Steal on a Ducar 212

[Rat]

Total PITA!
So the 9t refused to go on the new shaft so I mixed around old parts with new to get things together.
(I had to bore it over a bit and lightly sand the shaft I used it on to begin with)

I ended up needing a little more header clearance off sheaves (probably fine but I wanted to be sure) so I angle cut it a few times to tip it out and cut it off lower to swing it back in towards the frame. It's together and ready to test run tomorrow.

 

[BrownStainRacing]

Total PITA!
So the 9t refused to go on the new shaft so I mixed around old parts with new to get things together.
(I had to bore it over a bit and lightly sand the shaft I used it on to begin with)

I ended up needing a little more header clearance off sheaves (probably fine but I wanted to be sure) so I angle cut it a few times to tip it out and cut it off lower to swing it back in towards the frame. It's together and ready to test run tomorrow.

Seems like most custom work is a PITA,

Lmk how testing went.

 

[Rat]

Seems like most custom work is a PITA,

Lmk how testing went.

It might not happen today, I did a test fire with all the moving parts finally in place and saw something I didn't like so I'm making a few adjustments

 

[Rat]

I decided to burn up the yak hair belt for tuning and I think it might be safe to put the 10t on it because it pulls so hard from a dead stop.
Being dark out and not having any lights beyond trying to keep a small flashlight pinned out on the road ahead.

I did discover that the weight difference between the original idea and this Ducar 212 has made the steering scary to keep it mild.

I know exactly what the issue is, resolving it simply... that's going to be a different animal entirely.

When I lowered it I end up with a 60° head angle with a 3/4" offset straight fork so the trail measurement say the steering axis is 10-11 inches ahead of the axle... I've got lots of caster but no trail.

I need to cut the steering angle from 60° to 35° or less (32°-36° is the common norm)

 

[Rat]

I remedied the steering angle with the original fork because it sweeps forward and brought the steer height down thus making the steering angle more upright, so the given geometry change in that makes the steering feel a lot more normal.

I may end up reworking the head angle anyway.

 

[Rat]

I'm not messing with the head angle, but taller bars would be good.

Compared to my 208 this thing is a damn paint mixer, IDK why it vibrates so bad but I know I don't like it at all.

Could be the the engine mount since I absolutely halfaṣsed it... maybe heavier and more than just heavily tacked in place.

As for the gearing, a 10t will definitely work based on the hill crawl I just did in 3rd (24t) but I'm going to need an indexed 7s shifter because it's just too hard to gauge the proper throw per shift using a friction 6 shifter on 7.

Overall I am quite pleased with the build direction, a bit impressed even because I half expected chain drop issues and other nuisance things... NOPE rock solid.

You are a great sounding board to my process @BrownStainRacing

 

[BrownStainRacing]

I havnt ran into bad vibration problems with them.

My sons mini bike came to us with a 163cc that vibrated very bad. But it was the engine plate that was separated from the frame on 1 side.

I put a new plate and 1" square tubing welded underneath to the frame before I put his Ducar 212 on it.

I put the 212 on my grandson buggy and the ducar 224 on my son's mini, it's been so wet and nasty I havnt had a chance to test either of them.

 

[Rat]

I havnt ran into bad vibration problems with them.

My sons mini bike came to us with a 163cc that vibrated very bad. But it was the engine plate that was separated from the frame on 1 side.

I put a new plate and 1" square tubing welded underneath to the frame before I put his Ducar 212 on it.

I put the 212 on my grandson buggy and the ducar 224 on my son's mini, it's been so wet and nasty I havnt had a chance to test either of them.

That tracks with what I was thinking was the likely issue. I tacked it down quite solid but it's only pinned in a few spots with maybe a ¼" wide run each... I expected to have to cut it free and move it once I figured the gears out so I focused more on the expected position than anything.

The other thing that may be causing the vibrations is the engine isn't directly on the frame, I did a double rail from square tube, so that being somewhat floating is definitely contributing.

With 2 test rides and proof of concept it's now time to solidify and refine, I want to raise the engine and push it back probably 1" each way and that will give me the opportunity to put support pillars under the rails to the frame rail with will tighten up the total frame rigidity as well as remove a large portion of the resonance problem... hard to pull harder than maybe 1/3 throttle when you can't see for shıt after the first 1/4 because eyeballs are jiggling in your head

 

[Rat]

I'm officially just a bit afraid of this beasty the amount of pull of the line is just bonkers

 

[Rat]

Fun, but just a little scary too considering 1st gear will do 40mph without trying. It will accelerate up a decent grade in 2nd and barely lug doing the same in 3rd.

Yes, I did obscure the engine info with stickers (OMB warehouse)... lot of kart guys in the area from what I can tell.

 

[Rat]

This nasty sucker ate the drive splines off the jackshaft gear I made, guess that what I get for using an aluminum part.

if the replacement does the same, at least Ill be able to weld it in place I guess.