This guide book will solve all problems that you could possibly have with a pitbike, new or old old or new..
- Bike selection, what bike is the right bike for me?
- Basic maintenance
- Common issues
- Engine work
- Suspension maintenance
- Chassis strengthening
- Tuning the carb
- Aftermarket parts + bling
- Tyre choice
1. Bike selection
This is a common question that alot of people have trouble with and sometimes end up with the wrong bike for there application… To completely answer your question i need to know your scenario i will list some of the common ones below
1.a: Just starting out, 1st bike never ridden before.. but i have watched a lot of youtube and think its for me
1.b: My 1st bike, but have ridden mates and a lot of pushbikes (and over about 12 years of age if not look at 1.c)
1.c: Im buying my son/daughter a new bike what should i get her/him?
1.d: Certainly not my first bike and i am comfortable on a bike of any size looking to have some fun
1.e: Certainly not my first bike and i am comfortable on a bike of any size looking to go racing
a: I would recommend buying a pit bike depending on your size and budget i would go for a 110 (semi auto or manual) to a 125cc bike i can only recommend getting a manual (with clutch lever) 1st off instead of having to learn it later but if you have little confidence on two wheels the semi auto may help you get on your feet and comfortable.
b: It all depends on your confidence, instructor (if you have one) but you should be able to get comfortable pretty quick on a 150cc bike i recently started my mate who is 17 on a 150 pitbike and he had no dramas just cruising around in 1st however sometimes the power can be peaky and intimidating for a 1st time motorcycle rider so maybe a 125 (not gpx) would be better but you may feel your self wanting another motor after you are used to riding the bike *you will probably get a lot of enjoyment out of the 125 though and confidence but may get bored with it so if you have the budget to upgrade later/got the bike cheap it would be optimum
c: If the child is from 4-7 yrs old and you want to start them on a 2wheeler (i would highly recommend this because they tend to be stubborn when you switch them and are scared if you sart them on 4) i would look for a 70cc atomik or something that’s not going to run you too much $$ there pretty cheap new but if you can find a good one second hand you should be okay you can also go for 110 and 125cc but i found 70cc to be perfect and if you take care of them *Bike maintenance* they should go for almost ever and are really easy to ride, and don’t forget you can always get a new throttle that has a restrictor on it.
If the child is 8-12 years old i would certainly go for a 110cc + and if they have been on push bikes and whatnot they should be able to master the bike quite easily you can go larger as always but would not recommend it as because there very peaky and will probably scare them.
12 years + look at 1.c
d: I would recommend a 150cc + bike and if your large (tall) go for a midsize but a pit bike size makes it more fun/harder on a smaller power engine i would go for a yx150 powered bike with upside down forks at least (atomik nitrous is perfect) a 125cc will be fun for a little while but its more likely you’re looking for more power if you want a wild one you can install a daytona anima 150, or 190 it will be unmanageable and crazy fun if you don’t have the money for one strait up you can but a yx or klx style engine and do it up but more if that in the *Engine work link*
e: My 1st option would be a pitsterpro lxr 190, or what ever cc’s they come with good forks a linkage rear shock (great for handling and stability) have a look at *engine works link* to see what you can do to gain a advantage over others and most importantly look at *suspension link*
Maintenance is a important thing on all bikes and if left unattended can be costly.. it depends on what engine you have really and then there is chassi maintenance but there is little of that
Engine and chassis maintenance
The pit bike engines are all very very similar and depending on the engine cc’s and mods will change the maintenance schedule eg. a ducar 70 will require less valve adjustments compared to a yx160 that has to do with the valve spring pressures and the cam lift/duration
These figures will change depending on how you ride, eg at a track i would halve these maintenance hours infact i would do them almost every day of riding (accept oil to save costs)
Every 15 hours of trial/bush riding
- Replace engine oil (15w 50 should do it MOTORCYCLE OIL ONLY)
- Replace/Clean air filter (inspect for tears if so go buy uni filter and no other and oil)
- Do valve clearances (very important)
- Inspect every bolt on the bike
- Inspect suspension for oil on the forks, shock absorber and replace/rebuild (replacing to a dnm or quality product will last longer)
- Inspect tyre pressures
- Inspect chain tension/sprocket wear (if need to replace replace all sprockets and chain at once)
- Inspect spoke tension
- Inspect clutch actuation and freeplay (needs to have at least 1/8th leaver play)
- Inspect bushings for wear (on shock lift up and down and look at the mount bolts there should be 0 movement)
- Inspect the brake pads/actuation they should not be spongy
- Inspect while bike is running for oil leaks and smokey exhaust
- Listen for mechanical noise (a little from the valves is normal)
How do i do all that? *motor tutorials link*
Do i need any special tools to do all this? No nothing i would consider special just a socket set, pliers and some spanners (maybe).
