DB30 has no balls. Please help

Mini Bike & Go-Kart Parts

#1
Hey guys. I’m at a loss and I need the help of the experts. I’m trying to fix this db30 with the 97cc motor for a friend of mine and here is what’s happening. Bike has a new carb and new clutch. Starts first pull and idles all day long. Problem is that it won’t move at all. If I pick up the rear wheel and give it gas, it will take off and rev all the way to the limiter spinning the rear wheel super fast as it should. Then, as soon as you put the wheel on the ground, the bike struggles to move at all. Even with no one on it. I weigh 165 pounds and it won’t move an inch. You can tell it’s trying to move but it doesn’t have any power. I did the paper clip “mod” and adjust the air screw on the carb. Is it possible that it’s just that the motor is shot? I feel like it should Atleast get me moving on a flat surface. Please help.
 

Lizardking

Well-Known Member
#2
Welcome aboard the oldminibikes.com train.

Sounds like a clutch problem. How is the clutch secured to the engine shaft? Set screws or key and tap on the shaft? Did you over oil the clutch and maybe some got on the clutch shoes?
 
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#3
To be honest I haven’t pulled it off yet. He put a new one on because it was having this problem and he thought a new clutch would fix it. He said that it acts the same way with both clutches. Are these able to be adjusted?
 
#4
I will also add that when the rear tire is on the ground, the Rpms won’t climb. The bike isn’t bogging down, it’s trying hard but going nowhere. Rpms do not climb.
 
#7
Yes. It’s bone stock as far as I know. Only thing new on it is the carb and clutch. I did the governor thing to see if it would help. Nothing has so far. It’s annoying cause the motor runs perfect. It just won’t move. Best way to try and explain it would be, take a very large heavy person and have them start on a hill faceing up hill. Tell them to go from a dead stop. You can imagine how the bike would be struggling and not moving right? Well it’s doing that on a flat driveway with no one on it. But if you lift the rear so there is no weight on the back then it takes off and redlines as it should.
 

Lizardking

Well-Known Member
#9
If your friend messed with the governor spring before you then that might be it.

The gov spring was off on one of my engines when I first got it. I put the spring in the wrong section of the arm and my bike acted similar to your friends. I put the spring in the correct hole on the arm and solved my problem.
 
#10
These 97cc Baja engines aren't worth the time, trouble or money spent trying to get them to operate correctly. I've bought a few bikes that came with this engine. Knowing that I was going to replace the engine, I figured I would see how the stock engine faired with me on it. I'm also in at 165lbs. and the bike was nearly new. If I remember correctly it had a 75 tooth rear sprocket and it would still barely pull me around the yard, trying to go up the slightest incline, the clutch would just chatter. They just don't seem to have the power to keep the clutch engaged under load. I don't know what your budget is but rather wasting your time and money on a hopeless cause, buy a Predator 212, leave it stock and actually enjoy riding it. You can get a new Predator for $120 at Harbor Freight, if they don't have the Hemi, the Non-Hemi works just fine.
 

SAS289

Well-Known Member
#11
Yes. It’s bone stock as far as I know. Only thing new on it is the carb and clutch. I did the governor thing to see if it would help. Nothing has so far. It’s annoying cause the motor runs perfect. It just won’t move. Best way to try and explain it would be, take a very large heavy person and have them start on a hill faceing up hill. Tell them to go from a dead stop. You can imagine how the bike would be struggling and not moving right? Well it’s doing that on a flat driveway with no one on it. But if you lift the rear so there is no weight on the back then it takes off and redlines as it should.
Yeah it runs perfect as you say, but with no load. What if it is worn to the point of having enough compression to start and run decent no load but not have enough compression for power under load?
 
