Phreon Posted April 30, 2014 Report Share Posted April 30, 2014 I have a beater Nighthawk 750 I got for cheap I've been fixing up. It has a tick coming from #1 cyl. area that sounds like a stuck lifter or exhaust leak. These bikes have hydraulic tappets in them, so there should be no slack. I'm trying to decide if I really want to fully restore her - is it worth the money? Do I have to pull the lifters out? (I don't want to!) In the recording, I start with the mic over the tank, go back to the rear, over to the right near the valve cover, then around the back and to the left side valve cover. The tick seems loud, but the mic is an inch from the engine around minute 1:16. https://soundcloud.com/phreon/nighthawk-750-after-20w50-oil-change-and-hot I know these bikes have their own noises; worry about it or just ride? It runs pretty great for it's age. It's shockingly smooth coming from the '500 twin. If I ask for the redline, it accelerates to it right quick and delivers better than 45 MPG while being flogged. I catch a whiff of oil in the exhaust once in a while, but it's not visible nor is there perceptible consumption. I'm guessing these things just burn a little being aircooled? I'm in Cincinnati, any trusted shop you'd go to to get a health check for 'er? Thanks Quote Link to comment Share on other sites More sharing options...
Steve Butters Posted April 30, 2014 Report Share Posted April 30, 2014 If it's running fine, just ride it... I've never owned a bike that doesn't tick... Shit my bike ticks and it's brand new Quote Link to comment Share on other sites More sharing options...
whaler Posted April 30, 2014 Report Share Posted April 30, 2014 (edited) To conserve weight and make the engine as slim as possible, manufactures use less material for the valve covers. Also, there is no hood and no sound insulation separating your ears from the mechanical sounds of the engine.If you think that Honda is loud, do not purchase a Kawasaki...lol Edited April 30, 2014 by whaler Quote Link to comment Share on other sites More sharing options...
Gixxus Christ! Posted April 30, 2014 Report Share Posted April 30, 2014 Is it a 750 nighthawk or a 500 twin? It cannot be both. Quote Link to comment Share on other sites More sharing options...
Phreon Posted April 30, 2014 Author Report Share Posted April 30, 2014 I should have said it's smooth *compared to* my Vulcan 500 twin. Quote Link to comment Share on other sites More sharing options...
smccrory Posted April 30, 2014 Report Share Posted April 30, 2014 Having owned an '85 NH CB700SC, yours sounds completely normal to me. Quote Link to comment Share on other sites More sharing options...
Gixxus Christ! Posted April 30, 2014 Report Share Posted April 30, 2014 Ah....I see now. Yes perfectly normal. If it stops ticking I'd worry. Quote Link to comment Share on other sites More sharing options...
smccrory Posted April 30, 2014 Report Share Posted April 30, 2014 Ah....I see now. Yes perfectly normal. If it stops ticking I'd worry.+1. My V-Star 1100 was tons noisier. Valves tick. Quote Link to comment Share on other sites More sharing options...
mello dude Posted April 30, 2014 Report Share Posted April 30, 2014 I could be totally off, but that sounds like honda cam chain tensioner crap. btw - warm the bike up before reving like that. Quote Link to comment Share on other sites More sharing options...
Phreon Posted May 1, 2014 Author Report Share Posted May 1, 2014 The bike was hot. I got back from a ride, got the recorder and restarted. That's why the old girl fired up in a single blip. The tick is nonexistent or barely audible when the engine is cold. I've heard cam chains before and they seem to make a rattly, grinding sound in my meager experience, not a perfectly regular tick. Am I way off base here? Quote Link to comment Share on other sites More sharing options...
smccrory Posted May 1, 2014 Report Share Posted May 1, 2014 The bike was hot. I got back from a ride, got the recorder and restarted. That's why the old girl fired up in a single blip. The tick is nonexistent or barely audible when the engine is cold. I've heard cam chains before and they seem to make a rattly, grinding sound in my meager experience, not a perfectly regular tick. Am I way off base here? No, you're right - loosely tensioned cam chains rattle and grind against the tensioner (and worse things). I didn't hear even the slightest hint of that. But have you balanced your carbs this season? Do it, and if you come to Columbus I'll do it with you. Do this before adjusting your valve clearances. Do you have hydraulic lifters? If not, when were the valves last gapped? It's not hard, just tedious, and that may silence any excessive tapping. Quote Link to comment Share on other sites More sharing options...
Phreon Posted May 1, 2014 Author Report Share Posted May 1, 2014 (edited) The DOHC '750 has hydraulic tappets that the cam followers/rocker arms pivot on. I balanced the carbs a couple weeks ago - what a pain, each carb has it's own independent adjustment (except #2) instead of the nicer "ganged" 1-2, 3-4, then (1/2)-(3/4) adjustment procedure. They're close enough to be within the Clymer spec, though. It was mentioned to me that it could be an exhaust leak. it does seem to be almost silent at a 3500 RPM / 55 MPH cruise as compared to when I'm really working the engine and the exhaust is hotter (even at the same 3500 RPM for example). This might make sense since the #1 pipe has a dent in it. Are these double walled pipes? I figure if it's an exhaust tick, pulling a plug will reveal it. I expect the mechanical lifters in my '500 LTD to be noisy. That engine makes a racket until it's warmed up and even after there's still a mechanical cacophony going on. I'll break out the wrenches and feeler gauges when that bike gets quiet. But the hydraulic NH 750? I've driven cars for thousands of miles with valve ticks. Any particular danger doing the same on this Honda bike engine? Assuming it never grows into a nasty clang and I don't keep it pegged at 8500 RPM all the time? FWIW, I've worked on combustion engines since I was a kid and have rebuilt a few cars over the years, but motorcycles are relatively new to me. Thanks,No, you're right - loosely tensioned cam chains rattle and grind against the tensioner (and worse things). I didn't hear even the slightest hint of that. But have you balanced your carbs this season? Do it, and if you come to Columbus I'll do it with you. Do this before adjusting your valve clearances. Do you have hydraulic lifters? If not, when were the valves last gapped? It's not hard, just tedious, and that may silence any excessive tapping. Edited May 1, 2014 by Phreon Quote Link to comment Share on other sites More sharing options...
