CVT issues on Yamaha Riva 1983 180cc By wheels (Read 10,447 times)

[wheels]

Hi everyone.
I have a 1983 Yamaha Riva 180cc that needs some help. I will try and fill you in the best I can with what I have done so far.
First what happened is a larger guy was doing doughnuts with it (one leg on the ground kind) and it just some moving forward after that. So it sat for awhile.
After fixing the carb and getting the bike to run great it actually drove forward for a bit then it got hot (crank case cover was very hot) and it stopped moving again.
With the bike tire in the air the tire spins, the variant and the clutch does what it's suppose to do, goes in and out and belt up and down, and tire moves. But and pressure on tire, and I can even hold it with my hand, and it stops spinning
The whole time this happens the engine runs great never slugs down. It's just like the clutch is totally slipping.

What I did:
1: took the variant apart and looked at it. Plates are smooth no scratches lines wear anything, Smoothe.
2. The weights are nice and round no flat spots. Bearing and everything looks great.
3. The service manual said to grease the oil seal lip with Molybdenum grease (i used a valv marine grease) it also said to grease the roller weights, I did make the mistake and used the same heavy grease.

First question what grease should I use on the roller wights I have a spray Liquid Wrench white lithium grease or a spray silicone spray would these work?

4. I will put this back together, the variant looks great and does open and close easily and the belt goes up and down.

Clutch my big issue:
I have pictures but can't figure out how to post them, will after some lets me know how. I do have images on photobucket

I figured the friction plates (brake pads) would be very thin and under spec. The spec is new .12 in wear limit .106 in The three pales were .114, .114 .112 so they are still ok not new but fine.
The clutch plates look good no damage not warped.
The Clutch spring and Off Spring length is on the short end new is .84 in min is .79 in all of mine are .79 in.
Rollers are all fine, no flat spots.
Housing looks good no cracks edges look good.

I just don't see anything wrong in the clutch at all. No grease or oil on the pads. I will clean up everything with brake cleaner, not the pads ofcourse.


The large compression spring length free length is 3.62 limit is 3.35 in mine is 4.035 in not sure how it got bigger??
Question?? Is this an issue???

So I need help with some suggestions as to why the bike won't move forward with any pressure on it.

I did not change the belt I am going to get a new one Monday. The one I have is in spec and looks good, but I am not going to chance it.

Any ideas???

Thanks in advance.

I have pictures that I will post once I learn how.


Here is the clutch itself.


Here is the first rings taken off just prior to the first friction ring (Brake pad right?)



Closer picture of the friction plates


All the pieces out of the clutch



Here is the weights on the clutch



The main spring which is 4.035 in a 1/2 in bigger then it should be


Here is the Variant with the grease weights that I will clean up and just but on the white lithium grease.



I will be a pain for me to put this back together with the compression spring. Any ideas how I can do that without killing myself?

[JR]

First of all Wheels here is a how to on posting pictures with photobucket:

thescooterprofessor.proboards.com/index.cgi?board=directory&action=display&thread=90

Yes you are correct on the grease you used on the variator, if the rollers won't slide then the variator will not engage properly or ramp up nicely when rpms of the engine is applied. I use a good lithium grease for the whole thing even the center shaft and "U" slides.

There's lots of controversy about greasing the rollers at all some say no grease others use it and from what I've seen there are what is called a dry and wet variator, I use no grease at all with no issues but since the Yamaha service manual called for it I would again use a thin coat of good lithium grease.

On the clutch the question about the compression spring in it being the length it is, I would say that someone before you has had this clutch apart and installed the wrong spring? The length is almost 1/2" too long. I would replace the clutch and off springs they are on the edge of worn out.

We have had a certified Yamaha mechanic join our forum and I'll email them to join in on this discussion and get their input on this clutch so in the mean time get some pics up and we'll get to work on this.

JR.

[austinbikergirl]

Hi Wheels and welcome. You are on the right track with your diagnosis of clutch and drive. Judging from the photos you posted, it appears the clutch plates are burned. If they are not a good metal gray color, and have spots of blue or black, then they are burned. The heat incurred also affects the friction plates that it comes in contact with. We refer to it as glazing. It would be wise to replace all the plates in the clutch. It is important to pay attention to the clutch clearance measurements. ref. 3-48 service manual. There are 3 clutch plates with various measurements to give you the proper clearance. If you do not have this manual, there is one in the download library of this group. The spring seat and spring are an integral part for proper operation. If there is grooving on the spring seat from the spring ( ref. 3-51) or discoloration, then I recommend replacing them also.
You are wise in replacing ther belt, especially since we are talking about a rubber part that is over 28 years old. The specs may be correct, but rubber compound deterioates with age and heat.
As for re-assembling, if you do not have the mega-dollar special tool, you can utilize a bench vise along with a socket or such that doesn't damage, but be sure and use wood blocks also to prevent direct damaging contact to clutch housing,etc. You have to be creative, but also use common sense and mechanical aptitude when special tools are not accessible.
While you are at it, I recommend changing the rear gear oil with AMSOIL 20/50. The rear drive and gears can get pretty warm.
Another word of advice from someone that sees it alot: NEVER (that means friends also) let anyone ride your scoot.
I would like an update how it goes.

[JR]

Thanks Jennifer and congrats Keith on getting the pictures in they help a lot! Now I don't know if you know if but Jennifer is the person I mentioned about being a certified mechanic and she owns her own business I believe along with her husband and upon emailing her she got right on this problem.

