Hard start

[Retrax]

Ok, maybe this is "normal"? I have a 2007 XB12Scg that I just bought. The battery looks relatively new and tested 12.9 volts on my multimeter after I used a battery tender to fully charge it and then let it sit off the tender for about 8 hours. When I start the bike, it cranks over about two times and fires right up.

The issue I have is when the bike is hot and I go to restart it. If I am riding for a while, shut it off, and then go back to start it again after a minute or two it sounds like it doesn't want to start. The starter will engage for a fraction of a second as I hold the starter button down and then everything will go silent for only about a half second. The starter then kicks over the bike and it fires right up. If I let it sit for 20 to 30 minutes it will crank right over without the half second pause.

My battery seems fine and the connections are solid. This seems to be a heat issue. I always engage the starter with the bike in neutral and the clutch lever pulled in. I am just curious if this is the norm. My 2009 HD Streetglide will do the same thing if I shut the bike off while stuck in traffic and then go to restart a short time later...

 

[thrstrmech]

you're not alone with that issue...my '03 9s does the same thing when she gets hot, while in traffic I split the lanes to keep air flow across the cylinder heads

 

[fakameanrepresent]

my 2009 scg does that too, its the heat. Don't worry about it.

 

[user_deleted]

it's commonly called "compression bump". these are heavy cranks, big pistons, lot of cylinder surface area, and high static compression. when your motor is shut off chances are about 80% or more that 1 of the 2 pistons stopped just short of TDC on compression stroke with captured air above the piston dome. when you go to restart it the starter motor must immediately take that piston past TDC compression with literally no help from a any crank reciproctating energy meaning....the starter is straining. it doesn't hurt anything but does momentarily put a tremendous load on the battery and starter. try this: when it does it immediately let off starter button. wait a second and hit starter button again and it will spin right thru and start the bike. very common with big displacement high compression twins.

 

[Retrax]

That makes sense, thanks for putting it into terms I can visualize. I'll give the starter button release technique a try next time. That explains why it doesn't happen every time. It is just more noticeable and prevalent with the Buell compared to the twin cam 96 in my FLHX.

 

[user_deleted]

It is just more noticeable and prevalent with the Buell compared to the twin cam 96 in my FLHX.

you're correct, it is. H-D spent alot of time and engineering R&D money doing everything possible to engineer that annoyance out of the twin-cam motors. the H-D doo-rag and chaps crowd would never tolerate it while us Buellers find it part of the quirky brilliance that is Buell.