Phreon Posted May 1, 2014 Author Report Share Posted May 1, 2014 Correction - pulling a *plug wire* should reveal if it's an exhaust tick. Quote Link to comment Share on other sites More sharing options...
Al Z. Heimer Posted May 1, 2014 Report Share Posted May 1, 2014 Old school cheap trouble shooting .... Go to the hardware and get a 3 foot piece of 3/8" vinyl hose(it's cheap). Stick one end in your ear. Go over the engine with the other end and you will find the area of concern. Have a helper rev it and go around the header to engine area and listen for an exhaust leak. When checking for engine noise you want to want to put the hose flat as possible against the surface. Common sense here...the hose will melt on extremely hot (exhaust) areas. A stick or screw driver in the ear works for mechanical noise as well. Better yet get one of these...http://t.harborfreight.com/mechanics-stethoscope-69913.html?utm_referrer=http%253A%252F%252Fwww.google.com%252Furl%253Fsa%253Dt%2526rct%253Dj%2526q%253Dharbor%252520freight%252520stethoscope%2526source%253Dweb%2526cd%253D1%2526ved%253D0CBgQFjAA%2526url%253Dhttp%25253A%25252F%25252Fwww.harborfreight.com%25252Fmechanics-stethoscope-69913.html%2526ei%253DxsVhU97tAoWi2gX-2YCADg%2526usg%253DAFQjCNGtA-z1L9Aiot7X-sxcyX9MLsEi0wIt sounds like a lifter tick to me either caused by a sticking valve or lifter that is not pumping up fully. Try running some Marvel mystery oil in your gas. It won't hurt a thing and your carb slides will love it. If the valve is sticking this stuff may help. Quote Link to comment Share on other sites More sharing options...
Steve Butters Posted May 1, 2014 Report Share Posted May 1, 2014 Marvel mystery oil is the only thing that would make my old truck stop ticking... Great stuff Quote Link to comment Share on other sites More sharing options...
Phreon Posted May 2, 2014 Author Report Share Posted May 2, 2014 MMO in the gas? You thinking a stuck valve? I already toss a glug of Technron in every couple of tanks. Thanks Quote Link to comment Share on other sites More sharing options...
blueskeyes Posted May 6, 2014 Report Share Posted May 6, 2014 Sounds just like my old '82 Kaw 750. I'd honestly be more worried if you COULDN'T hear a tick. Quote Link to comment Share on other sites More sharing options...
Phreon Posted May 20, 2014 Author Report Share Posted May 20, 2014 (edited) It's definitely the valve train and I think it's getting worse. The Nighthawk 750 blew blue smoke when I started her after sitting a while. It sat about a week while I took a road trip on the Vulcan 500 with my buddy. Even loaded up, the '500 did everything I asked of it. Anyway, the 750 seems to be burning oil now. I'm guessing the valve guides are shot, letting oil by when it sits. The question is, what the hell did I do to it to cause this? It didn't seem to burn oil when I drove it home. Oil clog? The Bosch oil filter killing it? Briefly running Syth (T6) oil in it do something terrible? 23,000 miles on it - I'm worried that if the top end has issues, what else is going? I like the bike and it seems to run strong, but don't want to toss $$$ at a lost cause. Anyone in Cincy know these engines? Thanks. Edited May 20, 2014 by Phreon Quote Link to comment Share on other sites More sharing options...
Nighthawk Posted May 22, 2014 Report Share Posted May 22, 2014 (edited) I replaced the valve guides on my CB700SC. Smoked during start up and while running. Looking at 16 of them, new head gasket and exhust gaskets. How much are you in to the bike as far as cost goes? ish Getting the cam chain on and the timing right will take some time, so mark stuff as you go and take lots pictures. Edited May 22, 2014 by Nighthawk Quote Link to comment Share on other sites More sharing options...
Phreon Posted May 24, 2014 Author Report Share Posted May 24, 2014 (edited) $1200 + cost of new chain, sprockets, mirrors and brake pads. It worries me that the top end could be worn at 23k *and* theres a pretty good lifter tick. Makes me wonder if the top end is starved for oil. Or what the heck else is wrong with it. It seems pretty smooth and strong otherwise. I wonder if I could find a complete head with cams and valves and do a direct swap. There are things about the 750 I really like and those I don't. It's smooth, is great on the highway, comfortable, has good power. But it also feels like a heavy pig and a gutless wonder below 3000 RPM and the stock front brake/pads suck. I'd just live with the burning oil if I knew it wasn't getting worse. I don't want to give up on it, but I also don't want a white elephant. I could probably sell it at a loss and buy another one in better shape if the engine is too far gone on it. Or just save up for a V-strom, like I should have... I don't mind wrenching on it, but I don't want to wind up with a $4000 beater. Thanks. Edited May 24, 2014 by Phreon Quote Link to comment Share on other sites More sharing options...
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