Valve Adjustment Question

I have a 1992 Honda VFR750F that has 73,000 miles on it. Well, I just got the bike back and am tuning it (new plugs, new filter, carb sync, valve adjustments, etc.

Well, my question is about value adjustments. Factory specs are intake .13mm-.19mm and exhaust .22mm-.28mm. I only had a standard feeler set, not metric, so my values are estimates. Most of my valves were within these specs, but two of my intake ports were around .114mm, and three of my exhaust valves were around .216mm.

I just wanted everybodies opinion on if it would be OK just to leave them as is, or am I underestimating the .02mm difference and I should go through the hassle of pulling the cams, ordering new shims, waiting days for them to arrive, and then dealing with reassembling the shafts. I mean, if its not a huge deal, and I lose like 1hp, I'd rather not put myself through the extra work, but if its going to damage my bike to just leave them, then I have to do what I have to do.

And I know in an ideal world, you should always meet the specs exactly, but my worlds not ideal, and I just want your opinion on if these minor differences are overlookable.

Thanks.

 

Leave them the way they are.

 

.02mm is almost nothing. I wouldn't worry about it for now, but I'd check it again in about 4000 miles to see if they get any tighter. Don't let them get too tight.

 

if valves are out of spec .002 inches or more you should strongly consider resetting them......

 

The .016mm difference on your intake equates to about .0006", and the .004mm on the exhaust is about .00015". Probably not a concern. Like "eddievalleytrailer" says, I'd check them sooner than the maintenance schedule suggests, and see which direction they were going (looser or tighter). For what it is worth, I generally measure clearances a couple of times and wipe the feeler blade off in between, just to make sure I'm getting an accurate reading. Sometimes the oil film is enough to skew the results. It probably goes without saying that I make sure to put a few drops of oil on the surfaces after I measure them.

The biggest concern with tight clearances is overheating and/or burning a valve, primarily on the exhaust side.

 

Thanks guys. I didn't think it would be a problem, but seems like every time I say "nah, it should be fine" I find out the hard way I was wrong. I'll reinstall the head covers today and spend the rest of my time with the rest of the tuneup and trying to fix these darn electrical problems.

 

like Eddie and Lgn said, just keep an eye on em in a few thousand miles, not a huge thing, but I know how you feel once you know something like that, it can bug you.

 

Yeah, I love working on bikes. One of the head cover bolts snapped off during reassembly. I can't imagine I overtorqued it as after initially tightening it I finished with a torque wrench, but sure enough, snap. Luckily it snapped in a way that left sharp edges, enough so that I was able to back the broken piece out with its other half. Waiting on new bolts to arrive at my local shop. Fun stuff.

 

AAAAH, YES, The joys of working on motorcycles. Fun, ain't it?

 

Oh, tons of fun. It doesn't matter how careful I am, I always break something that wasn't broken before everytime I open a bike up. Guess I'm just cursed.

 

AH, If you ain't brakin' stuff, you ain't doin' nothin.

 

Yeah, figure I'd show what went wrong. Luckily it wasn't nearly as bad as it could have been. Sucks it was the front cylinders, because if it was the back, I could put the radiator back on while I wait for parts. Still not sure why it broke, I didn't overtorque it. Have two on order, just in case another one goes. I love the dual overhead cams too. First time I'd seen them in person.

 

Yeah, and those gear drive cams look a LOT easier to pull than those stupid chains on the 1st gens. :ballchain: