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Post by rcq92130 on Jun 30, 2015 21:42:08 GMT -5
Briggs & Stratton Idle Speeds
Model Series Type Idle Speed ( rpm )
60000 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
80000 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
90000 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
10A000 Thru 10M000 L-Head Aluminum/Cast Sleeve Single Cylinder None
110000 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
120000 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
130000 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
170000 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
171700 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
190000 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
191700 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
220000, 250000 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
280000 L-Head Aluminum/Cast Sleeve Single Cylinder 1750
230000 L-Head Cast Iron Single Cylinder 1200
240000 L-Head Cast Iron Single Cylinder 1200
320000 L-Head Cast Iron Single Cylinder 1200
400000, 420000, 460000 L-Head Opposed Twin Cylinder 1400
50000 OHV Single Cylinder 1500
85400 OHV Single Cylinder 1300
97700, 99700 OHV Single Cylinder 1500
115400, 117400, 118400 OHV Single Cylinder 1300
120000 Horizontal Shaft OHV Single Cylinder 1750
120000 Vertical Shaft OHV Single Cylinder 1750
138400 OHV Single Cylinder 1300
185400 OHV Single Cylinder 1300
200000 OHV Single Cylinder 1750
210000 Horizontal Shaft OHV Single Cylinder 1750
210000 Vertical Shaft OHV Single Cylinder 1750
235400, 245400 OHV Single Cylinder 1300
280000 OHV Single Cylinder 1750
310000 OHV Single Cylinder 1750
290000, 294000, 303000 OHV Twin Cylinder White Governed Idle Spring: 1100 / Red Governed Idle Spring: 1400
350000 OHV Twin Cylinder White Governed Idle Spring: 1100 / Red Governed Idle Spring: 1400
380000 OHV Twin Cylinder White Governed Idle Spring: 1100 / Red Governed Idle Spring: 1400
405000 OHV Twin Cylinder 1750
445000 OHV Twin Cylinder 1750
540000 OHV Twin Cylinder 1500
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Post by rcq92130 on Jun 30, 2015 19:38:38 GMT -5
But, then, at the low end if you actually can tune your beast well enough to get it to idle without dying at an indicated 1,200 (near super human) ... you think the thing is actually idling at 600 rpm  That's impossible for a 1 cylinder engine. |
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Post by rcq92130 on Jun 30, 2015 9:37:50 GMT -5
I'd like everyone to read this . this is true , but yet it is also false. Because there are two different types of ignition systems used by four stroke engines. www.mobiusinstitute.com/site2/item.asp?LinkID=10013&iVibe=1&sTitle=Analysis%20Definitions. Now let's say when installing these TACHS , the Chinese and others are going by this method. This means the TACHS installed will read twice the true rpms. I still find it very hard to believe that when these engines are near stall , they are still idling at 1200-1400 or more rpms! You can actually hear each exhaust stroke clearly during this time and it doesn't seem even close to those rpms. George - are you thinking when yuo are running WOT, and your tach is showing 7,500 ... the engine is really spinning at 15,000? |
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Post by rcq92130 on Jun 30, 2015 1:23:53 GMT -5
Here is another major issue. A 2 stroke tach is set for an every rotation fire. Many think these 4 strokes only fire every other revolution , however this is false. These 4 strokes fire every revolution just like a 2 stroke. So if our gauges are set to read every ignition fire instead of every true fire , then they are doubling the rpms to get the correct rpm. However by doing this they are doubling the true rpm. Not possible the tachs are doubling the actual engine speed .... otherwise they would be showing 15K or 16K at WOT. |
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Post by rcq92130 on Jun 30, 2015 1:22:18 GMT -5
Actually these scoots fire on every revolution. They fire at tdc each time it hits Tdc, but there is only ignition on every other spark. So every full revolution down then up , the plug fires. So every other spark is wasted. Each cycle is 4 strokes or 2 rotations, but every rotation the plug sparks. So 2 sparks per cycle. Once on the fuel compression stroke , and one as the exhaust valve opens to let out the gasses. The second is the wasted spark. Oh, that's right. Pickup on the flywheel (not valve train, and no gear reduction); no computer. Wonder what that does to the valves. |
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Post by rcq92130 on Jun 29, 2015 23:21:53 GMT -5
Remember, these are 4-strokes so 2 revolutions of the crank = 1 complete cycle - 1 spark (and 4 revs of the crank = 2 sparks).
The tachs I have are both non-adjustable, made for 4-stroke engines. At best I can get to about 8k rpm's. Trust me - that little COX-airplane engine is NOT going 16K (and also is not only going 4 K).
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Post by rcq92130 on Jun 29, 2015 22:02:43 GMT -5
I could tape a straw to the variator and hold out a piece of string, so the stew will hit the string every rotation. If its spinning slow enough to be able to count , then we will know the true rpms. George --- You KNOW I'm a big fan of us researching these machines to figure out what is really going on. However ... A tachometer is a very simple thing - just an IC that counts pulses. That is about as basic as an electronic device can get. True - some may be defective and not work properly (especially if made in the land of rice & pigeon's eyeballs). But aside from the defective units, they are probably reasonably accurate. How about this - since seeing something that is rotating at a rate of 15 times every second is close to impossible ... I have TWO tachs - one digital and one analog. The digital one isn't connected right now. but as soon as I get a chance I'll hook it up also and see how well the 2 compare. The odds BOTH would be wrong by the same amount are pretty slim. That work? |
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Post by rcq92130 on Jun 29, 2015 16:31:42 GMT -5
There is zero chance a GY6 engine would idle and not quit at 750 RPM.
