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Post by usmcdoc on Nov 26, 2011 20:45:02 GMT -5
Looking for input. Neighbor has a Jonway Hornet 2 stroke. He put on a Malossi 70cc BBK yesterday...and has been gentle with it....yet had 2 soft seizes this a.m. He premixes with the proper synthetic at a very rich 40:1. Sez he still uses the stock main jet......whatever size it is...I am not sure...I would guess #76 as that is what I see in most Minarelli engines. Does anyone think the stock jet is causing a seize by running to lean?...Makes a bit of sense to me....since with premix...less fuel means less oil as well. But I am just guessing...as only soft seize I have seen were on stock engines with oil pump maladjustments. If so....what size jet do you 2 stroke 70cc folks use?...Would raising the carb needle to richen it help also?..or maybe a combo of both?...Cause 40:1 premix is a rich mixture. My Husquvarna chainsaws use it...and scream top speed all day without a glitch. Both times he said it happened just about half throttle...slight bog first....then locked up. 3rd minarelli soft seize I have seen this week..the others were oil related due to improper adjustment of the pump cable....this one quite obviously can't be as it uses premix at 40:1...so much in fact it smokes like a Hollywood fog machine...lol... :help:
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Post by jmkjr72 on Nov 26, 2011 20:51:42 GMT -5
jet size is going to depend upon the carb
i know the zuma uses a 14mm tk and runs a 80 mj stock
and normaly with just a kit we upjet to an 82 to 84 and if its a kit and pipe we run a 84 or 86 heck some times even larger or a daytona 85 main jet when we can find the daytonas made for tk carbs
and we also raise the needle
if it has a 12 mm carb stock the best thing is to get a larger carb 12 mm carbs just cant flow right to run a bbk
heck even with a ported stock cyl i had to upjet the stock carb on the zuma
but if he is running the stock jet and the stock plug my bet is he is running lean hot and on the verge of detonation and thats what is causing the issues
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Post by usmcdoc on Nov 27, 2011 19:45:38 GMT -5
jmkjr72...took his jet out today...it is a 68....wow...I think chainsaws come bigger than that. Obviously :stars: it was a lean run...
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Post by jmkjr72 on Nov 27, 2011 20:04:02 GMT -5
well the zuma runs a 14 mm tk carb and 80mj stock the 2 stroke vino that has the restricted air box had a 64 with a 14mm tk
and the ones that came with a 12mm del had a 93 mj stock
but yeah i dont know what carb he has on his but any of them a 68 is small
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Post by usmcdoc on Nov 27, 2011 23:33:45 GMT -5
jmkjr72...carb is a Mikuni....appears to be 14 mm...
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Post by aeroxbud on Nov 28, 2011 16:25:25 GMT -5
i would think you need to up jet i would start of bigger then work down in size
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Post by jmkjr72 on Nov 28, 2011 18:25:31 GMT -5
i wish i had a chart for tk jet hole sizes and flow
i thought they were fairly close to tk jets
if you can get an 85 toss it in and go from there
i know on the zumas some of the guys have had a hard time getting the malossi sport kit to tune right
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Post by usmcdoc on Jan 19, 2012 10:06:04 GMT -5
jet size is going to depend upon the carb i know the zuma uses a 14mm tk and runs a 80 mj stock and normaly with just a kit we upjet to an 82 to 84 and if its a kit and pipe we run a 84 or 86 heck some times even larger or a daytona 85 main jet when we can find the daytonas made for tk carbs and we also raise the needle if it has a 12 mm carb stock the best thing is to get a larger carb 12 mm carbs just cant flow right to run a bbk heck even with a ported stock cyl i had to upjet the stock carb on the zuma but if he is running the stock jet and the stock plug my bet is he is running lean hot and on the verge of detonation and thats what is causing the issues What would I need...a hotter or colder plug?...what would the number be for it? Stock exhaust and airbox...#90 seems rich falls off and bogs at an attempt at WOT. Put in a #85 but been to cold n snowy to test it...  |
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Post by jmkjr72 on Jan 19, 2012 18:52:37 GMT -5
for the malosi cast iron sport kit i would run a br8hs or b8hs (depends upon if the scoot came with a resistor plug or not or if you are running a nolgy hot wire for a hot wire set up no r)
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