[Focusinprogress]

so, I'm new to the forum and also new to these mini-stunt bikes.... I bought a crf70f about a week ago after a friend let me hoon around on his crf50f.

for starters, I bought some cheap all-black plastics for it so I don't trash the near-new stock ones in the event I later get bored with this thing and want to sell it off as stock without damage.

I also have been told by all the local stunt guys that I should try running 10" wheels on it for various reasons (I'm no expert) so I've borrowed a set to play around with. I'll be sure to log all my experiences in this thread for my own and other's reference.

Anyways, I rent a shop space in a huge industrial building....and over time the owner has grown to trust me and my three friends that share the rental space with me.....and we basically can screw around in the entire building as long as we don't mess with his stuff....soooooo even in these cold snowy months we can goof around.

Soon as I got the mini "home" we got to some wheelie practice.

Plastics came in, and borrowed a spare set of 10's with scooter tires to mock up....have to make a few little parts to get these crf50 hubs/brakes to work(I dabble in hobby machining). Axles are the same size and the brake hubs fit but the notch for the drum's brake-stay and the sprocket are different.....have an idea for that I'll post as I make it.

pic with the new chinese plastics and borrowed wheels.

I'll likely make up my adapters for the brakes to fit this evening and see what's what.

thanks for looking!

 

[klxkilr]

why dont u relace the front wheel with a 12 inch rim.

 

[Focusinprogress]

klxkilr hit it on the head. For starters, there is NO WAY to make a 10" CRF50 front wheel fit without preventing returning to stock (which is my goal through this build). I've made the back wheel fit nicely, and now I have this complete 10" front with brakes/tube/motard tire I need to try to sell or swap it for some parts to build a 12" front wheel.....

I've gathered that 12" front wheels are not commercially offered for the CRF70....so my plan is to get a rear rim and complete spare front wheel, and shorten the spare front's spokes to accommodate the rear 12" rim. I'm equipped to shorten and re-thread the spokes so this shouldn't be bad.

here's how I did the rear:

I turned up a stub on my lathe and threaded it for a bolt, then used an end mill to flatten two sides similar to how the stock brake-stay nub is constructed. Then I drilled a hole in the axle plate and mounted my custom stub with locktite and a lock washer.

^ you can see the stock one slightly in the background of my new one in this pic.

As you see, the way I did it does not impede axle adjustment, and is fully reversible.

I did it for two reasons: I want to be able to return to stock in event of a future sale, and If I ever decide I want to rid this off-road again I can remove the stub and toss the stock rear wheel with knobby back on (and back and forth as I please).

If anyone wants this 10" front setup PM me.

 

[Focusinprogress]

So, I've purchased an extra stock front wheel from MX 219 on here, and a spare rear rim on ebay. Once both are in my hands I'll be shortening the spokes by an inch and re-tapping threads so I can lace up the 12" rear rim to the spare front hub. I'll document how once I complete it (I'll take pics along the way)

 

[Focusinprogress]

So, all my parts came in for building a 12" front wheel setup. I thought I would document my findings here, and may make a dedicated thread for the wheel build for future reference of other members.

numbered all the spoke locations for re-lacing purposes

So, here's where things started falling apart on me. My original thought was that I could extend the threaded portion on the stock spokes and shorten them afterward....so that the thread die could use the existing threads as a starting point. I tried to do this on one spoke and as soon as the die reached the end of the existing threads it could slide down the rest of the spoke....so the threaded end is just EVER SO SLIGHTLY thicker than the rest of the spoke.

so my next play was measure the long spoke versus the short spoke to see if I could substitute the short ones in place of the long ones....and then I measured a rear stock spoke and it appears I could substitute a rear spoke in place of where the stock short spokes should have gone.....before getting too far over my head and ordering stuff that won't work (like a set of 18 rear spokes)...I started lacing up the short ones in place of the long ones to see if they'd work as they were 1.125" shorter than the long ones....I knew it may be shy of what I need because we're decreasing radius by 1", I assume at this point before lacing I may be .125" shy of being able to do it this way.

Yup, not looking good. I continued lacing though just to see....

this is the LAST "long" spoke (using the short ones in their place on the 12" rim)

yup, about an eighth inch short. PISS.

so I took it all back apart. I guess I'm going to send an email to Buchannans since I have seen this wheel build mentioned as something they've done....I hope they don't bend me over too badly just for a set of spokes.....

 

[Focusinprogress]

not too much to report....still awaiting spokes from Buchanan's

though, in the meantime I decided since I have a black 10" rear wheel now, it wouldn't make sense for the front wheel to be different....so I asked my buddy kyle that recently bought a powdercoating setup to get into it if he wanted to coat my 12" rim black for practice

once the spokes get here I can lace this up and swap to a 12" front with street tire I have waiting.

 

[Focusinprogress]

Got my tracking info from buchanans this morning. $121 for the spokes with shipping included, scheduled to arrive 1/29.

 

[Focusinprogress]

Well, good news and bad news.

I got the wheel laced up with the spokes from buchanans and then mounted the tube/tire.....but I guess during mounting I knicked the tube and now have to demount and get another brand new tube. GRRRR

The more I mess around on it the more I think I need to upgrade the rear shock. So I guess that's next on the shopping list.

 

[DSR BLACK DEATH]

What rear tire are you using?
Stock gearing & stock engine?
Where did you get the plastics from and how much were they?
is it easy to wheelie?
What about a rear peg for stand ups?

 

[Focusinprogress]

I bought the plastics off ebay for like $35.

rear tire is a kenda 3.0x10 and I'm super happy with it.

I had to swap to a crf50 37t rear sprocket, and due to that with the 10" rear tire I went down one tooth on the front sprocket for it to be rideable again.

engine is otherwise stock, it's harder to wheelie than a 50 but once it's up its far more stable/managable than a 50 in my opinion.

I do have a peg on the back for standups, it does those with EASE.

 

[Focusinprogress]

there's my 10/12 setup.

 

[fincher1]

its your bike but i would ditch the 10 rear and do a 12/12 more for sizing of bike.

 

[DSR BLACK DEATH]

Yeah a12/12 would look bad ass

 

[poontappa]

I think crf70's look silly on 10's. Looks like you should have bought a 50!