'99 Prebug Zuma Build

[billwill]

Jan 18, 2024 9:59:47 GMT -5 Lucass2T said:

Jan 18, 2024 7:11:33 GMT -5 billwill said:

Wow this is pretty amazing... if I had more time and was more confident in checking timing/using a timing light, etc, I would give this a go. Heck, we'll see if this new CDI I have coming works and maybe I give this a go.

At the very least, I'm excited to see how this variable timing affects power at different rpm ranges.

A while ago I was on the brink of buying one of these red TP cdi's.
Earlier I found an Athena one 2nd hand (also with a timing curve). But it was faulty unfortunately.
www.athena.eu/en-us/cdi-kit-with-settable-advance-P27982.htm
cdn.athena.eu/2b649af1-fc18-403c-91c0-c6bf7c2bc1e2.pdf
Never followed through buying another cdi.
So I am really curious how you like it.

I'm curious as well, but man oh man, thought I was onto something with DHL worldwide shipping (1-5 business days) and it got stuck at some distribution center over in Germany due to weather for about 24 hours. Suppose to be here Monday 🤞 but I think Tuesday or Wednesday is more realistic. Not a huge fan of DHL here in the states.

[billwill]

Got the Kiesler wheel mounted up and 140 tire swapped over to it. Ultimately I want to get it powder coated white to match but I just couldn't wait and was having second thoughts about stripping and polishing the front wheel to match. So, for now I might plasti-dip it white.

Clearance is barely there but it clears. I may end up clipping off the hose tab/holder on the carb just for peace of mind and zip tying or re-routing the hose.

[aeroxbud]

Yes definitely lose the tab on the carb. Apart from that it looks great. 👍

[billwill]

Tried the tops variable curve cdi with 3° timing key and tried to run the scootertube pipe but i just could not tune the thing short of trying a polini 3g clutch to get higher engagement. Didn’t want to do all that so swapped the pipe out for a yasuni c16 and she’s happier now.





Hit 68mph at around 10,800 rpm on a downhill but speed on flat is closer to 60-62. Seems like it wants to rev higher so I may mix a set of 4 and 5.3 rollers I have.

Current setup: 

- yasuni c16
- 5.3g rollers
- red malossi contra
- mhr overrange
- polini pwk 24 w/45 pilot, 114 main, clip @middle (changed to 2nd richest position, see below)
- stage6 clutch w/purple springs

The bike rode the best ever but it still needs some work. Temps are only reaching 320°.

Still pretty sluggish on takeoff so I was thinking the clutch might need higher engagement or jetting changes. Just to see, and since temps were mild, I tried moving the main jet down to a 108 and it did NOT like this. Lean cackle and power loss on the top end.

I moved back to a 114 main and moved the needle up to be richer and this took care of the power loss on takeoff and the bike is so much better out of the gate. Feels like no clutch fiddling is needed. Engages right around 6500 or so.

I think that the 13/44 gears are just too ambitious for this setup. I have a set of 15/52s that I might swap in.

I've also been thinking about the variable CDI and timing key. Been getting some feedback from a facebook group that with the timing curve that the Tops unit uses, there will be a significant power loss above 9k rpms. I may swap in the Malossi fixed/flat curve CDI and leave the advance key in and see how it runs.

All this AND, started barking up this tree:

For anyone wondering, I did some research and took a chance and ordered an Aerox rear disc hub from scooter attack. Slides right on but seems like there will be some case work and machining or grinding needed. For the moment, riding without a rear brake since I already cut down the pivot pin for the brake shoes, but there is more to be done. 

I seems like I'll have to grind down the case in a few areas and then drill a few holes back there for the rear caliper adapter? I haven't had too much time to look into this but everything is slowly coming together.

[aeroxbud]

Yasuni do seem to make some of the best pipes. They seem to be able to get a wider power band than most.
I really liked the city 16. Just was so noisy for a city.
They rust pretty badly is the only downside. 😞

[billwill]

Jan 27, 2024 12:11:51 GMT -5 aeroxbud said:

Yasuni do seem to make some of the best pipes. They seem to be able to get a wider power band than most.
I really liked the city 16. Just was so noisy for a city.
They rust pretty badly is the only downside. 😞

Yep that’s the one thing about them as a drawback. I keep dusting it with wd40 in hopes it keeps that at bay.

My yasuni r on my vento triton that I revived earlier this year is already way darker and a few rust spots.

15/50 (not 15/52 like I think I said above) gears are in and the gearbox is topped off! Hoping to get a quick ride in tomorrow to see how that changes things.

[billwill]

Cold and rainy here today so no riding, but I did manage to fit this Polini air box that I was turned out to from a guy in one the facebook groups I'm in.

Ever since switching to an open air filter, I've HATED the noise this thing brings to my neighbors and get fed up with all of the attention it attracts so I was willing to roll the dice and try it.

