• Has your topic been discussed? Check this quick video for search tips. You answer/info might already be waiting!

CBR650F Difficult to start & may run on 2 cylinders after fall

neils999

2017
CBR650F ABS
Jan 27, 2018
Some help please - bike hit the floor this morning (left side) (due to the fact that the idiots at work gritting the car park and footpaths but not the entrance ... has some damage which I'm taking up with them but it started & run ok). Checked it at lunchtime whilst taking the photos and it started ok then also, however this evening will not start. Eventually sort of runs rough but cuts out - pump is priming and battery pack didn't make any difference (and the man from SOS Recovery couldn't get it going).

Would the drop made any difference to this or is this just coincidence? I'd like to know if / who should be paying if it is related or not!

Thanks, Neil
 

Robbymag

2015
CBR650F ABS
Oct 24, 2019
Sorry to hear about the touchdown I had a skid and a fall few years back and tried the council but was told. They font have to grit by law. I would have thought the fall might have made a wire loose like an earth check the battery.and fuel line does it smell of petrol good luck
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
You need 3 things to run an engine (to save baugustine @baugustine or miweber929 @miweber929 from hopping in and posting it :D):
1) Fuel
2) Electricity (spark)
3) Air/oxygen

Sounds like #1 is OK if the pump runs then stops as normal.
I doubt #3 would be affected by a slide at low speed in a car park.

So that leaves #2 ... you've eliminated the battery, which is a great first step.

You say it runs, but lumpy (2 cylinders? Dropping just one makes it rough as a**holes), so you may have jarred something loose.

I'd be looking at plugs, caps/leads and the coil packs for drop related damage. Coils are on the r/hand side just under the upper firing at the front of the tank. The fall may be moved/cracked something.

If you have done anything to a plug you'd lose 1 cylinder, lose a coil pack and 2 cylinders go down.

That's my take. I await my learned colleagues to skool me :)

J
 

neils999

2017
CBR650F ABS
Jan 27, 2018
Thanks Gents for your comments and help - now it will not start at all ... just turns over. Trickle charged the battery, checked the plug connections, checked the coil connections and checked all of the fuses. Suspect it is going to be a garage job
 

miweber929

2014
CBR650F
650 Alumnus
Staff
Feb 13, 2015
Woodbury, MN
Riding Since
1975
How long did you run it at lunch? Did you ride it or just let it idle? Have you attempted to ride it when it stumbled and ran poorly or just let it idle?

I’d guess it’s flooded and the plugs are fouled with fuel because short of a major fall or crash the odds of knocking something loose that easily would have been flakey by simple road vibrations.

Try the flooded start procedure in your owners manual or pull the plugs and dry them off. I bet it runs fine after that. If not, shop time.
 

neils999

2017
CBR650F ABS
Jan 27, 2018
thanks - wasn't ran for long at lunch but after fall, it was ridden about 100-200 yards. Tried the flooded procedure (and so did the recovery guy). It sputters but doesn't go!
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
The flooded procedure kills the fuel, so it should splutter for a while as it burns it off.

Once the spluttering stops, it may fire with a normal start procedure.

J
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
last chance then LOL ... grab the service manual from the resources section, take a look at the lean angle sensor. Bit of a long shot, but if the bike still thinks it's "laying down" for some reason it won't start the engine as a safety feature.

It's located under the airbox, above the engine (roughly speaking).

If you have a decent multimeter, you can probably check quite a few things yourself before getting a mechanic involved.

J
 

baugustine

2014
CBR650F
Staff
May 21, 2016
Ventura, CA
Back to Brammers @Brammers point above. You need spark, fuel & compression to run. No reason to suspect a compression problem in this scenario so make sure the coils are firing, there is proper fueling and check the plugs for fouling.
 
Top Bottom