#13
These 97cc Baja engines aren't worth the time, trouble or money spent trying to get them to operate correctly. I've bought a few bikes that came with this engine. Knowing that I was going to replace the engine, I figured I would see how the stock engine faired with me on it. I'm also in at 165lbs. and the bike was nearly new. If I remember correctly it had a 75 tooth rear sprocket and it would still barely pull me around the yard, trying to go up the slightest incline, the clutch would just chatter. They just don't seem to have the power to keep the clutch engaged under load. I don't know what your budget is but rather wasting your time and money on a hopeless cause, buy a Predator 212, leave it stock and actually enjoy riding it. You can get a new Predator for $120 at Harbor Freight, if they don't have the Hemi, the Non-Hemi works just fine.
You can catch them (212) on sale for $99bucks. MFG sells a MaxTorque clutch for cheap, and $6.99 shipping!
 
#14
Thanks for everything guys. I talked to him and just told him to 212 swap it. I already ordered the max torq clutch and the motor adapter plate. I said the same thing as you guys, it’s not worth it and to just swap it. Last question. Will I have to lengthen the chain on it for the new motor? Or will I have to shorten it and I can reuse the chain?
 
#15
Thanks for everything guys. I talked to him and just told him to 212 swap it. I already ordered the max torq clutch and the motor adapter plate. I said the same thing as you guys, it’s not worth it and to just swap it. Last question. Will I have to lengthen the chain on it for the new motor? Or will I have to shorten it and I can reuse the chain?
You should be able to re-use the chain as long as the new clutch has the same amount of teeth ( or close to it ) and you don't change the rear sprocket. Even if the new clutch has 1 more or 1 less tooth you should have enough adjustment between the engine adjustment and chain roller adjustment. I wouldn't recommend any cheap chain from the hardware/tractor stores, that stuff is garbage. RLV or EK chain is what I use, about the only way that stuff will let you down is if you installed it incorrectly.
 

I74

Well-Known Member
#16
Thanks for everything guys. I talked to him and just told him to 212 swap it. I already ordered the max torq clutch and the motor adapter plate. I said the same thing as you guys, it’s not worth it and to just swap it. Last question. Will I have to lengthen the chain on it for the new motor? Or will I have to shorten it and I can reuse the chain?
Need to know how many teeth on the clutch you ordered, & what the rear sprocket tooth count is also.
The DB -30 rear sprockets are usually 70 - 75 tooth.

Gearing I would recommend would be 5 - 1 with the 212.
That would be a 13t clutch & a 65t rear sprocket.
I guarantee that will still be plenty. ;)

You can get the 65t ''6 bolt hole'' sprocket on like Amazon ect.

Going with a larger rear sprocket than 65t with the 212,, you are going to have a ''wheelie machine'', with how much you Guys weigh,, especially if the rear sprocket that's on it is 70+ tooth,, & the clutch sprocket you ordered is ''less'' than 13t.


I don't use motor mount adapter plates either.
I just cut off the front drain plug flush, & mount the engine all the way forward up against the foot peg cross frame tube,, with drilling holes in the stock motor mount plate.
Not using an adapter plate will also help in lowering the center of gravity on the bike a bit, & save weight.

Added,,
The Max torque SS clutch generally comes with the ''silver'' 2,200rpm spring.
The best spring as far as I & most others are concerned, for ''larger'' engine ''Mini Bikes'',, is the Max torque 2,550rpm ''green'' spring.
It's night & day smoother & safer engagement for all around riding. ;)

There is a Max torque vid & others also,, for the spring changing procedure.
I highly recommend doing it.

I
 
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#17
I have a db30 that will go faster than 80 mph but thats another story, 212 engine and its a racer. but i also have a db30 that is complete stock (just not here for me to look at). It is stock as the day it was bought from PepBoys for like $279 15 years ago or so. The no balls problem on the 97 cc engine could be fuel/air mixture because on the virgin doodle, if you start it on choke and gas it on choke, it will make lots of noise with no power, not even enough to move itself. Choke off, it zoom zooms. Might look into carb adjustment. On a stock DB if you messed with the governor, all this advice is right out the window as a stock db30 runs like a governed engine is setup to run. BUT- throw out the 97cc engine that thing came with, its worthless if you want to actually use the minibike. Pick up a harbor freight 212 predator 6.5 horse and a max torque clutch. All you need is an adaptor plate and you have a great MB
 
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