My Yokomo story...Yokomo no 2 91 works...or is it?

[flustorm99]

So after getting my old Yokomo out of storage and giving it a light dustoff, I though hmmm these cars are fairly rare so maybe I should try and find some parts or a whole 2nd spare car for replacement bits...great idea...as I still really had not much of an idea of the timeline of these cars and the different mods etc I found a car in the UK that was listed as YZ10/91 so I had a look and won the bid...from the untrained eye it looked like it would be fine for parts...ANyway over came the car and I was excited and when I opened up the box I thought cool...problem was, I got a exactly what was listed, part yz10 part 91 and part 92..! so some of the parts would fir and a lot wouldn't ...anyway I gave it a quick clean up..put some lipos and a brushless engine in and away it went...seemed to run fine until until I stripped the spur on the TCS..yes it actually came with a TCS (I didn't know what that was back then) the spur was fairly worn anyway...little did I know what a bugger it would be to try and find a replacement! anyway that's when the 'other' cars came into the picture (see yokomo no 3 and 4..!..yes I had been sucked into the Yokomo trap and didn't even know it yet...!)

Anyway this is what I ended up with, as you can see...its a bit of everything...which was good I guess in the end..gave me an excuse to convince myself to 'get more'! You can see some of the good stuff it came with...drescher front arms,91 top deck, 92 shock towers (1 in carbon fibre) TCS and the rest was mostly YZ10 and a YR4 front bulkhead...

I had put the Suzuki hubs and JC wheels on as they cam with an older white set of JC wheels and standard 91 hubs

and here are some goodies to get it closer to a 91...although I now know these towers are 92....

so the transformation ..... turned out something like....

[flustorm99]

this....not 100% but a lot better then it was I think....only had YR4 bulkheads and all black ball cap ends, steering setup etc but I still think it came out ok. very solid in the front end now which is great. Enjoy and please feel free to tell me what is not standard 91..besides the shock towers, bulkheads, c hubs (93'), turnbuckles, (I do like these one though..heli ones I think?)

Sorry not the best pics...still gota sort that out...

[stickboy007]

It would appear that you have at least upgraded this one to a '92 Works spec, by which I mean the upper deck, lower deck, and shock towers (you already have the rear hubs). The upper and lower deck are the same between the 91 and 92, from what I've been able to tell, so it's really just a matter of the towers, rear hubs, and belt pitch. You clearly have other goodies on here, so it is of course not a stock '92 Works, but you do have all of the correct geometries for it.

Very nice work, btw. Nice and clean. I presume you got that purple motor mount from Hong Kong off of eBay? I just ordered two of those. They are exactly the same as the Suzuki motor mount, with the exception of the color (the Suzuki mount is blue). I am guessing that somebody decided to make a repro version of the Suzuki mount and anodize it in a different color. I plan on taking at least one of them and removing the anodizing to bring back the aluminum in its original color. I'll put that into my '91 Works. I have not started a thread on that one yet, as I am waiting on a response from Fibre-Lyte. They do not have any '91 Works parts in their catalog, but I offered to loan them mine to map them out...

[Coelacanth]

How do you like your Leopard Toro ESC & motor combo? I'm running the 12.0 version in my Optima Mid project and it's so smooth.

[flustorm99]

A 92' you say...hmmmm..so.very little difference between the 91 and 92 it seems. So whats the difference in the rear hub carriers? I cant make it out in the manual... I do know i had to put some spacers on the outer hinge pin to make it tight...also can u tell me how to tell the difference between alloy and magnesium bulkheads? I think the allow is heavier and doesnt polish as well? Also i ren the 3mm setup. After reading the issues they had in the day with the 2mm i didnt bother. Although there was a complete 2mm setup on fleabay the other day and i was tempted

As for the Leopard setup it goes like the clappers...its a 9T so its pretty quick for this car...i gear it down as one if my cars was popping mono's and was a bit to quick... Amazing what a couple teeth kn a pinion can do. I do get a little stuttering but thats due to the magnetic field in the car so i have read? Anyone else get this?

[aip47-2008]

A 92' you say...hmmmm..so.very little difference between the 91 and 92 it seems. So whats the difference in the rear hub carriers? I cant make it out in the manual... I do know i had to put some spacers on the outer hinge pin to make it tight...also can u tell me how to tell the difference between alloy and magnesium bulkheads? I think the allow is heavier and doesnt polish as well? Also i ren the 3mm setup. After reading the issues they had in the day with the 2mm i didnt bother. Although there was a complete 2mm setup on fleabay the other day and i was tempted.

Here are the 1991 rear carriers.

[flustorm99]

Ahah...thanks Aaron! Look like the 92 ones are a little more refined..

[stickboy007]

The cogging at low rpm in your motor has to do with it being a sensorless design. Sensored designs are able to "tell" the ESC what rotational phase the rotor is in, and therefore which set of coils on the stator to apply power to in order to make the rotor spin. In a sensorless design, the ESC is running "blind" and can end up cycling power between coils too quickly or too slowly. This means that the power applied to the stator coils is not in synch with how fast the rotor is turning. At high rpms, this is less of a problem, though.

