Yamaha Riva 180 Repair & maintenance information

Discussion in 'Battle Scooters' started by Kevinforesthill, Oct 15, 2018.

  1. SimonLeBon

    SimonLeBon Adventurer

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    Tried to install the TW200 carburetor yesterday and noticed the pull out choke will not work because the scooter frame is in the way. I had to take off the knob to fit the carburetor but there is no room to pull out the choke. I tried to start it a couple times but I don’t know what the other 2 connections on the carburetor are for. I assumed they are just air vented to the atmosphere. I only connected the fuel line. I haven’t checked the jet nozzles l yet but will do this tonight. It has not started yet.

    Also the throttle cable is too short so I need to order a longer one to make it work.

    Attached Files:

  2. Kevinforesthill

    Kevinforesthill Been here awhile

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    Damn that sucks. I know they make choke extension cables, but not really sure how to connect it to a rod style choke lever.

    You may be able to re-route the throttle cable to get a little extra out of it.
  3. Kevinforesthill

    Kevinforesthill Been here awhile

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    From what I am seeing on TW200forum.com, it looks like both of the nipples on the carb are open to air.....but it also looks like there are different style TW200 carbs out there. Below are links to different TW200 carbs that I found (I'm guessing yours is probably similar to the first link below)

    https://www.tw200forum.com/forum/te...nections-2-right-side-have-no-tubes-them.html

    https://www.tw200forum.com/forum/technical-write-ups/881-tk-carb-photos-parts-identification.html
  4. SimonLeBon

    SimonLeBon Adventurer

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    I was able to get it started yesterday after I made a stupid mistake the last couple days. I always turned the petcock to ON but there was not enough full in the gas tank. I had to turn it to RES to get fuel out of the petcock.

    It was running pretty good, but I now have to adjust the iddle RPM and find a way to connect the throttle cable to the carb.
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  5. Juvenile Senior

    Juvenile Senior Been here awhile

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    Hello everybody,

    I only just registered to this forum, and this is my first posting here. I am 46 years old and live in the Black Forest, which is a mountain range rising up to 1300 meters (I only live 950 meters) above sea level in the south west of Germany.
    Except for my Yamaha TDM 850, I became a lucky owner of a beautifull Cygnus 180 model 1986 several months ago. I almost feel the need to apologize, but my scooter has been well maintained by its previous owners, it starts rather willingly and rides really nice. Well, the old school way, that is.
    I will start with some pictures now and add some more details in my future posts.

    IMG_20190406_164231.jpg IMG_20190921_163600~2.jpg IMG_20190406_164040.jpg IMG_20190406_164137.jpg
    Keep 'em running and take care

    Juvenile Senior
  6. Wentwest

    Wentwest How's that work?

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    That's remarkable! I've never seen one that looked completely new.
  7. fullmetalscooter

    fullmetalscooter Let me take this duck off

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    nice
  8. Juvenile Senior

    Juvenile Senior Been here awhile

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    Thanks!
    Well... I wish I could take the credits for its condition. But as I said, I only just bought it in the last spring. It has not been used much all these years, and I also only managed to crack the 13000 km mark a couple of weeks ago, meaning that I only made some 600 km on it all this summer. And now it's startes snowing here, so there will not be much more kms collected this year I suppose.
    However, since this thread is dedicated to the technical aspects of this model, I don't just want to show off with my purchase, rather I would like to comment on what I have been reading in this Forum and in this very thread these last months.

    1. A couple of people called this scooter "fast". My scooter seems to be rather hesitant starting from a stop. I don't know if it's due to the tuning of the CVT or the carburetor, but if I open full throttle from a stillstand, the clutch seems to engage at a rather low rev, and the engine starts to stutter untill I turn the throttle a little back. That means I need to start gently from a traffic light, giving it a second or two to rev up before I can open full throttle. Is this normal?

    2. Again, relating to the term "fast". The middle range is indeed torky, pulling rather strong up untill about 80 kmh (50 mph). What happens above that can be measured in... minutes... Giving it time and space, it would hit the 100 kmh (62 mph) mark, but would fall back once klimbing uphill. I get the feeling as if it runs too lean at the top revs. However, the sparkplug is showing a healthy color, so I am not sure that it does. Can anybody chime in with their experience?

