Newbie??'s
 

Hello All,

I've been a lurker for a while and I am currently in the process of planning a build for my son. He has a 3rd Gen Yerfdog Spiderbox. Recently started smoking so I figured it was time for some father and son time doing a rebuild. While it's up on the stands I figured I'd go through it all and do multiple upgrades.

What we have planned for now id the following:

1. 155cc BBK with big valve head.

2. Installing an A12 cam

3. Either Jerseydevil or Hammerhead exhaust

4. New Performance CDI and Coil

5. New Uni air filter

6. Possibly a new carb

7. New 1500RPM spring and still trying to decide on the roller weights

8. New performance clutch

9. New front hubs with HD spindles (already have HD ball joints)

10. 10 inch polished aluminum wheels

11. Probably going to stay with a 20 inch rear tire for performance and a 19 inch front.

12. Relocated and larger battery

13. Going to do some research on new or drop in shocks. The stock ones are pretty sad.

14. Install a reverse kit

15. Replacing the stock lights with LED's

16. Possibly a strip and paint.

What else can you think of? The YD is bone stock as of now.

I have seen many parts listed on several sites so I am going to turn to you for some guidance. For starters, I have seen BB kits that pricing is right in line with scrap metal to very high priced to in between. I found a kit on ebay( http://www.ebay.com/itm/SCOOTER-GY6-...EAAOSwGvhUAPOe ) and after some reading on here and other sites the guys seem well respected for selling a quality part. What are you thoughts on these parts? I see engine kits from Taila that are priced much higher, what are the reasons for that?

I have seen many performance coils and CDI boxes listed for once again, little money to big money. Can someone steer me in the right direction for these items?

Both my wife and I agree our son was born to drive something. He started by racing 4 wheelers at 4 years old, now 11, and has not stopped wanting to drive. I looked into the Jr Dragster thing for him but that is a serious commitment both financially and with time. With my work schedule now, its hard to take off out of town for multiple weekends so we decided to do this build. In my eyes - at least it keeps him off his Ipad and it's some good father son time.

Any guidance would be very much appreciated. Thank you!

X

From one X to another, welcome to the site.

Here's my Yerf thread with lots of info for you if you haven't seen it yet.

http://buggymasters.com/forum/showthread.php?t=2601


First things first. Reinforce the front end.

1. The Howhit engine that comes on it, is pretty good. The head in particular can be cleaned up and breathe much better. (FREE mod) Not a bad head IMO. You can have it ported and polished if you want.

2. A12 is good. Try to find a quality built one, not just cheapest you can find.

3. Not knocking either one, but a cleaned up stocker and opened up muffler will make decent improvements. (FREE mod)

4. Don't waste your $$. No major gains from either of them. (maybe the unit that has adjustable timing, but don't think you're going to see much improvement)

5. UNI good. Will need to rejet carb.

6. Stock carb not too bad. I did notice a gain from my flat slide Mikuni though

7. Trial and error to find what works best for you/son. This is where you can notice a big improvement in performance by getting this dialed in right.

8. Don't waste your $$$. Stock is just fine. That's what I run with no problem. Just deglaze the clutch bell with sand paper and you'll be fine. I also run stock variator after trying a $80 performance variator. (gained me nothing)

9. I modified mine. They came out good. I do however think Jersey Devil's car/trailer bearing spindle mod is the best set up.

NOTE: when I say cleaned up, I mean grinding and polishing the casting flaws out of parts.

Port matching the intake manifold to cylinder head, and head to exhaust manifold frees up a lot of usable power. It's awful how far off these can be and the engine still runs.

Thank you for the reply Xlint89. I've read through some of your past posts and they were full of information. What are your thoughts on the ebay kit I posted vs. a Taila kit? I would like to run 22's vs. 20's on the rear but I'm afraid of loosing some power. My son loves donuts and he would like to be able to spin the tires on gravel or dirt as he leaves the line.

I need to sit down tomorrow and start ordering some parts just in case some are on back order. Once again, thank you.

I've gotten parts from them before. No problems thus far.

Kit looks to be a nice set for the price. Might be worth trying?

The beauty of these karts is pricing. Get a set of 20's and 22 rear tires. Remove 4 nuts and you can swap out a tire in seconds.

CAUTION: The valve springs seem to be a weak point for me at least. I've had valve to piston contact on 2 occasions now. Even with performance rated springs (NCY brand)

If he's going to be doing donuts watch the high RPM. The springs are weak and the valves float. When they float, you get contact.

That's why the "no rev limiter" CDI can be dangerous. And Tom from Syc powersports got me a set of American made quality valve springs.

You can also adjust gearing on these things too. Either by using different sprockets on the drive side, or the gears on the internal part. Really quite easy to swap. The Yerf does have good bottom end gearing stock already. I've found by installing a larger axle sprocket, RPM goes way up, and top speed is severely reduced in my kart.

Also, doughnuts can push your oil away from parts that need it..

Very true, I would need to watch that.

As the old saying goes, you get what you pay for. Tiada is the best in my opinion. There are several of my threads that I have written a book on the differences between higher priced and cheaper kits. The cheaper kits lack in consistency so one person will buy one and be completely happy but you can find instances which 3 people say there garbage. Companies with great quality control have great consistency and that is where the higher price comes into play. One company says it is close enough where as the other says it's out of spec so melt it down and start all over.