ta04evah

iTrader: (2)

Somewhat of an update on the issue I am experiencing.
After purchasing a new set of gears from the same manufacturer that I had some initial success from, the issue of a noisy gear mesh, binding and the car sometimes slowing down intermittently still remains.

After trying different motors, motor mounts, gears, bearings, lay shaft bulk heads, spur gears, pinion gears, checking shims, checking clearances between moving & static parts and belt tension I have all but given up on this car.
I have also swapped out every electronic component such as sensor cables, receivers and esc's.

It has been a very frustrating, dejecting and confidence sapping experience with this car and I doubt that I would even consider purchasing a 3 Racing car again.
Whilst I don't consider myself to be a RC Guru, I do consider myself experienced enough to track down and resolve problems on a car, which I have done so in the past on other brands/models.

I'm not trying to put the car down here, I'm sharing my experience with it so far. The car does handle well, but when there's something physically slowing it down it makes it very hard to be competitive with the car.
I have left the car with the friend who generously helped me out with parts and building/tuning knowledge to have one last try to fix the issue.
However I have invested too much financially, mentally & emotionally and I am prepared to cut my losses and let it go if it cant be fixed.

Thanks to everyone for their advice, help and suggestions to try and get the issue sorted out and I hope no one has the experience I have been through regardless of what brand/model of car they chose to race/drive.

Cheers
Rob.

6376vette

Just an off the wall thought. Do you have the aluminium hexes for the wheels? The plastic ones can wear and put pressure on the wheel bearings causing excessive drag and possible bearing failure.

If you want you are welcome to ship the car to me. I race at hotshots in marietta ga with a bunch of guys who run the sakura without problem. Fauxmako races there as well. I'm sure we can figure out what is wrong. I can only assure you that the sakura is a great car and you will enjoy it as soon as we get this issue solved. I have experience with 5 of these cars and I know fauxmako has at least 3.

If your interested in letting me and the hotshots crew check the car over shoot me a pm.

6376vette

Just noticed you are in Australia. Shipping may be expensive. The offer is still there if you are interested. Another option may be to post a video. One of a complete 360 view of the chassis another of the car experiencing the problem under power.

FauxMako

You need to break things down into sections to isolate all the individual sections to identify where the problem is.

As you take things apart pay attention and look for bent screws -- they'll feel weird when you are removing them. Locktite all metal to metal points as you are putting things back together -- blue locktite. Depending on what you've upgraded which screws need locktite varies. Make sure the chassis isn't tweaked.

I'd start by taking the belts off and work on the motor mount, layshaft mount and pinion to spur mesh. Take the motor mount off and make sure it's not bent -- lay it on a flat board and make sure it doesn't rock in any direction. Make sure the root/foot is properly attached to the motor mount. Make sure the motor mount is properly connected to the chassis. Depending on which mount you have it may also connect to the layshaft mount. Mount the motor and make sure it's not touching the chassis, that it doesn't move and is properly secured. Put things back together (minus the belts and pinion) and rotate the spur and make sure that there is no binding there. Check/clean the layshaft bearings. Add the pinion and set mesh. Make sure there are no bind points between the spur and pinion. I've had bad luck with 3Racing spurs, I'd definitely recommend another brand of gears.

Take the dogbones/axles out and add the belts back in one at a time. Again look for binding and shim things out to get everything lined up properly. Take the bulkheads off and make sure none of them are bent (and none of the screws are bent). Check the diff bearings and that all the cams are properly situated. Check the diffs themselves -- they shouldn't feel crunchy and should have the same resistance all the time. Rebuild them if necessary -- 3Racing has a YouTube video about diff building. Again look and listen for anything out of the ordinary. Make sure that the diff cams can't rotate on their own -- I had one of the nubs on an alloy bulkhead sheer off and that cam could rotate even though the bulkhead cover was securely attached.

Add axles/dogbones back to one end. Check the bearings at each upright. Make sure your hexes aren't rubbing the uprights -- the stock hexes are soft and will start to deform almost immediately and the alloy ones are cheap upgrades.

Pull one belt and put the other one on and do the same thing for the other end.

Put both belts on and check again.

Compare your shocks. They should be the same length compressed and extended at each end of the car. Make sure they extend/compress freely. Listen for air flow and rebuild any that are noisy. Make sure they are all full of oil and have the same amount of rebound. Check to make sure you have the same springs on both shocks at the same end -- don't assume 3Racing didn't make a mistake or you didn't get springs mixed up. I found after one rebuild that I was running my front shocks on the left side of the car and my rear shocks on the right side of the car and I was having some strange issues.

Add the wheels and make sure a wheel isn't rubbing on the upright. Again the stock hexes are soft. Some wheels have deeper hex holes and require thicker hexes or spacers between the wheel and the hex. Make sure the tire is still properly attached to the wheel. Make sure that you don't have a cracked wheel or deformed hex.

Look for rub marks on the inside of the body and/or run a few laps without the body to ensure you don't have a body rub. Add the body and look/listen for body drag spots.

I've got 3 Zeros and there are a half dozen others at Hot Shot as mentioned and they are competitive chassis. There is no reason why you should need to switch brands. It's a matter of isolating elements until you can locate the problem.

