Posted July 29, 2005 - 06:29 PM
1) What sprocket sized do you recommend on the front and back? 13/42?
2) On the intake, we are looking to keep the same carb., so do we just get a Uni filter?
3) On the suspension, need something tighter on the front, and would like to know if there is a swing arm which fits the back with no mods needed?
Any help will be appreciated.
Posted July 30, 2005 - 07:33 PM
The foam filters offered by hondatrailbikes.com for the 20mm carbs will fit the stock 70 carb!!! Supposedly there's a UNI available but so far I've not found it. Currently I have a K + N and a foam filter I got from an Amsoil dealer, although it's not specifically designed for the carb mouth size on the 70--it came with rubber adapters that seem to work although you have to make sure they're oil free and not to overtighten the hose clamp.
I preach the gospel of using 50 primary gears on the 70 for even more acceleration. The part numbers you need:
23110-GK4-010 big gear
23120-086-020 small gear
23112-GBO-910 clutch outer drive gear
The big gear is narrower than the 70's but if the 50 gears hold up under 88cc+ motors I figure they'll last on a 70.
Main jets are available from Sudco (sudco.com or 323-728-5407). They are part number 99101-116-(jet size). They're available in sizes from #50 to #120.
Also the intake manifold isn't matched well to the intake port of the head. The head hole is larger and off-center from the manifold hole. I copied the head hole location on a piece of paper, cut out the hole, and then used the the paper template to match the manifold to the head. I had to remove a lot of aluminum to get it to match. Won't give you 10 HP but every little bit helps and all it costs is your time!!
Posted July 31, 2005 - 04:15 AM
Posted July 31, 2005 - 08:53 AM
Posted July 31, 2005 - 09:41 AM
Posted August 01, 2005 - 05:56 PM
I have not changed the jetting yet. I still need to modify the air filter or put a pod filter on the bike. I'm at 5,000'+ so I'm probably a little rich as it is anyway.
Posted August 02, 2005 - 08:56 AM
fast 50's stiff fork springs/10 weight fork oil
fast 50's riser
1/4 turn throttle
extended throttle cable
12 inch front and rear with street tires
i like bmx bars but its all personal pref
werkes rear shock a must
cdi ripper box
kn air filter
bigger pegs and folding shifter helps
13/43 gearing but as sprokets are cheap i would play around with that
some guys are running a 19mm carb
some guys are running the 4 speed manual tranny i prefer the stock but you may want to play around with the clutch
i need to come up with some sort of lower fork brace as the lower tripple bends easy
and most likely you will constantly be working on the jetting
Posted July 02, 2009 - 07:40 PM
i have the crf70 2008...sweet bike stock but if your looking to throw on a little more power for little cash and without bore-ing your engine put a bbr round exhaust pipe. they are only 170$ and you can install your stock end cap so that its a simmal quieter sound. Go to bbr.com and check it out for yourself! its a pretty decent mod, as well try to get a aftermarket rev box its another cheap mod that helps with the power.
Posted July 03, 2009 - 10:29 AM
Honda CRF70F 2007 by ThumperTalk
Honda CRF50F 2011 by ThumperTalk
Honda CRF50F 2005 by ThumperTalk
Honda CRF50F 2007 by ThumperTalk
Honda CRF70F 2009 by ThumperTalk