Parts that should be replaced before installing the kit

Magneto seal (black rubber grommet in the front) needs to be removed and replaced with silicone.

High quality springed seals (learned this the hard way the other day).

My first kit first thing I had to replace was the fuel line, it was brittle and could be snapped apart. I got the fuel line then noticed the filter element wasn't fastened at all and ratteled in the holder so a new filter was bought. I liked the looks of the sick bike parts bolt and stud replacement parts. It was about that time I noticed the holes weren't tapped to the bottom of the holes, I got a new tap set...

I hated the exhaust pipe from the begining and ordered a SBP expansion chamber right off with the add-on muffler. Soon after that I got a 70cc hi-compression Puch head from treatland.tv.

I was modding this motor from the start but I'm a hotrodder at heart

These are the things that I do, I see that others such as the seals (which I've never had one go bad) mentioned. All these mods or replacements are most likely less then $50.00. Choose what works for you, ignore the rest, but here you have them.

1. Unpack engine
2. Check for any missing parts
3. Remove head
4. Mill head (flat glass and 230 (or finer) grit sand paper. Rub gasket surface to insure it is flat.
5. Tap cylinder stud holes to insure they are taped to the bottom.
6. Discard all studs and nuts.
7. Replace studs with Metric 8.8 (US Grade 5) Replace nuts with locking nuts. 8mm studs are either 1.0 or 1.25 thread, 6mm studs are 1.0 thread. 8mmX1.0 is not common, but I have 1 engine with them.
8. Replace spark plug with a NGK or the like.
9. Replace spark plug wire and boot (check with lawnmower supply) or rob from old lawnmower. Use wire core lead.
10. Mount the engine properly, no gaps between the bike tubes and engine mounts.
11. Torque 8mm to 150 to 200 INCH POUNDS
12. Torque 6mm to 60-70 INCH POUNDS
13. I install cylinder studs with lock tite, and let set overnight
14. I coat the head gasket with Copper Kote
15. May need to bend exhaust pipe for crank or frame clearance. Recommend using heat.
16. Remove or cap magneto white wire off.
17. Re solder blue wire on magneto.
18. Make sure all wires have a good connection and use tape or better yet shrink wrap.
19. Hook up kill wires AFTER you get engine running.
20. Try not to drill holes in the bike frame.
21. Do away with the clutch cable routing; there are a number of options.
22. On my kit the rag joint had gauge (Metric) 8.8 bolts, If not replace them. I replaced the nuts with lock nuts.
23. I replaced the chain to a better grade of chain. Bought from Tractor Supply.
24. I sealed the wires coming from the magneto with RTV.
Never had a axle bend on me.

All good advice ,especialy doing what works for you and taking any advice with a grain of salt...
And of course read Pre-Motorized Bicycle Information. - Motorized Bicycle: Engine Kit Forum before you tear. Into anything.

Mozenrath said:

I thought it would be a good idea to make a thread about components that should be replaced before installing the kit, since as we know the parts that come on the kits and bikes usually aren't of the best quality. This includes both parts from the kit and parts on the bike.

Click to expand...

Replacing the rag joint with a sprocket hub adapter is the first upgrade I
would recommend.

Fuel lines are junk and a hazard as they degrade fast and could fail
dumping gas on a hot motor with disastrous results.

Replace studs, nuts and bolts especially the ones on the chain idler if
you are using it. Sick Bike Parts makes it easy as they have the parts
so you don't have to waste time running around finding them.

Replace the junk Chinese spark plug. I have seen the porcelain crack on them
which could ruin your motor.

Replace the intake gasket, make your own and match it to the port.

If you have to use the tensioner because of clearance issues then replace the mounting nuts and bolts with grade 8 stuff. I bet the majority of tensioner/spoke collisions are due to the fact that with the stock hardware you can't tighten the bolts enough to secure the tensioner without stripping them. You should be able to kick it without it budging.

Of course if you can do without a tensioner that is the best setup. Second to that is upgraded tensioners that connect at both the seatstays and chainstays.

How many studs and nuts do I need to buy and where can I buy them?
Thanks for yor help.

4... 8mm X 1.25 (very few use 1.0) cylinder studs and nuts
2... 6mm X 1.0 intake studs and nuts
2... 6mm X 1.0 exhaust studs and nuts
2... engine mount studs (6mm X 1.0) and nuts (long)
2... engine mount studs 6mm X 1.0)and nuts (short)
9... nuts for rag joint bolts (6mm X 1.0)...that is if you already have Metric grade 8,8 bolts. If not bolts also.

