Turning a KX65 in to a trail machine.

[Arronduke]

Boy seems to be growing on weekbixs, don't feed him much else but grow he does.

So at 9yr old I doubt the Honda CRF70 will last 12 months.
Time for a new bike. Looked at the CRF80 and the KX65.....
Both it seems are good options, but I choose the KX65, why you might ask...

Anyway got the little machine with a fresh rebuild...from what I can see it a 2005, rebuild motor and it was delivered straight from a bike shop after the rebuild with recipts of work. cant argue with that!
So to get this little thing suitable for trail riding and not scarring the undies off the little chap I thought some changes are needed.

Hell I took it for a spin and it power wheelies.... very cool for old man, most not cool for 9yr old!

A little look on Google and the CRF70 makes a massive 3.6HP and the KX65 make a modest 14HP, one is a 3speed auto... and the other is well a real motorbike.. So I thought that I would look at options for making a KX65 user friendly for trail riding. Yep sounds easy I say.. "Boy here is a big set of balls, now get on with it."!

So the best options I found were... exhaust spacer and fly wheel weight.
Yep soooo simple, remove the exhaust chamber and add a spacer and then put the exhaust back on. ... 5min if your a leper.

The washer does not even need to be a perfect size, around 38mm and have a hole in it from about 14mm up to 22mm. The bigger the hole the more the little green machine will go in to the power band.
I have done the washer trick today and rode it before and after, all I can say is yep perfect for boy learning a clutch is and gets used to the bike. I rode it with and with out... I used a 17mm hole (standard washer) and it just enters the power band and then just stops revving... goes flat and smokes a bit. So when watching you can see when they are on full throttle.... the extra smoke.

Absolutely no lose of bottom end, the washer restricts the ability of the motor to expel the exhaust so the jetting is not changed.
Next up is the 10ounce fly wheel, on order. This easy mod will make it much easier to control the hard hitting power of the little KX. Most woods and trail riders will benefit. All beginner and timid riders will do better with the smoother power and less stalling that will reduce frustration and fatigue. Quick and easy installation, without any drilling, grinding or welding. The engine lock up tool (E-3) will make it even easier.... (from the site... obviously.. my English is not this good!)

And finally... its a kick stand. Yep this is a must.
So I have ordered all the parts for a KX60 and I will weld a bracket to the 65 frame and add the 60 parts... everything to follow.... parts are on order etc

Oh and option one fitted.

[nzspokes]

Random question, just getting my boy at 6 started. Have been looking at 50s but I think he may be a bit big for them. The 70 you had, could you limit the output of the 70?

Nice KX. Makin stuff for your kids is epic fun.

[Arronduke]

this might help...

but not much point de tuning a 70 @ 3.6hp, the 50 is 2.5

the KTM 50 = 11hp and the KX65 = 14hp

[cooneyr]

.... this might help...

Thanks for the spreadsheet above. I've got a 3yo I'm trying to convince SWMBO will be ready for a bike come next summer. PW50 looks like the go unless he has big growth spurt over winter.

Looking forward to when I can start mucking about with bikes with him. Whenever I work on my EXC he grabs a rachet and socket and "attacks" it. Thankfully not lost anything of the bike so far!

Cheers R

[nzspokes]

Thanks for the spreadsheet above. I've got a 3yo I'm trying to convince SWMBO will be ready for a bike come next summer. PW50 looks like the go unless he has big growth spurt over winter.

Looking forward to when I can start mucking about with bikes with him. Whenever I work on my EXC he grabs a rachet and socket and "attacks" it. Thankfully not lost anything of the bike so far!

Cheers R

My boy at 6 can pull the plastics off on my KDX when I give it a service.

[BM-GS]

Nice write-up. I'm contemplating a similar process for #1 son with an 85cc 2T, and I was wondering how to tame the 20bhps an 85 has over his too-small CRF80. The CRF100 just looks wrong, though it will be aircooled-Honda low-maintenence and our CRF150F is too heavy - and I don't want to be picking that up all the time, especially given the places he chooses to put it sometimes...

