Yamaha Majesty Scooter Forum banner
1 - 14 of 14 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
Wood Gas Composite material Automotive tire Machine

Wheel Automotive tire Gear Rim Bicycle part

Photograph Light Automotive tire Gas Automotive wheel system

Automotive tire Motor vehicle Tread Wood Engineering

Automotive tire Automotive lighting Wood Alloy wheel Automotive wheel system

Tableware Tire Dishware Wheel Automotive tire

Tire Wheel Automotive tire Tread Motor vehicle

Tableware Table Wood Cookware and bakeware Serveware

Automotive tire Cookware and bakeware Rim Gas Automotive wheel system

Automotive tire Tire Wheel Hubcap Alloy wheel

Hi Gals/Guys-
let me start by saying I do not own this scooter, nor have I ever worked on one like this (many motorcycles tho). I was asked to diagnose issues with this machine after original dealer it was purchased from could not diagnose the issue, had it for 6 months and has since gone out of business. It then went to another motorcycle dealership, they had it for over a year, threw a bunch of parts at it and still could only diagnose part of the issue.

The original problem: would not go over 30mph, etc. - Diaphram was cracked (known to be a problem from reading here), which last dealer replaced along with a new fuel injector that was installed, new belt and a brand new throttle body in a box scooter was better but would hardly do 50. Sometimes it would start sometimes not.

I now have this machine and have been tasked with solving the issue.

this bike has had the fuel pump gasket changed and the new harness for fuel pump recalls and has 2 punches on vin. I have since replaced the fuel pump with updated pump (solved starting problem) and am now working on the hardly 50mph issue. I went through all self diagnostics- everything tested fine with no issues or check engine light. so now im going after the mechanicals if the drive train. besides the typical caveman things done to to this machine prior to me like every other bolt head stripped from using wrong tipped screw driver/hex key, to every other nut rounded off from wrong size socket/12point vs. 6point. 🤦‍♂️ so now i have the cvt guts exposed and here is what I found. clutch and belt has been changed but drive ring looks glossed over so i dont think it was. on the variator side there are two distinct grooves on each side of the pulleys toward the outer edges, not only can i feel them with my nail but my finger plain as day, and when I took the variator off the shaft and slid it apart there were only 4 rollers/weights in it??? should there not be a total of 8? from what Ive read, the belt gets stuck in this groove, between that and the lack of 4 additional weights be causing the 50 mph senario? I should also mention the rpm are ruffly bout 5500 when at 55mph, machine is also consistently driven above 5500+ feet in elevation.

I look forward to any advice!
 

·
Registered
Joined
·
644 Posts
Start with a new set (8)of rollers. Look in the shop (not owner) manual and run thorough the various diagnostics procedure for the onboard computer. Also, check your conversation on this site from me.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #3 ·
thanks for reply Mini-
I do appreciate any and all input, if you read my post again, I stated that I did go through the self diagnostics, and everything checked ok. Thank you for the shop manual, if anyone knows the value of one, it’s me. Ive been around motorcycles my whole life, drag raced them as well, still repair them to this day.
this scooter is a different ball of wax, with the CVT transmission. I understand how it functions, and that anything out of tolerance can cause it to not work correctly. the missing roller weights is a mystery, chalking that up to prior peeps having their hands in it. I went ahead and ordered a new complete variator set up to replace the old one. so I gusess i have the roller issue solved, its more of a curiosity for me as to why they are missing. I would like to know about the grooves in the sheaves of the variator side, and what effects it had on the operation. I would like to explain it to the owner. He has spent a bunch of money on this machine and has not ridden it in over 2 years. needless to say he is hesitant on spending more money if its not going to fix the problem.
thanks again for any info!
 

·
Registered
Joined
·
644 Posts
Generally, the groves are caused by the sides of the CVT belt. Seems to happen more when Kevlar aftermarket belts have been used. If the grooves are really bad, either replace the sheave or do a light clean up on a lathe.
 

·
Registered
Joined
·
15 Posts
Visually, the sheaves don't look bad, or at least I've seen much worse. I'm curious how many miles are on the bike.
It's clear by the wear pattern on the sheaves the cvt is not getting to its top ratio due to the missing rollers.

Assuming the engine is running properly now I really don't think you need to replace the variator unless you're looking for like-new performance. I would have simply lightly sanded the sheaves, cleaned everything up well and installed new rollers. From what I can see in the photos, with a full load of rollers you would have no problems with the belt hanging up.
Usually, the groves occur out near the edge of the sheaves where the belt sits at the highest ratio (since that's the one spot where the belt sits most often). The most common problem when that happens is the bike won't "downshift" under increased throttle/load.

Whatever you decided, I suggest before putting it back together you take a wide sharpie and draw a couple of lines from the outside if each front sheave toward the center. If you're still having issues after the repair and need to take it apart again it makes it easy to determine how far up the sheave the belt if riding.

Hard to say what happened to the original rollers. Either one of the dealers disassembled and neglected to put all back in or a previous owner removed 4 to effectively keep the bike in a lower "gear" for any given engine load/throttle position.

When I picked up my Majesty it had 68,000 miles on it. The clutch was metal to metal with deep groves in the front and rear sheaves. It was jerky on take-off but still reached top ratio with no problem. I managed to find a complete front and rear sheave set with clutch with no measurable wear on Ebay for short money.

Good luck!

Matt
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #6 · (Edited)
Once again, thanks for replies!

