1988 CBR1000F. Here's my problem. Cranks over. Getting a weak spark. It putts enough to get the headers hot but won't run.

Here's what I've done.

Fuel tank cleaned and relined with Kreem. New tank screen, new fuel filter, carbs rebuilt with all new gaskets, jets, needles, float seat strainers, carb bodies soaked and cleaned w Berrymans Chem dip. New air filter. New ignition coils(old one's were not shot but borderline readings on ohmmeter), new spark plugs, caps, and wires. Cheched the reading on pulse generators. New Battery. Cleaned fuse block connections, cheched all the harness multi pin connectors.

Here's what some strange readings are.

I'm getting 10.5 VDC in places where I should be getting Batt Voltage, and I'm getting 5 to 6 VDC where I should be getting ZERO!!! HELP!!!! Before I lose my mind!!!

Thanks

titansuzi

 

First check the wiring on the coils.

Sitting on the bike, coil pack 1-4 and on the left and coil pack 2-3 to the right.

Both coils have Black/White wire on their left side.
1-4 has Yellow/Blue on its right side.
2-3 has Blue/Yellow on its right side.

Also, the plug leads across the two packs are as follows, from left to right, pack #1 (1-4) pack #2 (2-3).

This is a start.

 

check the wiresgoing to the coil under the tank , they have a endency to cut under vibration. i had that problem.

 

Ah, thanks guys, all that's been done already, another problem arose. I had a dream last night that maybe my bike had too much oil. I woke up. I check the oil. sure enough. too much. I changed the oil when I got the bike last october. mind you it has not ran yet, just my trials and failures. I drained a quart to get to the right level and? The oil is all cloudy!!!! Blown head gasket i think. I try to start the bike, it runs for about a minute!!! The longest since I've owned it!!! Then it dies and won't start again. I look into the cooling system! Bone dry!!!! Had I known the head gasket was blown, I'd have started there!!!! Ripped the top end off, sure enough. blown in several spots between cylinder sleeve and cooling jacket!!!! New one ordered already. Hopefully that will be the end of my problems. I'll keep u posted on progress. thx!!!

 

Interesting. Let us know how you make out, and I wish you luck!

 

Sounds like you have some mechanical sense so hopefully you will get her back to going better than ever. The positive is, if you get stumped on something, take a nap or sleep on it and maybe you will get another answer on what to do next!

 

Well, this beast will be the death of me. New head gasket installed. You can still see the hone cross hatch marks on the cylinder walls so I didn't bother re-ringing the pistons. Valve train assembled, all timing marks alligned without a hitch. Didn't drop the "Jesus" retaining pins on the chain tenssioner into the crankcase(whew). Compression is up, fluids changed. Still, the electrical problem persists, but now the 5.4 volts on open circuits has dropped to below 1 VDC. So that's a plus, still, very weak spark and I'm going insane!!!!!! Any input would be greatly appreciated!!! Thanks.

 

ok man i just went threw this last week i found out that my fuel cutoff relay that is located on the left side of the battery box was messed up and grounding out part of the volts going to my coils and other electrical components what you do is get a voltmeter or multimeter and start at your battery check voltage should be 12.4+- .3v then follow all wires going from the battery ocasionally checking voltage until you find where it drops then look for any relays or syloniods any electrical component that could be grounding out also check your ground to the battery its on the frame next to the battery tray. i found that when i unplugged the fuel cutoff relay the voltage returned to full battery voltage at the coils and the bike ran perfect but when you unplug the the relay you disconnect the fuel pump so use a jumper wire from the positive terminal to the gold/red stripe wire that went into the relay thats the power wire to the fuel pump. let me know if any of this helps.

 

thx happy_charly, i'll have to give that one a try tomoro. I've gone thru some wires already, my ground's good, though I'd have designed the harness a little better, not enough ground points in my opinion. I'll keep you all posted on the outcome! Thanks.

 

voltage on open circuits means there is a short somewhere. Check your harness, check the switches, anything with a wire, check it.