So now we've got to get some parts looks like and Jennifer what about that main spring that seems to be too long? Would it be correct to assume someone has had this clutch apart and installed a stiffer spring for quicker take off? If so do you think he should go back to an OEM one or can you kindly explain what to expect from this spring if it is indeed a after market install?

JR

[austinbikergirl]

The spring appears to be an aftermarket.Changing the rear tension spring can have good and/or bad effects if not properly balanced. In order to explain this, the rear torque-driver spring has a very specialized function which is to maintain enough tension on the belt to keep it from slipping. This also is a bit of balancing act because too much belt tension translates to inefficiency. It’s kind of like over-tightening the chain on your bicycle- power is wasted by over-stretching the belt. On the other hand, too little tension and the added power of your recent engine modification will vanish as heat generated by belt slipping and won't find its way to the rear tires. The trick is to find the just the right tension without overdoing it.
A secondary influence of the torque driver spring is that it has a slight impact on shift speed since the belt tension needs to be reacted against by the front sheaves. The higher belt tension tends to push the belt deeper into the front sheaves making the ratio higher, and revving the motor higher. Therefore, for a given desired rpm you would need to compensate with a higher roller weight to bring the rpms back down. After a torque driver spring change, it’s good practice to re-optimize the roller weights.
In my opinion, I would recommend going back to the original spring.

[wheels]

OK I had some big issues finding parts today for this 1983 scooter. I ended up actually finding most of them at a place in Baltimore who once was a big Yamaha warehouse and had lots of parts but didn't sell Yamaha anymore so I guess I lucked out. Phone is 410-636-0676 They gave me a break some what. They had what Yamaha said was discontinued and no one else had, but not everything. I did not get the original compression spring. I can order that from only one other place in the US. scary.
The other problem the belt, mine looks great and in spec. I want to replace but a new belt is $161.00 and only in 3 places in the US and one place in Hawaii. I will wait to see if all the other parts work before buying a belt. I have so much into this scooter it would be almost $600 with a belt so far.

If I could ask, how does this clutch work? Do the friction plates have constant braking pressure on so the drive shaft will turn. I think I understand that the pully is always turning and its function is to move in and out so the belt gains tightens and goes faster.

Thanks for help so far.
Will keep you posted

[JR]

Yes at the pulley is always turning and at idle the wheel shouldn't spin at all with it up on the centerstand, if it does you need to idle it down a bit. The belt when idling in the clutch pulley will be up on the outer portion of the clutch pulley while it will be down in the variator thus having it in a low range setting for take off when giving it gas and increasing the RPM's.

Once more RPM's are applied the clutch plates along with the springs all work together to start gripping thus transfering the pulley's power from the engine to the shaft that goes to the main drive gear in the transmission which is also set at ratio with other gears that transfers that power to the final destination the wheel.

If the clutch is slipping then you are not transfering the HP and Rpm's of the engine to the back wheel thus no movement. When you add the weight of the scooter and the person riding it to the equation then more power is needed from the engine thus tightening the clutch/plates/spring system to again make the back wheel move and make the scooter go forward.

As Jennifer pointed out with burned plates that's where all the heat came from that you mentioned and when this happens the fianl result is a burned up clutch and no movement of the scooter.

Can you list the belt size and I'll try my best to help find one at a better price than you found and you should also holler a Jennifer she might be of help also.


Here is a basics in the tech section and it's in the Chinese section but all the principals apply to all scooters, it's a good description of how the variator and clutch system work together.

thescooterprofessor.proboards.com/index.cgi?board=cvt&action=display&thread=100


JR

[buddah3360]

i have a 1984 Riva 180 with the same problem, i replaced the friction plates and bingo problem solved. only problem is I put the clutch back together incorrectly and the 6 springs on the clutch got destroyed. now my scooter cannot come to a stop with out dying. I need to find replacement springs ASAP, this is my only means of transportation, and ive been searching for the last 6 hours online i cannot find anything.. OEM yamaha doesnt make them anymore.. someone please help!!

[JR]

Welcome to the forum and is this the clutch?

.powersportsplus.com/parts/search/Yamaha/Scooter/1984/RIVA+180Z+-+XC180ZL/CLUTCH/parts.html" rel="nofollow" target="_blank">.powersportsplus.com/parts/search/Yamaha/Scooter/1984/RIVA+180Z+-+XC180ZL/CLUTCH/parts.html

And this is the spring?

.powersportsplus.com/parts/detail/yamaha/YP-90501-08748-00.html" rel="nofollow" target="_blank">.powersportsplus.com/parts/detail/yamaha/YP-90501-08748-00.html

I'll not only look but email Austinbikergirl for help.

JR

[austinbikergirl]

Since I am active in restoring vintage motorcycles, I realize that there will be parts for anything which will become unobtainium status and requires us to get creative and think outside the box. I recommend locating Yamaha dealers that have been in business for 20 or more years. They could possibly have some in stock sitting on their shelf collecting dust all these years. Some of these dealers still exist. Tuesday I will ck with my local dealer as he has been a good parts resource for my restoration of vintage Yamaha. Another option I find handy is ebay. Here is a complete clutch assy ready to bolt on, but the auction ends in a couple of days. Same clutch is used for 1983 and 84.

.ebay.com/itm/1983-Yamaha-Riva-XC-180-Clutch-JV3-/251132714157?pt=Other_Vehicle_Parts&hash=item3a78ad1cad&vxp=mtr" rel="nofollow" target="_blank">.ebay.com/itm/1983-Yamaha-Riva-XC-180-Clutch-JV3-/251132714157?pt=Other_Vehicle_Parts&hash=item3a78ad1cad&vxp=mtr