2007 QJ Rx8 build

[190mech]

49ccscoot.proboards.com/thread/3151/minarelli-injection-pump-adjustment-bleeding

[mattyslimz]

190mech Nailed it. Thankyou! It’s not that I was being lazy or anything looking it up, I just didn’t know what to put in the search bar. I see the marks on mine.

[mattyslimz]

So far the weather has been great for the tuning and break in process so I got lucky with that. I think I’ve got this 19mm carb with uni filter as dialed in as I could get with not having any different jets for it to try out. Today I used an gps app (looking for a better app, what does everyone use?) and top speed was 50.2 mph. With my weight at 165 lbs, I thought it wasn’t to bad. I’ve installed a larger yet lighter fan made by Str8 tuning and it blows much better through the other side of the cooling housing. I do not have a Trail-tech temp gauge but my instinct tells me it’s not running to hot YET with the cooler air and lower humidity we’ve been having in the mid-Atlantic. The temp gauge will be included on my next order of parts.

The take off is only so-so but I’ve found that mid-range changing over is slightly doggy. The carb is tuned the best it’s going to get, I tried the stock airbox after break-in and there was not much difference except for probably being a bit quieter and running a tad richer. The mid-range bog must be in part too the factory secondary-pulley with its strange angles on these. Further review of Mr. 90gtvert’s YT channel with video “Overrange options” (don’t quote me on that) shows it steep at one point and than turns.. This made me so curious as to take another look at my CVT. I only did a once over on it by just pulling the cover while doing the rebuild. I dug deeper this time into the variator and found that the weights HAVE been changed with what looks to be the Dr.Pulley polygon shaped sliders. I do not have a scale but I’m almost certain they are heavier than stock which would explain the low rpm bog and early shifting. So I came up with a plan to try and improve.

Polini Hi-speed variator kit (comes with a contra I believe)
Polini front pulley air-speed fan 16mm
Stage 6 torque control
NCY Zuma/Jog secondary pulley

There can be some improvements to squeezing a little more power out of my little 40qmb with its tired crank that I failed to change change crank seals or bearings on. I still plan on doing the CP 21 with better reeds and intake as they are both stock and anciently old.
Any input/advice for the improvements is appreciated. I will upload a speed run how it is currently once I can find a better gps/speed app.


*Edit Also need forks... seal is bad one one side and they are just plain shot. They are super sketch when I hit past 45mph. If anyone has a better set than these, I’m interested. Would prefer to pick-up but would consider paying the large shipping price. Thanks in adv.

[mattyslimz]

I couldn’t help myself but I broke down and bought an ‘05 BWS 50 (Zuma 50) for a mere $600. Mileage is 7600. The RX8 was running great with the new S6 sport cast streetrace bore, but broke down on me on the way home from work Thursday afternoon. The bike starts and runs fine for a minute or so and cuts in and out and finally shutting down. It’s not bogging down when it cuts off, but more of a spark- like issue it seems. My first thought was a fouled plug, changed out, same problem. The petcock seems to be supplying enough gas from the vacuum though I do NOT have clear lines to see if there’s any blockage. Cleaned the el cheapo 19m carb and jets of the minor white flake and still not it. I was tired of trying to track down the issue and I need to get to work. So kinda rushed and skimmed FB marketplace, CL, Offer up and letgo for a decent yet affordable bike.

The Zuma has a aluminum single ring piston and bore (not sure of the quality on Athena, previous owner  said it is an O-ring gasket head design.(I know they’re decent for Tomos etc. but not sure of Athena’s reputation with scoots as far as reliability, leaks etc. are concerned) Athena 70 kit with stock crank AND FACTORY OIL INJECTION! (Headshake) PO claims kit was installed 400 miles ago.. I’m thinking of putting on my Stage 6 cast on from the RX8 for reliability reasons, but not sure if it’ll work because pin size. The factory carb has been retained with PO claiming an upjet 88 main. And guess what, the factory airbox is still on there thankfully. After all the talk of keeping the stock airbox in place for keeping cool/lean conditions, I’m glad it’s on her especially with this damn bore that rips and gets hot quick from what I can tell, I think now is REALLY the time to go ahead and order that TrailTech or Koso (if Koso even makes an air-cooled gauge) and slap it on there. With the weather getting warmer and that kit I’am worried about temps. I wonder if my 1e40qmb oversized fan from str8 tuning will work on the Zuma? Thinking of putting Polini CP21 on this. I don’t know what the R&D/testing people were smoking out at Leo Vince when they released this “ZX” pipe, but it’s earshattering loud. Its almost like I’m riding a YZ80 with a Shorty silencer on the street it’s so loud (kinda feels like it (YZ80) with the power-band this thing hits at though.) Mid-range and high out are pretty good with the pipe, down low has a little torque as expected but I’m sure there’s better pipes out there for sure. I’m planning on doing “the ZX quiet mod” by modding the silencer here after this post, but ultimately just getting an S6 or Yasuni variant.

