with no mechanical experience? Are you sure it's oil? There shouldn't be any oil coming from the exhaust. The GS750 is a four-stroke, so the oil should all be contained in the crankcase/valvetrain. If it were a two-stroke, a bit of oil in the exhaust would be normal. Check to make sure it's actually oil. If it's unburnt gasoline, it's just you running rich. If it's oil... I'm not sure how it could be, since oil should burn into clouds of smoke on combustion, unless there's a lot of it. Did you leave the choke on the entire time?
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May 19, 2009 02:49
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Chris Knight posted:Bungie the backpack to the seat. I got a small dedicated riding "backpack" and it works infinitely better tied and bungied to the grab rail as compared to actually being work on the back. I can carry my bungie net in it, too, so I can actually haul a bit of stuff if I have to. Well, "haul" in bike terms, buy you get my meaning.
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May 29, 2009 03:07
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Anybody know where to find the brake pad retaining clip for a 1979 CB750? Pads don't come with the clip for some reason, and I'm missing mine (on both sides of the front!). This has worked fine for a year and a half of riding, but the brakes started squeaking today, and I remembered the clip at that point. Might not have anything to do with anything, but it'll be nice to have if I can get it. edit: also, the locknut for the clutch adjustment bolt (on the clutch handle). 
George RR Fartin fucked around with this message at 19:00 on Jun 2, 2009 |
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Jun 2, 2009 17:18
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Jack the Smack posted:Sport bikes aren't death machines, they just attract people who like to go fast and drive crazy, and those people are what attribute higher accident rates. People on scooters are just as likely to be hit and run over by cars and trucks, the real killers of motorcyclists. Every person I know who has fallen on a bike and not been hit by another vehicle has had zero injuries except road rash. You always give such horrible advice on this front, I don't know why you don't just stop. Every single time, someone says "No, JTS. A 600cc supersport is not ideal," and yet every time you parade this "powerful bikes don't kill people, dumb people kill people" thing out, and it's just like talking to a wall. Can people start on a 600cc supersport? Yes. Can people start on a litrebike? Certainly. Do beginning riders always have the ability to judge what they should be doing on these machines when they lack experience? Not generally. There are exceptions to rules, but you need to stop treating everybody as though they're it.
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Jun 5, 2009 20:29
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MrZig posted:What windshield is this? Possibly one off here: http://www.twistedthrottle.com/trade/productlist/292/ (The A603 looks very similar...)
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Jul 6, 2009 20:01
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I'm in need of the thumb-locknut for my clutch cable. The bike is a 1979 CB750. Does anyone know offhand of the measurement of this locknut so I can just get a nut from the hardware store? Service honda sells it, but I don't know that $12 total with shipping for a nut makes any sense. Would my local Honda dealership have this part in stock, do you think? I'd assume the measurements are more or less universal, because it's just a clutch cable nut, but just in case, I figure it's worth an ask.
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Jul 10, 2009 15:37
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bobula posted:If you're talking about the nut that goes onto the bolt that goes into the clutch handle assy for adjusting the cable there, just go to any bike shop around and you'll find one. It's a universal part that all the older bikes used. Ha, it's the first part. Thin locknut; a similar nut exists on cable brakes for bicycles, after you've adjusted brake tension, you tighten the nut to keep that setting. The function is exactly the same.
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Jul 10, 2009 17:26
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So my 1979 CB750 has been acting oddly. It warms up as well as it used to (this takes roughly 5-8 minutes, the last 90% of which requires leaving the choke infinitismally closed), but there are a lot of surges. What I mean by this is that if I apply constant throttle, the bike will go that speed and SURGE even out SURGE even out. It's not that it's really accelerating too much, but it makes low speed maneuvers a bit annoying. The carbs were cleaned and sync'd a year ago, valves are in spec. I was thinking (and hopefully this is it) maybe the clutch isn't engaging fully? I had adjusted it recently... I would think that maybe if it's not totally engaged, that might cause a fluctuation in what power's getting to the wheels. Otherwise, it may be an air leak or something, and I'm just not looking forward to that at all. I went through that process last year, and I'm completely sick of it.
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Jul 20, 2009 21:44
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I'll turn the pilots out another 1/4 turn; the bike takes so long to warm up I can't help but think this'll help all around. I'll do the spray carb cleaner all over the place thing too
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Jul 20, 2009 22:18
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Z3n posted:Well, if your pilot jets have been varnished mostly shut, as can happen sometimes, just spraying carb cleaner through it won't help...You'll need to run some sort of wire through it. I've used everything from wire brush strands to guitar string. This is why people will say they've "cleaned their carbs", but their bike still runs like crap. Sometimes the varnish is just too built up. Oh I know, I meant the test where you spray carb cleaner on the intake tubes and listen to see if the idle changes.
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Jul 20, 2009 22:35
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Took it for a long ride, and I'm not sure what it is. It's sort of warmed up by ten minutes, and after twenty, it's more or less perfectly fine above 10% throttle. Below that, no matter the rev range, it's very touchy. I'm thinking the damned jets have clogged up slightly in at least one of the carbs. Dammit.
