Predator 212 Swap on Baja Dirtbug - engine vibrations

#1
So I swapped a Predator 212 onto a Baja Dirtbug and it runs great. Used an engine mounting plate and it fits very tight but fits and works. But the engine shakes so bad at 1/4 - 1/2 throttle. It shakes so bad that it throws the chain. Any idea why this could be? I read that it could be because of the engine being brand new and it needs to just break in. Any truth to that? Thanks for the help friends!
 
#2
Break in will not fix an engine shake. Sounds like something is wrong. We can give you some steps to isolate where the vibration is coming from but first can you tell us the configuration of the bike.
1) How is engine connected to the rear wheel? Clutch? TAV? Jackshaft? If clutch which one, if TAV what setup plate or on the jackshaft?
2) have you checked that engine is tight on the engine mounting plate and no cracks on plate or welds to frame.
3) to see if it is the engine, remove the chain and clutch off the engine. Start it up and go to 1/4 throttle and see if the engine is vibrating or Shaking.
4) Is the engine stock?
 
#3
We have had a few of them and ALL of these Predator engines vibrate, some (much) more than others. It is the trade-off for being able to purchase a brand new 6.5 HP engine for only $ 100.00. That being said, if it is as bad as you describe I would return it and exchange it for another one.
Michael
 
#4
Thanks for the help guys. The shake has been getting better from riding it the past couple days. I'm going to keep riding and see if it helps. The engine is not stock, to answer your question.
 
#6
If a chain is aligned correctly you shouldn't have to over tighten it or it will over heat the clutch bushings. I usually like about a 1'' deflection or up and down movement.
 
#8
Oil lightly ...like one or two drops ....sometimes you need to take the clutch off and clean the bushing area and lightly oil the bushing. A lot of folks spray there bushings with spray lube.
 

Daniel Coop

Well-Known Member
#9
I'm wondering if the vibration and chain popping off are a simple result of chain misalignment? Go get yourself a cheap metal yard stick or straight edge and make sure the chain is straight. Maybe you're over-tightening the chain on top of it? I've also experienced a similar symptom (- the chain coming off) from a galled up clutch drum. Did it do that from the start? Was it a new clutch? I agree with Ole, remove the chain to try to isolate the problem to the engine
 
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#10
I have made sure that the chain is aligned. I have the chain on there pretty tight but it seems alright. The clutch is kind of squeeky though. Is that normal? The chain still pops off sometimes because of the engine vibration. I may get in contact with predator to see if they can send me a new one. The only thing is that I traded a guy off Craigslist for the engine and bike so I'm not sure what they'll be able to do.
 
#11
Not to be rude, but how much do you weigh? With a heavier rider, the engine will seem to vibrate as the clutch tried to lock up. If you're running a 12t on the clutch and the stock 70t rear, that's a pretty good gear ratio to start. However, if you weigh over 250, it may be a struggle. Also, are you riding on flat pavement, or around your yard?


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#13
Not to be rude, but how much do you weigh? With a heavier rider, the engine will seem to vibrate as the clutch tried to lock up. If you're running a 12t on the clutch and the stock 70t rear, that's a pretty good gear ratio to start. However, if you weigh over 250, it may be a struggle. Also, are you riding on flat pavement, or around your yard?
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Naaa, it should not shake/vibrate THAT bad. I am 6'1"/290 lbs. and we had that same setup on both of our DBs and it was not too bad.
Michael
 
#14
Naaa, it should not shake/vibrate THAT bad. I am 6'1"/290 lbs. and we had that same setup on both of our DBs and it was not too bad.
Michael
Good to know. However, I've seen it happen. I totally agree that some of these are filling removers right from the box. China's best![emoji23]


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#16
I'm only 145 lbs and I'm 6 foot. I know, skinny lol but yeah I'm not sure why it's doing it so bad. I'm gonna look into getting a new engine because I traded on Craigslist for the frame and engine and put it together and bought the other parts myself. It's a new engine though, do you guys think Harbor Freight would replace it even though I traded for it and don't have a receipt? Any clue on what number to call for harbor freight customer service because I have tried calling and can't find the right people to talk to. Anyone have any experience dealing with them?
 

Daniel Coop

Well-Known Member
#17
I'm only 145 lbs and I'm 6 foot. I know, skinny lol but yeah I'm not sure why it's doing it so bad. I'm gonna look into getting a new engine because I traded on Craigslist for the frame and engine and put it together and bought the other parts myself. It's a new engine though, do you guys think Harbor Freight would replace it even though I traded for it and don't have a receipt? Any clue on what number to call for harbor freight customer service because I have tried calling and can't find the right people to talk to. Anyone have any experience dealing with them?
I have returned many things to Harbor freight, but not a used engine, that I didn't buy. I would just assume it'd be a no, especially after you explained your story... If you were to be truthful. Excuse me if I missed it, but did you remove the chain and rev the motor to where you were feeling the vibration, like Ole originally suggested? To at least determine that it's definitely in the engine? Would take 5 minutes max...
 
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