Troubleshooting does not require a mechanical stig, but does require a little bit of time a patience and detailed information on the symptoms to solve.
There are many types of problems you can have when it comes to pitbikes, there engine there suspension and believe it or not chassis I will try to document all of the problems i can think of off the top of my head and if i find a new one i will post it here.
This is a hard topic to layout and make it easy to read so i will try to do my best (the causes are listed in numerical order as a process of elimination and so i can write the fix’s also in a orderly fashion
Engine is hard/impossible to start
- Carburettor jets/passages are blocked
- No spark *no spark fix link*
- kick start gears are broken
- valve adjustments are out
- engine is locked up
- No fuel getting to the spark plug, only running on choke
- No start, but getting fuel
- No compression when kicking feels like there is nothing connected to the kick starter
- Low/no compression.. noisy and extremely rattly when started
- Kick starter can not be pushed down
- Remove carburettor and disassemble and clean the jets and passages with carby cleaner and/or compressed air and look through them at a light, you should have a clear jet and also the little holes around the top (if any) need to be clear to work correctly
- Read this link
- Set the valve lash (link)
- Set the valve lash (link)
- Replace kick starter gears
4. Common Issues
5. Engine work
There are many pit bike engines out there, before we start talking performance you want to find out if your engine has a lot or a little of performance potential.. also the price for that performance, almost any motor can be improved its just a matter of time and money
1st off you need to Identify your engine and ask yourself how much is my budget and is my chassis up to the task (eg forks in good condition along with rear shock) because although its nice to have a strong motor its also nice to be able to ride it and not have a unexpected cost of a new rear shock (BELIVE ME )
Okay so now you have identified your engine i will start listing them in $$ order. i will try to do this cheapest to most expensive bare with me its quite hard to layout.. and also it may endup easier to drop $400 and just buy a tbv2 head or a takegawa head
$70 – $120 in parts cost:
Replace cam with a higherlift cam
according to the power you want and maybe to mods you want to do in the future
Depending on your cam you may need to replace your valve springs also (Note if your engine is a zongshen i would recommend doing this 1st off because your springs and redline is quite low as is)
Titanium valve spring retainers
(increases engine rpm without extra load on rockers like stronger springs have)
tb roller rockers are good enough or if you have the money then go for a takegawa rocker
with stronger springs, stock yx 5 plate clutches will not hold up to much (if you have a zongshen you have a 6 plate) stock 6 plate is running fine in mine with a tb v2 head and stock bore but with a bigbore it will slip most likely and need stronger springs
Port and polish
also while you’re at it you can port and polish, also i recommend replacing the valve stem seals, and maybe even the valves if yours look warn.. a port and polish costs nothing if you do it by hand and can even be done with a lot of time sand paper and a lot of sore fingers (a dremel will make your life much easier)
$200 – $350
Do modifications as above before you bother to go this far..
You can go to a bigbore kit, 184 kit will work with a 155 engine and will make it a 177 thats as large as you can go without case boring however depending on your machinist you may be able to do it in the budget but requires the whole engine to be stripped and 184s combine good power and maintenance costs for a perfect ride for most people anyway
You could possibly get a machinist to cut your valve seats larger and install a set of tb v2 valves ($70 a set approx) they also come with springs and retainers and put a tb high comp piston in (because you will need the valve relieves in the piston)
$400 – $$$$
$440 tbv2 head (cost includes required piston)
Great bang for your buck
Thats what i have chosen to run for ease of use and maintenance
larger ports and 30mm inlet and 27mm exhaust valve sizes with double valve springs and a tb s35 cam gives you many improvements over stock and a better power curve.. if your staying with a stock bore i would recommend a s25 cam because the s35 with the stock cam lacks a little bottom end but makes alot of power up top
$639 Tbolt works kit
most of the things i have listed above (but with out takey bits eg alloy roller rockers these are good quality but heavier along without the ti retainers)
Bang for your buck for sure, this kit will not leave you disappointed if you have the money i would go out and but this kit along with a decompressor install it and go racing the next weekend without any worrys about lack of power from bottom to top..
remember you can always chuck in the takey parts later on without issue if you really feel that you need any extra rpm
this is the kit i would like to get but cant save up to 600 to get, so i buy these parts separate.
$900 you can get a takeygawa superhead
Not so much bang for your buck but the main differences between this and your tb v2 head above is you get titanium valve retainers (higher rpm) and forged aluminum roller rockers and a slightly higher rpm limit.. skinnier valve stem (a little more flow) most likley better castings a intake manifold and a takegawa penis enlarger.. your paying alot for a brand name too hence why i chose the tb v2 head