I have a 1997 honda cbr600f and the fuel is running to rich at about 2-5k rpms then runs fine for the rest of the range, at this range it makes a big lag spot at low speeds, however at high speeds runs great! Also when rolling of it has now started to blow blue flames out the exhaust (looks cool but is it damaging)? Just had new after market headers (streetfighter( not sure if that helps with the make) and got a new K&N filter put in which did help a little but not enough? Now i have been reading a few forums and was thinking could it be something to do with the ram air system that comes open after 30 mph because it feels like it all happens bellow this speed, if so is there a way to keep the ram air open even at low speeds??
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
The Honda NSR125 doesn't have two cylinders - it has only one cylinder. If you have an NSR125 and it sounds like that, then you're "four-stroking" in the middle of the RPM range. "Four-stroking" (not firing exactly 50% of the time) is caused by too rich a mixture, which tells me that either your air intake has a problem or your carburetor wants more attention. If you only cleaned it by pouring carburetor & choke cleaner into the fuel tank, that's probably not enough - you'll probably need to disassemble the entire carburetor and run carburetor cleaner spray through every port & jet or put it in a dip tank until it's dead clean inside.
Since it seems to clear up at higher RPMs, it's probably not your intake - that's just get worse & worse at higher RPMs. I've gotta' say I believe your carburetor's still not clean inside.
Since it's running rich below 4KRPM, it should hurt anything except your pride & your bike's performance. It should NOT seize the engine - that'd happen if your fuel mix was too LEAN, but yours is too RICH.
Most likely fuel / plug. Easy to check. While running unloaded and miss-firing, try applying the choke just a little to increase fuel mixture (make run slightly rich), if clears may need carb kit. If it gets worse with slight choke running rich or plug faulty. Before you change parts try using premium fuel. If runs better problem solved.
Hi, Harrythespid it should be noted that the "AIR FUEL" mixture screw adjustment "ONLY" manages your idle and has no effect on any other circuit also any intake leaks must be repaired before the A/F adjustment procedure can be performed otherwise you will never obtain a proper idle and you will waste a lot of time chasing the impossible. The A/F mixture screw's purpose is to fine tune the fuel charge entering the combustion chamber. The following applies to both 2 and 4 stroke engines:
1. The mixture screw may be sealed at the factory with a Welch Plug please review the following video for removal. https://www.youtube.com/watch?v=wAXcksgvDkM
2. The mixture screw manages a range of 3 complete 360-degree counterclockwise turns from the bottom/closed position.
3. The mixture screw should have a spring and o-ring for tension and sealing integrity.
4. Turn the mixture screw clockwise until it gently bottoms out, this makes the fuel charge very lean and the engine should not idle if it does then the pilot/idle jet is too big and needs to be replaced with the next size smaller.
5. Turn the mixture screw 1 and 1/2 turns counterclockwise to establish a baseline for starting the engine.
6. To fine-tune the idle circuit, adjust the mixture screw 1/4 turn in or out to achieve maximum idle RPM, wait 15 seconds between each adjustment for the idle to settle.
7. Never go past 3 full turns out this will make the fuel charge rich, foul plugs, and produce black smoke out of the exhaust, if the engine RPM keeps increasing past 3 turns the pilot/idle jet is too small and needs to be replaced with the next size larger.
8. After achieving maximum idle back out the mixture screw another 1/8 of a turn then adjust the throttle cable idle stop screw to 950-1050 RPM.
9. This procedure works great on 99% of all engines, for the 1% that demand a more robust throttle response on aftermarket monster fuel delivery systems additional tweaking outside the box may be necessary.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day. XRV750 Adjusting the mixture synchronisation How Honda Shadow VT700C Running Lean Fix Pilot Jet Needle Shimhttp://service.tanga-moteurs.ro/data/Honda_XRV_750%28Africa_Twin%29%26XL_600-650_V%28Transalp%29_%2787-02_Service_Repair_Manual.pdf https://www.partsfish.com/page/oem-parts-for-honda Honda XRV 750 Owner Manual
The mixture screw is used to get the transition from idle to throttle up smooth, and not to bog.
Sounds like your jetting is to rich, or too big. Read your plug as it's probably black. Then go smaller on your pilot jet, run it and read it again. Make sure you run 32:1 mix, and jet the bike to match this.
Ensure your spark plugs,wires (ignition coil and spark) and your filters (air and fuel) are within 2 years of installation It's erratic at 800 rpm as the engine is cold and they like the 2200 range for 3 minutes before they kick down on their own. Press the pedal twice before inserting your key. The owners manual states depending on the outside temperature, the engine will require more priming. Update if possible.