"Po' White Trash" stretched DB30s payoff test ride

Daniel Coop

Daniel Coop

Well-Known Member
#41
#41
Spent a little time today mounting the new fuel tank, plumbing and routing some fuel line and 2 new filters (in tank and in-line) and setting up my throttle cable.
I also re-painted the back wheel centers to match
Then mounted it and a new 62t split sprocket on the bike

Maybe I will find the energy to cut some​ RLV Gold chain to length before I crash tonight...
 
Daniel Coop

Daniel Coop

Well-Known Member
#42
#42
Linked up... Just a final nut and bolt check, and back out on the streets to terrorize my neighborhood. Lol! 14t Noram Premier Stinger clutch to 62t sprocket via RLV gold chain.
 
Daniel Coop

Daniel Coop

Well-Known Member
#43
#43
So... Noram supplied instructions and 2 spacers with the clutch; 1 small chamfered spacer to go between the motor and clutch, and a larger crank extension/retainer spacer to give the clutch a little room to float on the crank. I installed them as directed and went for a rip. This motor/clutch ain't no joke... A few blocks from my house, coming around a corner into a straight I gunned it only to feel the back wheel violently lock up. Luckily I didn't crash, but the chain had walked off the rear sprocket and wedged itself between the frame and the sprocket. The chain was destroyed and the frame got all scratched up and the axle mount was bent along with visual damage (Deep scratches, gouges) to my polished sprocket adapter.
I suspected that the extra float in the clutch was my cause, so I removed the outside spacer/extension and left the smaller chamfered spacer behind the clutch but used a 1/4" flat washer inside the the hub to make up the difference, then just the typical fender washer and lock washer/bolt to remove all float.
I then disassembled the back end of the bike to smooth out and re-polish the sprocket adapter and touch up my scratched up frame. Replaced the mangled Gold chain and shaved 1/4" from the inside tensioner spacer to give me a perfect chain alignment.

Back together and now tested, this thing is ready to bust some ass. Can't believe how fast this is now. Can't imagine needing or wanting anymore power.
 
Daniel Coop

Daniel Coop

Well-Known Member
#44
#44
Went to fire up my bike to go for a ride yesterday and I heard a "PING!" noise, and saw a piece of metal hit the ground. It was part of my front under-seat tank bracket! It had sheared off completely at both ends. Cheap shit... My buddy had the same setup and his had already broke. I would not recommend that under-seat tank setup to anyone as this is obviously a common problem. Not being one to buy an item again after it's failed on me, I reached into my bag of tricks (old stock) and whipped up a new tank setup.
Had an old Tecumseh tank and bracket laying around. Just had to cut, drill and beat it into shape, to fit between the top of the Predator and top plate securing it with the bolts already there. Luckily, my fuel line was already the perfect length and with the Walbro fuel pump I need not worry about the tanks height . Cleaned up and stickered up, I think it looks good and now my seat is more secure, bolted directly to the frame without the hinge. The tank holds more fuel now and the cap design is better at reducing sloshing, spilling fuel.
I also painted the bracket to match...
 
Daniel Coop

Daniel Coop

Well-Known Member
#46
#46
danford1 said:
I Like that tank there. It looks right at home. Nice job.

Danford1
Click to expand...
Thanks man! Was torn on it at first and wasn't sure if this was going to be permanent, but am really digging it now. Works good, and doesn't rattle around like the other setup. Another thing I hated about the under-seat tank kit was it put your fuel line directly above the spark plug, and I was always a little worried about fuel leaks.
I have been working with a local Fastsigns on custom decals for a couple bikes. They helped me with my daughter's Motovox. (Build-Off winner). I had recently designed a personal logo for my little home mini bike shop and picked them up today. Had 2.5" round recoil housing decals made. Been making a little money on this great hobby now and needed a name.
 
FOMOGO

FOMOGO

#48
#48
Tank looks good mounted like that Coop. Helps to fill that open space. I bet you could make a bracket to mount a round tank like you put on the Motovox in that position too.

Doug
 
Daniel Coop

Daniel Coop

Well-Known Member
#49
#49
Too many hard launches, too much HP, the DB's frame is showing it's weaknesses. The axle mount hole on the sprocket side had become a bit wallered out and the wheel started having too much play, making it difficult to center the wheel in the frame. With the shock from 19HP and a 3900 RPM stall clutch on the chain and sprocket, it seems to cock the back wheel on hard launch and spit the chain off. After destroying 2 Gold chains and damaging the finish on my powder coated frame an equal amount of times, it was time to try to do something about it... I located these M12, metric bronze bushings at my local Ace Hardware that were a perfect fit for the axle and used a carbide bit on my angle grinder to just barely open up the hole to fit it. I also decided to remove some unwanted fat in the way of the chain guard brackets
I also shaved down the bronze bushing flush on the backside of the axle mount flange to not interfere with the spacers...
I then proceeded to touch up the frame with primer, then flat white spray paint.
I flipped the gouged up sprocket adapter over and replaced the hardware with 1/4 grade 8 boots. Back together again, it looks like I had originally built it this way and you'd have to look very closely, to ever know it'd been damaged and re-done...again. Now I know that bronze is softer than steel, and this might not be the best way to repair it, but it works for me, for now. With the wheel tightened down it shouldn't be an issue, and the bushing is easily replaceable. I just want to make it through the rest of the season anyway. I'd like to convert it to a 1 1/4" live axle setup this winter. I do also have a 60t sprocket and a 4 pc 8" aluminum sprocket guard on the way for it to replace this 62t. I'm hoping the sprocket guards will help keep the chain on also but worry they might not fit the bike. We'll see...
 
danford1

danford1

#50
#50
When I was looking at the pictures I was hoping I'd see a picture of an added brace from the axle tab to the rear frame. When I saw the painted pic I thought, crap, he didn't brace it.
With 19 hp and a 3900 engagement that tab is probably flexing forward. A brace added from the top of the tab to the rear frame up- right bar would reinforce that area a lot. Since it is flat white spray paint, in my opinion, you should add the brace and spray on some more white paint. The time and effort to do would be better for the long run. Add a brace to both sides of course.

Do you have an iPhone with the slow motion video option? If so record a side view close up of that area when you launch the bike hard. You will see things twist and flex back there. The chain is pulling hard across the top of the sprocket. The bottom of the frame may even bow down between the engine plate and rear wheel on a launch. That will make the chain loose too resulting in popping a chain off.

You mentioned breaking chains and buying a 60T sprocket. Are you switching to a stronger #40 or #41 chain? #35 chain seems to be a bit weak for your application (just my opinion - others will vary).

Building up a powerful minibike is like building up a race car. Every part of it has to be super heavy duty. The weakest part will fail. Then when you correct that something else will fail as it is now the weakest part. It is an endless cycle.

Keep us posted. I really like this bike :)

Danford1
 
Daniel Coop

Daniel Coop

Well-Known Member
#51
#51
danford1 said:
When I was looking at the pictures I was hoping I'd see a picture of an added brace from the axle tab to the rear frame. When I saw the painted pic I thought, crap, he didn't brace it.
With 19 hp and a 3900 engagement that tab is probably flexing forward. A brace added from the top of the tab to the rear frame up- right bar would reinforce that area a lot. Since it is flat white spray paint, in my opinion, you should add the brace and spray on some more white paint. The time and effort to do would be better for the long run. Add a brace to both sides of course.

Do you have an iPhone with the slow motion video option? If so record a side view close up of that area when you launch the bike hard. You will see things twist and flex back there. The chain is pulling hard across the top of the sprocket. The bottom of the frame may even bow down between the engine plate and rear wheel on a launch. That will make the chain loose too resulting in popping a chain off.

You mentioned breaking chains and buying a 60T sprocket. Are you switching to a stronger #40 or #41 chain? #35 chain seems to be a bit weak for your application (just my opinion - others will vary).

Building up a powerful minibike is like building up a race car. Every part of it has to be super heavy duty. The weakest part will fail. Then when you correct that something else will fail as it is now the weakest part. It is an endless cycle.

Keep us posted. I really like this bike :)

Danford1
Click to expand...
I totally understand what you're saying and agree that it needs some bracing, but I had told myself if I was going to do more fabrication on the rear of the bike, I would be switching to a 1 1/4" live axle. I hoped to be able to enjoy the bike for the rest of the season. The chains​ aren't breaking. They were coming off and getting stuck between the sprocket and the frame damaging the chain. I don't want to step up to 40-41 chain and have to change everything. The RLV gold chain is good shit and works great provided I can keep it on the bike.

60t Tuck & Run split sprocket and aluminum chain guard. Hopefully this will help keep the chain on the bike too
Tight fit, but it clears. I had to reverse my chain tensioner and spacers because the sprocket has now moved closer to the frame
 
Raskin

Raskin

#52
#52
I'm just tinkerer,but i notice you are using a static chain tensioner.I have more success with a fairly strong spring arm one.I wanted to see how it operated so i picked up the back and gave 1/2 throttle and the tensioner was going up and down and seem to be able to react to varying dynamic stresses and also on/off throttle would take up slack.It seems that is the reason the chain stays on better.Your high hp engines i would say create even higher stress.Maybe this help
 
Raskin

Raskin

#54
#54
Hmmm..maybe you got it w those guards..the chain bottom looks stable..the top bounces alot..well just thought may help..cheers..:drinkup:
 
Daniel Coop

Daniel Coop

Well-Known Member
#55
#55
Raskin said:
Hmmm..maybe you got it w those guards..the chain bottom looks stable..the top bounces alot..well just thought may help..cheers..:drinkup:
Click to expand...
Not sure what can be done about the bounce at the top of the chain, but I'm curious about a spring tensioner and might try one. Pretty sure I have one laying around somewhere. As long as it doesn't look like shit. I have also pondered swapping out the pulley for a slightly larger idler gear. I think that would work also.
 
Wheel Gun

Wheel Gun

New Member
#56
#56
I'm coming to the party late on this thread but just read it all the way through all I can say WOW, Very Nice! I'm inspired by your workmanship. WG
 
Daniel Coop

Daniel Coop

Well-Known Member
#57
#57
Wheel Gun said:
I'm coming to the party late on this thread but just read it all the way through all I can say WOW, Very Nice! I'm inspired by your workmanship. WG
Click to expand...
Never too late to join the party and thank you bro... Besides, this bike has been constantly evolving. I take this shit seriously and I definitely put my heart and soul into these minis...
 
balljoint

balljoint

Member
#58
#58
Building up a powerful minibike is like building up a race car. Every part of it has to be super heavy duty. The weakest part will fail. Then when you correct that something else will fail as it is now the weakest part. It is an endless cycle.

Keep us posted. I really like this bike :)

Danford1[/QUOTE]

Seems to be an endless cycle of pulling out his wallet, not cheap to go fast.
 
Daniel Coop

Daniel Coop

Well-Known Member
#59
#59
balljoint said:
Building up a powerful minibike is like building up a race car. Every part of it has to be super heavy duty. The weakest part will fail. Then when you correct that something else will fail as it is now the weakest part. It is an endless cycle.

Keep us posted. I really like this bike :)

Danford1
Click to expand...
Seems to be an endless cycle of pulling out his wallet, not cheap to go fast.[/QUOTE]

Not really too expensive either... It's a mini bike man. Parts are cheap and labor is of my own.
 
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