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Jul 21, 2009 01:18
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If I lower my 1979 CB750 via lowering links (or shorter rear shocks) and dropping the forks by an inch or two on both ends, aside from lower clearance for cornering (not too worried there), is there anything I should worry about? I'm sick of tippy-toeing, especially on uneven (or soft) ground. I'd shave the seat, but I'm a better mechanic than I am a tailor.
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Sep 14, 2009 17:02
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Okay: 1979 CB750K (DOHC). The carbs are remanufactured, but I still had to clean the accelerator pump due to it not working. Valve clearance is good (everything's .005" or above at this point), carbs sync'd. 20k estimated (the cluster was replaced last year with 19k on it, and I've gone maybe 1000 miles since but probably much less). The bike runs perfectly well most of the time, but requires the most infinitismal amount of choke unless it's been running for more than 20 minutes. I mean, you leave the choke like 2% pulled. If it goes in before that point, you risk stalling at stoplights. Now, the problem I had last year was that the bike would not idle below an indicated 1000-1100 RPM. This was resolved by unscrewing the pilots another turn (they're now roughly 2.5 turns out, maybe closer to 3), which allowed me to drop the idle speed a bit more. The tach is wonderfully useless, so it's an indicated 900 or so RPM, but if I drop it more, I can *hear* the internals struggling, so I just leave it where it is. Now, despite all this, if I sit in traffic on a day when it's over 70 degrees, the bike overheats. Not immediately, but after a good five minutes or so (say, waiting in traffic for a tollbooth). I assume some of this is just air-cooled quirkiness, but I'm not sure if the aforementioned problems are just being band-aided by my adjustments. I have an oil cooler I've been too lazy to install which might help a bit, but again: am I bandaiding this? I've read a bit on how ethanol increases temperatures, so maybe that's partially to blame, and I should be running a little rich at this point, so I don't think I'm getting a lean heatup going on. So the symptoms indicate issues with overheating...and not warming up enough not to need a bit of choke. I'm afraid my idle circuit might be clogged (as this seems the most likely scenario), but these carbs were spotless. What do you guys think?
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Jun 28, 2010 17:14
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The NonBornKing posted:What do the spark plugs look like? Good question. I'll check to see if they indicate a lean condition; I hesitate to unscrew the pilots too much, but in the worst case scenario, I just clean the carbs again. I did it so often in the last few years I can get the stupid things off the bike in like 15 minutes like a robot.
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Jun 28, 2010 17:59
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I'm back. Summary: 1979 CB750, idles a bit odd, overheating and needs choke for longer than it should. Okay; checked spark plugs, they were fairly white and crusty. Lean condition! Let me run this by you guys: I bought this rack of carbs off an ebay seller two years ago. They were refurbished, have nickel plated allen bolts, the works. They came highly recommended in the CB750F forums. However: 1. I had to clean the accelerator pump with compressed air, as it was clogged. 2. One of the vacuum slides was incorrect. For lack of a better explanation, three were "flat" and one was "angled" on a side. Since I had the old carbs (which were mostly fine, and in retrospect would've probably worked if I spent more time cleaning/syncing them), I grabbed a matching "flat" slide and threw it in. Everything matching, I stuck the carbs in, sync'd them, and everything is as it is now. I've turned the pilot screws out a half turn and in my "sitting-in-the-parking-lot" test, it runs a lot less hot now and will do so without choke. But I'm now at something like 2 1/2 or 3 turns out on each of these, and that can't be right. So how likely does this sound: The aforementioned ebay seller rebuilt the carbs, but they're for a smaller bike (maybe a CB650 if it has the same rack spacing). He used smaller jets, and the bike runs leaner than it should as a result. I'm not sure this is a sound theory, given the bike gets to speed just fine. Just as likely of a 'the-seller-was-an-idiot' scenario is that he may have used kit jets, and maybe they were a bit too small. I dunno. But in any case, these carbs are clean as they should be, and I'm grasping for what else might make me lean short of an airleak, which I can't have (I know what an airleak is like; I chased one down for a while, and the bike isn't that erratic). I think I might just get colder plugs and call it a day.
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Jun 30, 2010 02:06
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So I've learned another lesson. Went on a nice ride today, knew I had an appt at 7.30, so I pulled into a retirement complex to check my cell. A hose is on the ground for no real reason. I think "that can't really make me slip." Promptly lowside (5 mph at most), fly forward, probably break wrist (we'll find out tomorrow; arm won't move much, but ER visit would be exhorbitant;I'll wait for a referral to get a cast). Subsequently typing slowly, one handed. When I picked the bike back up (adrenaline) it leaked oil on the ground. Probably normal. Small oil patch on ground now where parked...maybe residual, maybe not. Bike is a 1979 CB750. Fell on left side. Dripping is by the shifter. Is there a gasket from which oil could leak there? Probably overreacting; figured I'd ask. I'm not sure where else oil could come from. It's not gas.
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Jul 28, 2010 03:05
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