Having trouble with my trailmaster 150xrx gy6 engine not starting. Any help or opinions would be greatly appreciated!

[max.burdine]

So about 2 months ago I got a trailmaster 150xrx given to me from a buddy of mine because it wasn't running. I changed the oil and swapped in a new 23$ amazon carburetor and it ran smooth but top speed on flat was only getting about 28mph.... so that's when I started doing upgrades. In total I've upgraded the:

Upgraded CDI but I swapped back to the stock
Fuel and Vacuum hoses
INGINTION COIL
SPARK PLUG
RECTIFIER but I swapped back to the stock
Cheap Amazon Carb
& my lastest upgrade was a
VARIATOR ASSEMBLY KIT with 3x 10g rollers and 3x12g rollers
And a new DRIVE BELT

Well everything seemed to be fine... slowly gaining top speed and acceleration with each part..... until about 2 or 3 days after the variator upgrade it started to randomly go from performing well, to all the sudden dropping to nothing very smilialr to if like i hit the fuel shutoff or something. This issue got more and more common until those interactions had become multiple times a ride. I thought it sounded like it was flooding at the time... so I had been dumping the float bowl and let it sit a second which has been working. This issue started about 2-3days after installing the new variator kit which worked perfectly fine before, but this last time I am yet to get it back to even fire with starting fluid. It is also appeared to be leaking exhaust or smoke and a very dark dirty oil from the intake manifold & Carborator intake when I attempt to crank it. Pretty sure I can feel compression on exhaust and carb intake, as well as seeing a spark when plug is pressed against frame.
Last thing is I decided to check was oil and replace it.. but even after changing the oil totally a week prior, I removed the oil nut and less than 1/4-1/2 cup of oil came out of the drain and it was absolutely filthy.

Here (https://photos.app.goo.gl/qmnWaRN7RAt2afy17) I've attached a video of me attempting to start it so you guys could hear it. Ive also added a photo from behind with filter off.
My only guesses are my valves are messed up or out of time or I've punctured the piston head.... I'm lost... any ideas I can try before removing valve cover and all??

 

[ezcome-ezgo]

Was it smoking while running?

 

[max.burdine]

Was it smoking while running?

Only when I first cranked it evert time. Smoked alot of white smoke... after 5ish mins no smoke at all.

 

[Hellion]

I don't think you were "upgrading" as much as "replacing parts". How fast did you end up going in the buggy before it went tits up? 28-30mph sounds like all it is really capable of. These buggies are limited by their gearing and all that massive weight from the "car" features....

Only when I first cranked it evert time. Smoked alot of white smoke... after 5ish mins no smoke at all.

I think the engine may finally be toast. The smoking on startup means worn piston/worn rings and it going away means the heat expansion sort of seals up the ring rap and the loose piston-to-cylinder gap. The low oil amount coming out is really bad news, to me at least. Most of these small engines do use oil even when new, so you have to keep on top of that.

I think you should do a compression test and then go from there.

Otherwise, lay out some cash for a spare engine: https://www.aliexpress.us/w/wholesale-150cc-engine.html?spm=a2g0o.home.search.0

 

[max.burdine]

Would a big bore kit fix those issues? Whooolllle lot cheaper for the whole 61mm drop in kit that includes cylinder, cylinder head, piston, and piston rings? Like this: https://a.co/d/aDCcaN4

Also is it possible I have a bad CDI that's not supplying enough power to spark in the plug?

Or is it possible I'm not grounded somewhere?
Or a wiring issue? This did start the same general time I blew the stock 15A fuse and replaced it with a 20A.

It's just so odd the plug doesn't seem wet when I check it like it's a fuel issue, but even spraying starter fluid in, it still didnt hit even once.

 

[Hellion]

You must confirm fuel, spark and compression. Test the spark by removing the plug, reconnecting the plug wire and letting the plug rest against the case while you crank. Or you can use a plug tester. You can place your finger over the spark plug hole while you crank it and it should blow your finger off the hole. Definitely could be a grounding issue. I hope you're not cranking it with the kill switch (or some other dead-man switch) enabled....

A big bore kit could fix some of the problems (because you are replacing the top end).

 

[gokartdave]

Would a big bore kit fix those issues? Whooolllle lot cheaper for the whole 61mm drop in kit that includes cylinder, cylinder head, piston, and piston rings? Like this: https://a.co/d/aDCcaN4

Also is it possible I have a bad CDI that's not supplying enough power to spark in the plug?

Or is it possible I'm not grounded somewhere?
Or a wiring issue? This did start the same general time I blew the stock 15A fuse and replaced it with a 20A.

It's just so odd the plug doesn't seem wet when I check it like it's a fuel issue, but even spraying starter fluid in, it still didnt hit

Hello max. I also have the same machine. Mine blew it's 15 amp fuse as well. I chased it down to a live wire off it's horn, it also kept shorting out an blowing fuses. I'm not sure how old yours is but I bought mine brand new from a dealer. It doesn't seem to have much problem hitting 39mph will hit 40 but it needs alot of room. Not sure what state you are in. Studz hardware in Dearborn heights mi sells those machines I'm sure they service them as well so they might be able to answer your questions.