Sorry - that is the real world.
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Post by rcq92130 on Jun 28, 2015 14:13:10 GMT -5
Rcq is a really good guy. I'm sure he can send it to you with free shipping. It should only cost the price of a stamp. Ok! I'll pm him with my address. Was just about to give up - had looked thru all the scooter parts i had -- and then on the very last cylinder head was that little NCY plate! In an envelope and will be on the way to you tomorrow (from san diego). If you spend 35 cents postage to return to me 35 cents for postage I'll be deeply offended ! Glad to help. ps: the gasket that goes between the NCY plate and the head came off pretty intact, but i still strongly urge you put a thin coat of gasket sealant (not Permatex) on the thing so you don't end up doing the job over. |
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Post by rcq92130 on Jun 27, 2015 18:28:51 GMT -5
I totally agree, the position is quite confusing. But my screw is just like the picture, so clockwise to lean it is. Hopefully when I make it more lean it will cure my starting/stalling issues I have and I might get my scooter running smoothly eventually haha! This whole thing threw me off a bit, as I read and spoke to people who says new scooters from the factory are set up very lean. So not sure why mine is rich. Your question makes me think this very good tutorial on how to tune your carb. might be of interest: itistheride.boards.net/thread/148/alleys-general-carb-adjustment-guide |
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Post by rcq92130 on Jun 26, 2015 19:09:48 GMT -5
I dont have money for gasket sealant. I do have some black permatex silicone automotive adhesive. I just removed the Pair system and cut outta some sheet metal a blocking plate for the hole on the block. I need to use a sealant to seal it. Will what i have work? I have an NCY plate (presuming you are speaking about the 2-bolt opening in the valve cover) that I no longer need. Let me know; if you want it I'll try to find the thing. You will still need to cut out a gsket to go between it and the valve cover. |
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Post by rcq92130 on Jun 26, 2015 17:08:13 GMT -5
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Post by rcq92130 on Jun 26, 2015 13:42:27 GMT -5
Good news - problem for sure identified. Over the long haul a few drops at a time will become a real nuisance and mess. The stock bolt does not really have an o-ring as a seal - just a rubber band under the head (there is no o-ring slot for an o-ring to fit in). So it might be a bit of a problem using a normal o-ring. Solution is simple --- just smear some gasket cement (silicone) on the o-ring, under the little bolt head and you will not have any drops leaking These are not car engines, small amounts of gasket material in the system and ruin these engines... I personally would NEVER use any gasket maker on any part of the engine as it increases the likelyhood of something going wrong. That's sound advice regarding the gasket under the jug and other areas where a lump of excess gasket sealant might make it's way into the oil galley and clog it. There is no risk of that from sealant under the chain tensioner bolt. I also am re-thinking the "no sealant" philosophy even regarding the 'under jug' gasket. Last time i used no sealant and the paper gasket worked it's way out - leak. I've jumped thru hoops trying to stop the leak w/o tearing the thing apart again and having to go thru another break in cycle. Next time I'll use a touch of sealant - just enough to wet the gasket. The key is to not have sealant squeezed out where it might enter the oil passage to the head. Anyway - that's where I am with sealant on these mouse fart engines. |
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Post by rcq92130 on Jun 26, 2015 12:34:27 GMT -5
well, i bought a new bolt, washer and o ring at home depot for a total of $4 but i have like 20 washers and o rings now... lol it was a perfect fit. The leak is mostly gone, but I do not know for sure yet. Went for a 10 minute ride, parked the scotter an hour later found one or two drops of oil, but could be old oil since I really did not do a good job cleaning it all out... anyway I am not going to worry about it if it one drop here and there... Good news - problem for sure identified. Over the long haul a few drops at a time will become a real nuisance and mess. The stock bolt does not really have an o-ring as a seal - just a rubber band under the head (there is no o-ring slot for an o-ring to fit in). So it might be a bit of a problem using a normal o-ring. Solution is simple --- just smear some gasket cement (silicone) on the o-ring, under the little bolt head and you will not have any drops leaking |
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Post by rcq92130 on Jun 25, 2015 21:41:34 GMT -5
Dont forget to get an "O" ring to make a good seal. If they dont have any presumably you could use some teflon plumbers tape to seal it in a pinch... I've never seen a tensioner with an o ring . the only gasket is between the tensioner assembly and the engine case. The center bolt just screws in. Mine is stripped and it never leaked once. I just barely tighten it down . I've even had the center bolt out before while the engine was idling and it doesn't blow any oil. Left mine out after the first BBK, thinking (like you) it was just to keep dust out. Gushed oil. Put a bolt in and it still weeped oil. Threw some gasket cement under the bolt head and it stopped leaking. |
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