I am supprised that you got it to turn over after running it dry. I am no machanic but I would think that you would have to go thru the whole engine and check for scoring and have them machined. One machanic told me that the cranks on motorcycles should not be turned like a car engine can. I would either find a good running engine and change it out or get a new 750 and part out the old or keep it for parts. Just my 2 cents. hope things work out for you.
Brian On Apr 20, 7:44 pm, Matthew Webb <matthew.web...@gmail.com> wrote: > Hi my name is Matt. I'm new to the group and I recently got my first bike, > a 1992 CB750 with 3,800 miles for $1,800. It was always garage kept and in > very good condition. > > I had had the bike for only about 2 months but had put almost 2,000 miles > on it already. At the time I was getting home from work in the dark and > the cold and kept putting off my first bike maintenance until a weekend > when I could do some work in the daylight. I made a big rookie mistake and > ran my bike dry and the engine locked up when I stopped at a traffic > light. The low oil indicator light had turned on that morning but I was > hurrying to a meeting and thought I would be able to make it before things > got serious. > > I got my bike back to my house, and a few weeks later poured some oil over > the top of the engine, manually turned the engine, and then was able to get > it to start with no problem. However, the engine didn't seem to respond > right. So I looked into the top more and found some pretty serious > scouring on the exhaust camshafts, exhaust camshaft holders, and > crankcase. It also looks like some of the rubber stuff on the defoaming > chamber covers melted, but I'm not sure. The rest of the top end looked > completely fine, even the intake camshaft. See > pictures<https://plus.google.com/photos/118089145265544102347/albums/573367372...>for > details but be warned, they are depressing. > > I am worried that pieces of metal may have gotten into the bottom of the > engine and wrecked more havoc. I'm also wondering if there may be more > damage than I've seen from when my engine locked up. Does anyone know what > damage is typical when you run your engine dry? Is it likely the entire > engine will need to be replaced? > > I have searched past messages but have not found much. Possibly because I > don't know what is best to search for. I've done a lot of other reading so > far and have some ideas but wanted to run it by the group first. > > To me it looks like I have a few options: > > 1) Sell the bike as is on CL for parts to someone who knows what they are > doing > 2) Purchase replacement parts for the damaged components and replace them. > With a quick search I have found these on ebay: cylinder > head<http://www.ebay.com/itm/CYLINDER-HEAD-CB750-NIGHTHAWK-91-93-92-1991-1...> > , another cylinder > head<http://www.ebay.com/itm/Honda-CB750-SC-Nighthawk-Good-Used-Original-E...>, > camshafts.<http://www.ebay.com/itm/Honda-CB750-SC-Nighthawk-Good-Used-Original-E...> > I don't have much experience working with engines but I do have a Clymer > manual. The camshafts and holders look easy to replace but the body of the > crankcase is also damaged where the camshafts sit. Would it be possible to > have a shop re-machine it so that I wouldn't need to replace it? > 3) Take it to a shop, have them replace the parts and open the bottom of > the engine to look for more damage. > 4) Purchase another CB750 and use my first one as a parts bike. Also part > out my first one on ebay since the rest of the bike is in excellent > condition. > > Any suggestions would be appreciated, thanks. > > - Matt -- You received this message because you are subscribed to the Google Groups "Nighthawk Motorcycle Lovers!" group. To post to this group, send email to nighthawk_lovers@googlegroups.com. To unsubscribe from this group, send email to nighthawk_lovers+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/nighthawk_lovers?hl=en.
