HPI Savage 25 - anybody have one?

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HPI Savage 25 - anybody have one?

Post by Bob Tenwick »

Just got one for Christmas. Having problems keeping it idling through the first tank to break it in. Throttle linkage seems sticky. Already wondering if I need this in my life... :? :lol:

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Post by Winston Cup »

Yep when they're rich for break in it's hard to idle them, especially when it's cold out, which is probably your biggest problem right now. You can use a hair dryer to get the carb warmed up at first. For breaking in I setup a fan, prop it up on the bench and set the idle just a tad high for a tank or two, then you can tune it in leaner. While it's sitting there breaking in just every once in a while go over to it and blurp the throttle to stretch out the rod a bit. Don't miss the fan part :o

Are there two or three carb adjustments on the HPI?

Welcome to the world of nitro motors Bob. You think women are touchy, you ain't seen nothing yet buddy. The difference is, these you can eventually figure out. :wink:
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Post by Goodwrench3 »

Hey Bob I hear ya I just got one last Sunday and I am doing the break in this weekend on the second tank of fuel I had trouble getting it started too. I had it flooded so I had to pinch the fuel line off to get it to start then ran it on sreet like the book says and noticed it kept stalling. I give it full throtle and let off every once in awhile it would stall, got to the third tank and seems to be better closer to the end of fuel run but still seems really rich maybe Monday I will get to forth tank hopefuly. If any one knows what tuning we may have to do after break in to get carb just right would be lots of help!

Thanks
Ken

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Post by Greg Hall »

Bob, just as Guy said, you will have a bear of a time keeping it running while the mixture is that rich. I have done the same kind of thing as Guy for breaking it in except for a couple of differences:

The engine needs a light load to help proper break-in. I made a load stand that connected a roller drum with a belt drive to a small fan from a track stand for a bicycle, that way there was both flywheel weight and resistance.

You also need to control the amount of air from your fan across the cylinder. Use a pyrometer to make sure you are not cooling it too much. I also suggest using a small deflector to shroud the back side of the cylinder so that you get even air flow around it. If you don't want to go to that trouble, just make sure the fan is blowing onto the exhaust side.
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Post by Winston Cup »

One more thing Bob. If it feels like it's locking up when you try to pull start it, it's hydro-locking from being way too rich, happens a lot when breakin setting are used so just pull the plug and let the pressure off and turn the main needle down a bit. Also keep an eye on the tiny wire in the plug. If it's shinney it's ok, if it's dull it's likely burnt and you need to change it cause it won't stay fired after you remove the ignitor.

Heck just send me the dang thing and I'll break it in for ya. Then I'll give it the full Chrest Terminal Velocity Certification Test free of charge. And if you act right now, I'll include a special bonus video of the CTV test in the basket right along with your truck. Shipping not included.
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Post by Bob Tenwick »

I know it's running rich 'cause I'm literally dripping oil out the exhaust. I start it no problem, my biggest problem so far is getting the thing to idle.

It almost acts like it has a vacuum leak. I'll have it at a idle like the book suggests with the tires barely turning and the idle speed will start to jump around, sometimes revving uncontrollably. The throttle spring has zero tension when the throttle is closed, this can't be right, can it? It's relying on the linkage from the servo to keep the throttle closed.

It seems to me I have two problems; a possible vac. leak and a weak throttle return spring, but I hate to start messing with something that ain't broke yet. Than again it might just be the spring, but it's a factory deal that's hooked up right, so I almost think it's supposed to be that way.

It's got a electric starter instead of a pull cord. Very cool. The thing looks pretty welll engineered with the exception of the throttle linkage. Plastic parts that seem to flex too much.

What's the fan for, to cool the head during break-in?

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Post by Goodwrench3 »

Hey Bob I had and am having the same problems. I found to get it started I had to place it on the bench on a block of wood with tires off and use the throttle linkage by hand to give it a little throttle to start it but then have to move linkage around little after running. It gets frustrating but once its warmed up it runs on its own and ideals better.
Hope this helps. Good luck I am in the same boat as you. The book should give more details for the beginners.