It's originally for CP carbs that use a smaller diameter intake mount but I was able to replace the plastic insert with a strip of rubber that I cut from some plumbing stuff I had laying around and make it fit on the PWK I'm running.

I'm very pleased with the noise difference and recommend it to anyone who still wants something high flow but quiet.

www.treatland.tv/polini-CP-carb-curved-air-box-46mm-ID-p/polini-cp-air-box-203.0014.htm

Originally made for paramotor setups but it works pretty well for mine.

[oldgeek]

I was thinking about one of those CP airboxes myself but they have no filter in them?

[Zino]

Next time your riding  the question I have
Does the new airbox change your lower your jetting needs ?

[billwill]

Jan 28, 2024 22:06:33 GMT -5 oldgeek said:

I was thinking about one of those CP airboxes myself but they have no filter in them?

Yeah no filter. And the guy, Burke, well known on the Facebook groups, says he runs no filter and not an issue. With the way mine sits with the bigger Pwk that’s bigger than the cp, it either needs to be at 2 o clock where it is in that picture. Or at 9 o clock in a position where it’s sucking in what I would guess to be hotter air near the cylinder. So I’m a bit leery and fixed some filter media at the top of it on the inside.

[billwill]

Jan 28, 2024 22:07:49 GMT -5 Zino said:

Next time your riding  the question I have
Does the new airbox change your lower your jetting needs ?

I’m wondering this too and hoping not much, if any at all. I may try it with and without a filter inside. It’s made to run with no filter though.

[TheScooterJesus]

I would definitely just put a 1 or 2 inch spacer on the carb inlet rather than cutting the tab off the bowl, just my 2 cents

[billwill]

Jan 29, 2024 14:10:53 GMT -5 TheScooterJesus said:

I would definitely just put a 1 or 2 inch spacer on the carb inlet rather than cutting the tab off the bowl, just my 2 cents

Hmm, not sure how that would have worked. It would have been the intake that connects directly to the MXS intake manifold block that would have need to be lengthened and I'm not sure how I would have done that without it being kind of janky and bulky.

I ended up just clipping the tab off with snips, came right off and clears the wheel now.

[billwill]

PSA for anyone considering or using a Stage6 R/T multifunction tachometer / temperature EFI (pic included)...

I had been using this thing for the past few months. I thought it was odd that temps seemed a bit low (200-220 cruising and 320º max WOT) but didn't think too much of it until I started tuning a higher end sport setup.

Temps would chang ever so slightly with jetting but not as much as expected. When I started dropping my main jet all the way from a 137 which ran just slightly rich based on feel to a 108, when things were very obviously lean, I suspected the Stage6 unit was wack.
Even when the bike ran dangerously lean, I was only seeing moderately higher readings of about 320-330º.

Switched to a Trail Tech unit and sure enough, I got into 365-385º territory in about 1/8-1/4 mile of WOT.

I'm not saying all of these Stage6 units are bunk (I actually really like S6 products, even if they put more into marketing than R&D), but proceed with caution if you're using one and if you have yet to pick a temp unit up, consider something else.

Also, I've seen these units sold by Polini and others, so its probably not even Stage6 but some bigger manufacturer.

[billwill]

Got into some rear disc action over the past few days. Someone on one of the facebook groups posted this video that I found helpful getting into it.

www.youtube.com/watch?v=cKySE2ImU2Q&ab_channel=LiloScooterPerformance

One of the things I had to do was grind down the rear drum pivot and brake shoe cam mounts on the rear of the case. He didn't document this in the video, but I had to do it so that the rear disc bolts would clear. Not a huge fan of doing this to the case but I was in too deep and this case isn't in the best shape anyway so if I need a new case at some point, good reason to just build a new engine lol.

For the brake pivot mount, the prebug uses a pin that is bolted in on the transmission side, inside of the gearbox. I completely removed this pin and then once the case was ground down, filled the hole with JB weld.

Like the guys shows in the video above, there was a ridge on the rear of the case that had to be ground down for the caliper adapter to sit flush against it. So I just took my time with a dremel and ground that down.

Mounting the caliper was a bit tricky. I used the same method of removing the tip from a sharpie and marking the holes on the CVT side of the scoot. I say tricky because the holes are marked from the CVT side of the bike but need to be drilled from the other side. I went back and forth trying to cut out templates and measure and finally just ended up measuring with calipers and eyeballing things and then drilling very tiny holes to start to make sure I was in the right spot. 

After a couple test holes I was able to step it up to the correct size bit and do the deed. Everything seems to have gone ok and test fitting looks good. 

One thing I'll note is that it seems like the Voca adapter could be a bit thick, causing the disc to sit about 1mm off center toward the passenger side of the bike. I might take it too a machine shop and have it milled down but the disc spins freely as is so I might try to just send it.