View unanswered posts | View active topics It is currently Sat Dec 15, 2018 11:58 pm



Reply to topic  [ 14 posts ] 
 YAMAHA ZUMA - rpms not down shifting on my zuma. 
Author Message
Scooterologist

Joined: Sat Aug 05, 2017 8:39 am
Posts: 33
Location: Arroyo Grande, CA
scooters and mods: 2005 Zuma, Athena alu. Sport 70cc, Giannelli Reverse pipe, NCY variator and clutch, UNI flat filter in 125cc airbox,
Post YAMAHA ZUMA - rpms not down shifting on my zuma.
I have a problem that showed randomly one day. My 05 with BBK, NCY transmission and big Zuma airbox used to pull up hills just fine and rip on the flats. Now it struggles to maintain 40mph on the flats and bogs way down on the uphills (not downshifting?). It also died at a STOP sign this morning on the way to work. I've probably only got max 300 miles on the NCY transmission kit. Any help is appreciated. I'm finally starting to under stand these CVT things...LOL

_________________
2005 Zuma 50, Athena Race BBK, Giannelli Reverse exhaust, NYC Transmission kit, Dual Headlight LED's, 125cc airbox & filter, carbon reeds in stock block, vented CVT cover, moto style kickstand, moto number plate stickers (+1/2HP)LOL,


Tue May 22, 2018 8:11 am
Profile
Newb
Newb

Joined: Sat Aug 05, 2017 6:33 am
Posts: 24
Location: Calgary, Alberta, Canada
scooters and mods: 2009 BWS 50, 70cc BBK, Dellorto Racing carb, Technigas exhaust
Post Re: Not downshifting?
It is possible that you are experiencing power loss from the engine, and not the transmission. The transmissions are fairly simple, so trouble shooting it should not pose too much of a problem. Check your rollers for flat spots, check belt for signs of slippage, wear, and width. Run your scooter with the cover off, and rev the bike. This will allow you to watch the variator and torque drive for proper operation.

The struggle up the hills, and the stall you experienced may be a result of loss of compression due to piston ring wear. Check that quickly, and go from there. Knowing your compression is good to know, even if that ends up not being your issue.


Tue May 22, 2018 11:35 am
Profile
Scooterologist

Joined: Sat Aug 05, 2017 8:39 am
Posts: 33
Location: Arroyo Grande, CA
scooters and mods: 2005 Zuma, Athena alu. Sport 70cc, Giannelli Reverse pipe, NCY variator and clutch, UNI flat filter in 125cc airbox,
Post Re: Not downshifting?
Thank you. I did notice quite a bit of belt material inside the case like, more so than I think should be in there. Little particles all over the place although the belt doesn't look worn. After pondering over everything today I started thinking maybe it IS the motor. Prior to this happening it sounded like the motor was poping (lean) and maybe that took effect before I could get it dialed in? Motor runs just fine when on the stand. I'll pick up a comp gauge today, Thanks!

_________________
2005 Zuma 50, Athena Race BBK, Giannelli Reverse exhaust, NYC Transmission kit, Dual Headlight LED's, 125cc airbox & filter, carbon reeds in stock block, vented CVT cover, moto style kickstand, moto number plate stickers (+1/2HP)LOL,


Tue May 22, 2018 3:29 pm
Profile
Scooterologist

Joined: Sat Aug 05, 2017 8:39 am
Posts: 33
Location: Arroyo Grande, CA
scooters and mods: 2005 Zuma, Athena alu. Sport 70cc, Giannelli Reverse pipe, NCY variator and clutch, UNI flat filter in 125cc airbox,
Post Re: Not downshifting?
I bought this scooter 3rd hand. How do I go about discovering which BBK I have? Can I throw any 70mm x 10mm piston in there or are they all specific?

_________________
2005 Zuma 50, Athena Race BBK, Giannelli Reverse exhaust, NYC Transmission kit, Dual Headlight LED's, 125cc airbox & filter, carbon reeds in stock block, vented CVT cover, moto style kickstand, moto number plate stickers (+1/2HP)LOL,


Tue May 22, 2018 3:54 pm
Profile
Scooterologist

Joined: Sat Aug 05, 2017 8:39 am
Posts: 33
Location: Arroyo Grande, CA
scooters and mods: 2005 Zuma, Athena alu. Sport 70cc, Giannelli Reverse pipe, NCY variator and clutch, UNI flat filter in 125cc airbox,
Post Re: Not downshifting?
Pulled the motor and cylinder last night. Found some minor scouring on the cylinder and piston but the rings look good to me.