[Coelacanth]

The cogging at low rpm in your motor has to do with it being a sensorless design. Sensored designs are able to "tell" the ESC what rotational phase the rotor is in, and therefore which set of coils on the stator to apply power to in order to make the rotor spin. In a sensorless design, the ESC is running "blind" and can end up cycling power between coils too quickly or too slowly. This means that the power applied to the stator coils is not in synch with how fast the rotor is turning. At high rpms, this is less of a problem, though.

Mine doesn't do that at all. It's smooth as silk throughout the throttle curve, and if you drive very slow. The same for the Bullistorm ESC & Tacon 11T motor in my Barney Optima; both are sensorless.

The one I'm having problems with (but I've been too lazy to swap out electronics yet) is the Castle Sidewinder ESC & SpeedPassion 17.5T motor in CYANide. I plan to yard out the Sidewinder because I've read there have been cogging issues with that ESC.

[flustorm99]

So with sensored stuff u dont get this? Better buy something better..like a reedy! So what about the magnetic field issue with recievers in the car? I have noticed noticed if i move it around it seems to be better? I also noticed it only seemed to start occuring, i think, when i flipped the car ?

[_timmy_]

Great looking car Flu. Not sure about the purple mount though, screams 'HPI' to me!!! Although it complements your pink spur.....

I have not started a thread on that one yet, as I am waiting on a response from Fibre-Lyte. They do not have any '91 Works parts in their catalog, but I offered to loan them mine to map them out...

I was thinking along the same lines, looks like you beat me too it, i've got a '91 chassis that's been drilled out all over, i was going to offer it up as a template.

[stickboy007]

Yeah...still waiting to hear back from them. I emailed them a few days ago and haven't heard anything yet. They're normally much quicker...

Correct, flustorm99, with a sensored system, you do not get any cogging, ever. Some sensorless systems can be fiddled with to result in low cogging, but you will never see a high end system that is sensorless, and for good reason. Even if you get low to zero cogging on a sensorless system, it will never be as smooth as a sensored system, especially at low revs. If you're just bashing around, it doesn't matter, but if you want to race 1/10 buggy, you'll need good throttle control, which means you'll need a sensored system.

As for the receivers, older AM, FM, and PCM receivers were more susceptible to noise than modern spread spectrum receivers. The convention was always to place the receiver as far away from the motor as possible, to minimize exposure to noise. Also, if you have a carbon fiber chassis, this can interfere with the receiver (and especially a transponder), and so where you mount the receiver can matter. I haven't noticed this problem with spread spectrum receivers (i.e., 2.4GHz), but if you take any receiver and bury it under a bunch of crap, then of course your transmitter signal will have to travel through more "stuff" to get to the antenna. Or even if the antenna runs to the outside of the body through an antenna tube, if you're wrapping it around a bunch of stuff on the chassis, then there could be interference. Again, though, I haven't had any problems with my receivers (I run Spektrum 2.4GHz receivers with a Spektrum module on my Sanwa Exzes Plus). The first thing you should do, though, if you have any receiver problems, is to put a capacitor on one of the available receiver ports (e.g., the aux or bind port). If that doesn't solve the problem, then you have to check your ESC. It should almost never be the receiver's problem with modern receivers, so the next thing down the list is the ESC and whether it is supplying continuous power to your receiver. If the BEC circuitry is poorly designed or burned out on your ESC, you can end up having power dips which "brown out" your receiver. Most BEC circuits are linear circuits, meaning it just uses a resistor to drop your battery voltage (7.4v) down to the receiver voltage (5v). This is very cheap and effective, but very wasteful since you're just throwing current out the window and generating heat across the resistor. Not a problem most of the time, but high amp draw servos, such as those used in 4x4 SC or 1:8 eBuggy, will overstress the BEC and can burn it out. Very unlikely to have this problem in a 1:10 buggy, though, since the servos used for this application do not draw as much current. Or maybe your BEC is fine, but there is a poor connection between the two cells in your lipo pack, occasionally causing it to go from a 2s output voltage (7.4v) to a 1s output voltage (3.7v). I've had that happen on occasion with my older lipo packs that have been over-abused.

[flustorm99]

Wow...thanks...my wite for the antenna out if the reciever is tiny..maybe 4cm long? Its a spectrum as well...i guess these days u dont need long wire anymore...i dont use a antenna tube as it would only run about 1cm up the tube....

Not sure if its cogging as the car doesnt move sometimes will just twitch when i have the throttle on..steering is fine...i think something must happened when i flipped the car as i have four of these setups and only on the two cars rhat flipped did it start occuring?? Wierd...anyway they are cheap so i guess u get wot u pay for...

[flustorm99]

Hey stickboy your a legend maaaate!! Turned out to be one of the battery terminals not connecting properly, fixed it up and now it runs sweeeeeeeeet! I never would have though it could be that?! Anyway thanks for your powers if deduction...also i am glad thats all it was...

[stickboy007]

More often than not, it is something simple