Gang,
The last few mornings I have ridden the VFR (2007), the temps are in the 38-45 degrees range and once it ticks over, she revs to 2500-3000 rpms and stays there. Once the temp reaches 155-160 she falls off to normal revs (1200). I searched for "High rpms on cold starts" but did not get results. Isn't this hard on a motor? My other in-lines never do this. Thanks in advance for you help, JD
[image: View Post]leanit, on 09 March 2010 - 04:46 PM, said:
Gang,
The last few mornings I have ridden the VFR (2007), the temps are in the 38-45 degrees range and once it ticks over, she revs to 2500-3000 rpms and stays there. Once the temp reaches 155-160 she falls off to normal revs (1200). I searched for "High rpms on cold starts" but did not get results. Isn't this hard on a motor? My other in-lines never do this. Thanks in advance for you help, JD
2000+ (I believe) bikes are equipped with a wax unit to increase the idle speed on cold start-ups. However, they increase it to like 1800-2000. Sounds like you may need to adjust your wax unit, but as this is in the V of the engine, and a pain to get to, if it was me and everything else is completely normal, I wouldn't worry about it until the next time you have her apart.
Mine does the same (about 2800 rpm when below 40 degrees). I think the vfr's cold idle wax gizmo is pretty low tech compared to the better EFI systems on other modern inline 4 bikes, and that's about the best it can do.
My gut is telling me yes this is hard on the motor. I think I read somewhere that on a cold motor the piston rings arnt up to temp yet and so not quite at the diameter they should be at so more revs=more wear on the piston rings?? Somebody much smater than me will chime in im sure...
I would consider that unneeded wear on that engine at that RPM. I don't know if 6th gen is the same or not, but the 5th gens have a nut on the shaft that pulls open the "high idle" circuit... maybe you can unscrew that a little and reduce the wax thingy effect?
Mine will stay at a low rpm right after starting until I give it some gas and then it climbs to maybe 3k rpm. No big deal if I am moving since the rpms will be that high while moving anyway. I tend not to let it sit at idle warming up. Just start it and ride off easy. Mince will drop back down to a normal idle well before the normal operating temp is reached. It would be nice if my fast idle was close to 2k rpm rather than 3k though.
[image: View Post]leanit, on 09 March 2010 - 04:46 PM, said:
Gang,
The last few mornings I have ridden the VFR (2007), the temps are in the 38-45 degrees range and once it ticks over, she revs to 2500-3000 rpms and stays there. Once the temp reaches 155-160 she falls off to normal revs (1200). I searched for "High rpms on cold starts" but did not get results. Isn't this hard on a motor? My other in-lines never do this. Thanks in advance for you help, JD
I had a similar issue on my CBR a few years ago and it turned out to be a couple of loose exhaust header bolts. O2 sensor was reading the engine was running lean and was dumping fuel into the cylinders.
Once everything warmed up and expanded, it cut off the leak and everything ran normal.
[image: View Post]leanit, on 09 March 2010 - 04:46 PM, said:
Gang,
The last few mornings I have ridden the VFR (2007), the temps are in the 38-45 degrees range and once it ticks over, she revs to 2500-3000 rpms and stays there. Once the temp reaches 155-160 she falls off to normal revs (1200). I searched for "High rpms on cold starts" but did not get results. Isn't this hard on a motor? My other in-lines never do this. Thanks in advance for you help, JD
FWIW, my 2007 does this too. I'm told (by the fellas here, though I can't find the thread right now) that it's normal. I don't sweat it.
[image: View Post]VFRgenius, on 09 March 2010 - 05:19 PM, said:
My gut is telling me yes this is hard on the motor. I think I read somewhere that on a cold motor the piston rings arnt up to temp yet and so not quite at the diameter they should be at so more revs=more wear on the piston rings?? Somebody much smater than me will chime in im sure...
Hmmm, seems like it would make sense, but if more RPM's were bad, why would Honda go through the trouble of having it idle faster when it's cold? All vehicles have this.
