2001 People 50 Restore, with BBK Install (50 2T)

[vdubn]

So, I started out my People 50 restore, with my 2001 that I just picked up a couple months ago.  It needed some body panels, and had about 13000 kMs on the odometer, and was smoking like crazy with no power up top.  After finding out that it had a tad over 120psi of compression (just barely minimum), and that the automatic choke was stuck on (hence the smoke and no power at top end), I decided to go ahead and install a 70cc Malossi BBK, a Malossi performance carburetor, etc.  As part of this, I decided to just pre-mix my fuel, so part of this thread will be to document the removal/disabling of the oil injection system.

To start us off, here are some pictures of the work I have been doing... I haven't seen this documented on here, at least with pics, so I thought it might help someone.  The BBK was about $200, and the carb kit was $170.  I got both through scooterworks.com, they seem to have good availability and prices are amongst the lowest. Finally, they were willing to answer questions.

After pulling the cylinder and piston, soaking the needle bearing and all new parts, I prepped the new cylinder with some new exhaust studs that I got to avoid having to pull and use the old ones:




Then I set out to disable the oil injection pump.  First I disconnected the oil line to the tank and drained the oil:



I may just remove the whole tank and connect the terminals of the oil light (thanks for the advice Peters), not sure yet.

Once the oil was removed, then I pulled the oil pump out of the block.  I then noticed that the gear assembly just came right out of the pump body, and on the end it looks like it threads into the pump.  I think that the threads are the actual pump that pushes oil into the motor.  You guys all probably new this, but, it was new info to me.  I pulled the clip and the seal out as well... here are the pics of it disassembled, and with the caps on the ports:






Then I reinstalled the pump, and plugged off the intake manifold as well and made sure that the O-ring was in good shape and sealed nicely when installed:




Finally, I cleaned up the cylinder mounting surface of the block, with my brillo pad attachment... it came out nice.



The carb kit should be in today, and if I get some time to look it over, I'll document the installation of it as well.

[Peters]

Awesome!

[vdubn]

Ok, so I got the BBK installed along with the new Malossi 19mm carb. I documented the process with pics, but will need to post those later.

For now, I wanted to ask a couple questions about tuning the setup. I bought the 90 to 108 sized Dellorto jets, and the carb came with an 80. I figured I would start at 100, and see how things go. It started right up and ran terrible just like before the BBK install. So, I figured way too rich (the stock carb had a failed autochoke).  So, I drilled three more holes in the air box lid, and dropped the main jet to the lowest I had, size 90.

It ran a lot better, but still bogs on the top end. It comes up to speed better, but I can tell its just not revving like it should. I think the 80 jet that came with the carb is probably too lean, but curious what others with the same setup might be running.  I'll try the 80, but figure I'll probably need to grab the 80 to 90 jet kit as well, since I'll probably end up around 86 or so.

Any thoughts?

[Peters]

No no no. Do not put the 80 in. You should be somewhere in between 90 and 100. Start high and work your way down. Work your way down from 100 til you get the results you want. You have two different circuits and the slide needle. The main jet mostly controls 3/4 throttle to WOT mix(high speed jet). The slide needle is adjustable also(can be raised up or down to control mid range mix). It mostly controls 1/4 to 3/4 throttle mix. The idle circuit(low speed or idle jet) mostly controls closed to 1/4 throttle.

It has been said it's best to start with the idle and work your way up from there. Do this because the idle circuit is still active at WOT. It's completely independent at closed throttle though(needle or main jet do not affect the mix at completely closed throttle). Changing the idle jet can throw the main jet off.

Actually, the best thing to do would be to get the idle right then the main and then change the needle setting if you're unhappy with the mid-range. If you get the main jet perfect and then change the needle setting, likely you'll have to change the main again. Works the same other way around. Say you're good on the mid range and too rich on the main. You would decrease the size of the main. In turn, this would make the mid range lean. It's a very delicate balance.

Read up on plug chops. It's the best way to tune a carb. A simple google search on "plug chop" or "how to do a plug chop" will yield better resources than searching this forum. It's basically all the same whether it's a scooter, airplane, or jet boat. Biggest thing is to make sure you continue to hold the throttle in the same position until the engine completely stops.

Hope this helps 

[zombie]

With an airbox 86ish sounds reasonable. Open filter may need upwards of 150ish

[Peters]

Hold on, 150 MJ?

[zombie]

I had a drilled out 147 in the ruima 50mm jug using a delorto 19mm from a scrap bike. It went down to a 100 with a 28mm delorto. ran best with an oko 24mm, and 127 main

[Peters]

Gotcha

[vdubn]

Ok, so I ran the thing around the block today, and it feels ok, just really sluggish once you hit midrange, and almost no top end.  I did a plug check, and its like chocolate in color, but its smoking quite a bit.  I know I put a bit more oil in the mix than normal, so that might be contributing to the smoke, but this has me baffled as the color looks good on the plug.  I expected it to be black or wet.

Its acting almost exactly the same as it did before I swapped out the stock cylinder for the 70cc, and the bigger carb (stock carb had a stuck choke, or so I thought).  If I put it on the center stand, and rev it, I almost immediately get studdering like something is cutting off spark, hitting rev limiter, etc... I can't get it to rev out.

Since I have a 90 main jet, and the plug is looking dry and chocolate, I think the jetting is actually close.

I am now wondering if the issue might not be spark related, like the coil, or the CDI.  I pulled the air cleaner off, with the 100 mainjet, to see if that would help it run better, but still ran into the studdering problem when trying to rev it.  No matter what jet I run, it still studders and will not rev out.

I checked spark and its not bright blue, but a bit yellow-ish blue.  The bike starts immediately though, so not sure.  I had a coil issue on another bike, and it showed itself by taking forever to start.  New coil, and it fired immediately.

Some have said that if there are any issues with the CDI, that the bike won't even start, so I am stumped.  I don't think its stator or pickup related, as the battery charges well, and the lights are nice and bright.

Any other ideas, is there a pickup on the flywheel for spark timing, or is that just part of the stator?

[Peters]

Sounds like it's a fuel issue. Likely rich. Just checking the plug isn't enough. You have to do plug chops. Make sure you get the idle mix right. Start with 1 and 1/2 turns out, then turn 1/4 turn at a time, either direction, until you get the highest possible idle. Then adjust the speed screw to the desired idle speed.

Did you check the reeds?

I'd lower the slide needle one notch and see what happens to the mid range

[vdubn]

Ok.... I havent checked the reeds yet, and I had heard that they can break sometimes.  Its easy to check, so I will do that tomorrow.

I'll google plug chops and get a better idea what to do there.

As for lowering the needle, you mean move the clip up one groove, thus lowering it further into the carb?

[Peters]

As for lowering the needle, you mean move the clip up one groove, thus lowering it further into the carb?

Exactly 

Check the reeds first. It's very easy to do.

[vdubn]

To me, it seems as though something mechanical is hindering it from running right... checking them now... too impatient to wait.

[Peters]

Never know. Double check everything. Try to be consistent with the oil ratio. It changes the air/fuel mix. Pre-mix requires a slightly bigger jet than if you were still on the injection system.

[vdubn]

Here are some pics of the reeds... I noticed that on one side the reeds are off of the reed cage just sitting static.  The bike has 13000 kMs on it, so I'm wondering if the reeds are week.  Thinking of flipping them over until I get another set.  I know there are people on here that cut there own, but anyone know where to buy a new set?

Also, thoughts on the weekness of the reeds causing issues?