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Post by 90GTVert on May 4, 2010 18:12:24 GMT -5
Oh,they were 'bottle fed'!That bottle runs out of juice real fast,then you're back to a turd.. Now you've reminded me why I wanna build a turbo 150cc big bore someday. Bringing this stuff up has also made me wanna try a bottle on a 2T... then again... I'm melting pistons on mild setups. Man, I bet that 99cc woulda rolled (maybe literally ) with a little juice though.
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Post by drawkward on May 4, 2010 19:46:10 GMT -5
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
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Post by 90GTVert on May 4, 2010 20:07:49 GMT -5
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Post by 90GTVert on May 7, 2010 13:45:36 GMT -5
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.
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Post by 190mech on May 7, 2010 14:16:26 GMT -5
you could 'eyebrow' the piston to clear the valve,then run that small chamber head.Ive made cutters out of old valves,install head,spin valve with drill,valve must be a bit larger dia than valve to be used.
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Post by 90GTVert on May 7, 2010 14:54:42 GMT -5
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.
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Post by 90GTVert on May 7, 2010 16:21:02 GMT -5
Engine's hooked up and won't start. Only way I can fire it is with carb cleaner. (50cc carb) I had enough so I came in for dinner. It just wouldn't be a build for me if one thing didn't go wrong after another.
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Post by 90GTVert on May 8, 2010 10:41:18 GMT -5
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.
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Post by 90GTVert on May 8, 2010 14:41:39 GMT -5
The good news is, I found the tick... The bad news is I may have another bent valve. The inside of my intake port has carbon buildup like an exhaust port. I haven't got a degree wheel back on it, but I can watch the piston and see that the flywheel is on correct... maybe a couple degrees advanced (where it should be since I marked it so I could install it 4 degrees advanced). The cam was right on. I must be missing something, because I'm not sure how my timing appears to be on and suddenly I'm smashing valves into pistons. I dunno, I'll have to go back out once my patience reserve builds back up a little more.
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Post by 90GTVert on May 9, 2010 10:32:14 GMT -5
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.
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Post by 190mech on May 9, 2010 18:51:45 GMT -5
Cam timing advanced too much,or play in the rod.You need to pour in some motor flush and rinse out that Gremlin!!
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Post by 90GTVert on May 9, 2010 20:37:07 GMT -5
I'm gonna install it with the degree wheel again and if it hits then
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Post by 90GTVert on May 10, 2010 15:26:05 GMT -5
When I removed the woodruff key from the crankshaft I stuck it where I couldn't lose it. Well, I can't find it. I installed the new flywheel in it's proper position the best I could and it appears to be on TDC. It could go a degree or two one way or the other, but it's hard to say for sure exactly wher eit would sit with the key installed. I mocked it up and used modeling clay to check piston to valve clearance. It looks like about 0.055" intake, 0.080" exhaust. I looked back and those are the exact same clearances I measured with the NCY cam, NCY head, and 47mm piston. It should be OK. I guess I messed up somewhere and got something out of time. That clearance is with the valve being in the relief though, so I'm still not convinced that the stock or 70 head would work. Wish I hadn't bent a valve so I could try again. It's not going back together until I find/get a woodruff key to fit and check to be sure of where everything is.
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Post by 90GTVert on May 21, 2010 8:51:57 GMT -5
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.
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Post by 90GTVert on May 22, 2010 13:34:57 GMT -5
I checked piston to valve clearance and still needed to go some more for the intake. After a couple of tries it looks alright. The exhaust valve is OK. Still not sure how everyone else bolts on these 50 and 70cc heads with no issues. Maybe there is more freaky stuff about this SunL than I have realized? I've been trying to figure out what the compression would be roughly. Not sure why.... I've never had much luck with compression numbers proving anything real world with scooters so far. lol Here goes anyway... I cc'd the combustion chamber and got 5cc. That's what I expected since this stock head is beveled like the 47mm head. I measured the head gasket compressed thickness and bore as well and measured the distance the piston sits below deck. Still won't be completely accurate since I'm not accounting for valve reliefs or any variation in piston shape (it's pretty flat though). Cylinder Volume : 81.3cc Combustion Chamber Volume : 5cc Head Gasket Volume : 0.5cc Volume Between Piston Crown And Deck : 0.6cc Total Volume Above Piston : 6.1cc Compression Ratio : 14.3:1 For the sake of comparison, I ran a few other figures... 47mm bore w/ same deck/gasket thickness/head: 13.0:1 39mm bore w/ same deck/gasket thickness/head : 9.7:1 47mm bore w/ same deck/gasket thickness 50cc head : 14.1:1 39mm bore w/ same deck/gasket thickness 50cc head : 10.5:1 So, as high as the calculated 14.3:1 sounds, it's not far over the calculated specs of 14.1:1 for a 72cc kit with a 50cc head that most consider safe. That said, it'll probably blow up because that's just what my scooters do.
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