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Post by brancher on Apr 20, 2012 20:50:44 GMT -5
well i added 21mmcarb, 20mm spacer under cyl, br8hs plug
now i have soft seize when i get on it from a stop at about 20mph. when i go down the road now it makes the knock at full thottle (from the little i drove it)
i drove it about 3 miles looks lean with open air filter and 95 jet.
added stock air box with neck removed and it seemed to run better but still looks lean. I can't beleive a 21mm carb with stock intake (carbon reeds)and stock airbox with 95 jet would be lean. Will have to get some jets.
i never experienced soft seize before. I don't like it.
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Post by stevo52 on Apr 20, 2012 21:44:55 GMT -5
I run basically the same setup as the OP. A stage 6 sport pro on my vento zip. No gaskets anywhere to get the squish to .75mm. However, as stated above you do indeed loose transfer port duration I noticed my piston wasn't completely clearing the transfer. So I took my cylinder off to mill it and add the shims at the base. Still tuning it though. However I ran the stock carb for 1 k miles and the 19mm for 500 miles. The cylinder still has the cross hatching and no noticeable damage from being lean, detonation, etc actually seems a bit rich and healthy. It ran fine with no gaskets. Only thing I noticed is it seeps out some gas/oil mix. I'm not sure why everyone runs such high squish clearance you guys are definitively missing out on power. Of course you do have to mill the head which can be inconvenient...
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Post by stevo52 on Apr 20, 2012 21:53:37 GMT -5
I doubt its lean with the stock airbox and a 95 main. I would check for air leaks at the exhaust, reed valves, head, etc. Are you sure its soft seizing? Its the cylinder scuffed? I could have swore I soft seized my motor a couple times but no signs of it. It was from improper a/f ratio. I really do think my oil saved me a couple times...Motul 710/800 is good stuff it can take a beating. I suggest you run a full syn oil too.
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Post by jmkjr72 on Apr 20, 2012 22:36:43 GMT -5
well the brand of carb is going to play a roll in the jetting
if its a del carb with the oem air box you will need to run about a 98 main jet with a w8 needle
with the open filter you will need some where around a 108
but if you did soft seize it you proably destoryed the piston if you hear noise the athena kit doesnt take well to soft seizes
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Post by brancher on Apr 21, 2012 6:36:43 GMT -5
I'm not positive it was soft seize. From what I read o here it was.
From a stop if I give it wot it takes of and then bog/ss then it takes off again. It does it like three times from a stop to 40mph. It Sounds like the motor completely stops for a secound or two and then takes back off. Is that soft seize?
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Post by brancher on Apr 21, 2012 6:38:22 GMT -5
well the brand of carb is going to play a roll in the jetting if its a del carb with the oem air box you will need to run about a 98 main jet with a w8 needle with the open filter you will need some where around a 108 but if you did soft seize it you proably destoryed the piston if you hear noise the athena kit doesnt take well to soft seizes Arreche Carb. |
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Post by 90GTVert on Apr 21, 2012 6:41:35 GMT -5
A soft seize means the engine completely stops usually, as in it dies out. It can be restarted right away at times or sometimes it has to cool a little. What you described sounds more like a lean condition to me. Sometimes when lean they kinda surge like that. Hit the throttle and they go, then run out of fuel, then build up enough for another surge, then bog again, and so on.
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Post by brancher on Apr 21, 2012 15:31:07 GMT -5
A soft seize means the engine completely stops usually, as in it dies out. It can be restarted right away at times or sometimes it has to cool a little. What you described sounds more like a lean condition to me. Sometimes when lean they kinda surge like that. Hit the throttle and they go, then run out of fuel, then build up enough for another surge, then bog again, and so on. so do you think with my set up their is any way it is lean? I'm glad to hear its not to lean. |
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Post by 90GTVert on Apr 21, 2012 15:57:30 GMT -5
I would definitely give a larger jet a shot. You said it improved with the stock airbox. That's telling you it's lean.
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Post by stevo52 on Apr 21, 2012 15:58:04 GMT -5
My arreche 19mm surged and hesitated like that as well at mid throttle ranges. It went away with the leaner taper S1 needle arreche makes. So in my case I was rich, fouling plugs and all with the stock 01 needle and an 85 or 90 main. I settled on the S1 needle and 80 main with the stock airbox. However, 90GTVert knows alot more about tuning than I do...maybe you are lean. You really just have to do plug chops. Honestly the carb was the most difficult and time consuming mod to get right.
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Post by 90GTVert on Apr 21, 2012 16:32:26 GMT -5
They will surge when rich at times too. I use two things to get me a ballpark of which way I basically need to go. 1 is sound... if it sputters (sometimes excessive smoke accompanies this) or kinda gurgles then that tends to be rich. If it's more of a hollow or smooth sound I find it's more likely to be lean. 2nd thing is just a quick look at the plug. Without even going into great detail you can get a ballpark on sight simply. If it's wet after a WOT pass, assume it's too rich. If it's dry it could be close or too lean. If you arent testing WOT for long or letting it idle or stay part throttle it's harder to tell. Sometimes for example the idle or needle settings can be rich, but the main jet lean. Then you might see a wet ring but dry center. It can get involved, but use the simple things like seeing what more and less restricted airboxes or lack of will do and the very basic sights and sounds to get a rough idea.
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Post by brancher on Apr 21, 2012 18:10:42 GMT -5
when you all do plug chops how far do you ride? I usually ride a mile and look. Then back a mile and look. Is that far enough?
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Post by 90GTVert on Apr 21, 2012 18:22:04 GMT -5
49ccscoot.proboards.com/index.cgi?board=gentech&action=display&thread=1727I do 1-2 miles WOT lately. If you are using short passes like that, you mainly just look for wet or dry and observe performance changes carefully in my experience. You can look for the mixture ring on short passes with a new plug each time, but that can be a real pain. If you are trying to get the caramel kinda reads, those usually take quite a bit of riding. The simple keys are experimenting with different jets and the sounds and wet/dry I mentioned above. Everyone has their own preferences and tricks though.
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Post by brancher on Apr 21, 2012 20:22:08 GMT -5
I have studied that post and have it saved. :spark:
I checked for intake leaks and have none.
This is my plug at wot for 1 mile.
Going to drill jet out and hope rain stops.
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Post by brancher on Apr 21, 2012 22:45:13 GMT -5
maybe its an arreche carb thing but the bit i went to start with says im only a 90 jet (going by chart) jet says 95. so i went with 93 for now and still looks lean at wot but now runs like crap at 1/4-3/4. ill wait till i get the main jet right before i mess with that.
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