tim horton this valve business sounds right i got quite a similar description from a bike mechanic who was considering doing the job he had done it before did say you could surface grind the shims but u are talimg about replacing them altogether also he said with the cam chain tightened it should show a remarkable improvement in terms of speed and power , again i am a novice and i am seetting it up for one day attempting these jobs as no one is really interested in working on these eclectic machines. paul polo
From: [email protected] Sent: Monday, April 26, 2010 10:36 AM To: Digest Recipients Subject: [Nighthawk Lovers] Digest for [email protected] - 10 Messages in 7 Topics Today's Topic Summary Group: http://groups.google.com/group/nighthawk_lovers/topics a.. 82' 750SC - Valve Adjustment [4 Updates] b.. Anyone know how to remove the limiter on a 85 650? [1 Update] c.. Periodic problems with my 85 CB 650SC [1 Update] d.. 83 650 Nighthawk Carb Problem [1 Update] e.. Hesitation/ Bogging at Partial Throttle [1 Update] f.. Bike turns over but wont start [1 Update] g.. Seems strange when you first turn key to on position!!! [1 Update] Topic: 82' 750SC - Valve Adjustment timhortons <[email protected]> Apr 25 05:19PM -0700 ^ I still need to do the valves on my 83 750, so I was looking into how it's done recently, also I know a friend of my dads has a CB750 with the same engine who's done the valves on his. The valves on Honda's have little shims of varying thickness which make the valves open and close to their proper specification, of course over time, they wear and thin out or otherwise distort. From what I've been looking at, on a 750 the shims are placed under the cam lobes, so what you do is use the tool recommended for compressing the valve spring, then pop out the shim and insert a new one. Of course, you don't touch them until you've measured them all and have figured out which thicknesses have to go in to bring the valves back into spec. As far as I know, the engine of an 82 Nighthawk is exactly the same mechanically as an 83's, so they both use this little shim scheme. Your BMW friend may be correct about set screw adjustments for BMW's (I don't know personally I've never seen internals of BMW engines), but that is not the case with these Honda engines. If doing valve adjustment for the first time, I would suggest setting up a larger allotment of time to do it in, but on the whole it shouldn't take very long at all, less than a day if you have everything you need to do it (you'll get quicker as you get more comfortable with doing it). I myself haven't done this procedure yet either, but like I say, my dads friend has and he tackles the valves on his other bikes too. For him, it only takes somewhere around an hour to do, of course, he keeps a pile of extra shims of varying thickness around, so he can pick and choose from without waiting around or driving somewhere to pick some up. You mentioned that you have a shop manual for the bike, so I haven't gone into too much detail about the procedure, I have a Clymer Manual which describes the adjustment pretty well, if you'd like to know how mine details the procedure I can do a little write up. Hopefully someone will reply who's actually done the valves though, bring insight to the nuances (if any) of doing it in reality. I think you can make a tool to compress the valves too, but I would probably just say it's less hassle to buy a valve compression tool so you can get them loose enough to pop shims in and out. -timhortons -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. mongoose22p <[email protected]> Apr 25 06:14PM -0700 ^ my 82 750 does that for about 30 sec when cold i fidgered it was the cam chain had some slack because it goes away thanks steve -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. Sharpey1 <[email protected]> Apr 25 06:30PM -0700 ^ Thanks both of you! Actually, was in the garage and took a real good listen....the sound did seem more like a "belt slap" than a metallic knock or ping. Right after the valve job section of the shop manual, there's a procedure for adjusting the cam chain. With the engine idling, there's a screw in the front of the engine right above where the exhausts leave the cylinders and one on the back....loosening each while the engine is idling allows the belt to reset it's tension. The procedure is pretty vague about what you're adjusting, is just said to loosen then re-tighten. I think the longer it's loose the better it can settle the proper tension, I didn't want something to pop loose or something, so I was loosening quickly. First couple loosen/tighten sequences didn't seem to do anything, but after about 10 times back and forth (and burnt wrists on the cylinders a couple times!) the noise pretty much was gone and was totally gone after some more warm up. If I tackle the valve stuff I'll update! -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. timhortons <[email protected]> Apr 26 02:25AM -0700 ^ I had to fiddle with the tensioners a little too with it running, unfortunately I stripped the front tensioner pinch bolt though, be careful with aluminum!! It's soft