2019/05/04 Savage X LRP30 Grass BMX bash

[olds97_lss]

This thing is either lean bog or stalling rich. Spent 2.5 hours and 1000cc's of fuel trying to get it running well. When I did have it running "ok" (still had high idle that wouldn't drop), when it stalled, it wouldn't start unless I richened up the LSN considerably. But then it wouldn't idle, it would just die. If I increased the idle, it would high idle insufferably after a WOT run, even though the HSN was so rich that it couldn't hardly clear it's through enough to shift.

By the end of the day, I had no skin left on my fingers and no patience left and I wanted to set the thing on fire.

This savage has ran like garbage regardless what engine I put in it. Almost seems cursed! I know that makes no sense... but I'm at the point now where I just want to tear it down for parts for my savage flux and call it a day.

 

[Seanthemechanic]

Nooooo don’t give up on nitro!!!! You’ll find the right motor

 

[olds97_lss]

Nooooo don’t give up on nitro!!!! You’ll find the right motor

I still have 2 more nitro's. They both run just fine and hold a tune all day long. This SavageX is like my own personal nitro nemesis it seems.

Prior to the 30, I had an LRP28 in it and for the life of me, couldn't getting it run right either. I've had 4 of the same engine. Each one broke in hard, but afterward, ran great and tuned great. I have one in my big block revo. Runs like a top, all day. The one I put in the X always had a mid throttle bobble to it that I couldn't tune out. So, I got the 30. At first, it reacted similarly, then I noticed my old OFNA tank o-rings and spring on the cap was really bad letting fuel leak out and pressure leak out. When I first put the tank on here I have now, it ran fine. That was 2 years ago. I ran it once or twice last year and it also ran fine, I had it geared too high, but it ran ok.

Now I have larger tires on it and lowered the gearing, but man... it just will not tune right. So frustrating to drive 45 minutes to a bash area, then spend 2.5 hours messing with something that fights with you so much.

 

[Seanthemechanic]

Yeah it drives me nuts when you go out to play and something breaks and the engine doesn’t run right. You want to throw the truck in the water

 

[ELWOOD]

@olds97_lss I'm sure you have looked at this already , sounds like engine might have a leak... Also one other thing , fingerless gloves , big help...

 

[olds97_lss]

@olds97_lss I'm sure you have looked at this already , sounds like engine might have a leak... Also one other thing , fingerless gloves , big help...

I had it sealed from before around the carb/backplate/cinch bolt. I'll tear it down completely and check everything. As much as I was fiddling with it, could have tore an o-ring on one of the needles or screwed it in too far causing a burr. Will try and figure it out this week before I give up on it completely. Maybe instead of trekking 45 miles to run it, I'll just take it and some fuel out after putting it back together and just dedicate an evening to it.

 

[olds97_lss]

Well... had a couple issues.
1) My bell shims were gone. So the bell was able to float around about 4-5mm however it saw fit. And by looking at it, it was rubbing against the spur and getting eaten alive. The bell was brand new and installed just before I took it out for this video. Shimmed with 1/2mm-1mm of play.

2) The shoes are pretty worn. I knew that, but I didn't have anything to replace it. Now they are more worn and uneven. I now have new 7075 dynamite 1/8th shoes I can put on. Hope I have springs that will work.

3) The exhaust gasket was a sticky gooey mess, but didn't show any signs of leaking. Will replace it with a new one just the same.

4) I had tightened the screw on the carb pivot/banjo/thing that connects to the throttle wire, that I deformed it a bit and it was squeezing on the LSN which explains why it was so hard to turn.

5) I found this bit of plastic stuck in the HSN inlet where the HSN seats:

While inspecting the internals, everything had a nice hearty coat of oil on it from the fuel and looked nice and clean. Aside from the top of the piston and bottom of the head button. The piston face was black black, which I thought suggested rich condition, even though the engine acted anything but rich.

Head button was dark with a brown tinge over most of it:

Can see the glow plug coil is a bit deformed, at least that suggested lean. It was brand new, I replaced what was in it before I started it up the first time for this video.

I also noticed a gouge inside the intake journal. At first I thought it was a crack, then I tried scratching at it to see if I could feel anything. I must have done this during disassembly, considering how shiny it is, but I have no idea how as I never stuck a tool in there. I used a plastic ziptie to push the sleeve out as I rotated the piston up, then I rotated the piston with needle nose at the crank and it fell out. Yet there is this gouge in there. I see no other scratch or gouge on any surface anywhere else. Just thought it was odd.

So, the manual says 2.75 turns from bottom on both HSN and LSN with .5-1mm for the idle. I have the idle at ~1mm open and both needles at 3.5 turns or so. So, it should be rich as a pig when I fire it up next.

I don't think I have another hardened 15T bell laying around... so will have to see if when this is installed properly if the teeth run on the damaged part or not. I doubt I'll get one quick enough to run it this weekend. Ordered one a few minutes ago on amazon.

Until next time...

 

[ELWOOD]

@olds97_lss If NITRO was easy anyone could do it. It takes a real man to stay in it . Props to you.

 

[olds97_lss]

The next run after doing all the stuff to it from today... yesterday, I really need to go to bed!:
https://www.hpisavageforum.com/threads/2019-05-10-savage-x-tuning-the-lrp30s2.19339/