The CVT is in desperate need of some mods. PO said it “may have lighter rollers” but I wont know the status of anything until I pull the cover off. The clutch seems strong as could be so it could be replaced or aftermarket already. The bike is screaming for more at 41-43 mph which feels like the restrictor may still be on the collar (boss) I’m not sure if Zuma 50s from this generation even came with them. You would think if the rollers were in fact changed as the PO claims, that common sense for more speed would to remove it, guess I’ll find that out soon too. I have the NCY secondary pulley in the package still ready to be put on to help with the weird angles for the pins to slide up and down, so coupled with a Malossi Multivar (real) I should have a decent budget overrange set-up. The tires are 100/90-10 front and rear by Kenda. I’m looking into a forged wheel set down the road.

I still plan on keeping the QJ Rx8 and figuring out its issue which I know MUST be minor, so that me and the ol’lady can ride together and to keep it as a spare bike for guests to ride. The Zumas a little clapped out looks-wise but I just ordered a nice seat cover for it off Ebay with white stamped YAMAHA logo for $30 on the “bay”, but it seemed like a decent price for what is and it already has the fender/tail delete and integrated turn indicators which is a plus in my book. Thoughts regarding mods for Zuma or insight on the Rx8 issue is welcome and appreciated. -Matt

[aeroxbud]

Nice find.
The ZX pipe should not be that loud. Perhaps the silencer needs repackaging. Would definitely try that before buying a new pipe.
They are not a bad exhaust really.

[190mech]

Right aeroxbud!The LV ZX is a fairly quiet expansion chamber,bet the packing is crapped out..That pipe also has some added sound baffles welded inside the chamber to deaden the 'ping-ping' sound..Decent daily pipe...

[mattyslimz]

You guys are probably not going to even fathom why I did this and probably laugh at me. But I did this “ZX quiet mod” found on a thread somewhere. I removed the silencer from the ZX pipe on the Zuma and carefully took out the packing and threw away the steel wool wrapping around the perforations, the wool was worn out. The problem it seems is, the ZX may be fairly quiet when brand new, but after time carbon deposits make the already small holes even smaller thus bypassing the sound proofing. Drilling larger holes in the silencer tube helps get the exhaust through to the soundproofing (Shasta style insulation) much easier. See the difference in the bigger bit used compared to the carbon coated factory holes..



The reason I goofed up in a sense (for personal reasons) is I made the ZX TOO QUIET! It literally sounds stock now. It has a slight bark too it only because of the kit. I wasn’t happy about it so I swapped silencers with the TT on the RX8. It sounds just right with the TT silencer on there, not too quiet, not too loud. Has a nice idle chop and power-band coming on and stop light thorottle crack slowing down, sounds real good. I’m not a huge fan of chrome but the aluminum TT silencer looks just at home on the plated chrome, not powder coated chrome ZX. I don’t like the angle in which the ZX is mounted on the Zuma, and plan on getting something with a similar angle mounted as the WJ and that better suits the kit on the Zuma.


I haven’t had a chance to hear the ZX silencer on the Rx8 yet because I’m waiting for a new CDI to get here Thursday. I bought the gold colored one because I just wanted something different than the millions of blue ones on there. I hope that it’s an AC unit and not DC. But it’s meant for a jog so why would it be a DC unit? Correct me if I’m wrong.

From my digging on the forum and chasing my issue I believe it to be the CDI or coil, because it is in fact NOT getting spark. The issue occurred after a slight overrev coming down a hill and I think the 13 year old unit just kicked the bucket.

[aeroxbud]

Never heard of the quiet mod before. Still learning. 😉

[mattyslimz]

Wow, it’s been a while since I’ve had a chance to wrench on any of my scoots. I’ve had parts sitting in the closet for months but too busy with overtime and working Saturdays to get anything done, so today I figured would be a good chance to relieve some stress buy wrenching and afterwards riding the QJ RX8.

Areas that needed attention were the CVT. The heavy 6 gram rollers that were completely shot were exchanged with Athena 15x12 4.5 gram rollers. I found the sweet spot with this engine to be up higher in the RPM range. Using my Prima Roller weight tuning kit, swapping between weights was key to getting the right weight. Even though this is a sports kit (cast iron jug and double ring piston) the Stage 6 streetrace 70cc kit absolutely rips. I guess between the port timing and the very lightweight piston it makes a majority of its power up high.