stuff, haha. Before I had a manual I thought I would foolishly take a stab at playing with the front one, unfortunately at the time I didnt realize the larger nut on the bolt needs to be loosened and tightened in a proper sequence... so in my haste I was just kinda spinning this and that *sigh*, apparently it can be fixed, but I'm a little disappointed I added to the list of things I have to address. Adjusting the rear alone made a huge difference on my bike though, my youtube videos are proof of that, the last owner before me must have never thought about doing anything like that because the chain sounded like it was going to jump out of the bike. Despite that, some noises I'm prepared to live with, it's good for the road, so that's where I want it. I'll buy a Harley if I want to sit in the garage all day ;) -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. Topic: Anyone know how to remove the limiter on a 85 650? [email protected] Apr 26 09:26AM +0200 ^ It's the way they do it usually : a plastic or aluminum restriction which can be in the exhaust hose of the carb, or screwed onto the engine. At 20:55 24/04/2010 -0700, you wrote: -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. Topic: Periodic problems with my 85 CB 650SC ThePoulsen <[email protected]> Apr 26 12:20AM -0700 ^ I think I have narrowed down the problem. I think the problem lies with vaccum buil-up in the gas tank, whenever I pop the tank or the sun warms it up it gets way better. So a little clean-up should be in order. -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. Topic: 83 650 Nighthawk Carb Problem Andy T <[email protected]> Apr 25 02:46PM -0700 ^ I need some suggestions on a carb problem on an '83 SC650C. The engine starts readily with choke when cold. It will run at idle with no choke fairly quickly after starting. But it will not accept any throttle at all (I mean zero) without stalling until it’s almost up to full temperature. This happens even with the bike in neutral and the clutch held in. Holding the choke partially closed when cracking the throttle open doesn’t help. After stalling it and restarting about 8 times, I was finally able to launch the bike by manipulating the choke and throttle simultaneously to keep the engine rev’d up to around 4,000 rpm and slipping the clutch a lot. Once I was rolling I had to play with the clutch and throttle to keep the rpm up or the engine would stall. Especially when going uphill. This went on until I had ridden almost 2 miles without getting out of first gear. When warmed up the engine idles smoothly at about 1,000 rpm and accelerates acceptably from idle to about 4,000 rpm. Then it really takes off. As if it had an accelerator pump. This tells me the main jets & circuits are OK. I’m wondering what to do to improve the drivability of this bike while warming up. My take is that the engine’s too lean at lower rpm. But according to the Clymer manual, the needles on these carbs are not adjustable, the slow jets are not replaceable and the pilot screws have limiter caps on them. So I’m not sure what to do to richen the low end up a little. Being that the bike is 27 years old, I wonder if old needle diaphragms could cause this? Getting the limiter caps off the pilot screws could be a job for a Dremel tool. Would richening up the pilot circuit help? Are the pilot screws fuel or air bleed screws? Thanks in advance, Andy -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. Topic: Hesitation/ Bogging at Partial Throttle Chris Payne <[email protected]> Apr 25 04:42PM -0400 ^ A carb sync with a homemade manometer cleared things up this afternoon. Thanks, Chris Payne -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. Topic: Bike turns over but wont start NytWing <[email protected]> Apr 25 10:48AM -0700 ^ It's possible that when the bike laid down, some of the sediment from the bottom of the tank clogged the screen on the petcock. That might need to be taken apart and cleaned. -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. Topic: Seems strange when you first turn key to on position!!! Minnesota Blue <[email protected]> Apr 25 07:32AM -0700 ^ I will start by saying that I am no mechanic and this is purely a guess on my part. I have an 83 650 and had a similar thing happen with my bike when I took it out of storage, except for me it would happen when I flipped the kill switch on or off with the key on. Never did figure out a reason, I just assumed it was condensation. Just bought a new house and stored the bike in the back of the garage. When I took the cover off it this spring it was covered in moisture. Until it got warm enough it would have some moisture on it every morning. I think moving it out from the wall helped also. Has not happened since. Not sure what part of the country you are in, but it's spring and we get a lot of warm days and cold nights and moisture in the air. If it is sitting for a couple days maybe you are getting some condensation built up in the ignition switch? Again, purely a guess. MN Blue -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en. -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en.
