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Post by 90GTVert on Apr 27, 2016 18:59:33 GMT -5
I have an 835 because I saw one made by Bando, but I will probably be trying an 842.
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Post by 90GTVert on Apr 27, 2016 20:30:25 GMT -5
I was doing a little searching and found little info of value about timing on the GY6. Most people seem to say skip the key and go with a CDI or pickup mod. Both are done, so unless I shell out $200-something for an MSD 4217, that's not terribly helpful.
I see many people saying the advance keys break. I had the same thought about them some time ago, but it's said around here that the taper is what holds the flywheel and the key is just for easy mounting. If that is the case, why are people breaking keys what seems like more often than not from the posts I've read on a few other forums? There should be no stress on it if the taper is doing all of the work. If there is indeed some sort of rotational stress that the taper can't handle on it's own, then the flywheel will not stay put 100% without a key. I only ran mine on the SunL without a key long enough to see how it did and then got a new flywheel (mine was 21 degrees off from the factory), so I've never tried it long term. Maybe everyone that used one should be lapping the flywheel? Can't say I've done it before, but if I remove the key or try an advance key I suppose I would.
There's some plain old weird info out there too. Like people saying you're better off to retard the timing and not stress the engine out by making it work against combustion forces before the piston is headed down. Whatever you say. There is some truth to it, but a point is being missed. This is not an instantaneous explosion like a detonation. It is supposed to be deflagration or burning. We use internal combustion engines, not internal explosion engines. The goal is usually to have peak combustion pressure something like 10 to 15 degrees ATDC, but creating a spark at or after TDC is not the way to go about it. A dense well atomized mixture will allow the flame front to spread from the point of ignition incredibly fast, to our eyes it would probably look like an explosion, but it does happen over a finite period of time and the piston is moving at very high speeds as well. The hard part is that there are multiple factors that can change how fast a flame front propagates and when combustion pressure will peak, so there is no one right timing for every engine, RPM, or load. You definitely don't want to advance timing so much that peak pressure is working against the piston on it's way up the bore, but you also don't want to retard timing so much that the piston is well on it's way down the bore before peak pressure occurs.
Anyway, I'm sure anyone involved in our discussion is aware of all of this. I just had to put it there in case someone finds it in a search one day beside some results about retarding timing.
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Post by Fox on Apr 27, 2016 21:15:51 GMT -5
Well I know I sound like a broken record but I say if you have a 150cc and you wanna go faster, better to buy a 250+ scoot rather than throwing money at a smaller one but you caught the modding bug years ago and we all know there's no reasoning with someone who "suffers" from that condition.  |
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Post by 90GTVert on Apr 27, 2016 21:19:29 GMT -5
As I've said in the thread before, I have considered just buying bigger, but I just have to play with the 150... smart or not.
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Post by niz76 on Apr 27, 2016 21:22:17 GMT -5
I had to lap the flywheel on my scoot because it was shearing keys. Never happened again after I lapped it. It's super easy and only takes a minute. Shoot, you might already have the valve grinding/lapping compound!  |
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Post by 190mech on Apr 28, 2016 3:59:12 GMT -5
I think the offset key is not allowing the flywheel to seat correctly on the taper,many applications use no key,lots of racing motorcycle race iggys have no slot cut in the flywheel for a key,the older Husky 2T MX bikes had a taper only to secure the counter shaft sprocket..Taper must be clean and dry when fitting and if there is doubt of machine work in the 2 tapers,use the lapping compound as Niz stated...
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Post by Fox on Apr 28, 2016 4:21:44 GMT -5
I think the offset key is not allowing the flywheel to seat correctly on the taper,many applications use no key,lots of racing motorcycle race iggys have no slot cut in the flywheel for a key,the older Husky 2T MX bikes had a taper only to secure the counter shaft sprocket..Taper must be clean and dry when fitting and if there is doubt of machine work in the 2 tapers,use the lapping compound as Niz stated... Exactly! The offset keys make it so you have to machine a groove in the flywheel "bore" and the crank to accept the extra material or you will end up with a wobble if my brain foresees the outcome correctly. I think lapping and clocking is the only way you will get the desired amount of degrees you seek. Maybe one drop of blue loctite will add that little som'n som'n that makes the difference as well once you find the sweet spot. I'm no expert but I would try putting all the electrical/CDI/flywheel/pickup timing back to bone stock with the "Zonko" CDI and try a 107 and a 105 jet with just the A-9 cam for power and see what happens. You may wanna experiment with different valve clearances as well. Closer to stock on the cam with a smaller jet may be the ticket to 55+ MPH. I have read that a thinner synthetic gear oil can add performance over a standard Hypoid 90 wt. in the tranny. Lastly and not to offend you but you are a big guy so maybe you can find a person like a 16 year old kid in a full-tucked position to do test runs on it. |
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Post by 90GTVert on Apr 28, 2016 5:45:11 GMT -5
Good point. I never even thought about that little extra bit that's on the advanced key.
Not sure I want to lean it out and make it run 450 degrees. I don't imagine my 2-3 degrees of advance will cool it enough to make it run as cool as it does with the larger jet. If by only the A9 cam for power you mean go back to the stock airbox and exhaust and cylinder, I have to say no thanks for now. My stock airbox is a pain to work with. I'm not even a big fan of open filters, but I hate working with this one. I have to heat the thing just to make it pliable enough to get it on the carb. The exhaust, I'm not as attached to, but I'd have to buy a new header and I don't think it will change much. The CDI stuff really makes no difference at WOT for speed. Probably 1/2 degree. I've tried it both ways there.
