I bought a Doodlebug, bought a Predator 212, got the install kit, and put it all together grinning from ear to ear. Fired that baby up and let her warm up a bit, jumped on, gave her some gas and the vibration taking off is horrible! After the clutch full engages it's just fine but taking off...............painful! Any ideas what to check guys? All the bolts to plate and to engine are tight. HELP!!!
Teeth rattling vibration on new build
Facts of life: ALL Predators vibrate, some more than others. If you got one that is REALLY bad (which is subjective of course) you probably got a "dud" and I would take it back and exchange it for another one. It is a tradeoff for being able to purchase a brand new engine for only $ 100.00. You could try reinforcing that puny (thin gauge) engine mounting plate that was only designed for the much lower torque of 2.5 HP., not that 6.5 HP beast you have on there now. That is what we did on both of our DBs and it did make (somewhat) of a difference. Do a search on this forum as the topic has been previously discussed many times before- there are various techniques you can read about.
Michael
Michael
If it is fine when clutch locks up I would think it is clutch related. Check for oil or contaminants on the bell or shoes. The RPM when it slips is a constant and lockup is only a few hundred rpm more. not enough for a bad engine vibration to disappear. Or are you saying low rpm = bad vibration high rpm = low vibration?
I have a flywheel that I'm certain is out of balance. I had it on two different engines, and my bike wants to rattle to pieces at certain RPMs.
Believe it or don't, I've taken it to 3 machine shops trying to get it balanced.
All 3 said the same thing, "I don't have a mandrel that'll fit it."
To which I replied to all three, "Hey, I got an idea, let's call a real machine shop!!!"
Believe it or don't, I've taken it to 3 machine shops trying to get it balanced.
All 3 said the same thing, "I don't have a mandrel that'll fit it."
To which I replied to all three, "Hey, I got an idea, let's call a real machine shop!!!"
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I've noticed the same thing on a buddy's single-speed DB-P212. I think it could be a few things:
Added stroke and bore over the Honda 196 may add some shakes.
Carb not made to pull a load through low-mid rev range.
Balance factor, also not suited for low-revs, high-load.
Light duty engine plate and chassis may be transmitting more, normal movement.
I was discussing the odd light-crank, heavy-flywheel setup with interweb pals recently too. Great for an engine that may strike an object while mowing, so the f/w can maintain momentum by key shearing, but not what the typical high-rev hotrod desires. I'm hoping to adapt a motorcycle-type full-circle crank and run a 3.5" sub-1lb f/w with a curved CDI and lighting coil. Maybe even chain-drive the cam so the engine can run "backward". leaning forward, eliminating the fan and shroud for free-breeze. Honda G400 ran cam by chain, as do a quadrillion other varieties of engine outside the ditch-pump world.
Added stroke and bore over the Honda 196 may add some shakes.
Carb not made to pull a load through low-mid rev range.
Balance factor, also not suited for low-revs, high-load.
Light duty engine plate and chassis may be transmitting more, normal movement.
I was discussing the odd light-crank, heavy-flywheel setup with interweb pals recently too. Great for an engine that may strike an object while mowing, so the f/w can maintain momentum by key shearing, but not what the typical high-rev hotrod desires. I'm hoping to adapt a motorcycle-type full-circle crank and run a 3.5" sub-1lb f/w with a curved CDI and lighting coil. Maybe even chain-drive the cam so the engine can run "backward". leaning forward, eliminating the fan and shroud for free-breeze. Honda G400 ran cam by chain, as do a quadrillion other varieties of engine outside the ditch-pump world.
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You say you used that pmr adjustable plate ..Try c-clamping the frame and the pmr plates together on back and front test if tight or helps.
..Never heard of anyone having to run bolts all the way thru both the adjuster plate and frames plate basically using it as a riser instead of its intended purpose..unclear if it is magnifying low rpm "chatter" on take off....I'm thinking out loud..my last resort thought:surrender:... :shrug:
..Never heard of anyone having to run bolts all the way thru both the adjuster plate and frames plate basically using it as a riser instead of its intended purpose..unclear if it is magnifying low rpm "chatter" on take off....I'm thinking out loud..my last resort thought:surrender:... :shrug:
250 pounds is alot weight to run through stock OEM clutch. i would chatter too if i had to push that much weight when taking off. i have also heard of that same problem with the stock 2.5/2.8hp doodlebug bikes and seen guys replace the stock clutch's with a max clutch with just a slightly higher stall clutch. not saying this will fix your problem with your clone/honda motor.
i got couple stock doodlebugs for the kids to ride and they chatter bad when taking off with me on it(#175). but with the kids on it....not so bad. just no weight for the clutch to fight with when a #80-#100 kid on it.
you did say something about replacing the clutch soon. interesting to see what happens?
torque converter would be better...... it's just more money:laugh:$$$:doah:
goodluck.......:thumbsup:
i got couple stock doodlebugs for the kids to ride and they chatter bad when taking off with me on it(#175). but with the kids on it....not so bad. just no weight for the clutch to fight with when a #80-#100 kid on it.
you did say something about replacing the clutch soon. interesting to see what happens?
torque converter would be better...... it's just more money:laugh:$$$:doah:
goodluck.......:thumbsup:
