HPI Savage 25 (n00bie help needed)

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T

tal_ux

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Hi folks,

I've recently made the plunge back into Nitro after 12 years of getting rid of them and even then I was a complete n00b and didn't really understand how the engines ran, how to tune them etc. However I've done my reading now and understand things a little more, however......

I bought a Savage 25 and love the feel of the suspension, overall size, look of it and the sounds of the engine.
I've had this running and idling in my back garden, but not wanting to annoy the neighbours, I took this to a field near me and started running it as if I was breaking it in. So taking it easy for about 10 minutes and then I started to see some issues.

1. The truck turns like an elephant!
  • Currently fitted with a JX-5512MG servo.
  • I believe this one should be adequate, however would anyone recommend an update?
  • I'm currently buying a replacement hump battery pack, in case the issue is purely down the to battery, with it being 2nd hand.
2. Every now and then the steering servo would go mad and the wheels would shudder from left to right.
  • I've never seen this before, but could this be the car is almost out of range of the transmitter?
  • Can this truck be upgraded to a different receiver, so I don't have to use the old crystals? I have the Fly-Sky FSGT3B and I'd like to use that instead.
3. Throttle trim doesn't affect the engine at all
  • Not sure what the issue might be hear at all. It's fitted with a acm-as16 speed servo.
  • Would anyone recommend an upgrade for this and if so, what?
4. When the engine is hot it seems to cut out, but will start with
  • I've not played around the with high / low or idle screws. Assuming this was 2nd hand the previous owner would have had this setup and running well, but who knows.
  • Can anyone please give me some pointers on this?
  • I'm currently running some 15%, just to test it out, but I have some 20% nitro on order and will be running it with that when it turns up.

1620676688219.png1620676726355.png1620676762899.png
 
engine tune has to do with atmosphere. u cant trust what the previous owner did. i would suggest u upload a vid of it running so we can ascertain the issues u having
 
Thanks for the response ManMgn. I'll do that as soon as I can, but should hopefully be the beginning of next week.

As for the steering servo, I think I'm going to upgrade the Tx to the Spektrum DX5 and the Rx will be the SR315. I'll do a little more reading first before buying though to be sure. The steering shudder seems to be very sporadic, so I think it will be hard to capture that on video. Especially since I'll be driving and recording on my own.
 
Me again - sorry.
Due to the carb being loose, it is affecting the throttle trim, as you can see here.

 
ok to fix the carb issue u have to tighten the screw under it. right on the crankcase
 
the screw u need to tighten is circled in red, also once u change the radio/receiver to ur spektrum turn down the endpoint on the throttle servo otherwise it will burn out
also make sure u have a fresh receiver pack
 

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You are a star sir! However I have a slight problem. Seems the previous owner decided to round it off for me. Also from the second picture, if there anything I can do to clean the top of the piston? Or should that be ok?
 

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tal_ux said:
You are a star sir! However I have a slight problem. Seems the previous owner decided to round it off for me. Also from the second picture, if there anything I can do to clean the top of the piston? Or should that be ok?
Click to expand...
u should take the motor apart and clean it with some nitro fuel or pure alcohol. then lube it with some caster oil when putting it back together. about that screw u might have to try to order 1 online. use some calipers to measure the screw to get the exact measurement
 
I got some spares when I bought and this is the smallest screw I can find. I’m going to assume I can’t use the bigger one. If not, can someone let me know where I can buy a screw set for the savage 25 in the uk?
 

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tal_ux said:
I got some spares when I bought and this is the smallest screw I can find. I’m going to assume I can’t use the bigger one. If not, can someone let me know where I can buy a screw set for the savage 25 in the uk?
Click to expand...
just get the exact measurement and look online. maybe even an hardware store has it. not sure about the uk as I'm in the states. alot of us use https://www.fastener-express.com/ in the states. if u get the M (width)mm x (length) mm u should be able to find online. even amazon possibly. get the width and length of the screw
 
If the loose carb isnt causing it to cut out when hot then it could be a worn piston/sleeve. You would find difficulty restarting a hot, worn engine. Disconnect steering servo linkage and see if you can easily move by hand the wheels left and right. Check servo saver adjuster isnt loose. If all ok then get a servo with more torque, label claims are sometimes exaggerated. Get a 2.4G Flysky FS-GR3E 3ch receiver for your GT3B, theyre cheap and will not have interference issues like 27mHz.,
 
Lokky, thanks for your response.
Starting the engine cold was fine, started first time and I was away. However when hot, I have to give it a little helping hand with the throttle on the Tx to get it going. You can hear the engine really wants to start when trying to fire it up when using the rota-start, but alas nothing.