Along to go with weights is a new Bando belt “788-17-30”.
Some knockoff Koso clutch springs +1000 and +1500 contra spring no-name brand. To finish it is an NCY TD (secondary pulley) for Jog 90. This has the slots with much better angles when transitioning to the scoots “2nd gear” if you will.





Im also putting on a new speedo cable and puck for the stock cluster. I hope it still works. Waiting on a few more cosmetic items to come in, seat cover, front and rear turn signals. As you can see all work is being done on the porch of my ground floor apartment patio, so it’s not really the ideal place for working on these things but I will see that it gets done. I need a star washer for this variator also and it’s coming with the next order of parts but it’s been on hold over 10 days because one part in my order wasn’t in stock. I’m going to figure out a way to make it work for just a test ride until it gets here.
The bike ran 53 mph with a somewhat doggy take-off before these add-ons. It still had more in her up past 53 but I didn’t want to push it, the original stock crank and bearings are making a little noise and would like to get a little use out of it before doing a complete tear down as I mentioned I’m not in the ideal work environment and do not have a case splitter yet OR any bearing puller. 

[mattyslimz]

I forgot I never uploaded a video of my RX8 after starting it’s revival this past March. It’s come a long way after sitting in my dads backyard for 5 years. I still ride it almost everyday to work to save on gas and PARKING!
Here is a video from today after installing a new front pulley from Naraku. It’s a solid spline peice that doesn’t need a key washer. Only minor shimming was needed to get the kickstart washer to engage.
All the parts on my prior post for this bike have been put on hold until I can get a vice or the proper clutch tool. Only the Bando belt has been put on. The NCY TD, Yellow Contra and blue clutch springs will be ready when I get those tools to do it properly.
Top speed is 55.2 MPH cruising 48-52. That’s all I need to comfortably stick with traffic. The CVT parts to be installed will surely help with my acceleration.

Sorry for low quality I don’t know how to set up the video stuff on Apple.

[geoffh]

Matty,you can fabricate your own clutch tool, I use 2 alloy plates 4" x 9" 2 6mmx100mm bolts and a hole in one of the plates large enough to get a socket on the clutch but,but some people just use their feet to compress the contra spring have look on utube.

Geoff

[mattyslimz]

Oh why thank you geoffh I really never put that much thought into it. I just got to the part where it was ready to disassemble the clutch and rear TD, saw that I didn’t have a socket or channel locks to fit that huge nut and moved on. I will look into it though. I know Brent has some videos regarding not needing ‘special’ tools for this job on YouTube.

I found some more spare parts for the RX8 in my goodie box. 
A new seat cover from Scootertuning.ca.
Some rear turn signals from Tun’r

I’m not really impressed with the fabric durability of the cover or its fit, for $26 at Scootertunings prices! What did I expect? The seat cover from EBay at the same price that I bought for the Zuma is of much better material, better fit and has a Yamaha logo. The fitment with this new cover could possibly be related to the years of neglect and the foam disintegrated.

[mattyslimz]

New kickstarter (lever) from STR8 and more pictures.

[mattyslimz]

If anybody was wondering, Amazon has/had these Pirelli Angel R tires on sale. I guess these are the tires that come on some new Vespas (Piaggio). Speed rating “P”. I picked up one for the back 130/70-12 but I didn’t see my front size listed maybe because it wasn’t on the sale or sold out. $49 shipped.

[mattyslimz]

The new Angel rear tire feels sooo much better than the hard as a rock Chen Cheng that was on it. After about 200 miles of break-in it seems smoother. I really need to find a deal on a front tire. I may just bite the bullet and pay retail for a matching Pirelli Angel for the front.

I’ve come to notice an air leak on the bike at idle. CHT’s have also climbed into the 260s-270s on long pulls whereas I’d never see past 240 even on the hottest days. I know there was leakage on the crank seals upon install of the bbk, but it has become worse. No soft
seizures (yet) but I’d like to nip it in the bud before it does. I’m going to do something I should have done a long time ago and what members here told me to do in the beginning.. throw new seals in it. I took a gamble on the brand new bbk to begin with by putting it on with old seals. I’m still running this thing on the original STOCK crank AND bearings if you can believe that! I just hope it lasts another month before it starts getting to cold and I’m forced to switch back to 4 wheels to commute plus pay astronomical DC parking rates. Plan is to go big bore/stroke something similar in 90GTVerts realm with a TPR or Airsal 86-90cc range over the winter to keep me busy.