    3. Many inmates report starting problems and general frustration with the cold start system on these Scooters. As I mentioned before, the scooter starts willingly and idles well when cold (knock on wood). But in the first minutes after rolling off, it tends to stall at each stop, unless I keep the throttle slightly open (just enough to keep it reving without making the clutch engage). This bad behaviour disapears after the engine is well warmed up, but it appears again after the scooter has been standing for a while. Even if I start it after 3-4 hours of cooling down, it would not keep its idle, I need to help it with the throttle.
    I've never seen another one. Period. Therefore I need your reference on those old scoots to know what I should expect from them and, if mine has a problem at all or is it all just normal for the scooters of the period.

    Thank you all

    Juvenile Senior
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  9. Wentwest

    Wentwest How's that work?

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    My experience with old scooters that haven't been used recently is that they need to be run quite a bit to get the fuel system working right. There's probably some accumulation of varnish and grit in the carburetor causing your problems. I would be sure to use top tier fuel, and perhaps a small addition of something that cleans carburetors like Techron or Seafoam.

    Have you removed and cleaned the air filter? That can cause what you describe.
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  10. Juvenile Senior

    Juvenile Senior Been here awhile

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    Indeed, the first thing I did when I got the scooter was to fill it up with fresh gas and add a good portion of carb cleaner. I did get the impression that the stalling in the mildly warm engine phase decreased, but that only appeared lately.
    As for top tier fuel, here in Germany you can choose between 10% Ethanol and 5% (which costs a couple of cents more due to tax policies). I use the 5% version since I am worried about the old rubber lines.
    Also I didn't dare leave the scooter with carb cleaner over the winter, worrying that it would eat its way through my fuel system. I filled it up with fresh fuel for storage in order to prevent the tank from rusting.

    By the way, were you aware that if you press the horn botton before you stick the key

    IMG_20190406_163621.jpg

    There is a light turning on around the switch,

    IMG_20190406_163907.jpg


    to help you find it in the dark alley when the show ist over and you want to go home?

    That was state of the art luxury back then in '83!

    Cears

    J.S.
  11. Kevinforesthill

    Kevinforesthill Been here awhile

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    That is a VERY nice and clean Riva. Congratulations on such a nice find, there are not many out there that are still that nice.

    To me it sounds like your variator rollers have developed flat spots on them, which is typical for old rollers, and would cause the problems that you are describing, especially the "pulling rather strong up until about 80 kmh (50 mph). What happens above that can be measured in... minutes". Could also be a few other things, but you state that it starts up nice and runs very well and it just has problems with smooth acceleration and reaching top speed.....so i would bet money that your problems with off the line acceleration and acceleration above 50mph is variator related. Could just be old gummed up grease, but more than likely you probably need to change your variator rollers as well. I installed the Dr Pulley Sliders and I have really liked them, even though they are a little more pricey that standard rollers.....and you don't grease the sliders, so no worries about the grease getting old and gummed up in the future.


    I am going to have to try the horn button trick when I get home and I have not experienced any problems with running 10% ethanol blend, in California (where I live) all fuel has been a 10% ethanol blend since 2010. I am curious though if it would run better with a 5% blend instead of the 10%.....I took my Riva out for a ride on Saturday and I noticed that it was feeling a little sluggish with the older gas I have in it (probably about 6 months old).
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  12. Juvenile Senior

    Juvenile Senior Been here awhile

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    @Kevinforesthill : Thanks!
    I was actually considering opening the variator and inspecting the state of the components (I still need to buy an Impact Wrench to make it easier, or how do you do it?). I even bought simple rollers of 5.2 and 5.8 grams and was thinking about mixing them to get the effect of about 5.5 grams combined, in order to raise the revs just a bit.
    I had very good experience with the Dr. Pulley thingies in my Majesty 400. It actually felt as if someone has added another cylinder to the engine. You could rev up the engine during acceleration, if you wanted, but you didn't HAVE to. The problem is, I couldn't find the right size for the Cygnus (Riva). Its 18x12 mm and 6gr seem to be a rather exotic combination. Could you tell me which modell of the Doctors should fit my scooter? Moreover, since the kits count six rollers, I would have to buy two kits, to replace my 8 rollers.
    In other vehicles I could not feel or measure any difference in Performance nor in consumption between 5% and 10% Ethanol.
    Chears
    J.S.
  13. Kevinforesthill

