Bike keeps nosing over at 3/4 throttle

The idle speed will be dependent on model, particularly if 4- or 2-cycle, 2, 4, 6 cylinders, etc. If your engine uses carburetors, I'd say no less than 600 RPM, maybe up to 850 RPM at idle. If your engine is fuel injected, the computer should set the idle speed and air mixture for you (if it's functioning correctly), and a big twin could idle as high as 1150 RPM .

Your Idle air mixture settings are important for proper idle. A good approach is to let the engine tell you what it likes. For this method you will need either a tachometer or a vacuum gauge. Here are some steps to guide you.

1) If the engine will start and run, go from there. If not, a good initial setting is to turn the idle screw(s) all the way in (GENTLY--don't break the seats!), then back them out about 1 1/2 to 2 1/2 turns.
2) Attach either your tachometer or vacuum gauge to your engine. Tach is connected to the ignition system (usually at the coil); vacuum gauge would be connected to a manifold vacuum port. (The bike's built-in tach MAY work for this, but they are often not graduated finely enough.)
3) If using a tachometer, warm up the engine. Working on only one idle mixture screw at a time, begin turning it IN until RPM begins to decrease. Then back the screw OUT again until you achieve maximum RPM on that screw. Feel free to "play," turning the screw in and out until you achieve highest RPM at at minimum turn-out (if you leave it turned out too far, bike will run rich and foul spark plugs; if not far enough, bike will run lean and hot). Now do the other idle mixture screws the same way. Finally, go back and do all the mixture screws again (and again and again, if necessary) until all throttle bores are synchronized.
4) If using a vacuum gauge, engine temp is not as critical, but go ahead and warm it up anyway. Similarly to the tachometer method, turn the mixture screws in until RPM drops, then out until max vacuum reading at minimum turn-out. If you have multiple mixture screws, do the same on each, then repeat on all screws until you feel they are all synchronized.
5) Throughout the process of adjusting idle air mixture screws, you will probably have to adjust the idle screws to keep the engine in the RPM range you want it to idle. (If adjusting air mixture screws has no effect on the engine idle, the minimum requirement is probably a carburetor rebuild.)
6) Have fun getting to know what your engine "likes!"

If the bike is equipped with a carburetor, try not using the enricher (choke) so long. The enricher circuit in the carburetor is extremely rich. I see people let their bikes run for almost ten minutes with the enricher on and they can't figure out why they are fouling plugs. Only run the enricher until you can get the engine to run with the throttle. I use the throttle lock located on the underside of the throttle grip. Just idle the engine up that about 1500-1700 RPM, turn the enricher off, and tighten the little knob just enough to hold the throttle and keep the engine running until it warms up. Prevents you from fouling plugs. If this is not the case or you have fuel injection on your bike, you may need to take it to a qualified mechanic. I don't advise tearing into your carb or fuel injection unless you know what you're doing.

Good Luck
Steve

there should be an idle screw down be the throttle body of the motor give it a turn to the right a little that should raise the rpm a little to keep the bike going

hello lloyd...... definitely pull the carbs and rebuild them. Since you did everything else right, this alone should fix the problem. Joe
Thanks for choosing Fixya!

The carburetor jets, there are 3 bands; A low, mid range and high range rpms. 10k would fall in the Mid range power. I would let the bike warm up a little bit and tweak the middle knob on the left side of the bike and keep in mind you need the right mixture so turn it quarter turn one way at a time per testing the mid range rpms while riding, tweaking 1/4 turns in between tests. If it gets worse, turn it the other direction until you find that sweet spot in the mixture of fuel/oxygen. The carburetor jets, there are 3 bands; A low, mid range and high range rpms. 10k would fall in the Mid range power. I would let the bike warm up a little bit and tweak the middle knob on the left side of the bike and keep in mind you need the right mixture so turn it quarter turn one way at a time per testing the mid range rpms while riding, tweaking 1/4 turns in between tests. If it gets worse, turn it the other direction until you find that sweet spot in the mixture of fuel/oxygen. The carburetor jets, there are 3 bands; A low, mid range and high range rpms. 10k would fall in the Mid range power. I would let the bike warm up a little bit and tweak the middle knob on the left side of the bike and keep in mind you need the right mixture so turn it quarter turn one way at a time per testing the mid range rpms while riding, tweaking 1/4 turns in between tests. If it gets worse, turn it the other direction until you find that sweet spot in the mixture of fuel/oxygen.

You may have disconnected a wire somewhere or damaged a wire, check all wire connections if all are good pull a spark plug out connect it to the plug wire turn bike over to check for the presence of spark if spark is present reinstall plug. The bike may be flooded if so give the bike full throttle while turning over and as it starts don't let up on the throttle until the rpm climbs up to approx. 5,000 rpm.

Hi,
I have a gilera RC 600 which has the same engine as the nordwest, the problem could be the carb needs to be stripped and cleaned and replace the foam air filter with a paper one. For accurate advice and spares which are quickly posted, contact BOB WRIGHT at 0044193451033. He is the official UK gilera specialist, tell him I sent you, say the guy in southern Ireland, and he will look after you. Good Luck.
PS please rate me if this helped

check your spark plug if it burns ok. if it burns white its ok, also clean your carburator and the air cleaner after that start the engine again. if it does not change the problem is youre cdi unit.

Install new sparkplugs. Activate choke. Do not touch throttle. Push starter button. Do not touch throttle. If bike stalls repeat until it stays running, then you may give it a little throttle. If I give my TL any throttle on start up it floods. It usually takes 2 or 3 tries where the bike starts then stalls before it stays running. DO NOT TOUCH THROTTLE UNTIL IT IDLES. THEN GENTLEY.

I believe that you should give the carb jets a clean as this sounds like a fuel delivery issue. there is no electrical reason why there should be a break in performance like that.