Attachments:
File comment: scouring on cylinder
IMG_8682.jpg
IMG_8682.jpg [ 646.16 KiB | Viewed 1649 times ]

_________________
2005 Zuma 50, Athena Race BBK, Giannelli Reverse exhaust, NYC Transmission kit, Dual Headlight LED's, 125cc airbox & filter, carbon reeds in stock block, vented CVT cover, moto style kickstand, moto number plate stickers (+1/2HP)LOL,
Wed May 23, 2018 9:33 am
Profile
Newb
Newb

Joined: Sat Aug 05, 2017 6:33 am
Posts: 24
Location: Calgary, Alberta, Canada
scooters and mods: 2009 BWS 50, 70cc BBK, Dellorto Racing carb, Technigas exhaust
Post Re: Not downshifting?
I do not think you can use any piston with your cylinder. The design of 2 strokes match pistons with the ports in the cylinder. Any piston may work, but that is a big gamble. I am going to pull my old cylinder and piston out of the scoot, and once I find out which cylinder it is, will likely get new rings (and piston if needed). The scouring on the cylinder does not look to bad. It could probably be dressed up assuming there are no deep grooves. Did you test your compression? Were you able to determine which manufacturer made the cylinder?

I recently cleaned out my transmission case, and installed a new belt. It was not many miles in, and there was a lot of belt dust in there. Everything works fine in the transmission though, so I will just give it a good blast of air to clean it out, and monitor.

Keep us posted. It is good information for us noobs!


Wed May 23, 2018 12:05 pm
Profile
Scooterologist

Joined: Sat Aug 05, 2017 8:39 am
Posts: 33
Location: Arroyo Grande, CA
scooters and mods: 2005 Zuma, Athena alu. Sport 70cc, Giannelli Reverse pipe, NCY variator and clutch, UNI flat filter in 125cc airbox,
Post Re: Not downshifting?
Ah, makes sense now on the specific piston needed (new to 2 strokes). No luck on ANY identification marks on the cylinder anywhere. Thinking I might just clean up this 'other mans problem' and go all new with something that suites my desires (larger carb, upgearing, etc.)
I got all excited to have a reason to pull a 2 stroke motor apart (again, new to 2 strokes) and, getting ahead of myself, forgot to check compression first like an excited child on christmas day.... It's definitely got just a single piston ring which leads me to believe it's a higher performing BBK ( i read that somewhere sometime). Question though;.... Why do people shy away from the aluminum BBK's? Seems logical in the 'cooling department' to run it.

_________________
2005 Zuma 50, Athena Race BBK, Giannelli Reverse exhaust, NYC Transmission kit, Dual Headlight LED's, 125cc airbox & filter, carbon reeds in stock block, vented CVT cover, moto style kickstand, moto number plate stickers (+1/2HP)LOL,


Wed May 23, 2018 4:48 pm
Profile
Newb
Newb

Joined: Sat Aug 05, 2017 6:33 am
Posts: 24
Location: Calgary, Alberta, Canada
scooters and mods: 2009 BWS 50, 70cc BBK, Dellorto Racing carb, Technigas exhaust
Post Re: Not downshifting?
As far as I know, all aluminum cylinders use a single ring, and the iron ones use dual. I just ordered an iron cylinder kit myself, and was on the fence with aluminum or iron. I have read the iron is more reliable. I also live somewhere (Alberta, Canada) that does not get too much extreme temperatures, nor is my bikes build too extreme. As such, I did not feel I needed the extra heat dissipation of an aluminum cylinder. I did order an oversized fan (not one of the mega ones that requires modding) to help keep things cool though. A bigger carb is a nice option. I have a Dellorto PHBG 19mm, and I really like the tuneability of it. I know some guys are running 21mm, although I am not sure that big of a carb is needed? From what I recall, a larger carb can result in loss of air velocity which can affect the lower end, although I doubt that is noticeable with this high revving little two strokes? I am also considering an upgear, but am on the fence as I love the strong launch. I suppose it depends on the type of riding you do. Sometimes, those few extra MPH help keep you moving at the same speed as traffic, which makes it a good upgrade.


Thu May 24, 2018 5:10 am
Profile
Scooterologist

Joined: Sat Aug 05, 2017 8:39 am
Posts: 33
Location: Arroyo Grande, CA
scooters and mods: 2005 Zuma, Athena alu. Sport 70cc, Giannelli Reverse pipe, NCY variator and clutch, UNI flat filter in 125cc airbox,
Post Re: Not downshifting?
I wish someone without a "Newb" designation would chime in. I think we're close but there's still speculation on both ends. Would like to get another BBK on it's way ASAP.

_________________
2005 Zuma 50, Athena Race BBK, Giannelli Reverse exhaust, NYC Transmission kit, Dual Headlight LED's, 125cc airbox & filter, carbon reeds in stock block, vented CVT cover, moto style kickstand, moto number plate stickers (+1/2HP)LOL,


Thu May 24, 2018 1:34 pm
Profile
Forum moderator
Forum moderator
User avatar

Joined: Thu Mar 20, 2008 5:27 pm
Posts: 14875
Location: portage wi
scooters and mods: 08 zuma dual headlight tmod rally kit cutom red paint koso mirros red anodized trans bolts
Post Re: Not downshifting?
Yes pistons are specific to kits
No not all al kits are single ring arisal has a 2 ring al kit and I believe top performance made one for a while too

Big down side to al kits is you can’t hone them to rebuild them you take the plating off

Most sports kits are cast iron Athena offers an al one and stage 6 sells a clone of it

