Bonneville SE 09 efi wont start

It could be the clutch sensor. Damn thing has been playing up on mine as well, still haven't gotten around to try and fix it. Have to reeeeeally pull the clutch lever for the bike to start. And it's a bit random as well, just like you mention.

 

Hi Elphin, I would suspect a battery problem by your description. Next time it won't start, try jumper cables onto the bike and a known good battery - if it starts straight away you know the bike's battery is at fault.

 

I had a similar problem last year, only the bike would cut out whilst riding it. Turned out to be a loose negative terminal on the battery. It did some strange things at the time that you'd never associate with a loose battery, stuff like the speedo showing 70 mph when I was doing about 30 and the rev counter all over the place. I was lucky because apparently the voltage fluctuation can kill your regulator but once the terminal was tightened up I tested everything and I'd got away with it.

 

I had a duff battery when I bought my 2012 Bonnie, did the same - just got the click and the sound of the fuel pump.

 

Duff battery probably

 

I am not too sure about battery problem being the problem all of the time, I have recently purchased my 2012 T100 and my mate bought one too, a 2015 and we are both experiencing the same problem, having had the bikes on trickle charge over night they started perfectly, no problems, ride down to the local filling station and bingo, press the start button and it turns over once then nothing, try it again and the same happened, tried it a third time and it started no,problem. It would seem there is an underlying problem with the model. I believe that they are designed not to start if the battery is slightly less than fully charged which I find strange. anybody got any views on this?

 

The efi model certainly demands a healthy battery merely to turn over while the carbed 865 needs a pretty healthy battery too or it will wheeze away until it catches or the battery fades out. It pays to fit a quality battery as it is physically quite small and needs to throw out a good 180 CCA.

 

I am told you can rectify the problem by swapping a couple of wires round but haven't been able to find out how to do it yet.

 

I imagine you might theoretically disable the ECU battery canbus monitoring but it would not put power in the battery if it is not there!

 

Just as a comparison, my 1992 883 Sportster has a 20 Ah battery putting out CCA around 300. Whatever other cranky little ways it might have, it DOES start in pretty much any weather!

I have to suspect that the T100/T120 batteries aren’t really up to the job. I’ve had issues from leaving the bike for several weeks while I’m at sea.

I do see now, people using high-tech batteries of surprisingly low Ah ratings, sometimes as low as 4 Ah on Sportsters although I wouldn’t care to go below 7 Ah... its the CCA that counts for a quick spin and a quick start!

 

I suspect you are right and am currently looking at buying a bigger battery in the hope that it solves the problem. Thanks for the info.

 

A lot of riders don’t understand the relationship between CCA (Cold Cranking Amps) and total capacity. You don’t need a 20 Ah battery if you can get 300 CCA from a 7 Ah, provided the system gets enough voltage. Sportsters, especially older ones, don’t need much for their fairly basic electrical systems to function. So you can have a quite small battery, because once it’s running, the huge generator runs everything quite happily.

There isn’t a lot of space for batteries on the T100..

 

This is a pretty good price/performance mix.

https://www.tayna.co.uk/motorcycle-batteries/yuasa/ytx12-bs/

About the same price from Halfords with a Trade Card.

 

I have had this issue also not 100% certain but i think it was my sidestand switch faulty doing this symptoms were push starter button after a run engine would crank once and stop.

 

A little annual service is needed. Pull the rubber boot off and wiggle the switch and blast it with WD40 or similar then re-pack it with Di-electric (silicone) grease. Replace boot and forget for 12 months.

 

Cheers for the info ive never touched it and the bike is 9 years old so possibly needs some tlc