If the washer mod works well I may even be able to put that into a KDX200 to calm it for the Mrs for a bit, til she gets used to it. I was thinking about disabling the KIPS valve, like my old RD350 used to sometimes do, but the KIPS system is mechanical and all inside the head, not controlled by electronics and the amount of water that's got into them. That put me off a bit (I'm happier unplugging something than dismantling it) but this sounds like a plan.

Ironically, the kids are easier to follow now that they're faster, as KDX is in a higher gear, so less bucking and rearing going on. Of course, if I had any ability, this wouldn't be an issue.

Don't suppose anyone knows the best sized washers for a KX85 and a KDX200? Dyno printouts?

[gwynfryn]

You a missing a couple of classic bikes - Suzuki jr80 and yamaha pw80.

With the kdx200 the standard expansion chamber does a good job of limiting the 'hit' and so does the restrictive air box lid and snorkel. Most have been geared down a bit with a larger rear sprocket why not go back to stock. Should be cheap enough to get those parts in fact i think i have them all.

[nzspokes]

You a missing a couple of classic bikes - Suzuki jr80 and yamaha pw80.

With the kdx200 the standard expansion chamber does a good job of limiting the 'hit' and so does the restrictive air box lid and snorkel. Most have been geared down a bit with a larger rear sprocket why not go back to stock. Should be cheap enough to get those parts in fact i think i have them all.

Your not kidding, I rode a stock KDX the other day.

[Mike77]

Cheers for the write up and bike size chart, this page just went in my favourites!

[Arronduke]

Thanks for the spreadsheet above. I've got a 3yo I'm trying to convince SWMBO will be ready for a bike come next summer. PW50 looks like the go unless he has big growth spurt over winter.

Looking forward to when I can start mucking about with bikes with him. Whenever I work on my EXC he grabs a rachet and socket and "attacks" it. Thankfully not lost anything of the bike so far!

Cheers R

Great answer... made me remember getting boy 1 his first bike...

The boy was 4 or 5 can't remember but he had being saving for a bike, I find one on trade me in Tauranga so off we go with the trailer when we get there, boy gives $10 of small change to the man, shakes his hand and thinks that he just paid for the bike. proud like man.... Z50 (wrong bike... should have been PW50, second boy got this).... $800 yep first rip..!

PUT bike in the boot, had a station wagon... empty trailer.... shake my head.

Get pulled over for 100km, with a trailer, limit 90km @ 5km tolerance. I told Boy 1 that the cops want to take us to jail for speeding. Boy 1 burst in to tears.
So cop approaches car.... Boy one is hyper ventilating. Cop get to window, kid is hysterically crying, Cop looks at kid and I say..."Its OK son, the nice Policeman will not take us to jail for following the traffic"

Cop says the trailer has no WOF or REG.... and you were doing 100km. and glared.
Cunt gave me a ticket for the whole lot... $550 from memory. Could have brought a new one...now that fucked me off.

PW50 cool bike and when the throttle is held open they fly.

Resale of bikes is great.

Z50 $800 - Yep got taken for the Z50 sold $500
PW50 $500 mate ... hee sold $700
CRF50 $1300 own owner 1/4 section. great buy... had to drive 1.5hrs... still own
CRF70.. $1700 from mate... wanted to sell for $1900 but two mate wanted to buy it... cant charge them 1.9k... sell for what I paid.
KX65 $2250 purchased.. with matching riding gear, stand and ohhhh a BUTT plug..... and manuals etc on how to use it all.

Fact is... all the riding gear is the same for kids... you will lose FA... after the first bike its like... cheaper to up grade...

[Arronduke]

Its raining and we went to the top paddock.
Boy 1 first time with a clutch was..... very frustrating I found myself yelling at him many times to the point of swearing.... and no shit I don't swear at home in the family house... cant say that for the wife!

But after 1 stall he did not stall again, but ALWAYS for got to pull in the clutch when too slow....)
And to add the washer thing was great... he things its real fast... haaaa so it great.