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Post by andyreeves on Oct 20, 2006 7:09:29 GMT
Last night i have just finished building my XRS and it is all ready for the first mid west regional at coventry on sunday. Had a little go in the road last night to make sure everything was ok and all i can say is i am now really looking forward to racing it. This is my first pred so was a bit of an expirence to build.
All that can be said is bring on the weekend ;D
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Post by alfonzo on Oct 20, 2006 10:07:39 GMT
Good luck and keep contributing to this forum, knowledge is power!  |
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Post by andyreeves on Oct 22, 2006 19:54:00 GMT
Thought i would post after the first meeting. well what an expirence. car was awsome in practice may be a little tail happy but was still pleased. Then round 1 on lap 2 stripped the spur. I managed to get a spare of Tom ( cheers Tom) and then it took me a little while to get it back up and running properly (like to rounds  ) so car was ready for round 4 when on the 4th lap stripped another spur  so that was it time to pack up. What after talking to a few people we think was happening was when i was lading on the back end of one of the jumps the chassis was flexing and catching the motor mount brace as on mine it runs very close. So the brace will be going into work and having a flat machined onto it ;D hopefully that will solve the problem. next run is in 3 weeks time at kiddy. |
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Post by chris burgess on Oct 25, 2006 11:00:53 GMT
that sounds a little unlikely considering the positioning of the spur and the motor mount - i don't see how it could flex in that area enough to strip a spur gear.
are you sure it wasn't the motor moving a little away from the spur gear, and then stripping it? This is much more likely, and it is a recognised "problemette" with the predator.
what you need to do is rough up the facing edges of the motor mount and clamp, and then when you install the motor tighten it up as much as you dare - and then a little tiny bit more! I actually tighten my motor in with another allen key through the hole at the top of the main allen key to get a little more leverage!
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bigboss
Full Member
preds rule,the others are too slow!
Posts: 196
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Post by bigboss on Oct 25, 2006 15:45:12 GMT
Yeah man What he said.
Check out the "fixes" on this forum, concerning the motor coming loose. It has happened to most of us so there are a few fixes for it.
Wish you luck & patience.
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Post by andyreeves on Oct 25, 2006 20:10:27 GMT
ok thanks for the advice. i am still going to modfy the support bracket just for my on pice of mind. The funny this was that both spur gears went at exactly the same part of the race track which was when i had the car landing back end first, hence why i think it might be ue to chassis flex. or is that jut a coincedence  |
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Post by chris burgess on Oct 26, 2006 8:34:49 GMT
i see why you would think chassis flex, but it's because it's after a jump where the car is landing on its back-end that makes me think it is the motor moving!
let us know how you get on!
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bigboss
Full Member
preds rule,the others are too slow!
Posts: 196
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Post by bigboss on Oct 26, 2006 18:40:02 GMT
"Tail-slap" I think it's called, when the rear of the car hits the ground as it lands from a jump or after a set of bumps, that's what's happening to your car, I believe. this is what moves the motor(&pinion) out of alignment with the spur gear,and strips it. Replace the original button head(2mm) screw (on the motor clamp) with a cap head(2.5mm) that's a little longer, and really tighten it down. the numbers in brackets are the size of Allen driver bit to tighten the screws with.
Or you could remove the clamp screw AND the bottom screw all together and use one very long bolt (counter sunk of course) all the way from the underside of the chassis to the top of the motor clamp, and use a nylock nut on top of the clamp to hold the motor mounting disk in place. With this system however do not over tighten or you might snap the bolt or strip the nut of it's threads.
good luck bubba.
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Post by andyreeves on Oct 27, 2006 16:52:16 GMT
ok i will re-try all these thank wou for all the help. on one other point would a slightly bent main shaft cause this to? as i have put another new spur on tonight and put all the front back on and when i rotate the centre shaft i can feel some binding. so i looked directly down and could see the saft moving slightly. so perhaps that could be a problem to.
What do the epirenced pred racers think this could also help to this?
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Post by chris burgess on Oct 27, 2006 19:36:14 GMT
hi andy - if the centre shaft is only slightly out of "true" it should not cause this issue, however if it is considerably out of kilter, then it could cause problems.
Approximately how much does the shaft move, and where abouts is the movement more noticeable?
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bigboss
Full Member
preds rule,the others are too slow!
Posts: 196
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Post by bigboss on Oct 27, 2006 19:54:07 GMT
Err, Andy binding is a no no.
The only thing I can think of is the diff & pinion gears not meshing correctly, that said, If you replaced the spur gear, that's where i would start. Retrace your steps & find the binding culprits.
Looking at my own car I see that the shaft is no true, but nothing to worry about, just a slight wobble as the shaft turns. No binding on mine.
Let us know what you find on yours.
Oh yeah who is WOU?
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Post by chris burgess on Oct 27, 2006 19:58:15 GMT
oh yea - missed the binding part out as cliff said, definate no no that - the X10 transmission, without a pinion attached to the motor is the freeest and smoothest one out there. |
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Post by andyreeves on Oct 30, 2006 6:54:03 GMT
Thanks for all the help guy's. The car over the next 2 nights is going to be completely re built and hopefully i will be able to source the problem. Def agree with the smoothness of the transmission i was very impressed when i first built the car.
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Post by andyreeves on Dec 3, 2006 21:12:38 GMT
just thought i'd add another comment. After a few more teathing problems today i was down at Tiverton and finally managed to run a full day without any problems. The car punched out of the corners and felt awsum. (this was also my first trip to tiverton) Think i had the car slightly to stiff as the front wanted to push alot but iwas running kit set up and didn't really want to change much as not really running the car that much.
The one slight problem i do have is that the rear diff always sounds a bit noisy even when its been re-build does anyone have some ideas how i can cure this?
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Post by chris burgess on Dec 4, 2006 9:36:34 GMT
if you mean the diff sounds noisy when you spin it "on the bench" then it is likely that there is some grit or dirt in it, or there may be some scratching on the surface of the diff rings.
if you mean the diff sounds rough when you are driving the car, then I would suggest that you haven't spaced the diff wheel/pinion close enough, so you should add another shim and see how it sounds.
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) so car was ready for round 4 when on the 4th lap stripped another spur 
so that was it time to pack up. What after talking to a few people we think was happening was when i was lading on the back end of one of the jumps the chassis was flexing and catching the motor mount brace as on mine it runs very close. So the brace will be going into work and having a flat machined onto it ;D hopefully that will solve the problem. next run is in 3 weeks time at kiddy.