Ken

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Post by Winston Cup »

There really is no throttle return spring to speak of, at least not on any I have had, it's too hard on the servos and burns them out, the servo holds it shut. Now maybe this is something on the HPI, I never had an HPI so I can't vouch for that. One thing to look at as far the the sudden reving. Does the servo actually move and open the throttle when it does this? You should have the cars servos turned off if your bench running it because otherwise it'll get stray signals if the remote is turned off and the cars servos are turned on. The fan is to cool it as you run it on the bench. try backing off the main a tiny bit since it's dumping out the exhaust, a little spitting is normal for breakin though.

Give me a call later and I'll help you out with some tips.
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Post by Bob Tenwick »

OK, here's where I'm at. I got it to run through the first tank by messing with the low speed mixure screw. (more on that in a sec.) I ran two tanks through it on the street like the book says, 1/2 throttle, coast, 1/2 throttle, coast, ect., ad nauseum, forever and ever. So far so good.

The problem is the book says the low speed screw should be 3 turns out from the bottom and mine only runs if it's backed out like 7-8. I haven't counted but it's a whole bunch more than 3, which is rich anyway for break in.

this brings me back to the vacuum leak theory... thoughts?

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Post by Winston Cup »

Well that's why I break it in on the bench. Just fire it up and leave it. The books way of breaking it in is a pain and trust me, my way has the exact same result and zero chance for error too. Takes me two tanks and a couple of beers is all. First Bob you gotta go back and answer my questions, then I can help you. The first step in tuning is the high speed, or main needle. Do this in a parking lot so you can run it at speed. Then once that's set correctly you can set the low speed. Right now you have the low speed making up for the high speed. One more thing, nitro evaps and gums up like nothing you've ever seen. If you have run the car without running it dry and then let it sit for a day or so, chances are the carb is gummed up. After run oil is a must.
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Post by Greg Hall »

Hey Bob,

I bet that I can fab up some mounts and slap a small block Chevy on there if you can't get that thing running right!

Otherwise, we might have to spend a couple of hours in my trailer getting it bench tuned this weekend.
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KX 100 My 11 year old son's
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Post by Bob Tenwick »

Guy Chrest wrote: First Bob you gotta go back and answer my questions, then I can help you.
Does the servo actually move and open the throttle when it does this?

The idle surges went away with the LSN adjustment, but I wonder if I overcompensated a air leak by enriching the idle mixture. The electronics were all turned off during the first tank.

Are there two or three carb adjustments on the HPI?

Two. a LSN and a HSN. Oh, and an idle screw.

I'm gonna have to call you later when I get to mess with it this afternoon. The neighbors are still numb from the break-in yesterday :lol: .

Adjusting the HSN is most definately my next step.

check out this thread here...
Last edited by Bob Tenwick on Tue Dec 30, 2003 7:20 am, edited 2 times in total.

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Post by Bob Tenwick »

Greg Hall wrote:
Otherwise, we might have to spend a couple of hours in my trailer getting it bench tuned this weekend.
Yea, before Wilson shows up and smokes me with his new X-Terminator, lol. 8)

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Post by Greg Hall »

Rest assured that I can't/won't be sucked back into that black hole of a money pit!

I will of course bring the video cam! And document the carnage!
Greg Hall
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'98 KTM 620SC
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KX 100 My 11 year old son's
KFX 400 also my son's bike
LT 500..all mine

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Post by Bob Tenwick »

OK, this is funny.

As a deprived childhood suffering middle-aged man I can totally understand why I ran down to the hobby store and bought this toy three days after Chrismas upon hearing that my duning buddy found one under his tree.

