76 340 LF won't run up
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- Posts: 168
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76 340 LF won't run up
hi
I recently acquired a 76 340 liquifire. it will start cold first pull and idle like a champ but wont power up at all, in fact, rpms actually decrease as I apply throttle - no stumbling or missing or backfiring, only decreasing rpms. Weird. What gives? it has fresh gas, new plugs and caps. spark is good and compression is 160 per side.
thx!
Lloyd Neufeld
Beausejour, MB
I recently acquired a 76 340 liquifire. it will start cold first pull and idle like a champ but wont power up at all, in fact, rpms actually decrease as I apply throttle - no stumbling or missing or backfiring, only decreasing rpms. Weird. What gives? it has fresh gas, new plugs and caps. spark is good and compression is 160 per side.
thx!
Lloyd Neufeld
Beausejour, MB
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Re: 76 340 LF won't run up
Besides crank seals I would check the ohms of the high speed winding.
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'76 440 cyclone
'76 440 liquifire
'78 440 Cyclone
'75 JDX8 (sold to a member here)
'78 Liquifire(CrossCountry Clone)
'80 Liquifire(sold)
'76 440 liquifire
'78 440 Cyclone
'75 JDX8 (sold to a member here)
'78 Liquifire(CrossCountry Clone)
'80 Liquifire(sold)
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Re: 76 340 LF won't run up
By the way, plugs very wet...engine seems to be getting too much fuel...black exhaust too
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Re: 76 340 LF won't run up
Give it choke then let us know what happens
1975 340/s Speed Run Sled
1975 340/s I500 #161
1980 Liquifire SN# 4995 From WA Speed Run Sled
1980 Liquifire SN# 4996 From MN
1983 Sportfire
1984 Liquifire Deep Snow Tunnel 4/6 motor
1984 Sprintfire (2)
***Duelling Deere Garage***
1975 340/s I500 #161
1980 Liquifire SN# 4995 From WA Speed Run Sled
1980 Liquifire SN# 4996 From MN
1983 Sportfire
1984 Liquifire Deep Snow Tunnel 4/6 motor
1984 Sprintfire (2)
***Duelling Deere Garage***
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Re: 76 340 LF won't run up
thx sledhead but when I got ur reply I already had the carbs off. I went thru both carbs, not really dirty, however, cleaned them up and reassembled, and then had them pressure tested. they both failed - so needle/seat shopping I go - see what happens after those are replaced.
thx guys, i'll keep ya posted
thx guys, i'll keep ya posted
Re: 76 340 LF won't run up
x2harleysportster wrote:Besides crank seals I would check the ohms of the high speed winding.
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"There's No Iron Like Old Iron"
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Re: 76 340 LF won't run up
installed refurbished carbs last nite...fired rite up, however, not much difference in result. got some increase in rpm to point of clutch engagement but that's about it. lots lots lots of smoke as I try to throttle up.
by the way, applying choke made things worse
plugs are wet
how do I ohm check the high-speed windings?
thx
Lloyd
by the way, applying choke made things worse
plugs are wet
how do I ohm check the high-speed windings?
thx
Lloyd
Last edited by luvzvintage on Mon Mar 14, 2016 3:45 pm, edited 1 time in total.
Re: 76 340 LF won't run up
"There's No Iron Like Old Iron"
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Re: 76 340 LF won't run up
Greetingz,
wanted to visit the topic page to view measuring points but can't access - can anyone help with this as I'd like to check the readings now that I've got the engine apart.
Polcat?
thx!!!!!!
Lloyd
wanted to visit the topic page to view measuring points but can't access - can anyone help with this as I'd like to check the readings now that I've got the engine apart.
Polcat?
thx!!!!!!
Lloyd
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Re: 76 340 LF won't run up
best I can deduce is that I've got 54 ohm measuring from blue wire to stator ring. this sound ok??
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Re: 76 340 LF won't run up
ive got a parts engine that's still together and untested - its high speed coil measures 78.6 blue wire to gnd
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Re: 76 340 LF won't run up
??????
seriously, can 25 some ohms make such a difference?
seriously, can 25 some ohms make such a difference?
Re: 76 340 LF won't run up
If you think about how many turns of copperthread you need to get 25 Ohms, yes it can make a big difference in what voltage you get out from the coil.
And probably you have a shortcut in the coil, that's why the resisrance has dropped 25 Ohm.
And probably you have a shortcut in the coil, that's why the resisrance has dropped 25 Ohm.
Sleds...
2xJOHN DEERE SPRINTFIRE 1983.
YAMAHA GP292b 1973
OCKELBO Trioman 1975
YAMAHA SRV 1982 (shrinked)
YAMAHA SRV 1990
YAMAHA SRV 1991
LYNX Rave 600ACE 2013
LYNX BOONDOCKER RE 3700 850 ETEC 2018
2xJOHN DEERE SPRINTFIRE 1983.
YAMAHA GP292b 1973
OCKELBO Trioman 1975
YAMAHA SRV 1982 (shrinked)
YAMAHA SRV 1990
YAMAHA SRV 1991
LYNX Rave 600ACE 2013
LYNX BOONDOCKER RE 3700 850 ETEC 2018
Re: 76 340 LF won't run up
Replace the crank seals before messing around too much more. They are undoubtedly dried up and leaking... Had same issue on my 340 Kohler Spitfire... Tried it all, electrical, carb, etc... It was the seals... Once replaced, runs like a top!