HRC tip, idle increase - 650R


11 replies to this topic
  • jdubb75

Posted March 15, 2008 - 07:20 PM

#1

So today I made the switch to the HRC tip on my R and when I started it the idle increased about 400-500 rpm. The bike was warmed up when I made the switch because I had just run it with the modified, stock tip so I could see what the difference in sound was compared to the HRC tip. I understand the HRC tip should flow better, but I didn't think it would increase the idle by that much. Has anybody else experienced this? :confused:


BTW - My stock tip was drilled to 2" and had the standoff baffle snipped off. I didn't notice a big difference in sound. Now it has more of a crisp exhaust note with the HRC tip, whereas the modified tip was a little more muffled and not as snappy. All in all, I didn't notice a big jump in sound. I really don't think it's too bad at all. Don't know what the neighbors think though. Maybe I'll ask them in a couple months. :excuseme:

  • knuklehead

Posted March 15, 2008 - 08:15 PM

#2

Did your power feel diff between the two?

  • resurrection

Posted March 15, 2008 - 09:48 PM

#3

Make the idle screw your friend .
Honda made it easy to access for a reason you should not let it lug at start up .
Keep the r's up alittle untill she's worm then turn it down alittle untill she's at temp .
The higher R's will pump more oil at start up. I'm not talking about hitting the rev limit ya know just up alittle.

  • jdubb75

Posted March 16, 2008 - 05:45 AM

#4

Did your power feel diff between the two?



The jury is still out on that one. It was raining so I didn't want to get real crazy on the pavement with my non-dot knobbies. I took it for a little spin to do a sound check, but I'll have to report back on the power.

  • jdubb75

Posted March 16, 2008 - 05:54 AM

#5

Make the idle screw your friend .
Honda made it easy to access for a reason you should not let it lug at start up .
Keep the r's up alittle untill she's worm then turn it down alittle untill she's at temp .
The higher R's will pump more oil at start up. I'm not talking about hitting the rev limit ya know just up alittle.



I used to use the idle screw during start up, but I don't do that anymore. It usually fires on the first kick and then I'll just hold it at about 2500 for a minute or so with the throttle. After that I let it settle back down to idle (about 1500).

The reason I quit using the idle screw is because I felt like I was always fiddling with it. What I mean is I would turn it up a little before startup, then turn it back down to idle. The problem is the idle would change a little as it warmed up and if I didn't have it turned down low enough initially, the idle would hang for a bit. I just didn't like having to adjust the idle when I pulled up to a stop light a few miles down the road. :confused:

  • resurrection

Posted March 16, 2008 - 07:00 AM

#6

Ok I wont argue with that you get the point .your top end is happy with the extra oil trust me.

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  • hondacrf150f1

Posted March 16, 2008 - 07:13 AM

#7

I have similar problems with my 650R when its cold out...on those 30-45 degree days, when i start it up the idle will be reading 900-1200, so i hold the throttle open every so slightly as to keep it around 1400-1500 where it idles good.

After about 30 seconds of that i let off, it still idles low, but doesnt stall on me. If i turn the idle up so it idles at 1400 when its cold, it will be hitting 1800-1900 when warm:bonk:

  • resurrection

Posted March 16, 2008 - 07:29 AM

#8

Ya mine does the same .
Ever try the second notch on the choke lever ?
I still prefer turning it up alittle makes me cummfy about not luging the motor.

  • husky123

Posted March 16, 2008 - 09:34 AM

#9

As resurrection mentioned above...if you have the stock carb and depending on the weather (cold weather may take a little longer) come of full choke when you hear the idle start to drop. Leave it on half choke (middle position) until it can come off an idle without dying. A properly jetted bike will do this without much fuss.

Your idle increasing with the tip change is normal. More flow, a tad leaner and the idle will increase. You may have to turn your fuel screw out a little to compensate. If you go more than 3 1/2 turns out it's time to go up on the pilot and conversely 1 turn out and it's time to go down on the pilot. The fuel screw and pilot work hand and hand together. Think of them like a faucet tip opening (pilot) and the faucets lever or turn wheel (fuel screw). The more you open the faucet the more water it flows but after 3 1/2 turns you are limited by your opening in the faucet (pilot) and then it's time to get a bigger one. Wow I'm rambling. Anywho's hope this helps.

