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View Full Version : F1 diffing out...


JuniorWKR
2009.05.12, 09:00 AM
http://minizracer.com/forums/attachment.php?attachmentid=27224&stc=1&d=1242136918

im running the kyosho f1 diff with 64 pitch.. the diff is set for when the car is going straight but when i go around the infeild it diffs out... even iff i lock the diff... i guess it may be part to the chassis lifting also... any advice to aid in the repair of this problem would be greatly appreciated...

MantisMMA
2009.05.12, 09:06 AM
have you shimmed the right side of the motor mount? also locking the diff will make it worse, i have found that running the diff as loose as possible works best, mine will slip for about 6" from a dead start.

MantisMMA
2009.05.12, 09:07 AM
tires make a HUGE difference on F1's and i can only run the k20 rears and k30 fronts anything else gives me problems.

JuniorWKR
2009.05.12, 09:08 AM
yes i did shim so that it doesnt spin out... but no matter what i have tried it diffs out around the infeild and almost comes to a stop then kicks back in once straightened out...

JuniorWKR
2009.05.12, 09:09 AM
tires make a HUGE difference on F1's and i can only run the k20 rears and k30 fronts anything else gives me problems.

i run k20 rears and k40 fronts... the 30s had way to much bite

hrdrvr
2009.05.12, 09:57 AM
What do you mean by "diffing out"? Do you just mean the diff is unloading?

JuniorWKR
2009.05.12, 10:11 AM
not to sure to be quite honest... when i go through the infeild and around the tight turns... i guess you can say halfway through the turn it unloads cause the car slows down and then once straight it kick back in... but it doesnt do that froma dead stop...

MantisMMA
2009.05.12, 10:12 AM
^^^^ Yea, i dont really understand that either....it stops when straight????? maybe you have the left side spacer on the shaft too tight, you should have some axle play.

JuniorWKR
2009.05.12, 10:16 AM
me either... i never had this problem before... do you think its the 64 pitch on a kyosho diff... i shaved everything down as need and the diff is super smooth... i will have to check the spacer though... do you think it could be to lose?

hrdrvr
2009.05.12, 10:40 AM
Make sure the shaft of the motor is not moving so much that it is binding the pinion and spur together. Ive had that happen on cars where it would really hinder power coming out of a turn....never so much it would stop the car, but still a spot to look. You should be able to power the car up lifted up, then shift it side to side. If you hear a difference in sound, then there is some friction coming from the travleing motor shaft. Youll either have to adjust the pinion, the motor shaft, or change the motor if thats the case. Ive got some stock motors with almost 4mm play on the shaft :eek:

JuniorWKR
2009.05.12, 11:01 AM
yea i gotta figure this out because i spent alot of time on the car and it handles beautifully bisides the diff not working... if i can get this sorted out it will be a very competitve car for this upcoming pn regional race at our LHS...

MantisMMA
2009.05.12, 11:40 AM
last week i converted one of my f1's to 64p and the diff did not work right either, it felt smooth but slipped alot and after about an hour of messing with it i discovered that the spur gear had a casting "nipple" on it where the diff balls are!!! so i shaved it off and it worked perfect. this may be your problem. what happens is that one side of the diff is not working properly and makes the opposite side drive which can cause it to pull to one side! sorry i didnt think of it earlier but thats probably the issue. i will be at the NJ event so if you dont fix it by then i will help ya!

JuniorWKR
2009.05.12, 12:04 PM
last week i converted one of my f1's to 64p and the diff did not work right either, it felt smooth but slipped alot and after about an hour of messing with it i discovered that the spur gear had a casting "nipple" on it where the diff balls are!!! so i shaved it off and it worked perfect. this may be your problem. what happens is that one side of the diff is not working properly and makes the opposite side drive which can cause it to pull to one side! sorry i didnt think of it earlier but thats probably the issue. i will be at the NJ event so if you dont fix it by then i will help ya!

yes i believe i shaved that off... but if not fixed i will definitly take you up on ur offer, thank you...

MantisMMA
2009.05.12, 03:28 PM
we need to push for an f1 modified class! wonder what the first step would be? what motor do you run in yours?

MantisMMA
2009.05.12, 03:34 PM
what diff rings are you using? have you done a conversion before? you realize that the spur gear ends up being as thin as the center part, there can no longer be a lip on the spur gear at all. just for kicks try putting some mr02 diff rings on it.

JuniorWKR
2009.05.12, 03:40 PM
i will definitly try the 02 discs... i might just go back to stock if i cant get it to work...

i would love a F1 mod class... or we can call it semi mod... a spec motor would be awsome... right now im running a atomic stock motor... good torque, decent top end... never gets hot... a pn speedy ad would be a awsome hand out motor for that class... that motor wit silver brushes would rock...

70t is definitly way to slow for that chassis...

MantisMMA
2009.05.12, 03:45 PM
im runnin a stock r with the silver brushes turned 90 degrees and it is INSANE!! thats a good idea, an f1 spec motor hmmm, im gonna try a 35t this week and see how that feels! how about a pic of the spur gear, that may clear up a lot of guessing.

EMU
2009.05.12, 04:06 PM
You definitely have to shave down the lip on the spur... so that it does not rub the right wheel.

I think Speedy 07 is a good speed for the F1. 70t is too slow, but then the focus is maintaining as much momentum as you can. Definitely not how you drive a real F1...

JuniorWKR
2009.05.13, 09:13 AM
i will try to take some good pics tonite and post tomorow... i really want to get this chassis working good... i like this class alot and want the car to be smooth..

herman
2009.10.06, 09:45 PM
hmm... did you get your diff to work? what did you do?