Minimac, Matt- Owner opted for the Malossi variator, it is now installed. it did change the scooter in a huge way as far as throttle reaction, it still tops out at 5k in rpm and 50-55 mph. the pressure sensor was a little out of tolerance so i ordered a new one anyway, although there was no check engine light.

I unplugged the pressure sensor to put computer into “limp mode” took it out for a ride, with no difference in how it operated, 5k rpm, 50-55mph. owner said it would do 70-75 all day long at 7500’ in altitude.
I should also say, with scooter on lift it revs 6500+ rpm no load.

so far here is what has been done:

self diag test- no codes stored all functions-pass tests.
new fuel pump seal (recall, stamp in vin)
fuel pump harness added (recall, stamp in vin)
updated fuel pump (installed by me)
new malossi variator (installed by me)
new fuel injector (installed by ?)
new diaphragm in throttle body (installed by ?)
new clutch bell (installed by ?)
new clutch (installed by ?)
new belt (installed by?)

with no check engine light, and all self diag tests passing, what else could it be? bad sheaves on clutch, low compression, valves not seating correctly? all things I have not checked as I was told by said “?” that they were all checked and they were good.

almost acts like timing is not advancing? 🤔
waiting on adaptors for spark plug hole, so I can do compression test and leak down test.

anything that I might have missed in all the tons of reading i have done?

TIA!!
 

·
Registered
Joined
·
15 Posts
Sorry for the delay, I don't check this forum very often.

I think your transmission is fine, if you weren't reaching the top drive ratio your speed would be low and rpm high, the same if the belt or clutch were slipping.

I did a little bar-napkin calculation, primary reduction of 2.214, secondary reduction of 2.625, top ratio of the CVT 0.892:1, rough outer diameter of my 150/70-13 Pirelli Diablo is 77.9". If my math is correct 5k at the engine should be 57 mph. It would have been easier to take my Maj for a quick ride but I'm lazy.

It looks like the engine is not producing the power it should, my Majesty will cruise at 85-95 (indicated) with no problem. How does it run at top speed, any indication of miss-fire, back-fire, etc.?
If so you may want to look at ignition.
How does the plug look after a high speed run?

I agree with a compression or better yet a leak down test. I also agree ignition timing could be an issue but I don't believe there's a mechanical advance on these. It's most likely just the algorithm in the control unit though I haven't checked the manual. If so it's unlikely the control unit would fail that way and the timing is probably non-adjustable, again unlikely a crank sensor would fail like that. Electric units usually just stop working altogether. I don't think it could be a temp sensor, that would most likely lead to hard start or running rich when warm (black exhaust and fouled plug).

I'd start with the basics, visually confirm the throttle plate is opening completely and the intake tract is not restricted. I'd also check the diaphragm again to make sure it was installed correctly, no cuts or tears (was it installed by the same person that removed the weights from the variator?). Confirm no vacuum leaks or blockage in the vacuum supply to the diaphragm. Does it slide up and down smoothly, no binding at all? Is the spring correct? If the spring is too heavy it will not open all the way, you can have the throttle plate fully open but if the slide only opens half way you're not getting full power.

What happens when you snap the throttle wide open from a standing start? My bike quickly jumps to around 6.5-7k and remains there until I let off the throttle. The same if I go wide open throttle from any rolling speed.

Let me know if everything looks good at the throttle body, if so I start digging around in the manual.

Matt
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #9 ·
when I get on throttle from a standing start it revs to 5k and will only go 50mph, sometimes it will rev to 6.5k and will run 65-70 which is “normal”. when im rolling, if its doing the 50 mph thing, I can go wide throttle, hear the throat open up (intake suction gets deeper) with no change in speed. when its not doing the 50mph thing, I can snap the throttle and you know about it. it can be all normal, turn it off, 5 seconds later start back up, and 50 mph again, like a governor was turning on or off.

Thanks For the input Matt- its late now and wont be able to work on it till this weekend.
👍
 

·
Registered
Joined
·
644 Posts
I wouldn't take for granted that everything that was checked by "?" is indeed good. I'd take a good hard look at the clutch and associated parts, then at that diaphram for starters.
 

·
Registered
Joined
·
15 Posts
This issue's intermittent, that changes things a bit. I don't think compression is a possibility which is good news.

I'd still take a good look at the diaphragm and slide though.

I'm thinking maybe the throttle position sensor or circuit, when I have some time I'll take a look through the manual and update, should be before the weekend.

Do you have a service manual? I downloaded one from scootertime.net, other than the watermark on every page it's a good PDF, all the links work.
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #12 ·
I have a manual that was kindly gifted to me.

I also have that entire throttle body that was purchased by “?” with all sensors attached, owner of scooter would like to get his $ back if he can for it, if i can get scooter going without installing it.

not sure if I mentioned before but only has 10k on the clock. when I run TPS test in the diag mode, it shows throttle closed within range and throttle open within range. I did double check diaphragm and slide, no tears/cracks/stiffness, normal wear on slide, moves freely.
will install new pressure sensor this weekend.

thanks!
 

·
Registered
Joined
·
7 Posts
Discussion Starter · #13 ·
Hi Guys-
I got the pressure sensor installed, so far it runs as normal. when I started it and took off, i sure felt the malossi variator hook up and take off right from the get go (something that was hit or miss before) Ive stopped it, let it cool bout 4 separate times, so far so good. going to continue to test several more times see if it reproduces the problem.
 

·
Registered
Joined
·
15 Posts
Sorry again for the delay, had a little run-in with C-19.

The MAP sensor makes sense, sounds like the owner has a nice scoot with a lot of miles left on the clock now. Nice job!
 
1 - 14 of 14 Posts
Top