[image: View Post]flash1034, on 09 March 2010 - 08:15 PM, said:
Im curious... What is this "wax unit" you guys are referring to? Ive never heard of it?
Thanks,
Flash
At is the name for the piece that increases the idle speed until the engine warms up. It's called a wax unit because it literal has wax in it that melts at a certain temperature. Basically, carbeurated vehicles have a choke, which, by drawing in less air creates a richer mixture and also serves to increase the idle, but because there's no choke on an FI vehicles, the first FI VFR's had a "choke" lever that only increased the RPM's until warm, and later models come with a wax unit to do this.
[image: View Post]vthoky, on 09 March 2010 - 08:11 PM, said:
FWIW, my 2007 does this too.
Mine doesn't. ;p
I've been riding in weather hovering around 40F in the mornings quite a bit lately, and my bike runs up to 2000 rpm, and that's it. It's like clockwork. Once the engine temp comes up, it's a 1200-rpm idle.
I'm not sure that 3000 rpm is all that much worse on the engine than 2000 rpm, but if we are saying that both 2000 and 3000 rpm are "in spec" for bikes in relatively similar cold-start scenarios, I would find that quite unusual. Ah, well... maybe the "ultra-high cold-start idle" is just another reason to use synthetic oil. :ph34r:
My '04 doesn't do that and I've been out in down to ~25 degrees F now and then and freezing is very common. Some mornings it feels a bit too common... The only thing I have issue with is every once in a while, like once every two months, I will pull up to a stop or something similar and the bike will barely idle, it's pulling maybe 400 RPM and the tach looks like the motor isn't even running it's so slow. Blip the throttle and it "wakes up" and doesn't do it again for months. So I don't worry about it much.
I'm not real impressed with the wax unit but it seems to work well enough and it's simple so I'm not complaining.
[image: View Post]leanit, on 09 March 2010 - 04:46 PM, said:
Gang,
The last few mornings I have ridden the VFR (2007), the temps are in the 38-45 degrees range and once it ticks over, she revs to 2500-3000 rpms and stays there. Once the temp reaches 155-160 she falls off to normal revs (1200). I searched for "High rpms on cold starts" but did not get results. Isn't this hard on a motor? My other in-lines never do this. Thanks in advance for you help, JD
Every vehicle that I know of does that as for being bad on a motor, heck just starting a motor is the worst you can do. Granted, running a cold motor hard is bad and I mean riding it hard but a high idle with no load on it, just ride it and take it easy till it's warmed up and remember the oil is going to heat up slower than the coolant does.
As long as you got correct oil pressure... you can't hurt a thing at any RPM it chooses to run... why at the factory they run them to red line 12 minutes old...
It is an IAC in the traditional sense, it just works more like a radiator cap and less like an electric motor to achieve movement. The naming Honda uses makes sense.
[image: View Post]VFOr, on 10 March 2010 - 12:23 AM, said:
[image: View Post]flash1034, on 09 March 2010 - 08:15 PM, said:
Im curious... What is this "wax unit" you guys are referring to? Ive never heard of it?
Thanks,
Flash
The service manual refers to it as "IAC thermal valve", Idle Air Controller, instead of wax unit.
You know, I've never actually given much thought to it, until now. Cold wax, high idle, normal wax, normal idle, seems simple enough, but how does this actually work? That is, what specifically happens that raises and lowers the idle speed as the wax melts and solidifies?
My 02 only revs to about 2K on a cold start, but when you put it in gear, and let the clutch out a bit, right when the clutch switch kicks out, the idle goes up about 100-200 rpm. Anyone else have this? I figure it's an anti-stall feature.
