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Post by kevinx on Aug 10, 2008 20:54:06 GMT -5
I have a 1E40QMB motor can i just add a 70cc cylinder kit and be good to go or do you have to add exhaust and a new carb i really don't want to
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Post by Karl on Aug 10, 2008 21:01:32 GMT -5
I just did some research on that the other day and they say that you can just bolt it on with no other mods. But you MAY have to downsize your main jet one size....i.e....go from a 70 to a 68 or 67.5. You would think that you'd upjet but a big bore creates more velocity and pulls more fuel. This in turn could make your engine run too rich. Start with stock settings and see how it works. I ordered 70cc kit from eBay for about $110 with shipping. I couldn't find another one for $110 but here's one for $140 shipping included. tinyurl.com/6kd2m7There are better deals out there if you look for them. Remember that you need to know if you have a 10mm or 12mm wrist pin bearing. |
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Post by 90GTVert on Aug 10, 2008 21:45:40 GMT -5
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Post by Karl on Aug 11, 2008 14:00:32 GMT -5
PM 90GTVert (Brent) and he'll send you a link to where he got his.
Brent, don't you like how I just put it all on you? ;D
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Post by kevinx on Aug 11, 2008 14:09:43 GMT -5
I got a 70cc kit from scootertronics and an exhaust from parts for scooters
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Post by kevinx on Aug 11, 2008 14:13:39 GMT -5
When i pit the scooter back together i am not using the oil injection again i will premix the oil and fuel. what should be the Premix be? 50:1
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Post by Karl on Aug 11, 2008 14:21:47 GMT -5
This one's cheap. I just ordered it and haven't recieved it yet but will give an update when I do! tinyurl.com/5wcsdc |
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Post by 90GTVert on Aug 11, 2008 21:31:01 GMT -5
When i pit the scooter back together i am not using the oil injection again i will premix the oil and fuel. what should be the Premix be? 50:1 People argue about premix ratios all the time. I like to run at around 45:1 with a synthetic, but start off with a mineral oil for break in and mix the oil a little rich, around 30:1. There are oils out there that allow you to mix up to 100:1 like amsoil sabre. |
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Post by rallyrrr on Aug 12, 2008 19:57:51 GMT -5
Kargo. That kit looks like it has a quiescent-type combustion chamber. Not real racy but you may not be looking for that. High performance ones have a squish-type combustion chamber. Those with squish-type can run higher compression ratios and take high rpm better. You can't beat $90.00 for a displacement upgrade though. Have you thought about altering your port timings on it? I'm sure you will check out the chamfering though.
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Post by Karl on Aug 12, 2008 20:17:27 GMT -5
Rally, you and Brent are the real Gurus around here (and we're glad to have you), I was just given the title because I modded a couple other forums and was decent at troubleshooting ;D
Funny that you should ask because 90GTVert (Brent) and I were talking about porting/polishing some 90cc motors that we may be running across in the near future.
As for this kit, I'm just going to bolt it on and take it from there. What do you suggest, bud?
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Post by rallyrrr on Aug 13, 2008 16:08:09 GMT -5
Karl and Brent,
Please don't go heaping praise on me, I'm the one ruining pistons after all! Getting high performance from small engines has been an interest and hobby of mine since back in the mid seventies (I guess that kind of dates me huh?) I had three Datsun 510s. The first one I turbocharged. The last one I bored 0.060 and put high compression 240z pistons and a Weber carb on it. I installed the factory rally suspension from Datsun Competition on all of them. I was the terror of Weyerhaeuser gravel roads around here. These were great cars and were termed "the poor man's BMW" since the engine and suspension mimicked their 3-series at the time. Tough car indeed! That first one had a clearly visable sag on both sides between the front and back wheels I pounded and jumped it so much! Bilstein struts and shocks and M&S tires all around were a staple diet of me and my 510. I wore out a come-a-long winching myself out of ditches and other mishaps. I am truly blessed to be alive today. If you want to feel alive go over 100 MPH down a tree lined one lane gravel road! Have you figured out where I got my handle from yet? I attended many SCCA Pro rallies in Texas,Oklahoma, Arkansas and Missouri but was never fortunate enough to compete in one. I think I would have done pretty good though since I practiced almost every day. Enough reminiscing. I just wanted you to know that I come by my need for speed honestly.
Okay, back to two strokes. Did Brent check into that book I referred him to
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Post by rallyrrr on Aug 13, 2008 16:37:19 GMT -5
Crap. I don't know how that happened. I don't remember hitting the "post reply button". But anyway, I suggest you get a good reference like "Two Stroke Performance Tuning" I referred to under the "What Octane..." post in the Two Stroke section. It was about $40.00. The other book I could have gotten was $70.00 or so at Books-a-Million.
If I could figure out how to post scanned images here I wouldn't mind sending pages out of the book, especially on porting. But you know how we old guys and computers get along. Also I am a hunt-and-peck typer and posting is pretty time consuming for me.
Cheers,
Reg
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Post by 90GTVert on Aug 13, 2008 18:00:44 GMT -5
I actually got the 2 stroke tuners handbook by gordon jennings that was available local. Maybe someday I'll get around to reading it. I've been looking into some other things lately and with browsing the forum and such I get my fill of reading.
I'm no guru but I can accomplish what I want to do for the most part. I forget formulas anyway, so I'd have to look it up again when it comes time to use it. The only way I'd ever remember the math is if I dealt with it very often. That said, I do plan to read up and greatly appreciate the info on a good book.