  • hondacrf150f1

Posted March 16, 2008 - 10:24 AM

#10

As resurrection mentioned above...if you have the stock carb and depending on the weather (cold weather may take a little longer) come of full choke when you hear the idle start to drop. Leave it on half choke (middle position) until it can come off an idle without dying. A properly jetted bike will do this without much fuss.

Your idle increasing with the tip change is normal. More flow, a tad leaner and the idle will increase. You may have to turn your fuel screw out a little to compensate. If you go more than 3 1/2 turns out it's time to go up on the pilot and conversely 1 turn out and it's time to go down on the pilot. The fuel screw and pilot work hand and hand together. Think of them like a faucet tip opening (pilot) and the faucets lever or turn wheel (fuel screw). The more you open the faucet the more water it flows but after 3 1/2 turns you are limited by your opening in the faucet (pilot) and then it's time to get a bigger one. Wow I'm rambling. Anywho's hope this helps.


Haha my bike wont start on full choke, i kick it on half choke, and wonce it starts i turn off half choke within 3 seconds...:confused:

Its proble running a little rich...i keep switching between vented and non-vented panels without jetting change, because i cant figure out what jets to use on the vented panel:foul:

To rich with stock panel...
to lean with vented panel...

  • husky123

Posted March 16, 2008 - 11:28 AM

#11

I have the Edelbrock but I'm pretty sure that when I had my stock carb on I ran a 68S with vented side panel and a full FMF. That's at sea level in Virginia weather....

  • Thumpage

Posted March 18, 2008 - 12:38 AM

#12

As resurrection mentioned above...if you have the stock carb and depending on the weather (cold weather may take a little longer) come of full choke when you hear the idle start to drop. Leave it on half choke (middle position) until it can come off an idle without dying. A properly jetted bike will do this without much fuss.

Your idle increasing with the tip change is normal. More flow, a tad leaner and the idle will increase. You may have to turn your fuel screw out a little to compensate. If you go more than 3 1/2 turns out it's time to go up on the pilot and conversely 1 turn out and it's time to go down on the pilot. The fuel screw and pilot work hand and hand together. Think of them like a faucet tip opening (pilot) and the faucets lever or turn wheel (fuel screw). The more you open the faucet the more water it flows but after 3 1/2 turns you are limited by your opening in the faucet (pilot) and then it's time to get a bigger one. Wow I'm rambling. Anywho's hope this helps.


I would like to contribute and add some details in regards to determining the correct pilot jet size on 4 stroke carbs.

If the optimum *tuned* fuel screw setting falls under 1.5 turns out [after] going through the pilot jet tuning procedure, you need a smaller pilot. If the tuned setting takes more than 2 turns out [after] the tuning procedure you really need a larger pilot.
In short terms, with the correct size pilot jet, the tuned fuel screw setting should fall somewhere from 1.5 - 2 turns out.
Read below for the proper tuning method for dialing in the fuel screw.

"Make sure your engine is fully warmed up and set the pilot screw to 1.5 turns out. Then with the 68s installed, turn the pilot screw clockwise until the idle slows. Then turn the pilot screw counterclockwise until the idle slows again. Make a mental note of how many turns you made in between the low idle points. Then turn the pilot screw half way between the low idle points to finish the adjustment. If you turn the adjuster counterclockwise and the idle doesn't drop down, then you need a larger pilot jet. If you turn the pilot screw clockwise and the idle doesn't drop down, then you need a smaller pilot jet. After adjusting your pilot circuit, re-adjust your idle speed if necessary."

This was quoted from this XR650R website on Faq. question #4 of the 'fuel system'.
http://www.xr650r.us/xr650r_faq/#6c
You will notice that the pilot tuning instruction states needing a larger or smaller pilot if you get no noticable idle drop down in one direction or the other. This is true if you notice no idle drop down when you first try to find the low idle point in one direction or the other in the tuning procedure. This would be the first and obvious sign that the pilot jet is clearly not within the ballpark.

There's my added rambling,

Happy tuning.





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