[image: View Post]leanit, on 09 March 2010 - 04:46 PM, said:
Gang,
The last few mornings I have ridden the VFR (2007), the temps are in the 38-45 degrees range and once it ticks over, she revs to 2500-3000 rpms and stays there. Once the temp reaches 155-160 she falls off to normal revs (1200). I searched for "High rpms on cold starts" but did not get results. Isn't this hard on a motor? My other in-lines never do this. Thanks in advance for you help, JD
Would like to make another point, whenever the idle goes up the oil pressure goes up and that is a good thing. Think any motor that is idling is doing more damage to itself than if it is just sitting with the motor running at a reasonable high R.P.M because of oil pressure. Understand?
[image: View Post]landlover, on 10 March 2010 - 05:48 PM, said:
[image: View Post]leanit, on 09 March 2010 - 04:46 PM, said:
Gang,
The last few mornings I have ridden the VFR (2007), the temps are in the 38-45 degrees range and once it ticks over, she revs to 2500-3000 rpms and stays there. Once the temp reaches 155-160 she falls off to normal revs (1200). I searched for "High rpms on cold starts" but did not get results. Isn't this hard on a motor? My other in-lines never do this. Thanks in advance for you help, JD
Would like to make another point, whenever the idle goes up the oil pressure goes up and that is a good thing. Think any motor that is idling is doing more damage to itself than if it is just sitting with the motor running at a reasonable high R.P.M because of oil pressure. Understand?
I understand and my only worry was the first few seconds of start-up. I use Rotella synthetic so I should be okay. This morning wasn't too bad since the temp was 50. I did try one thing differently and that was hitting the starter button a few times just to turn the motor over but not firing it up. Probably not helping other parts though. Just a few more weeks and it won't be an issue any more. COME ON WARM WEATHER!!!
[image: View Post]leanit, on 10 March 2010 - 06:02 PM, said:
[image: View Post]landlover, on 10 March 2010 - 05:48 PM, said:
[image: View Post]leanit, on 09 March 2010 - 04:46 PM, said:
Gang,
The last few mornings I have ridden the VFR (2007), the temps are in the 38-45 degrees range and once it ticks over, she revs to 2500-3000 rpms and stays there. Once the temp reaches 155-160 she falls off to normal revs (1200). I searched for "High rpms on cold starts" but did not get results. Isn't this hard on a motor? My other in-lines never do this. Thanks in advance for you help, JD
Would like to make another point, whenever the idle goes up the oil pressure goes up and that is a good thing. Think any motor that is idling is doing more damage to itself than if it is just sitting with the motor running at a reasonable high R.P.M because of oil pressure. Understand?
I understand and my only worry was the first few seconds of start-up. I use Rotella synthetic so I should be okay. This morning wasn't too bad since the temp was 50. I did try one thing differently and that was hitting the starter button a few times just to turn the motor over but not firing it up. Probably not helping other parts though. Just a few more weeks and it won't be an issue any more. COME ON WARM WEATHER!!!
When a motor is turned off most of the oil goes to the pan, some clings to the internal parts, so at startup it's not pure metal against metal, there actually is a term for it but can not remember it and synthetic is the best. It's your bike and you do what you want but if it's cold outside and the bike was run within six months I just press the starter but if it's over six months I may take the plugs off and turn the motor to try and get the oil going through the passageways and go where ever it needs to go. Probably would not let it sit that long though, the injectors would still put fuel in there if I just cranked it and don't know how to shut the injectors off. Like what was said would not let it sit for six months without running it. Here are the two worst things you can do to a motor one start it and yeah laugh but think about it and two running a cold motor hard. Done rambling.
If the ambient temp is below 10C when I start the bike, once it reaches about ~48C (coolant temp) the bike goes into a fast idle pretty much right on 4,000RPM. Once the bike reaches 78C it drops right down to 1,200. Happens EVERY cold start. And (dangerously) it will do it whether I'm riding, or it's idling. Clutch in to stop during the high idle, and it stays at 4K. Not so bad now that I know it does it, but man was it unnerving the first time.
Mine is an 02, Canadian bike with ABS. Don't know if that has anything to do with it, but the Canadian part probably does.
End of thread · 25 posts recoveredWayback Machine snapshot 10 Jun 2011
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