Yet another DuneRunner :)

[Ice_2k]

yeah, that's a good point I guess, but as far as loctite is concerned, shouldn't be a problem, I'll just do my burnout at the end of the day I'm also going to do it when the tarmac busters are completely done, so I'll have to stop my running anyway to fit the slicks on the rims

 

[Ice_2k]

Are these the correct brake pads for the DuneRunner? Any other upgraded parts I could purchase when my stock pads wear out? And btw, how do I know when the pads are weared out?

 

[Ice_2k]

Yet another DuneRunner

Double post, pls ignore

 

[Ice_2k]

Took the car out today, built myself a nice street circuit using miniature traffic cones, got my video glasses ready to shoot the whole thing and what do ya know, damn thing refused to start ))

With choke on, it popped exactly on the 3rd pull as it always does and then with choke off it started exactly on the 4th pull, as it always does. However, instead of reving a little higher (i use an idle up on my radio that keeps the throttle at ~10% to start it easier) it just started "coughing" so to speak, like it was only igniting every 3rd rotation or something like that. It did that for 1-2s tops and the revs kept going down and down until it died and that was it, couldn't get it to fire after that.

What do you guys think? From my (rather limited) experience it sounds like maybe the spark plug died.

 

[talunceford]

Took the car out today, built myself a nice street circuit using miniature traffic cones, got my video glasses ready to shoot the whole thing and what do ya know, damn thing refused to start )) With choke on, it popped exactly on the 3rd pull as it always does and then with choke off it started exactly on the 4th pull, as it always does. However, instead of reving a little higher (i use an idle up on my radio that keeps the throttle at ~10% to start it easier) it just started "coughing" so to speak, like it was only igniting every 3rd rotation or something like that. It did that for 1-2s tops and the revs kept going down and down until it died and that was it, couldn't get it to fire after that.

What do you guys think? From my (rather limited) experience it sounds like maybe the spark plug died.

Yeah, that would be the first thing I would check for sure.

 

[designed2survive]

Are these the correct brake pads for the DuneRunner? Any other upgraded parts I could purchase when my stock pads wear out? And btw, how do I know when the pads are weared out?

I'm 99% sure it is the right part.

 

[designed2survive]

Spark plug likely like you said.

 

[Ice_2k]

Thanks for the input guys, I'll check it tonight and keep you posted (not that you care that much, but still haha)

 

[designed2survive]

Thanks for the input guys, I'll check it tonight and keep you posted (not that you care that much, but still haha)

I do as this is how we all learn. Let's say it's the spark plug, then we have confirmation of our diagnostic. If not, then we get to go deeper and learn more. And that, in this hobby is always helpful. Aside form the fact that I enjoy seeing other people build and runs.

 

[Ice_2k]

Thanks man! Hopefully I can confirm this diagnostic tonight, I've been really happy with this engine so far, the only times I had problems getting it going it was user error (incorrect carb settings to be precise), this is the first time I knew what I was doing and I failed starting it. I'll probably carry some backup plugs from now on.

Btw, is spark plug failure a fairly common occurence? Is it normal for an NGK plug to fail after ~10 tanks or so?

 

[phreerider]

spark plug is my guess, season change temp and humidity forcing rich settings couple gulps of air at the finish can trap just enough moisture to cover electrode.

for me season change is plug foul constant almost the hallmark of "ok put this up and do something else"

and too , the tune can be an issue, even a slight change adjustments for environment can be foul producing .

 

[Ice_2k]

OK, that actually makes a lot of sense. I kept the car in the house for the last couple of weeks and now when I took it out there was probably some condensation from the cold, right?

If this turns out to be the issue, what can I do to avoid this problem in the future? Also, would the spark plug be ruined or just in need of cleaning?

 

[phreerider]

carb screen/ filters is a distance consideration if new plug is not improving things, more of a heavy offroad/ super dusty issue.

 

[designed2survive]

Thanks man! Hopefully I can confirm this diagnostic tonight, I've been really happy with this engine so far, the only times I had problems getting it going it was user error (incorrect carb settings to be precise), this is the first time I knew what I was doing and I failed starting it. I'll probably carry some backup plugs from now on.Btw, is spark plug failure a fairly common occurence? Is it normal for an NGK plug to fail after ~10 tanks or so?

Due to the nature of our engines, spark plugs can fail anytime or last forever. I have one of those that came with the Baja when brand new and it's still kicking (including break in) lol!

 

[Ice_2k]

carb screen/ filters is a distance consideration if new plug is not improving things, more of a heavy offroad/ super dusty issue.

What is carb screen?

 

[Ice_2k]

Yet another DuneRunner Ok, looked into the issue this evening. I removed the plug, grounded it to the head and pulled the starter, there was some spark but I think it should have been stronger. Not sure about that though. I looked through the hole and there was some black residue on top of the piston, it wasn't the usual clear metal color. Then I turned the car over and pulled the starter 10 times or so to make sure it's not flooded and then installed a new plug. Choke on, 3rd pull it popped. And man, did it pop. I didn't hear such a loud pop in a long time. Then choke off, 4th pull it started with no issues. Revved it a bit (7-8000rpm) and then shut it down, all seemed good. Here are some photos of the old plug:View attachment 7891View attachment 7892View attachment 7893













/monthly_2015_11/ImageUploadedByTapatalk1447878965.557313.jpg.093f2c21c84a3063750e2410d1ad2c59.jpg

/monthly_2015_11/ImageUploadedByTapatalk1447878980.145686.jpg.6ba5d0a14d38fa0ea5294a7131544de2.jpg

/monthly_2015_11/ImageUploadedByTapatalk1447878987.525571.jpg.ca662f9a0446daaa2c2d8484591c2dde.jpg

 

[talunceford]

Ok, looked into the issue this evening. I removed the plug, grounded it to the head and pulled the starter, there was some spark but I think it should have been stronger. Not sure about that though. I looked through the hole and there was some black residue on top of the piston, it wasn't the usual clear metal color. Then I turned the car over and pulled the starter 10 times or so to make sure it's not flooded and then installed a new plug. Choke on, 3rd pull it popped. And man, did it pop. I didn't hear such a loud pop in a long time. Then choke off, 4th pull it started with no issues. Revved it a bit (7-8000rpm) and then shut it down, all seemed good. Here are some photos of the old plug:

View attachment 7891

View attachment 7892

View attachment 7893

Looks fouled for sure. Coffee color is what it should be. From what I have read.

 

[Ice_2k]

I think that color needs to be checked after killing the engine while at max rpm, not sure if it's relevant now

 

[phreerider]

the pic indicates rich.

full bore shut down is a hair splitting step to check burn.

what you are looking at is total average of burn and is looking to be rich.

so a rich setting in humid summer, the same tune setting during cooler dryer fall would be too rich and the plug would look^^^ ...just like that!

the water vapor in the air is hogging the space, once its(the water vapor) gone the space can be filled with more fuel. a 10 degree in ambient temperature change DEMANDS a tune.---> pinch hi speed forward to squeeze for dry scream, then tiny tick back to keep it wet. and the lo speed just the opposite , wet slo and sloppy to quick n buzzy as its closes to dry it out.

heres a look typical burn , maybe tiny rich, and thats mostly the idle richness that coats(the electrode) like that, with the "general look" the average burn to be light powdery dry brown.

 

[phreerider]

What is carb screen?

a screen element in carb body, a layer of super fine debris can clog beyond clunk/in-line filters , good practice to dismantle and clean if you jump carbs to other mills frequently, the swap handling is usually entry point or maybe just a mountain of time in the dirt!