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Savage 25 running question.

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stinkfist

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I just got a Savage 25 ss kit used but in good condition. I have ran it a few times for a few minutes but today is the first time I have ran it any length of time. This thing is SWEET!

I was trying to get it tuned and was haveing a little difficulty. I got it running and it wasn't running very good. I was slowly richening it up until it would run decent. I got it to a point where i couldn't get it any better but it still wasn't right. I decided to keep runing it and after about 10 minutes it just started running Awsome. it was really flying and almost picking the wheels off the ground from a stop. I was really happy with it.
Then it ran out of gas. I filled it and had a very hard time getting it started again. I made a minor adustment to the lower needle screw and got it started. Then it was running really bad again. but after about 10 minutes it just started running perfect again. Whats going on?

I noticed my carb got really gummed up and was hard to open and close. I sprayed some WD40 on it and it worked good again.

Also the whole time its running It's not getting a really good stream of smoke. It has some but not would I'd consider enough. If I richen it any it just bogs really bad.

Any Ideas?

Thanks,
MIke
 
How cold was it there today?
When you tweek on needles, until you get familiar with it, never move them more than 1/16th of a turn. If you mess with both before it's running you can really get things confused.
The LSN is only for idle and low end punch. The HSN is for WOT.
If you got it used, the first thing you should do is replace the glow plug, then return both needles to factory settings, get it started, then tune both needles for performance. Keep a nice trail of smoke.
 
It wasn't real cold. Probably in the 50's.

Where can I get factory setting specs? I couldn't find them in the manual.
I did put a new glow plug in when I got it.

Thanks,
MIke
 
The factory setting specs are in the little S-25 engine manual.

HS = 4.5 turns from closed
LS = 3 turns from closed
 
straight from the manual for the nitro star s-25.....after break in both hi & low speed needles adjust from 2-1/2 to 3 turns out ...never go less than 2-1/2 turns out

hope it helps
 
Ahh, I see you noticed the self-lean issue with Savage tanks. That is why it runs like a raped ape at half tank and less. I think it's because the damn thing is oversized at 160cc and is hard to keep pressurized. I always tell people to tune their engines using a half tank of gas.

If you have a tank with the primer, I suggest getting one without one.
Since it was used, replace all of the fuel lines with some good silicone stuff from GS, etc, and get a fuel filter. You can also mod your Savage to accept a 1/8 scale buggy tank or add a heli header tank to solve the self-lean, but since you just got one you may want to stay away from those mods for now. I have a 2 year old SS and I've learned how to deal with the stock tank.

Good Luck
 
Hey thanks for all the great info guys. I just downloaded and printed the engine manual from HPI's website.

Very interesting info darthracer. Deffantly something to think about while tuning. I don't have a primer on my tank.

I have to go to the LHS to get a Gearbox bulkhead set to fix some damage that happened while jumping it today. I am amazed at how tuff this thing is. Me and a budy with a XTM Mammoth where jumping a ramp he built. I was getting easy 15 foot of air he was getting probably 10 foot. I probably landed bad about 5-8 times with the last time breaking mine pretty good. He broke his the second time he jumped stripping first gear on the landing. I'm very happy with this truck. Just need to get it dialed in and it will be crazy.

thanks again,
Mike
 
Hey Darth,
I've got another question. Having just bought a Savage, I didn't notice a primer point on the tank or in-line. Did they possibly discontinue it? I'll be doing my final break-in tomorrow afternoon (78 degrees down here :) and will attempt to tune it. Any advice on tuning it?

Rolex,
What say you on this matter?
 
All new Savages come with a primerless tank. This is a better tank than the primer tank. The Uniflow mod will solve the self leaning issue. You can see how to install this mod on my build page here:

http://www.rbartick.com/hpi/
 
Most tanks with primers have problems. Sooner or later a seal fails and it's one more place for an air leak. Priming is done just by pluging the exhaust while turning the engine over.
When it's past it's initial break-in, don't go for ripping performance right off the bat. I do it a little at a time through another 4 or 5 tanks.
Lean the LSN a bit to improve your low end take off. Don't be looking to wheelie, just up it's performance. Lean the HSN to improve the WOT. Same thing here, don't be looking to max it out, but just make if fun to drive. Next tank, a bit more.
Keep a temp gauge on it, and through the next few tanks bring it up to performance, and recommended temp.
Go easy adjusting the LSN. No more than 1/16th turn at a time. When you have good take off to half throttle, only adjust the HSN for top end.
The HSN might need to be tweeked daily, according to temp and humidity, but the LSN should be good. Adjustments on the LSN also affect the idle, so adjust that to keep the engine running without the clutch chattering.
Good luck.
 
Thank you very much, both of you!
Temp has been in the low to mid 70's for the past few weeks, this is our average winter temp down here.
When I tune for performance, I always used to go by temp,how well the vehicle runs and the color of the smoke trailing out the pipe. My manuel says 245-275. I was talking with an engine builder who said 265-285 was safe as long as you're using good quality fuel. Any recommendations?
 
I concur. Good tuning info here.
My tuning tips - shorthand are:
1) Temp guns and guages are good. Every nitro head should have one. Just use it to make sure you are within safe temps as outlined in the manual.
2)Tune to performance while remembering the above.
Start with the needles at break in, but the HSN will probably need to be leaned about 1/4 turn to start. The LSN should be set so it has OK takeoff.
3) Tune the HSN to performance, again remember #1.
4) Tune the LSN for good acceleration / takeoff. You may need to re-adjust the HSN slightly after this as both needles affect each other.
5) Set your idle after the HSN and LSN is set using the carb set screw. Please do not adjust idle by the LSN or radio trim.
6) All adjustments should be made in small increments and you should give the engine 1 or 2 min to adjust to the new settings.
 

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