In the begining...

Avolio G

New Member
Joined
Aug 21, 2017
Messages
11
New to the forum and considering my first build. I'm curious as to what any/everybody might thing of the bike I am hoping to start with.
The basics that I have...
Frame - '96 Kona Cinder Cone size small 14"
Shock - Marzocchi Atom Bomb Z2 60mm travel, Coil and Oil
Head Set - Chris King
Stem - Diamond Back Billet
Bars - BMX style handle
Drive - RaceFace cranks, single speed 34/19
Brakes - XT side pulls - front and rear
Wheels (F) Rolf Dolomite or Alex 18, (R) LX/Mavic
Kona wo motor.jpg

I was a bit worried about being able to squeeze a motor in the triangle but I think after mocking it up with a friends parts motor, it will work. I think it will need an offset intake and I will need to grind a little from the mounts.
Kona w motor.jpg

Does anyone have an opinion about using a light butted cro-mo frame?
I have a little welidng experience and own a small mig and have considered adding a few gussets in some corners.
I'm not sure of a direction to go other than the obvious... keep it light simple sort-of motocrossish.

Again, I am new to this, and looking for suggestions and input before I move forward.
My current plan is to pickup a basic 66/80 kit and see where it takes me.
Thanks for taking the time to look.
MF
 


Frankenstein

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Joined
Jun 24, 2016
Messages
5,078
Well everything seems good at a quick glance, butted and cro-mo is probably as good as you ask for too, the frame will probably outlast you if it doesn't end up being crushed at some point. Make a point of not crushing yourself either and wear a damn helmet.
 

FurryOnTheInside

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Joined
Sep 23, 2013
Messages
3,358
I would change the wheels to something much heavier and with 36 spoke disc compatible hubs before starting, personally. I don't ever want to try the rag joint!

I would pick a lower rise bar, too; but that's personal preference.
 
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Timbone

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Apr 20, 2014
Messages
1,100
I wouldn't weld into that CroMo steel frame (especially if it's FluxCore) unless it's absolutely necessary.

The weak spot in the entire system is the rear wheel. My experience and experiments have shown me that a "normal" 3/8" bicycle axle is not adequate for long term durability. That's a tough hurdle to surpass and I am working on an improvement. I think 1/2" axle is almost mandatory for safety. Everything falls on the rear axle.

So, in lieu of a new design, a normal bicycle rim will not stand up to the stresses. Get a bicycle rim designed for downhill racing. They can take it.

As for the rag joint, done right they can be s good cheap alternative to the clamshell adapters. But $ for $, a good fitting hub sprocket adapter will save you tons of problems. Still, even with thread locker, you must check the bolts often - they can come loose!
 
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Frankenstein

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Jun 24, 2016
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5,078
Oh and I forgot to mention it but you reminded me, he shouldn't even have to weld a gusset anywhere on the frame, it really should stand up to the challenge unless he gets as crazy as some of us do with getting max power from a motor.
 

Avolio G

New Member
Joined
Aug 21, 2017
Messages
11
It's taken a minute. Thanks to everyone who took an interest. The build is moving forward, all be it a little slower than I maybe thought it would.
First off, I received an old touring bike, I robbed the rear fender to modify for the build, also the matching chain guard. Switched out the front rim (more spokes), Conti town and county tires, different crakes and gear ratio(a perfect fit, no need for a tensioner), and I have already 86'd the gel seat pad.
IMG_20171010_001315.jpg

Finally got an engine kit last week. Came as expected. $125 delivered, seems all intact, probably in the same box it came over from China in. It's a good thing I've seen a few different bikes and feel that I am fairly mechanical. I could have sworn the seller said there was some documentation that should have been in the box.
As I thought, it is a pretty tight fit. The following pics were taken after I cut 1cm from the rear mount block and filed about 3mm, adjusting the front mount.
IMG_20171017_020042.jpg

IMG_20171017_234220.jpg
IMG_20171017_020055.jpg


Real tight indeed. You can see the first thing I had to tackle, there is certainly no room for a carburator. I tried an offset, no luck. The angle was way off. The carb was no where near level.
So what does someone who sees himself as being crafty do??? Builds a custom one of course.
IMG_20171022_000022.jpg