    Kevinforesthill Been here awhile

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    Double check the roller/slider size.....mine were 17mm x 12mm (6 gram) not sure if the European models were different but that is what we have here in the states (measured with a dial caliper). And yes, I would suggest an impact but you can do it with a breaker bar (with 30mm socket) and a pulley wrench, I just use an impact to take off and put on with a torque wrench (torque 36 ft lbs (50 Nm)) and pulley holder (Pulley wrench is a must have so you don't break the fins on the variator cover). The Dr Pulley part number I ordered was 169-254-6g (Dr Pulley 17x12 - 6 gram) and yes, you would need to buy two since it only comes with 6 sliders.

    I purchased my Dr Pulley Sliders from:
    https://www.partsforscooters.com/169-254_Dr_Pulley_Roller_Weights?quantity=1&custcol16=1
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  14. Juvenile Senior

    Juvenile Senior Been here awhile

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    That means that you have tried the docs on your Riva... Was it worth the price?
  15. Kevinforesthill

    Kevinforesthill Been here awhile

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    By "Docs" do you mean the DR Pulley Sliders? If so, then yes those are what i am currently using and yes I think they are worth the extra price (in fact I just purchased a pack of 5gram so I can try a 6g/5g slider combo). I found that it is hard to find good quality 17x12 rollers and when I do they want pretty close to the same price as the Dr Pulley sliders. I have a bunch of cheap 17x12 rollers from when I was experimenting with different weights (4, 4.5, 5, 5.5, 6, 6.5, & 7 gram sizes) and they always use really cheap plastic around the weight that needs a lot of grease to function properly (wheel bearing grease is the only grease I could find that worked well - lithium grease & graphite were a waste of time & money). I found 5 gram overall (4.5/5.5 mix) to be about the lowest that the Riva will still drive under, and I really liked 5.5 gram combo (5g/6g mix) but the 6g overall (all 6g) Dr Pulley Sliders gave me roughly the same acceleration as the 5.5g roller combo, but with better top speed and was much smoother through the powerband. I also like that they are greaseless....variators and grease are two things that just shouldn't go together n my opinion.
  16. Kevinforesthill

    Kevinforesthill Been here awhile

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    Here is everything required for the variator roller slider change (a copy from my post on page 6)

    Tools required for roller/slider change:


    Phillips screwdriver (JIS 2) - side fairing, air box cover & variator cover
    10mm Socket - floor board
    12mm socket - foot peg
    5mm allen head (aka 5mm hex key) - clutch/variator outer cover
    Flat head screw drive - Variator tab
    30mm Socket (I strongly suggest using an impact gun) - variator nut
    Pulley Wrench
    Brake cleaner - to clean variator belt surface

    approximate time start to finish = 1 hour [if it is your first time it will probably take longer, I have done this procedure probably 20 times on this Riva]


    **PRO TIP: The sliders should be installed with the "Dr Pulley" lettering on top
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  17. Juvenile Senior

    Juvenile Senior Been here awhile

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    Thank you @Kevinforesthill, you just saved me a lot of Scrolling.
    Reflecting on the grease issue, I suppose it wouldn't take long for any kind of grease to fly off a quick spinning pulley and leave it nicely dry.
    What I don't really understand is, why should rollers 10% lighter than standard have any influence on top speed. But I intend to start a new thread on that toppic, this is not directly a Riva issue.

    Juvenile Senior

    Edit: I am just about to order an electrical impact wrench. My question is, do I still need a retaining tool for the Vario if I am using an impact wrench or will the impact make it obsolete?
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  18. Kevinforesthill

    Kevinforesthill Been here awhile

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    You can get away with no having a pulley wrench, but it will be hard to hold the variator while tightening the variator nut. It only needs 36 ft/lbs of torque so it doesn't need a whole lot of force. I have used my hand to squeeze the belt around the variator to hold it, but it doesn't work well. If you have a couple bolts and some scraps you can make a pulley holder pretty easy.....or you can use the impact driver to tighten it but you have to be careful to tighten it enough without over tightening it.


