I just swapped in a bunch of new shims. I now have a few intake valves with .008" clearance, as well as a few exhaust valves with .012" clearance. My thinking is that being .001" "loose" beyond spec will be ok, as they will only get tighter or remain the same. Anyone think this will mess me up when I go to synch the carbs by throwing off the vacuum?
Since they are out of spec, they wont open as far. This can effect the engine as it wont have the same air flow. Now that said, I know of a lawn mower that has valves that are 0.030" out and it runs just fine. Stalls easy but thats it
Thanks Zen I understand that, I'm just getting tired of wrenching on this thing and wondering if it's going to have a noticeable effect, or can I just leave well enough alone without it coming back to annoy me. Would you guys bother to go back in, or just button it back up?
From my Honda 2002 manual: You have a tolerance of + or - .001" for "normal" side and .003" for VTEC side.
Just updated my info so everyone can see that I have a 4th gen. Allyance - my Honda Service Manual for '90 - '96 VFR750F indicates: Intake clearance of .006" +/- .001" Exhaust clearance of .010" +/- .001"
Yes, but, consider your technique in measuring, is it precise enough to feel the .001"? Maybe you're right on spec? That's the trouble with doing valve clearances once every 3-4 years, do you have the "feel" that a day to day mechanic would? I'd say go with what you have if you don't do it regularly, if you're confident it's out of spec swap the shims.
The 'feel' on the wire type is learned. On the finger type there is no feeling to learn if it fits then add another 0.001" and check again. If it still fits swap to the 0.002" and keep going until you have the point at which it wont fit. Subtract 0.001" from that guage size and thats the gap. Just make sure when stacking 2 or more together you write down each size and add them up. So to measure 0.006" you need the 0.005 and the 0.001" guages stacked on top of each other. After 0.010" the usually step by 0.005" increments.
Thanks Capn, I'm confident in my technique so the measurements are accurate. Anyone interested in trading some shims? It would be much quicker and cheaper that ordering new.
What is the odometer reading? What were the before readings--how far out was it that caused you to want to pull the cams to get to the shims? Nobody can tell a difference of 0.001" in valve clearance over the spec, especially when the engine gets up to temperature. How much is the cam lift/valve stroke anyway--if it was 0.180" then you would only be 0.5% under full lift. Not gonna matter on a street bike. i would leave it as is and ride it till the stirrups were draggin' in the dirt.
Kenny, the bike is new to me with 17K on it. Looks like someone was in there before me swapping shims. The intake clearances were all either .003" and .004" with one at .005". Exhaust clearances were 3 at .004", 1 at .005", 4 at .006", and 2 at .009". I took 2 separate sets of measurements, followed the manuals to the letter. The cam lift/valve stroke for intake is .006" +/- .001" and for exhaust is .010" +/- .001". I have no problem leaving things as they are, as long as it's not gonna mess me up when I go to synch the carbs by throwing off the vacuum. Opinions?
Never can tell what previous owners might have been doing--or some fat-fingered newbie kid doing his first valve adjustment at a dealer service shop-- you know just give him the 'easy' jobs... A before and after compression test would sure be interestin after seeing those tight exhaust numbers on 1 and 3, which are going to be running the hottest and may have been holding open. i figure the valves grow about 1 to 2 thousandths in length per 100 degrees change in temperature. Anyway you did the right thing to get them opened up to spec, and you are within only one shim size away. Nice weather is on its way--leave it and go ridin, it will run much better than before. Unless you got that AR gene and can't help but fix it better, then hustle up to order them shims. Do a thorough cleaning of the carbs and bench synch them using your favorite method--several were discussed here recently. i like to use the drill bit method and have had excellent results with bikes starting right up the first time and able to quickly dial in the idle mixture and no call-backs-- never needed to experience the roasting of forearm skin or back of the hands trying to synch carbs on a running bike. Although i do remember burning foreskin after messin around with them dry chicks on bike night at the strip club...
Thanks Kenny. I do have that AR gene, but like you said the warmer weather is just around the corner and I'm itchin' to get this biatch on the road. Bike was not running when I bought it, and I've not done a compression test, so I have no benchmark for comparison. On another note, I'm going to be reassembling carbs today. If I need to adjust float height, I do so by bending the metal tang on the float valve? It looks so frigging tiny . . .