I can also understand why my other duning buddy three doors down picked one up last night after seeing mine. 8) I also understand another duning buddy which is duning buddy #2's brother is going to buy one before his next desert trip, lol. (Tip, buy stock in the company that builds Savages :wink: )

Anyway, we were in the garage breaking my neighbor's truck in so I got chance to compare one truck's behavior to anothers, and here's what I found:

The LSN (low speed needle) setting is very tricky and very critical to initial start up. The book says the initial break in setting should be "three turns out from bottom", but, as was suggested on the hpisavage forum, the screw really never "bottoms" out. What it does is if you screw it in to far it starts lifting the slide in the carb. The idle screw also obviously lifts the slide, so what we did is to set the idle screw so we could see a 2 mm gap between the bottom of the slide and the carb body like the book says, than turn in the LSN until it just barely starts to move the slide, than back it out three turns.

Here's where it gets a little tricky, cause from this setting you have to adjust the screw left or right 1/4 turn at a time to find the exact setting that she wants to start at. Too rich and you hydraulic lock the piston, too lean and it won't start.

It ended up taking about the same amount of time to burn his first tank as it did for me to just get mine started. The second time was a LOT easier.

Hope that helps you get yours dialed in Ken, I know I'm not as worried about a vacuum leak as I was before.

So far it looks like this is one very well built truck. Now it's time to bail to the desert to thrash it. 8)

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Post by Winston Cup »

T-Maxx's Rule!

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Post by Bob Tenwick »

sweet!

I noticed you turned your tires around. You did that for better flotation, right? I was advised by Mr Hobby Store Kid to run T-Maxx tires backwards instead of paddles in the sand.

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Post by Winston Cup »

Ya it works fine either way really though. But that is the theory anyway.
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Post by Winston Cup »

So Bob how'd that thing do out there? Are ya still happy you brought that thing into your life? :lol: :lol: :lol: :lol: :wink:

Pics?
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Post by Bob Tenwick »

Oh Yeah... they thing is as much fun (almost) as the dunebuggy. My neighbor brought his new Savage too, and we both agree they blow away the Xterminator. Acceleration, top speed, handling bumps, name it.

I launched the thing a bunch of times and didn't break anything. It's running bitchin' too.

What's cool was to stand on top of the trailer Sunday after the wash emptied out and run that thing all over the wash.

Waay cool.

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Post by EBCMIKE »

I am really glad I read this thread, I was feeling like a schmoe for buying a T-Maxx and a Savage within 1 week of each other.

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Post by Bob Tenwick »

Perfect. Now we can get an unbiased comparison.

Mike?

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Post by EBCMIKE »

The savage kicks the Tmaxx's butt! with everything except the steering. The tmaxx has more responsive steering....but that hardly compensates for the tempermental motor of the Tmaxx My HPI was a breeze to tune in, I still havent got the Tmaxx tuned in.

The Tmaxx is also a lot more fragile than the HPI. Went to a track (first time ever) and BEAT the savage. But the first day I had the Tmaxx, my friend ran into my left rear tire and snapped the spindle and cracked the lower a arm. The impact wasnt anywhere near the force the HPI was taking at the track.

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Post by Bob Tenwick »

I still haven't been able to break the Savage except for a stripped spur gear when the screw on the back of the motor backed out. $4.00 in parts and some locktite and I'm back doing cartwheels. :lol:

Fun stuff.

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Post by Greg Hall »

The real problem is what is in the path of Tenwick's Savage......get the hell out of the way!
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Post by Winston Cup »

Well let's see some pics of this bad puppy.
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Post by Papa Perry »

Well I finally used my discount with HPI (they are a customer and I get employee cost once a year) and picked up a Savage 25 RTR.

We picked up 4 of them. Unfortunately the Open lot across from work has buildings going up on it now.

Need to break it in this weekend.

Greg do you have your break in setup at home? If so, mind if I come by with a few six packs..... :D

Perry

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Post by Greg Hall »

PerrySoCal wrote:Greg do you have your break in setup at home? If so, mind if I come by with a few six packs..... :D

Perry
Naw....I wish I did but I had sold it a few years ago. :oops:
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'98 KTM 620SC
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KX 100 My 11 year old son's
KFX 400 also my son's bike
LT 500..all mine

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Post by Papa Perry »

Bummer, guess I'll have to do it how they recommend.

1st R/C car, so I amy ask you for advice.

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