    "Reflecting on the grease issue, I suppose it wouldn't take long for any kind of grease to fly off a quick spinning pulley and leave it nicely dry." That is very true. That is why I use the wheel bearing grease, it is the only grease I could find that would remain in the variator and it is what was in my variator when I originally opened it (probably from the factory). You really do not want the grease flying out and getting all over the belt surface.


    "What I don't really understand is, why should rollers 10% lighter than standard have any influence on top speed" The weight of the rollers is directly proportional to when the variator opens and closes....too much weight or too little weight and the variator and clutch spring will fight against each other and it will not function properly. As the variator spins the centripetal force on the rollers pushes the variator inward making the variator close and giving the belt a larger diameter to ride on, at the same time the clutch spring on the opposite belt surface does the exact opposite and opens giving the belt a smaller diameter to rotate on.....basically like a small gear spinning a large gear (low rotation speed / high torque) that changes to a large gear spinning a small gear (high rotation speed / low torque) . Many time people who race scooters will try many different roller weight and clutch spring combinations to find the best performance out of the CVT. Stiffer clutch springs will take more rotation speed to open the clutch ramp and lighter rollers will close the variator ramp sooner....its all about roller & clutch spring balance. A perfect balance will give you the best acceleration and top speed possible, but that takes a lot of trial and error.....I just try to find the best roller weights to match the clutch spring that's already on the Riva, usually going for lighter rollers to give it better acceleration but not so light that it kills the top speed.

    How a CVT transmission works video:
  19. Juvenile Senior

    Juvenile Senior Been here awhile

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    Dear @Kevinforesthill, eihther I didn't understand your explanation, or you got it all rong.
    The rollers are actually pushing the sheaves on the input pulley together, making the gap narrower, forcing the belt to run on a bigger diameter the faster the pulley spinns. So at the beginning the ratio is low, and it gets higher (the diameter at the input increases, and the one at the clutch end decreases) as the revs increase.
    My point is, that the end ratio is given by the way that the sheave at the input pulley can travel. Once the sheave reached the end of the pulley, there is no change in the ratio anymore. From that point, only the RPM changes, the transmition ratio remains set.
    Now let's take my Riva at the original set up. It accelerates at a more or less stable RPM up to about 65 kmh. From that point, the vatiomatic spinns so fast, that the rollers push the pully togather, the sheave of the input is at the end of its way.
    If I now install lighter rollers, the engine would need to spin faster in to make the rollers push the CVT to the same ratio. The engine will spin faster all through the acceleration phase, untill the CVT reaches its final ratio. Once it got there, again, we are at the same ratio as we were in the original set up. Up from this point, only the RPM changes (with) the speed.
    Unless we install rollers that are so light, that the CVT cannot reach its end ratio before the engine hits its RPM-Limiter, at the top speed, and a good measure beneath that, the transmition ratio is and remains as in the original set up.
    Therefore as long as we don't go too wild with choosing our light rollers, the top speed should not be influenced.

    By the way, the same goes for too heavy rollers. If we install heavier ones, the end ratio would be reached at lower RPM and speed. But once we have reached that ratio, it is as if we were traveling at the (very same) top gear all the way from bottom RPM to the top speed. If we don't choose such Rollers that would stall the engine at the bottom RPM, there is no reason why we should reach a top speed any different than the original set-up!

    You hope my formulation is clear enough to understand my point
  20. Kevinforesthill

    Kevinforesthill Been here awhile

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    I understand what you are saying, but I believe that you are incorrect in assuming that with lighter (or heavier) rollers the CVT will "reach the same final ratio". The clutch spring will prevent that due to the rollers and clutch spring being out of balance. the rollers and clutch spring work in harmony and not independently from each other.....You will not reach the end of the sheave with a roller/spring imbalance. In order to reach the same final ratio the clutch spring would need to be changed also.

    You are correct though, I had my analogy backwards (now fixed).