A couple days ago I over revved(comming out of a turn in 2nd and ripped back on the throttle but did not shift soon enough) the bike in lost power and back fired a little. Would only hold about 55, pulled over idled fine revved slugishly... turned it off. Fired it back up . Then took off a few seconds later it started running correctly...
Today I over revved again... does the ignition modual have some protection circuit? So far it has not reset
I don't think the early shadows had a rev limiter, thus the reason for the tach. Slow down and learn how to shift before you turn it in to a parts bike. (If you haven't already)
Weird thought... after tge bike was painted I noticed that there was paint overspray in the tank... could that have gummed up and partically clogged a fuel line
That's the early version of Honda's rev limiter. Guaranteed to bring the revs down, but unfortunately not before the unwanted mating of parts that shouldn't. They later re-engineered it to include gnomes that live in the electronics bay and count the revolutions. When the revs get too high, the gnomes run out and pull the lead wires off until the revs drop.
^^^^ Above about learning to shift and manage the throttle. You shouldn't be over reving on a regular basis.
These are hydraulic lifter engines on the 700-750's. I remember hearing on cars that they would pump up the lifters when revved too high, and you would loose compression until the lifters bleed off enough to run good again. Not sure it could happen with our bikes but it sort of fits the symptoms. If it bent a valve a little it could stay running badly. Do a compression test to rule that out.
That being said I will be compression testing today after church. I feel like it will end up being fuel related... after all the bike sat for 3 years and the tank was pretty rusty inside... I have witnessed rust getting past filters and into carbs on other vehicles...
If it runs pretty decent and smooth up to 4500 RPM it probably is fuel related or spark failing for some reason. That would explain the backfire also. Not a bad idea to check compression anyway- with the throttle open.
Anyway... the readings are low but equal... 110ish front and rear...
I read a few reviews that says harbor freight compression testers read low. I find it hard to believe that both cylinders would be that low even harder to believe they would be that close...
So hmmm... is it really low compression? Btw test was done with temp needle at the mid way mark and throttle plate open..., air box and filter on
Take it back and tell them the gauge is really off and get another one. Probably worth trying that.
Most of their equipment is cheap but it should be close enough to get a reading in the ball park. Another set would tell if it is really low or not.
These harbor freight compression testers dont have a check valve in the bottom... my old mac did... the hose on this thing is 20"... thats like 10-20cc... I feel like addingthat much volume control easily read cause everything to read low...
I tested with another random tester (also didnt have a valve in the bottom)... got 150 front and mixed readings rear, ranging from 90 to 148