Rpm redlines when starting

you have to adjust the valve FIRST or you are just wasting your time and efforts. how to do it AIRHEAD VALVE ADJUSTMENT with Pics
KD tools 2274 metric feelers order at any autoparts store
make a carb sync tool from hose or the baby battle method 10$

How To: Make a 2 bottle synch tool

http://www.xjbikes.com/forums/threads/5-carb-sync-tool.4191/


http://www.xjbikes.com/forums/threads/old-school-method-of-one-vacuum-gauge-carb-sync.2132/

 

The carbs needing syncing. I have never needed to do it before, but that was so bad it wouldn't start again. Only one was close to being right. Now it starts up perfect and runs pretty good. When I can afford what I need I will finish syncing. I knew I could fix it, although it was frustrating.
I still wonder because it ran fine for 20k miles then all of the sudden would't start. Cleaned the carbs then all it would do is start red lining. Got that solved with a cleaning and it started, but only one carb working right and before long it wouldn't start and I read up here on bench syncing the carbs. Did that and now she starts and runs good FINALLY.
It is different for me, with it being my main transportation. An XJ750 has been my main transportaion for well over 10 years.

Thanks for the carb syncing info. Will have to finish that soon. I am suprised at how good she runs now. Before I adjust the valves I will get a valve cover gasket. Need a color tune plug to dial in the air fuel mixture since I know that was adjusted before.

One day I may be able to rebuild the front forks. I have ridden at least 100k miles between 2 different XJ750s with front forks that needed rebuilding,

 

I had this issue a few weeks ago after installing a new jet kit, turns out I didn't install the throttle cable correctly in the guide/bracket on the carbs and it held the butterfly valves nearly 3/4 open.