With the engine being out and me trying to find a you tube video of someone dismantling the same / similar HPI engine so I can take it apart and clean it, I'll flip the truck and give your suggestion a go later on tonight. I was hoping to post a video on the engine starting and failing to idle this weekend, but with the loose carb, I want to sort that out. So I'm on the hunt for a replacement screw and washer, since there was no washer either.

As for the GT3B, it seems the LED screen is now dying on me :cautious: and I'm struggling to see some / most of the screen. Got some new batteries on order for that as well, so hopefully it's a quick and simple fix, since I obtain this when I bought a 1/5 Yama Buggy 2nd hand. Yet another project for me in the summer months, but this Savage is taking priority at the moment.
 
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tal_ux said:
Lokky, thanks for your response.
Starting the engine cold was fine, started first time and I was away. However when hot, I have to give it a little helping hand with the throttle on the Tx to get it going. You can hear the engine really wants to start when trying to fire it up when using the rota-start, but alas nothing.

With the engine being out and me trying to find a you tube video of someone dismantling the same / similar HPI engine so I can take it apart and clean it, I'll flip the truck and give your suggestion a go later on tonight. I was hoping to post a video on the engine starting and failing to idle this weekend, but with the loose carb, I want to sort that out. So I'm on the hunt for a replacement screw and washer, since there was no washer either.

As for the GT3B, it seems the LED screen is now dying on me :cautious: and I'm struggling to see some / most of the screen. Got some new batteries on order for that as well, so hopefully it's a quick and simple fix, since I obtain this when I bought a 1/5 Yama Buggy 2nd hand. Yet another project for me in the summer months, but this Savage is taking priority at the moment.
Click to expand...
if the engine starts easily when cold vs warm its a sign of low compression. or it could also be needle settings as when a engine get up to operating temp of 200 to 269 F thats when u can see how well a motor is tuned. also make sure the idle gap is appropriate. the gt3c is way better as it uses no AA's
 
tal_ux said:
To fix the loose carb, if I can't find the screw I need, am I correct in thinking this is the correct part I need, as the Savage 25 has a S-25 4.1cc nitro engine?

https://www.hpiracing.com/en/part/1406 - Nitro engine
https://www.hpiracing.com/en/part/1434?show_disc=true - lock pin for carb
Click to expand...
Tal, that's the part you need. You may be able to just replace thw screw and the sleeves may still be good. If you have an old .28 size motor that's no good, you may be also able to use it from that. Also make sure to seal up the motor if it's out if the truck. Plenty of threads on here about sealing nitro engines.
 
The screw you need for the carb will most probably be the same size but that could be a savage 21 not a 25, it's definitely the 21 cooling head, does it have 21 or 25 on the side of the crankcase
 
The crankcase of a big block motor is the same across the board. It's the internals that make up the sizes (displacement) of the motors, I.E. .21, .25, .28, .32
 
If you have not fixed the carb screw yet you could cut it to size. I would recommend that you have a nut that fits on there first before you cut it as the nut will straighten the threads as you take it off
 
Hello all I've just bought a hailboxing Tigershark apparently that's what it is I'm a total newb, it has a hpi 3.5 big block engine which is leaking from glow plug when I turn fly wheel is this engine done for??
Also how do I tell if my clutch shoes are worn please
Sorry to jump in this thread but I can't seem to giggle out how to start my own
 
I took engine out because it won't start at all thought I'd clean it up and have a check, but then I found that when I turn flywheel I get air bubbles come out around glow plug
Does it mean engines knackered
 
Tiddy said:
I took engine out because it won't start at all thought I'd clean it up and have a check, but then I found that when I turn flywheel I get air bubbles come out around glow plug
Does it mean engines knackered
Click to expand...
there is a sealing issue around the plug. it could be that the copper washer isnt sealing with the head and plug or the head threads might be stripped. change the copper washer that sits under the plug and see if that fixes the issue
 
OK ill try that, thank you.
What about clutch shoes how do I know if they are worn or not?
I'm new and had serious troubles getting it started its a hpi 3.5 big block engine in apparently a hailboxing Tigershark
 

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What do the shoes look like? If they still look like they make a circle while on the flywheel then I would say they are still good. I’ve gave the. A scuff with sandpaper just to remove the smooth on them and the bell would help get some grip. Just my opinion not sure if anyone else does that.
 
Here's my clutch shoes
 

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Is this the bell
 

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Tips of the shoe pass the base of it where the pin is. I would say they have been well used. Should still work but I would order more
 
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