Quad Insurance; Short Answer - go see your local agent that handles your Home Owners and/or Auto Insurance.
I live in NJ and insurance is such a pain. I needed Insurance to ride in an ATV park in PA (basically you can't ride anywhere in NJ, unless on private property).
I went to Progressive on-line and basically found out that they list Chinese quads but won't insure them (switch the selection to a Japanese quad & and it takes it). Found out that for bottom line coverage - liability only at $5K / $10K or $10K / $15K (forget which) the cost was $76 per year (but still not a Chinese quad) .
Went to Geico - on line and found out that they don't even list any Chinese quads as a selection possibility - and they won't insure anything less than 150 cc's (I have 3 Chinese quads - 2 @ 250 cc's & 1 @ 110 cc's).
After 2 to 3 hours on line, researching, filling out screens - gave up. Went to my Agent (State Farm) and asked "do you offer ATV Insurance" - answer: "Of course".
For NJ (covers anywhere you go) it ended up being (for $100K / $300K; will only sell the same level as your auto) $28 per year / plus "uninsured motorists" (NJ and State Farm requirement - you know they might jump the Route 80 guard rail & get me) $20 per year. Total $48 per year !!!! ( $144 per year for 3 quads for $100K / $300K Liability Coverage) Oh, yes; I also added my $1,700 trailer for "collision & comprehensive" with a $50 deductible for $6 per year. (oh, I do have a good driving / claim record - so I am sure that is part of the low cost factor).
The morrow of the story - check with your Agent !!
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While in the USAF I worked on Jet Engines for C-130's (In left Pic a C130 is Air Unloading an Army Tank) and B-52's (In Right Pic of B52 that's a School Bus in Lower Right)