Currently using Mobil 1 synthetic 75W90. I'd be more likely to switch to a synthetic engine oil, though not super thin. I'm currently using the same cheap Shell Rotella T 15W40 that I use in the TaoTao. I've thought about switching, but the new cylinder was fresh and I have Rotella T sitting here so I just stuck with it for now. I'm more concerned with protection than power/losses where oil is concerned. Even race teams usually switch out the thin oils when qualifying is done.
No offense taken. I'm the better part of 300lbs. I should be smart enough to lose weight and keep it off, but I'm just not gonna be a light rider short of cutting myself in half. I'm looking for real world use out of this thing and of course a bit of a learning experience, not the bragging rights of a number less than my 2Ts and similar to what people claim on 139QMBs.
I had a 150lb friend ride the SunL and go 51MPH or so when I was stuck at 48MPH and trying to get 50MPH. I hadn't accomplished 50MPH regardless of what the scooter did with another rider though, so I had to keep working on it. Would be the same here. I wanna ride. I don't want a stand in.
If it sounds like I'm shooting down your ideas Dave, I don't mean to. I appreciate your input and do put thought into it.
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Post by Fox on Apr 28, 2016 5:56:10 GMT -5
Remember when I used to tell newbs to just "stare at it for a while and it will all make sense" and it worked for some. I'm telling you that now Brent. You'll figure it out. Back to basics. It's an air pump. I'm sure if you stare at it long enough you'll reach your goal.
That said as someone who has dealt with these thing for a while I am leaning toward a stock(er) spark timing for peak performance but if you prove me wrong I will relish it.
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Post by cwazywazy on Apr 28, 2016 7:07:10 GMT -5
NOS. Just sayin.
Forgive me if this was already posted somewhere in the thread, but what are you getting in terms of compression?
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Post by 90GTVert on Apr 28, 2016 8:43:31 GMT -5
Forgive me if this was already posted somewhere in the thread, but what are you getting in terms of compression? 10.57:1 static compression ratio. I haven't used a compression tester if that's the number you were looking for. It was 203-204psi with an Actron tester before I did anything to it and I measured actual CR at 9.69:1 then. Seems high, but that's what I got. |
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Post by 190mech on Apr 29, 2016 3:50:49 GMT -5
Trying to figure out your non timing light issue,,could it be the pulse/pickup coil is moved enough to be 'out of phase' in relation to the stator/flywheel??
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Post by 90GTVert on Apr 29, 2016 4:40:59 GMT -5
I didn't try moving it yet, but it does work just fine on the TaoTao with the same mod. It's worth a shot. Every ignition component has been swapped out to check other than the flywheel, so I'm about out of ideas.
EDIT : Actually I guess I did try that. The replacement stator was not modified.
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Post by 90GTVert on Apr 30, 2016 15:31:40 GMT -5
I rode to a friend's house today and when I came back the scoop for the fan shrouds had arrived.  I'm not a big fan of cheap chrome, so I scuffed it up and painted it flat black before installing it. The holes didn't line up with my shroud well at all. Once installed, it didn't fit well. There are gaps all around it's edges. There were two ways I could install it to have it sort of facing the front to act like a scoop. I chose to leave it most open on the top side, thinking maybe it would draw less air from near the exhaust.    I also noted that the inlet diameter is 3 5/8" with a big central bar through it. My shrouds are 4 3/16". So I've got a scoop with a smaller inlet and big gaps in it that I think would prevent it from taking full advantage of any air it scoops up. Didn't seem like a winning recipe to me, but I might as well give it a shot. I was happy because it's not a great day at 50F and cloudy, but the temp has only changed 2 degrees since 9AM, the wind has stayed about the same, it's still full cloud cover, etc... Conditions are great for being fair to try something like this. I took it for a ride similar to what I did earlier, which was a 50MPH road so it had to be WOT to keep up. By the time I was nearly as far as I was earlier in the day WOT, I let out of it because it was getting hotter than I wanted, above 440F. On the earlier ride, I never even noticed it above 421F, so I assume it hit 433 only briefly. This was staying there and willing to climb higher. I actually got back on it on another stretch and it did go higher, to over 450F. Here are two shots of the Vapor's max temp recording. The first is from the morning ride without the scoop and the second is from the ride with the scoop.   Even when I let out of it, it didn't cool like it normally does. Usually if I back out just a little bit, the temp will go down to 400F or less. I had to drop into the mid 40s to get it to cruise from 390-410F. Once again, nothing works for me like it does for anyone else on the internet. There are plenty of people saying these things work and their engines no longer overheat or feel better or they don't think they're as hot and so on. Mine did totally the opposite and made it run hotter... kind of like you'd expect by limiting the inlet diameter and having a leaky path to the shroud really. Maybe I just got a junker and the others fit great? Maybe most people don't monitor temps closely and want them to work? In defense of scoops, I have built them for my 2Ts and documented that they work. Those were as large or larger than the inlet and sealed to the shroud and a bit larger. They did make the engine run hotter by a little bit at idle, but when I was WOT or moving at all and more concerned with temps, they did cool the engine slightly better. Needless to say, as soon as my gear came off, the scoop was removed. |
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Post by 190mech on Apr 30, 2016 15:59:45 GMT -5
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