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True 'budget' build dh bike, Chumba F4

supermoto

Chimp
Apr 20, 2008
19
0
Hey,

Here is my first dh bike. True 'budget' build i think... i am only $1300 into it and couldn't be any happier. The only thing giving me trouble is the fork (04 888r), the compression side doesn't work. Any suggestions? It probably has never been serviced. I will probably replace it after this summer with a boxxer to lighten it up. Currently it is at 40lb even and front heavy because of the fork. See you at northstar!
 
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davep

Turbo Monkey
Jan 7, 2005
3,276
0
seattle
The 'compression adjuster' only effects the last two or three inches of travel in those forks. There are bleed holes in the cartrage between about 1 and three inches from the bottom, so all the oil flows out the holes rather than through the compressoin piston until the piston is passed the last hole.

If you want more LSC and prevent the excessive dive that fork has, close up some of the bleed holes. Marz made a way overpriced sleeve for the purpose, or you can fab something with PVC or heavy duty shrink wrap.

go-ride had a good article on tuning this fork a while back. It might still be on thier site.


Hell of a ride for the $$....you should put the Paul Frank seat on your bike.....
 

supermoto

Chimp
Apr 20, 2008
19
0
The paul frank seat is comfy! And thanks davep for the help. I'll open up the fork and see what i can do with some pvc.
 

davep

Turbo Monkey
Jan 7, 2005
3,276
0
seattle
The paul frank seat is comfy! And thanks davep for the help. I'll open up the fork and see what i can do with some pvc.
no problemo, here is the go-ride info:
http://www.go-ride.com/WSWrapper.jsp?mypage=RidingTips.htm
click 888 tuning.

Just flip the bike over and let the oil drain 'up' into the stanchions. Then pull the lowers to access the cartrages and see what you are dealing with (this way you do not loowe oil or need to deal with it at all).

I modded my sleeve to a setting not offered by the marz part. IIRC, I covered all holes on one side and left a progressively smaller set of holes open on the other side. Remember to back off the 'adjuster' when you do this, or the when you pass the last hole, the damping will REALLY kick in.
 

Ringer

Monkey
Mar 4, 2008
152
0
That you victor? This is scott who had the r9. if you need help tuning the 888 lemmie know. ive done a few now. glad you got a bike.
 

supermoto

Chimp
Apr 20, 2008
19
0
What's up scott! You'll have to pm me your number because i forgot to save it. And some help on the 888 would be great. Did you sell the r9?
 

supermoto

Chimp
Apr 20, 2008
19
0
Haha, ya gotta save those grams!

I ran out of regular sized ones and all i have are those tiny ones!
 

Bulldog

Turbo Monkey
Sep 11, 2001
1,009
0
Wisconsin
I've always loved that super compact layout of the F4, but dayum if a bike ever needed a chainslap guard that is it!!!!

Awesome work for $1300! How much did you pick that frame up for?
 

supermoto

Chimp
Apr 20, 2008
19
0
Thanks for the kind words and tips...

As for the chain guide, do i have it set up with too much tension?

Also, which bolt snaps? Is it the upper shock mount bolt? I'll be sure to carry spares.
 

homepiece

Monkey
May 22, 2006
234
0
OHIO
Thanks for the kind words and tips...

As for the chain guide, do i have it set up with too much tension?

Also, which bolt snaps? Is it the upper shock mount bolt? I'll be sure to carry spares.
Lower Dogbone linkage bolt. I have snapped 2 on my f4.
 

rockwool

Turbo Monkey
Apr 19, 2004
2,658
0
Filastin
As nice new and expensive stuff is, they don't come close to the feeling of a few hard earned $ put very selectively on a nice budget build. :thumb:
 

Spunger

Git yer dumb questions here
Feb 19, 2003
2,257
0
805
As for the chain guide, do i have it set up with too much tension?
The guide needs to be rotated. The top part of the guide should point up at 12 o'clock. You can tweek it a little bit from that point but it's overly rotated.

As for the chain it looks like it needs to be shortened a bit. I know on Shimano/SRAM site there's some good info on this as well as Park tool's site. You'll want to get some sort of swing arm wrap on as soon as you can because at the current setup your chain will eat through the swing arm in no time.

Nice budget build! I just got done doing this for my brother and it's a good feeling to know that on such a limited amount of $$$ what can be built. As long as it works for you you're fine :)
 
Jun 20, 2007
349
9
Excellent bike, wonderful price. My DH bike was a budget build.

I also like your girlfriend's beach cruiser. My wife is buying me a cruiser for my birthday, I can't wait.