Engine exhaust backfire

[codeman11]

Hey guys any help would be great. First time ever experiencing this, and at a loss.

I have an ESP modded and tuned 34cc Zenoah. It was running great for 2 tanks, and the low end seemed a bit rich after the 2nd tank as it would bog a little at idle and stalled out. Restarted no problem after, so I leaned it slightly (1/8 of a turn) nothing major at all from stock carb settings.

Engine won’t restart now. When it fires, I get a loud hiss from the exhaust pipe. Installed on my Kraken TT. Can’t figure out what the heck happened, never had this before and am usually pretty good with engines. Bottom end too rich, too lean?

The only thjng maybe I can think of is the exhaust is fairly close to the fuel lines, maybe cause some sort of Vapor lock in the carb or something. I did protect it with heat wrap … but even after letting the engine cool, it did the same thing … loud “hiss” and then nothing.

 

[codeman11]

Nevermind ... found the issue. It was fuel building up in the exhaust, and turning the engine over caused a "hiss" & "pop" as too much fuel built up; on top of the the coil died and became flaky.

Darn Vekta TT sucks in a ton of grass and crap right into the front of the engine. Overheated the coil it seems. Hope it didn't damage the engine at all, but it was running pretty rich with a ton of smoke on its first couple tanks anyhow so hopefully just the coil died.

 

[cmbscx10]

Glad it went well and wasn't too costly.

Besides my OCD for it being clean the grass and dirt after my test run was not going to work for me. Though Fullforce doesn't make one for the TT I bought the Buggy one and modded it. A little snip here and their and I now have a crap guard for my TT. Pair that with my windshield and it will be what it is but less caca than 100% open.

 

[codeman11]

Thanks! I’ll go buy one of those now. Ridiculous design flaw (and one of many so far I’ve noticed) on these Krakens. No effort or thought put into dirt protection, especially considering the orientation of the engine.

Yeah hopefully just the coil, and didn’t do any damage to anything else. Compression is still high enough to lift up the truck off the table when cold so that’s a good sign.

 

[cmbscx10]

Ridiculous design flaw (and one of many so far I’ve noticed) on these Krakens. No effort or thought put into dirt protection, especially considering the orientation of the engine.

I can't 100% agree with Dirt Protection Design Flaw. Is Kraken the only MFG that has the motor in the position it does? See my Losi 5 pic and it's 1st run after BL conversion. I made my own Kydex guards before any future runs. Same went for my KM Baja / truck. I made Kydex side guards and extended the windshield area to keep out as much crud as possible. Nothing will keep an RC 100% clean but we try to do our best to bring that % down.

Kraken's focus on the "Scale" look more so than probably any other 1/5 scale RC. Why i now have 3 of them. They are definitely different and like any RC at any cost will need improvements. No RC and i mean NO RC is 100% perfect. The more the RC is on the market the more it will get attention to address any flaws or improvements needed from the MFG or the aftermarket. I've seen videos comparing the Vekta 5 to a Losi 5T. Fun to watch but that is just silly. They aren't even the same platform. IMO they are compared because they are 1/5 scale and have a motor. Pretty much everything else is for the viewers.

 

[codeman11]

Kraken made no attempt at all whatsoever. I'm not talking about eliminating dirt, that's not realistic especially in a dusty environment. My running space is pretty pristine compared to your photo there. Barely any dirt; all just grass clips. I've owned the DBXL 2 gas, and it got way less dirty after 1 run. Much more protection there, as well as you can see even in your photo side guards.

I'll have to make something. No RC is perfect, but the 5T and the Vekta TT are in the exact same class ... both trophy truck designs. They're directly comparable, how is that silly? Also the comparisons are general comparisons, not design comparisons. How does it perform, how does it hold up, is it prone to flipping etc. Perfectly fine comparisons IMO.

Of course, I bought the Kraken as well for the kit and scale looks ... mine is apt to be more of a shelf queen. The driving characteristics are OK, not great. Parts fitment out of the box ... hit and miss, all over the place. Needs a lot of upgrades to make better, and improve form, function and fit. But boy does it look cool for sure!

 

[Mick Mars]

100 percent recommend outerwear products. Got them for 5t 2.0. Its amazing how much air these engines pull .I have air cleaner, crankcase and pullstart/fan covers.On 2nd set after 4 years because they were filthy. Shock covers too.My air cleaner still looked brand new !!!!

 

[cmbscx10]

No arguments with anything you said at all. Just chit chat and opinions.

To me the 5T and TT are not the same. The Drive line alone will make them totally different handling RC's.
5T = IFS-IRS, 3 Diffs and 50% of the suspension travel. 15-20lbs lighter.
TT = IFS-Solid Axle, 2 Diffs and 1 slipper and way more suspension travel. Fat Girl.
IMO, Body wise the 5T looks like Short Course Truck more than a Trophy Truck.
Most if not all 1:1 4WD Trophy and Short Course Trucks have IFS-Solid Axle.

The only RC i F-in hated was my Traxxas Slash 4x4. In the end i care about how much my RC makes me feel like a 8yo kid again opening up his Tamiya Frog at Christmas. Just looking at my Kraken's makes me feel that way.

 

[codeman11]

I agree there for sure, if you get to the nuts and bolts they’re different vehicles.

Still, more thought and care could’ve been put into the performance characteristics of the Kraken and some of the finer details. I feel like they over focused on the cool factor of the 4 link setup. Even the setup is odd … in the front there’s positive toe (toe in) which makes the handling twitchy and not track straight on power versus off (which you can mod with shorter steering links etc), the parts precision on the plastics especially is pretty horrible. Tons of slop etc etc. If they were going for scale they should’ve actually copied the rear shock setup etc. there’s so much riding on how different it is; they do a very good job on the body design and the rear axle is very cool and expensive to produce. Overall I think it looks sweet; I love just looking at mine and I do like the bit softer suspension to see it working more while driving. There are definite poisitife points for sure. I just feel like it’s missing the mark on being a premium product … it’s got potential but it’s missing key points, the poor tolerances and worst off is customer support blocks you and is quite rude unless you kiss their rear and apologize for having an issue with your kit. Any hint of problem you lay the blame on them for is immediately met with attitude.

The Vekta on the other hand. Massive pile of overweight more of the same with hugely exaggerated track width to compensate for poor handling. About enough said there and even with the TT more suspension travel but you can’t even get full compression on the front and rear anyways and definitely out limiting straps with the weight of it or you’re for sure stretching plastic ends and busting shocks

I would love to design one myself, and focus on all the points missed and have a seriously hobby grade product out there. Expensive, and nothing spared but freakin’ awesome. That’s just me though …

100 percent recommend outerwear products. Got them for 5t 2.0. Its amazing how much air these engines pull .I have air cleaner, crankcase and pullstart/fan covers.On 2nd set after 4 years because they were filthy. Shock covers too.My air cleaner still looked brand new !!!!

Same, I use outerwear products over all my air filters and have way back when I used to race 1/8 scale nitro buggy too. I completely neglected to think of a cover for the engine though, as I've never had an engine die like this ingesting this much grass and crud - I always would just open things up every "10th" run and spray anything out with an air compressor and call it a day.

Cover for the pullstart, and I'll be installing a plastic shield as well for sure.