I'm planning on getting a taotao 250d ATV or Vbike 250-V4D and after reading many post
I'm thinking the following should be done to the V4D / 250D when I first get it.
but have a few questions? Any help is greatly appreciated.

1. Use premium gas

2. Change out the spark plug to a (NGK) NGK D8EA (cost: $4)
do I need to adjust the gap? .02 - 025?
? is their another brand that is better and what model number?

3. Change the oil and use a synthetic oil (cost: $20)
? any suggestions on the best brand?

4. locktight all nuts (cost $15)
are their any problems doing this? should I use a torque wrench on the nuts and if so at what torque?

5. New Chain (428H KMC with 3/4 inch max play) (cost: $15)
? I noticed the max *** is 150 for this chain. Since this will be a 250 CC , do I need to consider a different chain? 118 or 120 link?
The 520H chain is for a 400cc max ATV so is this a better choice and will it work?
? what is the best chain to consider brand and model?

6. Change the front sprocket to a 13 or 14 tooth (13 tooth front JTF259 sprocket) (cost: $10)
a. should you also change out the rear sproket at the same time to ensure a quality sprocket? or is this not needed? Is this a simple replacement?
would it help reduce chance of chain comming off?
b. if the bolts touch the chain with the 13 tooth, doesn't this cause problems later on? should I go with a 14 tooth instead or is the 14 tooth too little of a change from the current 15 tooth that comes with the ATV.
c. also is a chain tensioner recommended and if so what brandand model.

7. Any other suggestions I missed?
Do I need a back up battery (if so what brand and model)
When I need to replace the tires will any 8" brand tire work? Can you change them out to 10" tires or does this cause other problems?
anyone know of a good swing arm bushing that will fit?
should I get a set of nuts to keep on hand incase I loose one out on the trail?

I know this sounds like a little bit of work but I'm hopeing to to be able to do about $100 in upgrades and have a pretty good reliable ATV.

Thanks  

1. 89 octane is good enought
2. gap is .028-.030 i like denso plugs better than ngk
3. do not change to synthetic oil until the engine had a chance to break in, change the oil when you setting it up with conventional oil then after 10-15 hours of riding change the oil to a synthetic, but to me it's a waste of money using synthetic oil.
4. use locktight, lock washers and if you have a drill motor and a #50 drill i'd recommend drilling and lockwireing all the exhaust bolts, brake caliper bolts and engine mounting nuts. this is the only way to make sure the nuts and bolts don't fall out.
5. don't waste your money on a KMC chain,they're cheap ass chains. if you're going to up grade the chain wait until the ome chain needs replacing, then replace with a good chain such as a diamond, RK pro, ect. no you can not replace a 428 chain with a 520 unless both spockets are changed to 520 spockets.
6. if the quad comes with a 15 tooth spocket i would try a 14 tooth before a 13 tooth, 13 tooth maybe just a little to low geared for my taste.
7. buy a deltran battery tender, and plug it in every time you're done riding for the day, these will make your battery last for years and you're never have any surprises when trying to start the quad.
8. 8" tire will only work on 8" rims, if you want 10" tires you'll need to replace the rims with 10" rims.
pull the swing arm bolt out when setting up the quad and lube it.
if the atv was correctly set up with locktight, lockwashers and lockwire as suggested then you shouldn't have a problem loosing bolts or nuts.
proper torque is very important. you can find a standard torque chart on the net. find one and use it.  

Thanks for the feedback.

The thought on replacing the chain when you first get it is that their are many reports on the chains comming off on these Chinese ATVs.   Some think the stock chain continues to stretch and are made of cheap material thus replacing the chain and sprocket would have reduce this problem  

Bill,
also are saying to use a locktight washer and loctite thread locking sealent or do you not recommend the loctite sealent?  

you'll find tht most bolts already come from the factory with lockwashers, the bolts and nuts that are not already lockwashered, you're need to lockwasher them,myself i use very little locktight , they're eaither lockwashed or i have them lockwired, i'm from the areospace industry, so i belive in lockwireing. having a bolt lockwired their's no way under any conditions can a bolt work loose and fall out  

seriously, a good used yamaha blaster will last you a lot longer than the chinese atv will.
plus the yamaha blaster is alot faster than the chinese atv would be.

seriously you might want to recondsider and buy something else.
the chinese atv's are very poorly made.  

wolf,
I agree.  I've been looking around on craigs list and other sites and the only thing for under $1800 (ATV Utility) I've found has been very old in bad condition ATV.  I was planning on getting A chinese version for around $1150.
If I can find an OK *** or polaris model for under $1800 I will go with it.  

The following is a correction to my original above post:

taotao 250d ATV  -  Vbike 250-V4D - Aim-Ex ATA-250D
Maintenance or Upgrades
I'm thinking the following should be done to the V4D / 250D when you first get it.
but have a few questions?  Any help is greatly appreciated.

1. Use premium gas
(mid premium gas about 90 octane or high premium 93 octane)

2. Change out the spark plug to a (NGK) (cost: $3)
recommended gap?  .028
Plug: NGK C7HSA is what my manual has down others have mentioned a D8EA?
most of the bikes are coming with this plug already.
I picked up a couple of these at Autozone for about $2 each

3. Change the oil and use a ATV specific oil (cost: $3)
chaneg after  break in period.
Autozone has a valvoline 10/40  ATV oil.  The key is to have an ATV specific oil.
I was considering a synthetic oil but it sounds like an ATV oil designed for wet cluthces is best.
use an oil specific for ATVs (use no additives with regular oil)


4. locktight all nuts (cost $4)
blue loctite and maybe locktight washers maybe lockwire
I would like to use a torque wrench but I cna't find any guide lines on torque of the bolts for this ATV, I guess you could use the guide lines for other ATVs.

5. New Chain  3/4 inch max play)(cost: $27)
best chain would be RK Heavy Duty Pro 428
The 428 chain is not ideal for a 250 cc ATV.  The RK heavy Duty was the only chain I foud that came close.  If go with anyother chain check the tensile strength and MAX engine size.  Most of the other chain have a max engine size of 150cc
I would get a 120 link and then you can cut off a couple of links if needed.

6. Change the front sprocket to a 14 tooth (14 tooth front JTF259 sprocket)(cost: $10)
I think I am leaning to a 14 tooth over a 13 tooth.  I think if I lived in the mountains and did a lot of vertical hill climbs I would go with the 13 tooth but since I'm in Texas and do only a few small hill climbs the 14 tooth would be best for me.

7. Other replacements later on:
- back up battery (anyone knwo a good  brand and model)
When I need to replace the tires I will liekely go with an all terain tire.
anyone know of a good swing arm bushing that will fit?
I think this is the bushing from roketa.? atv-17w-150-04-08   this is for the 14mm bolt size? anyone know of a good bushing for this?

I also went and picked up an extra metric socket set to have on hand for tightening or removing any bolts.

I know this sounds like a little bit of work but I'm hopeing to to be able to do about $50 in upgrades and have a half way reliable ATV.

Thanks

I've recently purchased my TaoTao 250D I'll let you know how it goes.  

Chinese upgrade....Dont waste your time.These are the BIGGEST P.O.S.. I have one I got for my son. Big mistake. 4 yes 4 hours of total riding for $800. over 75 hours repairing the junk. Inferior metal, all galvanized junk, poor welds, Junk electrical and Junk Honda copy, give honda a bad name just to have theirs copied after. WARNING dont buy one, or I GUARANTEE you will regret it...Any ???????? I'll gladly answer them for you.....