I really believe if daughters have strong dads, they're a lot less likely to get into trouble later on.  I have two step-daughters 7 and 8.  Full disclosure: Their dad is very involved in their lives, and lives right around the corner.  They live with us, so naturally I see them more.  But he's a great dad, so no put downs there.  Just not real "manly/tear **** apart and see what happens, etc, etc".  The 7 year old likes to ride, but gets bored easily, so she's not into working on stuff.  My 8 year old is a brainy geek (spoken by a brainy geek) and as such loves to see how stuff works.  I got a little '73 TS-50 dirt bike the other day for $50 off Craigslist because it needed rings.  The parts dealer had rings, but couldn't get the base and head gaskets.  I know I could get them, but I wanted to buy a Honda copy HF engine anyway, so I just bought the 2.5 HP engine for <$60 OtD.  I plan on putting a cent. clutch on it and making a little mini bike type rig out of the old TS-50. 

My 8 yo has been bugging me all week to work on the bike, so after I got the kitchen finally cleaned up from the remodel, we went outside for the first night tear down.  We got the left side cover off and the clutch exposed.  I already had the head and the jug off, so we got to play with the piston and I showed her how the piston made the wheel go around by explaining how combustion works and how the power from combustion gets transferred the rear wheel.  Then we started working on getting the engine off the frame so we could take the case apart and I could show her the actual engine guts.  She was enthralled the whole time!  She kept poking and playing and messing with stuff.  She also got her first tool lesson:
Topics covered included:
Differences in socket drive sizes
Metric vs SAE
Deep vs Shallow well
Proper way to use a wrench
Lefty loosey, righty tighty
Top cabinet vs bottom cabinet of the tool box

It was an awesome time.  We didn't stay out too long, I just let her be the guide.  When she got bored, we came inside.  There's no deadline, so I'm taking all the time in the world to work on this with her.  Soon enough she'll be grown and hopefully we can reminisce about the time we tore apart the dirt bike.  She's already talking about painting pink.......   

Here's the obligatory pic:

Well done!  An old saying I always had with my kids is if it hurts, you had just a little too much fun, it quits huting when the pain goes away, and if you cant fix it, dont break it.  "Yes, I'll help you fix it"  has way more value then doing it for them.  If they wont help, it stays broke or gets fixed and sold.  Thats the two choices offered.
Again, great job and enjoy these precious years, once they learn independance, they only have what they learned when they were young.

What a wonderful colaboration, it will be a teamwork thing that she and you will remember for a lifetime. Mine are grown and gone now, but they used to help me clean-up my bikes, pack my bikes and even help me un-pack them. I now let my 2 grandkids, when they are here, join in the family tradition of cleaning Dad's / Grandpas bike. And my grandson is an expert at 10 on packing a bike, he has his own list, which is a decent copy of my list, he checks it off and runs it down like a seasoned pro.
So enjoy your time it will fly by faster them a bugs a$$ hits your windscreen at 75 mph.
Everyone ride safe out there.
Greg

After teaching high school shops for thirty years I can tell you that girls are either the best to teach, 95% of the time, or the biggest headache, 5% of the time.

I used to say that when I was trying to teach a student some procedure that the boys would take some of what I said and did, some of what they thought I said and did, some they made up, some they got from dad or grand dad and throw it all togehter and wonder why it didn't quite work. Girls on the other hand watched, followed directions, did things in proper sequence and were quick to point out if I didn't follow my own procedures. They usually achieved much better results with a lot fewer problems than the boys.

Just reminded myself of the time I was running a welding production line. We tracked the output of various parts and had hit the wall on increasing production. Hired a young woman MIG welder and she did one less in her first day than the guys did after several runs. The other guys did two more than they had ever done before. We got better from there.

I think the best was when I went back to teaching after a couple of years in industry....early eighties kicked me good....anyway I took over an automotive program and metal working. The previous teacher wasn't very popular and I had a particular class of boys who figured they were the pack leaders. Anyway it was a small class and I had some kids transfer in when the kids found out that there was a new teacher. Then about a week into class I had three grade 12 girls show up and say they had signed up for the class. Those three were followed by a fourth. Turns out I had the social elite girls taking the class. Being semi rural 2 of the four were farm girls so they had a good idea on things. Was there ever a change in the class dynamics.

Anyway...enjoy your time with your step daughters, don't talk down to them and give them a chance to show you how they solve problems...you will learn something.....