Hello Ladies and Gentelmen,
I have a 2004 cr125. My bike has JD Jetting and was running great. I wanted a bit more power so I bought Vforce 3 reeds. I installed as per the instructions. Went to the track today and the bike had a bog when I blipped the throttle and when landing off jumps, but mostly when I blipped the throttle from idle. I turned the air screw in and it got much better, but it still happened occasionally. Since I had the bike jetted perfectly before, I really don't want to mess with the jetting (that was a freaking hassle!). If I have to do that, I would rather just put the stock reeds back in or buy some Boyesen reeds.
Here are a few things I thought it could be:
1. Maybe lean out the needle by a notch.
2. Put RSV on gasket (maybe there is a small air leak)
Last question, would the Vforce reeds tend to make the bike richer or leaner? To me, more air would make it leaner, but it could also be getting more fuel as well, which would mean I need to richen a bit.
Hope you all can help! Thanks in advance!
Adam
Did you have to do the hacksaw job to modify the manifold?
It was common for that mod to cause an air leak.
Sounds like an air leak.
No, luckily I did not need the hacksaw!
Yeah, I will try the RSV.
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@profeshenal125 should have some advice
If it got better turning the air screw in... then put one size bigger pilot jet in, and put the air screw back to 2.
This. New/better reeds will flow more air right off throttle. You need to richen the slow circuit, which is why turning the screw in helped. Go up one size on the pilot and you should be fine.
Thanks for the reply! Gonna try some Yamabond this weekend to see if that helps first. Been reading a lot about air leaks with the Vforce. I'll test first to see if I can find any bubbles coming from the intake area. Will post results when done.
Your pilot jet is now lean.
If you had a air leak between the carb and engine it would most likley rush on idle. And if it don’t, you can spray some contact cleaner or body spray (anything with gas) around the intake while the bike is running and if it revs up you have a leak.
But as the others have said, it’s probably just lean but here are some things to test or think if you are looking for a leak.
So, I took the intake apart today and added some Yamabond to both sides of the gasket and the reed block. A few hours later I started the bike. Low and behold, no bog! Looks like I must have had a small air leak that was causing a lean issue. Just from my experience, I would always add some kind of sealant to a Vforce 3 reeds. Really, I should have added this from the start. Thanks to all that commented. FYI, on the 2004 cr125, I did not feel a real boost in power from the Vforce reeds, however my son has a 2003 kx125 that has the Vforce reeds and it is significantly faster than the cr. I know, I know, the 2004 cr125 isn't the fastest, but I was hoping to feel a power increase. Anyway, glad the issue is resolved without having to mess with the jetting.
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