CB900 Scrambler - Rally Approved!!

Well I got the 900 cleaned up but then I got distracted.

I bought a Honda PA50 Moped to race...

http://www.youtube.com/watch?v=WyxVR77dsRo

http://www.youtube.com/watch?v=ursjbzcU-8I

https://www.facebook.com/thethunderdrome
http://www.cyclecanadaweb.com/articles/10440/
www.thunderdrome.com[/QUOTE]

I don't have time to do it before the ThunderDrome in Sept but I plan to brace the frame and make it a top tank kinda like this....

Wilnic1.jpg


But with a street tracker style seat/tail. A micro-tracker of sorts.

classmar_600.jpg


Time for a new build thread over in trackers.
 
Re: Re: CB900 Scrambler - Rally Approved!!

Rich Ard said:
Forgive my ignorance - what IS THAT?
Click to expand...

that's a bad ass Honda RS750 factory racer that was built in the '80s to complete against the Harley XR750 on the flat track !

http://motorcyclemuseum.org/asp/classics/bike.asp?id=25
 
The 89 Honda transalp used a similarly dimensioned 600 air-cooled v-twin if that's your thing Rich.

4840649599_3c93a265d5.jpg
 
LBC said:
Well I got the 900 cleaned up but then I got distracted.

I bought a Honda PA50 Moped to race...

http://www.youtube.com/watch?v=WyxVR77dsRo

http://www.youtube.com/watch?v=ursjbzcU-8I

https://www.facebook.com/thethunderdrome
http://www.cyclecanadaweb.com/articles/10440/
www.thunderdrome.com
Click to expand...

I don't have time to do it before the ThunderDrome in Sept but I plan to brace the frame and make it a top tank kinda like this....

Wilnic1.jpg


But with a street tracker style seat/tail. A micro-tracker of sorts.

classmar_600.jpg


Time for a new build thread over in trackers.
[/quote]


Never thought I'd say this but after watching those videos I'm wanting to get a moped. Although I think I'd look like one of those bears riding a tiny bicycle in the circus.
 
This is a brave venture. As the proud owner of a 900 lump sitting on my garage floor that I've had to move out of my way too many times, flogging this thing must take some serious effort. I've had dirt bikes that maybe weighed 50 lbs. more than that engine alone. Very bold, but I have to ask. Why not a v-twin or something lighter? Also, what gearing did you go with? I've never actually rode the bike. Brought it home, got it running nicely and then stripped it down. I have heard though it's more of a top-end machine which I would think is a burden for this type of riding. I want to build mine into a muscle-bike/boulevard machine and am just wondering how much gear a guy can get away with before 1st gear is only good for removing massive quantities of rubber from the rear tire. Excellent riding, btw. That takes balls.
 
jlgace said:
This is a brave venture. As the proud owner of a 900 lump sitting on my garage floor that I've had to move out of my way too many times, flogging this thing must take some serious effort. I've had dirt bikes that maybe weighed 50 lbs. more than that engine alone. Very bold, but I have to ask. Why not a v-twin or something lighter? Also, what gearing did you go with? I've never actually rode the bike. Brought it home, got it running nicely and then stripped it down. I have heard though it's more of a top-end machine which I would think is a burden for this type of riding. I want to build mine into a muscle-bike/boulevard machine and am just wondering how much gear a guy can get away with before 1st gear is only good for removing massive quantities of rubber from the rear tire. Excellent riding, btw. That takes balls.
Click to expand...

I got stuck on the inline DOHC idea after seeing the bikes in my first post. I have a lighter purpose built off road bike. THis bike can hang with those bikes on open fire roads and I never see anything like it at bike nights so it's a win for me. ;)

I'll take a look at the gearing tonight as I don't rememeber off the top of my head but I think it's 17T front and 48T rear. It's the the stock '79 Cb750k gearing.
 
Side Note: I got my rad Honda moped going so I'll start a build thread on that soon. It does 40mph in a reliable state of tune so I'm content to start making it look cooler.
 
So the CB900 has developed a weird erratic knock that sounds like something in the bottom end. It seems to go away at about mid RPM. No metal in the oil(yet).

Any DOHC guys care to venture a guess at where I should look first?

Many thanks!
 
does it go away at 3k or so rpm?

of so cam chains

if it goes away when the clutch is pulled in could be the clutch basket

the starter clutch on these can also make a knocking noise
 
Pull the cam cover and check front chain guide. They are known to break, rattle around and eventually have chain saw a hole through front of cam tunnel. I only ever do cam chain tension with the cover off as you sometimes need to loosen both the tensioner bolts (the one holding tensioner into head/cylinder between carbs). Rock crank with big socket to make sure tensioner is moving and goes down to tension chain properly
The other thing to check is the starter gear and starter clutch. When the Allen bolts come loose it sounds like big end has failed
 
cxman said:
does it go away at 3k or so rpm?

of so cam chains

if it goes away when the clutch is pulled in could be the clutch basket

the starter clutch on these can also make a knocking noise
Click to expand...

crazypj said:
Pull the cam cover and check front chain guide. They are known to break, rattle around and eventually have chain saw a hole through front of cam tunnel. I only ever do cam chain tension with the cover off as you sometimes need to loosen both the tensioner bolts (the one holding tensioner into head/cylinder between carbs). Rock crank with big socket to make sure tensioner is moving and goes down to tension chain properly
The other thing to check is the starter gear and starter clutch. When the Allen bolts come loose it sounds like big end has failed
Click to expand...

It does go away at higher rpm. I'll dig in this weekend and look at the cam chain tension and guides. Thanks for the insight fellas.
 
fred1090 said:
I know I'm brand new, but I'd love to know if there has been any progress on this build.
Click to expand...

Pretty much just ride it and smile! The extra height with the other suspension setup was a bit too much. Low CG is the best thing going for it on fast gravel roads.

It has some dirt that is baked in here and there but it really suits the character of the bike. I like that I don't have to really worry how or where it's ridden.
 
You must log in or register to reply here.

DTT Light or Dark

  • DTT Light
    • www.jadusmotorcycleparts.com
    www.lostapostle.ca/
    www.sparckmoto.com

    Spread the Love

    Back
    Top Bottom