BTW, how did you index your plug exhaust or intake? I know people debate it and I was wondering if the book you read gave any opinion. I always heard to index toward the exhaust port to reduce fouling on a 2 stroke. Others say you should treat it just like a 4 stroke and aim at the intake so the spark is not shielded by the ground electrode. Some say its pointless on 2 strokes because fuel/air enters from different directions. I don't honestly plan to index my plug, just curious. It's generally agreed that it can create a 1-2% power increase for 4 strokes. It should be the same or less for 2 strokes, so when you make say 5HP you gain .05-.10 HP.
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Post by Karl on Aug 13, 2008 21:18:34 GMT -5
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Post by rallyrrr on Aug 13, 2008 22:03:59 GMT -5
Brent,
You may be right about it not mattering which way the plug is oriented. I could have sworn that I remembered seeing pictures of a plug with different thicknesses of compression rings in my book but I can't find it now. I remember turning the open side toward the top (boost ports) because when I checked a new plug after running at about 10,000 rpm for about 20 minutes the plug was clean on this side as if the flow stream hit this side first. Remember I raised my boost ports to open before the other transfers. This increased my intake duration and got the stagnant exhaust gasses left in the combustion chamber area moving toward the exhaust port right off the bat upon intake opening. Today's two stroke filling theory, with so many transfers (5-6) and their being directed mostly across the top of the piston in a fairly slow and gentle fashion is prone to trap a pocket of residual exhaust gas here. Hense more fuel/air with less dilution from hot exhaust gasses and thus more power.
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Post by Karl on Aug 13, 2008 22:13:43 GMT -5
Rally, I have what looks to be some sort of emissions thing on my scoot. It looks like a hose leading from the exhaust to a petcock, and then that hose leads to the frame tube. WTH is that thing?
Karl
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Post by rallyrrr on Aug 14, 2008 0:12:04 GMT -5
Man, you got me on that one. Exactly where on the exhaust is the tube hooked up? You're not putting me on are you?
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Post by rallyrrr on Aug 14, 2008 1:21:27 GMT -5
I just now saw the pictures of the 510s. Almost got a woodie. I had two four doors and one two door. Also owned two 1200 fastback coupes (one of the favorites of import drag racers now it seems). They sure are hard to find. My brother had a slick 240z. Used to sync his Hitachi/S.U. carbs for him. The 1200s were the model T of the time. Dirt simple and a joy to work on. You could just bend over and remove/replace the starters on them. They weighed less than 1700 lbs. In fact, I went a whole summer bump starting one singlehandedly, as it had no starter on it at all while going to tech school.
The roll cage and turbo from my first 510 are still in the attic where I live now.
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Post by rallyrrr on Aug 14, 2008 1:29:18 GMT -5
Just looked at the pictures again and had to forceably abstain from playing with myself. I had the classic four spoke American Racing "Mags" on mine, popular at the time on these. I had it painted matellic silver.
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Post by 90GTVert on Aug 14, 2008 10:51:14 GMT -5
Rally, I checked the tuners handbook out and it mentions nothing of indexing spark plugs. It covers spark plug location in the cylinder, but it is referring to the way the head is cast not aiming the plug.
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Post by rallyrrr on Aug 14, 2008 21:07:14 GMT -5
Brent,why does indexing work on any engine?
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Post by 90GTVert on Aug 14, 2008 23:04:48 GMT -5
It should expose the spark to the incoming air/fuel mixture instead of shielding it with the ground electrode. Kind of like having a stronger spark, without having a stronger spark.
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Post by rallyrrr on Aug 15, 2008 1:40:47 GMT -5
What is the logic on four strokes? The valve(s) have closed probably 120 degrees before ignition point. The air/fuel is being crushed with resulting turbulence and by the time the spark plug fires air and fuel is homogeneous. I can only see advantages with direct fuel injection ala the new Mazdas. What do you think? It is probably an issue with the hot exhaust valve(s) that if the open side of the plug with the fatter spark kernel sees cooler denser fuel/air when it is turned toward the cooler intake(s) the combustion process kicks off stronger. The same should hold true for two strokes though because of the hot side of the piston where the exhaust exits. I say turn the gap side away from the exhaust side four stroke or two stroke.
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Post by 90GTVert on Aug 15, 2008 1:53:02 GMT -5
That all sounds logical to me.
I hope you don't take this the wrong way, but I try not to overthink this stuff. In cars, you can find dyno proven info on indexing for different setups. Follow proven advice. There are certainly way smarter people than me out there that have already figured it out. Kinda the old work smarter not harder thing. I cant find reliable info for the 2 stroke scoots and a few different opinions make sense to me. Since I don't know for sure and we're talking .05-.10 HP if I were lucky, I just screw the plug in and let it point where it may. It has to make you wonder if there's really a good benefit when the two stroke community cant seem to agree on this topic.
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Post by Karl on Aug 15, 2008 15:16:23 GMT -5
Speaking of, have you guys seen that Indian guy who carved patterns into the head of his engines and the turbulence from those simple patterns make combustion more complete, cooler, quieter and gave better economy? It was a few years ago that he did this.
Karl
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Post by 90GTVert on Aug 15, 2008 17:23:05 GMT -5
Can't say I have.
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Post by kevinx on Aug 16, 2008 13:21:06 GMT -5
I need to know what side if the piston goes up the solid part or the part with the two nocthes up toward the carb down toward the exhaust
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Post by Karl on Aug 16, 2008 13:29:22 GMT -5
Kevin,
The arrow on the top of the piston will point toward the exhaust port, if that helps.
Karl
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Post by kevinx on Aug 16, 2008 13:33:42 GMT -5
Thanks i just don't want to put in on backwards
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Post by rallyrrr on Aug 16, 2008 13:36:37 GMT -5
Notches on skirt away from exhaust. They work with the boost ports for crankcase filling by extending intake duration.
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