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HPI R40 Nitro Car Forum

Old 05-09-2005, 11:04 AM
  #6511  
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Default Re: cclutch

Originally posted by athrun
I think i may have found the problem with my clutch.I was comapring it to a mugen clutch and found that the pins on the flywheel stick through the clutch about .5mm.Will this cause the clutch not to adjust right.If so what is the solution.
Take your flywheel off and tap the pins down with a hammer. They go right down with light tapping. Place the flywheel on an old peice of wood because the pin will poke out the back just a pit when you are done.
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Old 05-09-2005, 11:07 AM
  #6512  
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Ok im stripping mine as we speak. I found a spring shooting out the side so I figured it was time to take a look. I dont know how the guy before me had his springs connected but they came apart easy. I know how to make sure they never come off.

Also my pins stick out about the exact same...so this isnt good you guys are saying?
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Old 05-09-2005, 01:12 PM
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not good at all if the pins are sticking out you really should either tap em with a hammer so they don't stick out past the clutch shoe or grind em down with a dremal.

since the pins stick out a bit they tend to rub the inside of the clutch bell causeing it to heat up a bit shortening the life of the clutch for one and it mkes it much harder to sort out the shims if you have no previous experiance with a centax clutch.

Before I ground mine down I was haveing a hell of a time getting it to work properly, now it works like a dream, I have almost instant engagement before it would rev fairly high then takeoff so hard I would have to steer it straight now it launches in a straight line.
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Old 05-09-2005, 02:11 PM
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Awesome. Totally reworked it and tapped em down. I noticed the previous owner is also not using the o-ring Ill have to get that later.

You guys all say use this piece right. Im talking about the o-ring that lays on top of the clutch spring.

Redid the spring , cleaned everything fully with simple green then alcohol. Went back to the 3 shim setup. Pins are now behind the clutch shoe and things are feeling great.

That odd bearing came apart....luckily had a spare. Clutch feels and sounds so much better now. I cant wait to start this sucker up tonight.

Also yeah thats how my car was I just thought it was these type of clutch, LOL!!!!! I would rev ultra high, then snap it would take off like a rocket. Also yeah there was a pretty nasty line on the inside of the bell housing. I just went ahead and use some aluminum polish to smooth it up and clean the surface.

Its perfect now! Cant wait!!! I love this forum.
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Old 05-09-2005, 02:49 PM
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I take it you mean part # 87099 seen HERE

I belive that is there to ensure even pressure from the clutch weights to the clutch shoe.

As for the spring I've heard of people takeing it off and saying that they see no difference in the clutch engagement others say it's night and day. Me I just leave it on.

Last edited by regg151; 05-09-2005 at 03:31 PM.
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Old 05-09-2005, 03:14 PM
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Weird. Completely disregard that. I was in the sun when reassembling this guy. I could have sworn there was a rubber o-ring that sits on top of the spring.

Seems everything is assembled correctly then, no missing parts.

But I did remember someone saying they do omit something in assembly. Im guessing the 87099 is the part. I would figure that thing is pretty important in keeping the spring in?
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Old 05-09-2005, 03:22 PM
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the spring is put on the 4 clutch shoes to prevent them from sticking to the upper single clutch shoe base. there isn't much need for this, as I haven't found the shoes to be stuck, ever.
removing the spring allows for harder launches, with no resistance for the shoes to fly outward and engage.
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Old 05-09-2005, 03:39 PM
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Yea what he said
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Old 05-09-2005, 03:40 PM
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Default What do you think?

What brought on all these clutch issues was that this weekend if i had to slow to much or bumped a board the engine would stall.Put it back on the starter box and it would fire no problem.Disassembled the clutch and found that the little spring had broken.Also the engine started overheating.Does this sound like the clutch was sticking?The few laps i got to run the car was handling very well.The bumping the wall and the car dying drove me crazy.Maybe got 10 laps for the day.Help!!!!!!!!!!
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Old 05-09-2005, 03:46 PM
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sounds like the spring my have gotten lodged between the plates causing the clutch to engage erraticly.
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Old 05-09-2005, 03:56 PM
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Originally posted by JAG Racing

Why arent you running foams since the surface is asphault? Just curious. Seems to me you would be much better off running 40/42 combo or even 40/40 (Front/Rear).
Short answer is that was what was in my pit box, besides the kit tires, that is.

I can't run 30mms in the rear because they hit my header under compression. "Your header?!" I hear you say, yes my header because yours truly decided it would be nice to save a bit of $ on a Nitro Star .12 R even though it was a side exhaust. I had to hunt for the right header, shim the engine mount up, and then when I finally get to the track I find out that 30mm tires hit the header when the suspension is even a little bit compressed.

In the meantime I blew some cash on a Spektrum system, so it's going to be a while before I can afford a new motor....

Thanks for the tips!, I will check it out tonight.
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Old 05-09-2005, 04:09 PM
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Originally posted by Artificial-I

But I did remember someone saying they do omit something in assembly. Im guessing the 87099 is the part. I would figure that thing is pretty important in keeping the spring in?
It should be 87097 (the o-spring thingy that goes in the grooves of the clutch shoes). I have left it out of my assembly. I've also heard of people having problems breaking that little spring. So I figured I'd save myself the trouble. It was suggested to me by my LHS that I instead run a heavier main spring (87103), but I haven't tried that yet. If anything it's engaging a little late.

I think it also depends on your mill. If you've got a lot of power and you're going to leave the o-spring out, you'll have to run a heavier spring. I think mine is pretty mild as motors go, so I stay with the stock main spring for now with no o-spring.
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Old 05-09-2005, 04:16 PM
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Yeah I figured out what it was, when I was in the sun from a far the o-spring looks like an o-ring . I thought to myself odd oh well and continued.

But im really glad I got the help guys I cant wait to see how this thing engages. Funny thing too the front face of the 87098 part looked pretty new. Now its going to actually get used now.
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Old 05-09-2005, 06:05 PM
  #6524  
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hey guys,
I finally completly finished putting my r40 back together, I started it up and immediately it starts reviing to what would be about 1/4 throttle. Im thinking its the clutch. I took it apart and Im going to see whats up with it. I know I need a new spring so far. I went to adjust the engageing time with that 1.5mm set screw behind the 2nd pinion and I stripped it!! Whgat does that goe to , the clutch nut? Also, how tight should I put the clutch nut onto the crank shaft?? Once I figure out these things, I will certainly have more questions.

Thanks

Edit: How tight is that clutch spring supposed to be that goes around the clutch weights?
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Old 05-09-2005, 06:51 PM
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Sounds like the idle screw is high or the servo trim is incorrectly set or the servo horn is on wrong.

Did you check the carb gap when closed, shouldnt be much more than 1mm.
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