That list needs to be a stickey!

smemo666 said:

How many studs and nuts do I need to buy and where can I buy them?
Thanks for yor help.

Click to expand...

Sick Bike parts is the best place to get them.
Sick Bike Parts LLC - Performance parts for your motorized bicycle

Replace the single clutch ball bearing that presses onto the clutch bucking bar.
Found some of the Ch... bearing disintegrates almost instantly.
Even before use, those bearings are not round, not case hardened enough, or not at all.

Go ahead and place everything from the kit out on the table or floor, taking notes with a pad and pencil or pen (I perfer black ink- not blue- says "girlie"!)

Write down everything that came with the kit (engine, tank, carb, CDI, etc..) as you'll need to quickly replace those items with custom aftermarket parts (start googlin') and make sure you order at least two of those parts- at least two! Don't bother mounting the original kit onto your bike, those custom parts are what really matter.

After mounting your custom aftermarket engine kit, mixing the oil and gas and putting on your helmet- get ready- because now it's time to drive around and vibrate everything off!! Double nut it- lock whatever it- it will come off! You're Motorized bicycle wants to come apart, that's it first and best destiny. Before engine seizure, before bents wheels or sputtering carbs'. This Kit wants to get off your bike no matter what- watch and you'll see!

The stock air filter should be replaced ASAP. Especially if riding in dusty areas. They stop rocks from getting in but that's about all.

"the prussian" Shop Dogs said:

That list needs to be a stickey!

Click to expand...

I have it in WORD... copy and paste...heck no one reads the "STICKIES" that's apparent from all the duplication of questions asked.

Not only that..if posting a question, in the title specify the problem, that way when and if someone searches, the title pertaining to the question is listed.

Hit search and type in Dust Cover, or Bearing Cover, or Coaster Brake....and the title of my post comes up. The search leaves much to be desired...it really isn't that great. That's why noobs find it hard to find what they need.

i was thinking of making a thread like this.

i would say don't order a "kit". just get the engine & buy all the other pieces.
everything that is part of the kit i have either replaced or i am going to replace.

even the mounts have broke.
here is a tip.
i found that a "u-joint repair kit" for a chrysler with some grinding to widen the bolt holes is awesome for the seat mount. it is the "HELP!" brand part # 81006 @ advance auto.

find a real gas tank.
get a real throttle.
get an extra magneto.
get a real chain from a place like tractor supply.
not one from a bicycle shop. i have multiple stress fractures from a bicycle chain.
spend a lot of time mounting the engine
if the rear drop outs can accept adjustable stays use them. (can't remember what they are called)
again spend more time to adjust the engine to try & not use an "idler pulley".
it will take quite a few tries to get both chains to be properly tensioned on both side of the rear tire.
a chain breaker highly recommended.
a tool bag to carry on the bike. carry the chain breaker & a few links of extra chain.

if can afford it, get a shift kit.

decoherence...if you broke mounts then the reason is that it wasn't mounted correctly.. The only part I have go bad was a magneto...lasted 3 days. Yea...I got a chain from tractor supply. Forgot about that one.

Its not a part that needs replacing, but I just made my exhaust port about a quarter inch bigger. By cleaning the cast flashing out of it.
Ive also learned you need to make sure there are no blemish's in the chrome coating on the cylinder wall.
The next motor I get will be completly gone thru and polished,piston,rod,wrist pin,bearings,crank. Every moving part will be polished and lubed. Plus quality bearings.

Al.Fisherman said:

decoherence...if you broke mounts then the reason is that it wasn't mounted correctly.. The only part I have go bad was a magneto...lasted 3 days. Yea...I got a chain from tractor supply. Forgot about that one.

Click to expand...

i probably didn't write clearly. i only broke those cast aluminium pieces that actually hold the bars.
they didn't break while running.
they would slip down the eat stays. so when tightening they shattered. the 2nd one i tried to tighten less & it would slip. when i tightened. it broke.
changed to a u-joint repair kit. i can tighten all i want.
i'm 3rd generation radial air plane mechanic. well ok, i'm not a licensed mechanic but i didn't need once since i worked in the shop that is licensed.