I'd also recommend going back to a setup that's as close as possible to what is in the manual. Then start tuning again. I've found that I'll start chasing a problem and get so far away from stock that I'm sure I've gone past a good setup and am out in left field somewhere.

Make one change at a time and isolate areas to eliminate them as possible problems and you'll figure it out.

Wow, that turned into a wall of text.

Anthias

Hi.

I have almost the same setup as deadman. But i have 30 oil both front and rear. I have tried same springsetup, i have also tried even softer. 6 f 6.5 r. But the car still spinn out in tight turns when off power. Should I go harder front or rear springs? Or should I go stock springs front and rear?

I changed tires from sorex 28 to foam tires. Now it is ok to drive, but still a bit light in the rear.

What should be the first ting to adjust?

ta04evah

iTrader: (2)

6376vette & FauxMako,

My Sakura is more a Zero, than a Zero S as a friend gave me all the alloy & cf parts to upgrade it, there was a couple of parts missing but I bought them new to complete the car. The only S components left on the car is the lower suspension arms, rear hub carriers, front C blocks, steering knuckles & gear diffs. I also have the alloy wheel hexes installed.

If I was in the US I would gladly take you up on your kind offer, but I think the cost of the shipping would add up to almost the cost of a new Zero S.

I have done all the steps you have mentioned in your posts. The drive train is extremely smooth and free running when turned over by hand and there is no sign of binding at all. It's because of this I have been pulling my hair out trying to track the problem down.
As I mentioned in my previous post, I have left the car with a friend who is more experienced in the Zero than I am to try and find out why it is happening.

I also agree that is a good car to drive as it handles very well, but this issue has all but turned me off it. It's at the stage now that if my friend cant find and/or resolve the issue, then I will be looking for a different car. My other car which is a back up car, is on it's last legs and will be too costly to replace all the parts that need replacing, so there is a degree of urgency to get the Zero going or start looking at a different car.

Again thanks for all your help and suggestions, I will let you know the outcome be it a positive or negative one.

Cheers
Rob.

FauxMako

At this point my only suggestion/advice is this: Plastic parts flex and give and return to their normal shape unless pushed to the breaking point. Alloy parts are stronger, but once they bend they stay bent. Don't assume that those alloy parts are all still in the same shape that they came in.

The main reason I have 3 Zeros is that you start with a $120 chassis and can upgrade or replace parts at your own pace. 2 of my Zeros are like yours, pretty much fully upgraded, but as I said above, don't assume that just because a part is alloy or CF that it can't be the cause of the problem.

ta04evah

iTrader: (2)

You have a good point there, I was even considering trying the lower deck that came with the kit, I would have tried the upper deck but I loaned that to someone.
I was even contemplating on buying another S kit, build it to out of the box spec and then try adding the alloy & cf parts one by one. But as before, I'm not willing to invest a great amount of $ & time unless I'm absolutely sure that will fix the problem, as I'd rather put the $120 towards a different car.

Cheers
Rob.

6376vette

Go with less rear droop first. try 2mm. Next try harder front springs then try thicker front shock oil. 30 should work but but it could be a touch light. 35 or 40 may feel better. You could also add a degree of rear camber.

6376vette

I just went back and reread some of your posts. are you still using a tamiya spur? If so are you using a tamiya pinion? Tamiya uses a metric pitch to their gears. if you use a standard pinion and a metric spur they will mesh together but it will bind and sound like hell

jdeadman

iTrader: (41)

I just did some testing on our tight track and I removed the Sway bars and went 5.5 in front and 6.5 Springs rear with 50wt in front 45 rear and it was much better. I have the track width at the front of 190mm and rear 188.

Those changes changed the car but the only Issue I have now is the right edge of the chassis scrapes the carpet during the fast right hander but it doesent upset the car yet

Anthias

I changed from 6 to 5,75 to 5,5 front spring today, still 6,5 rear. I feel it handles a bit better around the corners. I also changed rear camber from 1,5 to 2.

It is better, but still I sometimes get a full spinnout entering turns at off power...

Is it to little or to much front grip/weight I have?

6376vette

Even up your track width. a thinner rear will cause it to be more agile but more unstable. You shouldn't have to remove the sway bars to handle properly but at least its driveable while you continue to tune.

I was just discussing chassis rub with a high level racer. Its not a bad thing to have. it keeps the car from traction rolling. Just keep the chassis clean. As the rubber the chassis picks up and accumulates it can start to cause it to grip the racing surface instead of gliding over it.

buckeye dan

iTrader: (11)

just bought second zero for new usgt class at our track in fort wayne. classes are really growing there.they will be holding a national usvta race there
March1-3... come on out and join the fun. right we are working on live rc coverage working out the bugs it says we are brocrasting but the track name does not show up at live rc web site. any ideas ?

6376vette

You are transferring too much weight to the nose and the rear gets light and loose. the rear droop reduction will help a lot. it helps to keep the weight on the rear. thicker oil will slow weight transfer while stiffer springs help to try and push the weight back towards the rear.