Advice on <$500 dirt bike for 12y/o son.

[Cobia]

My 12 y/o son has got a hankering for a dirt bike as a Xmas present. After riding with dad for a couple of years the bug has set in. He's 5'6" and about 140lbs. so the 50cc and 70cc are out, so are the parts store chinese numbers - Baja and the likes. Hard to get parts for them!!
So, I ran accross a 2004 Yamaha YZ80 bored out to 110cc for $400. VIN number says its a 2003, but I guess it sold as a 2004, same as some of our XS's. What's strange is that Yam stopped making 80cc bikes in the late '90s.
So I surmise that it started out as an 85cc.
My local MC salvage yard owner advised me that in order to achieve a true overbore on this type bike the cylinder had to be re-sleeved!!
I'm definetly doing a compression test before making an offer and will try to get it running as well (fresh premix fuel and starting spray - ether). Owner states that it's out of gas and hasn't been run for 6 months.
Will be checking it out on Friday.
Any thoughts or advice??

[motoman]

My daughter's YZ80 was an '03. Made it more ridable for her by replacing the 14T counter sprocket with a 12T. Even at that having a six-speed tranny it would top out bout 60mph. Decent handleing bikes, even with the stock suspension they were pretty quick around the track with a good rider aboard.

[Cobia]

Thanks, that's good info Motoman.
It's kind of what I expected with this bike, light but with generous grunt at the low end. And with six gears, the top end speed is impressive.
A possible cause of concern with a 12 y/o!!

[fredintoon]

My 12 y/o son has got a hankering for a dirt bike as a Xmas present. - - -
I ran across a 2004 Yamaha YZ80 bored out to 110cc for $400. - - -
I'm definitely doing a compression test before making an offer and will try to get it running as well (fresh premix fuel and starting spray - ether). - - -
Any thoughts or advice??

Hi Cobia,
if it starts, go for it, what else?
Learning to ride in the dirt is the best possible way to learn how to control a bike on the road.
I started my two boys on dirt bikes and they are more skillful riders than I am because of it.
Be prepared to spend as much again on appropriate riding gear, eh?

[motoman]

Actually, any of the 2-strokes up through 125cc lack any bottom-end as they are moto-cross bikes with a light fly wheel to rev quickly with not much centrificul help there for any bottom end........hence the reason for counter sprocket change along with slowing down that top-end speed which was close to eighty.

[soccer4m]

go BIG

HI Motoman,,,as a Dad of a now grown son who rode dirt bikes all our lives,,,,I would recommmend go bigger on the frame and engine. Now that your boy is going on 5-6, 140 lbs,,,,he is going to get large real quick and that yz 80 is going to be like a minibike soon. I would recommend get him a 125 which is large enough to scoot and not super huge in power to get him in too much trouble. There are lots of them and cheap since most riders want to go to the larger 250 which would be too much for him now. Anyway, there is plenty of 2 and 4 stroke 125's that could fit him much better than a pee wee 80. Maybe try him on the 4 stroke 125 which is a bit smaller than the 2 strokers and see how he fits it, even the honda 100 is a great bike. It wont be long before your boy wishes he had a larger bike and smoother power. Personally, anyone that bores out those little 80 engines should of just gone to the next size engine. It causes all kinds of carb issues and exhaust funkiness. Good luck, Mike in San Diego, happy to have yamaha yz250 and the monster yz490 in the stable.

[motoman]

Didn't see the height/weight........your exactly right Mike, too big for that bike. I used to jump on my daughters yz80 occassionly and it would really try to dive under itself and do all kinds of wierd stuff if "pushed" with the extra weight and size on it. Not a whole lot different with me at 5'10" and 170. Either of my son's bikes, rm125 or the cr125 they were racing then would be the better choice. I would say the cut-off weight for the smaller 80's to still handle well and not give you a "tank slapper" would be around a 100lbs. I gave my oldest son my 97yz250 after having won the RMXA series here in Colo. back in '03 riding the 50+ class. Definitely the 125cc is the correct choice........as is ATGATT.

[ManagerMike]

Agreed, too small of a bike. My 12 year old girl, at 5ft nothing and 85 pounds fits her '97 RT100 just fine.

[Cobia]

Well here it goes, as exposed in another thread, I went ahead and bought this '03 YZ85 with good compression and spark for a good price (mainly one I could afford) but it didn't run w/out starting spray. Compression checked out at 150psi, it had spark, and apeared fairly decent except all the plastic was gone. Brought it home, discovered that the intake manifold, carb connector to the head, was totally cracked. Sealed it with liquid electrical tape, until I get a replacement, and got it going. Cleaned the carb while my boy sealed the cracks, and got it going this afternoon.
What a thrill!! The thing wants to wheelie all the time!!
Scares me even!! Palmer is 5'7" and 150 Lbs at 12 y/o!! You tell me!!

[windjammergump]

bike for sale

i am 47 and can play on the 85 beast ....you can upgrade just teach him....look out for your surronding and wear a helment a split second is all it takes to loose him....i ran supercross so i know what a helment can do....