Sunl SL50QT-16 : Resto-Mod

Where could you get a turbo that small?! Would be amazing to hear that thing spool then slam like a two stroke power band!

Lol, 99cc would have needed a wheelie bar to handle the nitrous shot

I got everything back together and added an extra brace to the bracket to make sure there's no scissor action.



I went to start it and it acted like there wasn't enough juice in the battery or the starter was stuck. I cranked for a minute and stuck the charger on. It kicked over kinda sluggish a couple times then quickly. It seemed like it had low compression. Oh crap. Well, I guess I won't be running the 47mm head with the 50mm piston.



Kinda hard to tell from the pic, but the intake vavle on the left is bent a little.



I thought maybe my timing could have been off or something (others say they use the stock or 47mm heads with these kits) so I installed another intake valve and went ot put it together to check clearances to be sure it wasn't just my mistake or something. Well, the intake valve from the 49cc head is slightly different and the rocker doesn't line up with the valve just right.

Back to the 50mm head I guess. Considering I tell people to check piston to valve clearance if you are at all in doubt, you'd think I'd heed my own advice. Well, here's exactly why I usually recommend checking it.

I'd need to get a new valve that would fit first. Not really looking to spend any more money than I have to to keep the Venus and SunL going... I miss T1 and T2.



It's already back together with the 50mm head anyway. Well, the engine's together. Not in the scoot.

The pilot jet was clogged. Fixed that and it fired right up with a loud ticking. It ran like crap. No power at all. Smooth idle but after the clutch engaged it struggled hard to do anything. I swapped back to the 150 carb because I could do that without pulling the engine back out just to see if the power issue was at all related to the carb. Still ran like crap. I tried using a stethoscope, but I really couldn't tell where the tick/tap was coming from. Just as I found when I tried a stethoscope on my 2T once before, these engines are so small that it sounds like it's coming from everywhere.

I pulled the engine out this morning and found that one of the wires from the stator was gnawed through from contact with the flywheel. It was the white wire, which is either lighting or charging, not ignition. I fixed that. I pulled the valve cover off and checked the valves. They were still at .002". I always set them at .003/.003 or .003/.004, but I had read about other folks using .002 so I thought I'd try it and see if the valvetrain was silent and functioned properly. I set the valves back to .003/.004 and made sure the vavle timing was OK. I hooked everything up to the engine but didn't bolt it in and fired it up. Still makes the tap from somewhere in the engine. I didn't really think it was the vavles becuase it seems like a little more dull sound than the vavles usually make. I hope that dull sound doesn't mean it's deep in the engine. Not sure if it has any more power now, I shut it off and came in after hearing tht tick again. I'm just getting tired of all the SunL's issues so I lose my patience with it pretty quick lately.

The valve doesn't appear to be bent so I cleaned out the worst of the carbon, lapped the valve, and re-installed it. The correct flywheel came in from scrappydogscooters yesterday too (they let me keep the 150 flywheel for free!). Hopefully it will line up with TDC properly and I can put the key back in the crank so installing the flywheel will be much faster.

I'm gonna install it with the degree wheel again and if it hits then

I got the woodruff key and the timing really is within about a degree now. I realized that my intake tappet wasn't lining up with my intake valve very well when I reassembled the top end with the big valve head. It was doing this after I put a new valve in the other head too. I had no trouble re-installing either of the valves after checking/replacing them so I thought (although it did seem far fetched) perhaps I bent a rocker arm and replaced that. I went to take the valve out of the big valve head and it stuck about half way out. Hmmm. I went to remove the valve from the 70cc head and the same thing happened. I can't for the life of me figure out how I could get the new valve in the 70cc head with no trouble and reinstall the valve that didn't look bent in the big valve head with no trouble... then next thing I know they are stuck in their guides.

I ordered a new 50cc head for now, and it came in yesterday. I might have my machinist look at the other heads at some point and see if he can do something with them, but this is cheaper and I can see if this thing can handle higher compression. After my previous experiences, you better bet that I checked piston to valve clearances. You can see here that the valve cut all the way through the clay. There was never any interference like the valve was hitting and stopping the engine from turning over, but way too close regardless.



I used a flat dremel bit that is just slightly larger than the intake valve to try and cut my own valve relief.



Certainly not a professional or pretty job, but it should work. It's kinda hard to get a nice straight cut without some sort of jig when the dremel is trying to jump around. I'll re-check the clearance when I can. Once I know the intake is good to go I'll make sure the exhaust is alright as well. I dunno if it's from my clay sitting around or what, but lately it wants to stick to everything no matter what I put on it. For that reason it's been easier to keep the clay in one measurable piece checking one valve at a time.