Ok i have been having starting problems in the cold for awhile so this Christmas i did the valve job and did the intakes at .005in tight and the exhaust .007in loose. Took the carbs off and went through and cleaned them. I even bought a new battery but it is on its side right know since it does not fit upright. I do not have the coolant hooked up yet since it always helped me pouring hot water to heat the engine up. The bike runs great for the most part and stumbles every now and then when i am high in the rpms. My problem is i am still cracking on it alot to get it to start. Some times it will just start right up and other it takes awhile. Usually the trick is to crank on it a little and let it sit for about 10min and then it starts. The starter sounds normal and turns over fast. I dont know if the starter clutch is grabing or not and wanted to know what test to do for that. I am having a feeling that i will have to replace the starter clutch and damper and was wondering where i can find these cheap or if there is an aftermarket or soemthing. The bike is a 90 CBR1000F and has about 45,000 miles on it. Thanks

Steffen Sparks

 

First off, unless you're running a battery that's designed to operate on it's side, change it ASAP, if only to stop the battery water from draining out all over your swingarm, and destroying the battery, when the water gets too low. You can also damage the regulator/rectifier and the stator if the battery runs dry.
Some questions -
Is your choke connected and operating correctly ?
Is your vacuum hose to the fuel line not leaking ? This will cause the bike to get insufficient fuel.
Are your plugs clean and the right ones ? NGK DPR9EA9 or irridium DPR0EIX9
Check the voltage across the battery terminals - anything less than around 12.6 volts and the bike will turn over, but it won't start.
Are your rubber inlet boots on the carbs in good order, and fitted correctly (right way round) ?
Check your killswitch - they sometimes operate sporadically, and will cause symptoms such as you describe. So will a defective sidestand switch.

I don't think it's your starter clutch, but if so there was a complete stator on e-Bay UK over the past few days.
Best I can do from here- hope it helps...........

 

First job is to get the right battery in and make sure it is fully charged.
Second it to get system filled up with coolant - it may help you initialy to get the bike fired up - but then what ? you cant exactly go anywhere so it isn't really letting you make any progress.

Once the bike is set up like it should be then you can start down the path of getting her running right.

Whereabouts you you Steffen?

 

Not that I'm any kind of expert , but if it stumbles at high RPM's could it be fuel starvation?

 

Thanks for the replies guys and i will try to explain everything that i can. As far as the battery the last one i had was a yusha? battery and it was sealed and also on its side. I dont know why but it worked for several years. I do notice when the bike is warmed up and i shut it off it will start right back up with ease. As far as the chock it is working since i checked that out when cleaning the carbs. I can check the boots again but they looked good! Will spray carb cleaner around them to see if it stumbles. Forgot to mention i replaced the plugs with these NGK DPR9EA9, a month back and pulled them from the bike doing the valve job and saw they where a nice light brown on them but where loose for some reason. I will check the voltage tonight and see if the kill switch is bad. I am not running a fuel pump and do not have a fuel filter as well. Do you know why it is starving for fuel? I also leave the petcock on all the time. I am located in Las Cruces, NM in the states. I guess not to many bikes made it over here. lol Thanks

Steffen Sparks

 

yes and no. If it's a sharp and noticable miss than it's a spark problem if it a soft bogging out then it's probalbyfuel.

 

def put the batt in right the only batts i know of that can be mounted sideways are gel cell batts.

 

So i tried a few thing out. I do not have leaks in the carb boots since i sprayed carb cleaner and did not get a response from the engine. Starter fluid DOES NOT start my bike what so ever. I have placed the battery right side up and made it fit. It was 30 degrees F this morning and i had to crank on her ten time and then let off for about 10min and then the next crank she fired right up! I had the coolant hooked us just drain it every night or so and add hot water. My starter sounds strong and cranks fast and not slow. What do you think the problem is? I notice whe i did my valve it did great for about a week and then went back to its old self. I do notice it starts up faster in warmer weather though. Thanks

Steffen Sparks

 

As far as mods go it just has the K&N, big bore kit, gutted vence and hines exhaust, no fairing, no glass light in the front fairing, and no rear brakes such as rotor and caliper. Thanks
As far as the driving it does great when it is warmed up and have notice the valve adjustment difference. Thanks

Steffen Sparks