IMG_20171022_000042.jpg

Went to the local big box store and picked up some 19mm steel tubing and some 1/8 inch strap. Bent the pipe, a little heat and some persuation with the ball peen, drilled the plate and stuck it together with bronze braze. Got it all cleaned, heat stained and clear coated tonight.
IMG_20171023_234730.jpg

IMG_20171023_234810.jpg

IMG_20171023_235827.jpg

The intake is about 5 1/2 inches long. And can be shortened about 1.5 inches if needed. if I shortened it I will not be able to access the idle screw because of the seat tube. I have also started to look for a place to attach the cdi. Any opinions??? Up front under the tank, or back on the seat tube???

Next thing I need to do to get a little closer I'd modify the exhaust. The left pedal does not clear it. Hit about dead center of the muffler. Anyone had good luck bending them? I would like to get it to line up with the down tube if possible. I may have to make several small slices, bend and weld. I plan to build a full custom exhaust after I get a chance to break it in. I will have plenty of time, I won't be riding much during our Michigan winter

Hope this was not too long.
Looking forward to comments, ideas and insight.
 

FurryOnTheInside

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Sep 23, 2013
Messages
3,358
Looking great so far! :)

Intake length is from the front face of the carb slide to the rear face of the piston, 7-7.5" for best grunt according to a couple of sources so I think you probably have it about right. :)
The carb will need to be secured against the seat tube with a strong cable tie to prevent the vibrations from cracking the brazed joint, I reckon.

I read that a shorter spark plug cable is better, and the CDI likes to be kept cool but idk how much difference it makes.
Certainly the cable and boot from the kit is not high quality. A replacement wire and NGK boot is inexpensive enough to be well worth getting.

I had the left pedal hitting the muffler too. I just had to elongate the holes in the flange so I could rotate it slightly, then also dent the side of the muffler just a bit, which worked fine. :)
The muffler needs support to prevent it cracking off, just like the carb.
 

Steve Best

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Joined
Sep 22, 2012
Messages
1,193
Your build looks great. That Kona should be a tough bike, no worries.
I didn't like a long intake, it cut from rpm too much for me, but you clearly have the skills to experiment with that.
 

Avolio G

New Member
Joined
Aug 21, 2017
Messages
11
Well I have not posted much about the Cinder Cone since I started. Was a lot of fun cruising around this fall. May have been riding it a little hard for the break-in, but it all seemed to stay together.
Per my first post I took care of that exhaust. Again a little heat, some leverage, and the occasional love tap with the hammer got it tucked under the frame and out of the way of the pedals.
IMG_20171025_233616.jpg

I also had some challenges with the stock chain tensioner. I modified it, adding a pivot and turnbuckle for adjustment. It held up pretty well.
IMG_20171106_005456.jpg

Then 3\4 flat bar ended up getting twisted like a pretzel. I replaced it with 1 inch aluminum c channel, a little lighter and a whole lot stiffer. You can see it in some of the next pics.
I did not care to leave the fuel filter loose in the breeze so I created a mount for it from some copper pipe straps. Holds it place real nice and I'm not worrying about kicking it or catching it on anything.
IMG_20180205_175230.jpg

I am working on two more mods right now. It's been real cold here in Michigan, so not much riding for me.
First a chopper style seat with sissy bar. I've created it from seat stays from some bike I picked up during bulk trash clean up this past fall.
IMG_20180205_175117.jpg

IMG_20180205_175401.jpg

I've lost the quick release rear wheel.and went with a bolt on. Way easier to center the sprocket with 36 vs 32 spokes. Plus it gives me a place to mount the vertical braces for the seat. Those too were salvaged from one of the donor bike, front fork blades.
I've started the seat pan, need to score some foam and I think I will be good will shopping for some knee high leather boots to upholster it with.
I'm also starting to work on an expansion chamber. Once the seat is done I plan to do a little port work, based on some of the great threads, articles, and info I have gathered here and elsewhere. Then with numbers in hand I hope to build something similar to Jaguar's torque pipe.
Does anyone have any opinions on that?
With the small frame and tight spaces I'm not sure it a bolt on will fit without nearly as much work.

Always looking to hear what others think. I will post again when a few more thing fall in to place on the bike.
Cheers!
 
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