I personally like top performance for the price and the fact that they are the high performance arm of the company that designed our engine

_________________
2008 zuma dual headlight mod koso mirrors liquid cooled polini corsa kit leo vince zx stage 6 variator rally kit custom red paintFUEL INJECTEDsoon to be 100cc
2008 stella olive custom ported 177 cc kit dechromed ford tear drop tail light alive and breathing and awaiting cosmtic surgery thanks to an trump cager
1985 elite 150 how long can i leave it stock


Thu May 24, 2018 7:41 pm
Profile
Scooterologist

Joined: Sat Aug 05, 2017 8:39 am
Posts: 33
Location: Arroyo Grande, CA
scooters and mods: 2005 Zuma, Athena alu. Sport 70cc, Giannelli Reverse pipe, NCY variator and clutch, UNI flat filter in 125cc airbox,
Post Re: Not downshifting?
jmkjr72 wrote:
Yes pistons are specific to kits
No not all al kits are single ring arisal has a 2 ring al kit and I believe top performance made one for a while too

Big down side to al kits is you can’t hone them to rebuild them you take the plating off

Most sports kits are cast iron Athena offers an al one and stage 6 sells a clone of it

I personally like top performance for the price and the fact that they are the high performance arm of the company that designed our engine


In the above photos, would you say the cylinder needs to be replaced also or am I good with just a new ring and gasket?

_________________
2005 Zuma 50, Athena Race BBK, Giannelli Reverse exhaust, NYC Transmission kit, Dual Headlight LED's, 125cc airbox & filter, carbon reeds in stock block, vented CVT cover, moto style kickstand, moto number plate stickers (+1/2HP)LOL,


Tue Jun 26, 2018 1:42 pm
Profile
Forum moderator
Forum moderator
User avatar

Joined: Thu Mar 20, 2008 5:27 pm
Posts: 14875
Location: portage wi
scooters and mods: 08 zuma dual headlight tmod rally kit cutom red paint koso mirros red anodized trans bolts
Post Re: YAMAHA ZUMA - rpms not down shifting on my zuma.
The bore was seized at some point
I can’t tell from the pics can you feel anything when you drag your nail across it
But what does the position look like what are the pistion to wall clearances
What does the pistion look like with those scuff marks on the bore I bet the pistion is done for
Can you get plus sized pistions for your bore kit they are specific because it effects port timings

_________________
2008 zuma dual headlight mod koso mirrors liquid cooled polini corsa kit leo vince zx stage 6 variator rally kit custom red paintFUEL INJECTEDsoon to be 100cc
2008 stella olive custom ported 177 cc kit dechromed ford tear drop tail light alive and breathing and awaiting cosmtic surgery thanks to an trump cager
1985 elite 150 how long can i leave it stock


Tue Jun 26, 2018 7:58 pm
Profile
Scooterologist

Joined: Sat Aug 05, 2017 8:39 am
Posts: 33
Location: Arroyo Grande, CA
scooters and mods: 2005 Zuma, Athena alu. Sport 70cc, Giannelli Reverse pipe, NCY variator and clutch, UNI flat filter in 125cc airbox,
Post Re: YAMAHA ZUMA - rpms not down shifting on my zuma.
This is INSANE. All I did (before the problem started) was install carbon reeds (which, once I got in there I noticed the previous owner had already installed them so I left them) and switched to LED headlight bulbs. Then all of a sudden the bike started running like crap. It's hard to imagine these other problems (roached piston and cylinder) all coincidentally started at the same time. Now, with that said, do I really need a new cylinder and piston? What if that doesn't solve it? These bikes are more of a pain than a real motorcycle.

_________________
2005 Zuma 50, Athena Race BBK, Giannelli Reverse exhaust, NYC Transmission kit, Dual Headlight LED's, 125cc airbox & filter, carbon reeds in stock block, vented CVT cover, moto style kickstand, moto number plate stickers (+1/2HP)LOL,


Mon Jul 09, 2018 2:50 pm
Profile
Forum moderator
Forum moderator
User avatar

Joined: Thu Mar 20, 2008 5:27 pm
Posts: 14875
Location: portage wi
scooters and mods: 08 zuma dual headlight tmod rally kit cutom red paint koso mirros red anodized trans bolts
Post Re: YAMAHA ZUMA - rpms not down shifting on my zuma.
Who knows how long the issue was going on
Hell when you took the intake apart you could have left a minor air leak that could cause this
A bad exhaust gasket can cause you to be lean too
Maybe it was never tuned right you bought it used

If you need speed you need a bigger scooter or bike or you learn to fix them and fine tune them as needed

_________________
2008 zuma dual headlight mod koso mirrors liquid cooled polini corsa kit leo vince zx stage 6 variator rally kit custom red paintFUEL INJECTEDsoon to be 100cc
2008 stella olive custom ported 177 cc kit dechromed ford tear drop tail light alive and breathing and awaiting cosmtic surgery thanks to an trump cager
1985 elite 150 how long can i leave it stock


Thu Jul 12, 2018 7:43 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 14 posts ] 

Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by STSoftware for PTF.