Aprilia Ownership, Day 1

"Decay buys too many beaters" (decay) 05/08/2018 at 13:28 • Filed to: Decay's Beaters, Tiny Racebike, Aprilia, 50cc

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I started troubleshooting the idle issue the bike has been having. Basically, you have to keep the idle above 3000rpm otherwise it’ll stall out (for reference, correct idle setting is 1100rpm). Pretty obvious given that the bike sat for about a decade, that the problem is somewhere in the fuel system. Figured I’d start with the carb, so I took off the fairings, tank, and airbox to get access. You do have to dig pretty deep into the bike to get at the carb, but everything is well placed and nothing was particularly difficult.

I got the carb out and gave it a good soak in cleaning solution, blew out all the passages and ran some guitar string though the jet. I’m actually not impressed by this Dellorto SHA at all. First off it’s only a 14mm throat so I’m fairly certain it’s a choke point. Shit, I upgraded to a 20mm slide carb on my 50cc Ruckus (stock is a 15mm CV carb) and the low speed fueling can still be dialed in.

But size aside, my biggest complaint is that there is ZERO adjust-ability. The only serviceable jet is the main jet, the only control is the idle adjust screw. That bell has no smoothing features to aid airflow. With those complaints in mind, I ordered a new Malossi PHBG 21mm slide carb as an upgrade. It should give me the adjust-ability I generally like to have and will have extra headroom if I decide to put a bore kit on the bike.

Since I couldn’t do anything else on the carb until the new unit comes in, I decided to go in and do a full fluid service. Changed the coolant and the gearbox oil.

Other things I found. There is a broken wire coming off the coil. The colors do not exist on the wiring diagram, so I’m not really sure what to do with it yet.

PartyPooper2012 > Decay buys too many beaters 05/08/2018 at 14:02

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Good luck wrenching. nice looking bike too.

Akio Ohtori - RIP Oppo > Decay buys too many beaters 05/08/2018 at 14:31

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Sounds like fun!

When I first saw your headline I just about shit myself. a Lancia Aprilia is on my “must own” list of cars and I thought someone on Oppo had just bought one. Imagine my surprise haha.

sn4cktimes > Decay buys too many beaters 05/08/2018 at 14:43

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Fuel filter? Might be plugged up. Debris in tank? Might even want to change out the fuel line(s). 10 years is. Pretty long “rest”

Decay buys too many beaters > Akio Ohtori - RIP Oppo 05/08/2018 at 14:44

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I did not know that was a thing. Its gorgeous! Plus, I bet that sounds fantasic with a V4!

feather-throttle-not-hair > Decay buys too many beaters 05/08/2018 at 14:45

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Well. I’ve had a day to think about it. I still love this thing.

Decay buys too many beaters > sn4cktimes 05/08/2018 at 14:47

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Nahh, fuel flows easily out of the tank. First thing I did was drain the tank and fill up with fresh gas. The previous owner was running premix, I never do when there is an oil injection pump. Sunday night I filled up with gas, primed the oil injection system, and found that it was still having the same idle issues.

I’ll be replacing a bunch of stuff as I go, but getting it running well comes first so I can see just how deep I need to dig in to the motor.

Decay buys too many beaters > feather-throttle-not-hair 05/08/2018 at 14:52

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I can’t freaking wait, it’s going to be so much fun. But it’ll be a while before it’s 100% needs tires and a chain BAD once I get it running.

feather-throttle-not-hair > Decay buys too many beaters 05/08/2018 at 14:55

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Right on, i will live vicariously through you. This was a fun post, hope you take the time to continue making these!

Decay buys too many beaters > feather-throttle-not-hair 05/08/2018 at 15:03

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Thanks! I’m hoping to keep it up. I used to write a lot more during my lunch break at work, but now our firewall prevents all uploading of images onto kinja. What I’ve started doing is putting up a blank draft full of photos before I head out in the morning, then I can fill in the text on my break.