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Author Topic: backfires on start up.  (Read 6601 times)

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Offline PE MAN

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backfires on start up.
« on: October 07, 2011, 05:52:57 pm »
last weekend had a problem, starting to back fire on the way back to the car. an would die with anything more than half throttle. suspected it to be a blown head gasket made sense when i took it home an one of the head nuts was starting to come loose. pulled it down clean everything up. re-anealed the head gasket an put it back on. put bike back together an went to kick start it. same problem. except it wouldnt start. just loud backfires. plenty of spark to the plug when kicked over. i am stumped any help? is it possible for the timing to shift. you wouldnt think it was the flywheel as i had a new one installed a year ago. bad batch of fuel?? it was from a failry big BP an is 98. spark plug? dunno its a new plug?
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Offline AdamN

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Re: backfires on start up.
« Reply #1 on: October 07, 2011, 06:04:57 pm »
Sheared woodruf key maybe?

Adam
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oldfart

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Re: backfires on start up.
« Reply #2 on: October 07, 2011, 06:10:54 pm »
Check base plate timing marks also .
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Offline VMX247

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Re: backfires on start up.
« Reply #3 on: October 07, 2011, 06:32:28 pm »
Quote from: monaro308 on December 03, 2010, 02:14:46 pm



This pe vmxer maybe also able to help !!
cheers


« Last Edit: October 07, 2011, 06:38:10 pm by VMX247 »
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Offline lukeb1961

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Re: backfires on start up.
« Reply #4 on: October 07, 2011, 06:45:17 pm »
Quote from: PE MAN on October 07, 2011, 05:52:57 pm
last weekend had a problem, starting to back fire on the way back to the car. an would die with anything more than half throttle. suspected it to be a blown head gasket made sense when i took it home an one of the head nuts was starting to come loose. pulled it down clean everything up. re-anealed the head gasket an put it back on. put bike back together an went to kick start it. same problem. except it wouldnt start. just loud backfires. plenty of spark to the plug when kicked over. i am stumped any help? is it possible for the timing to shift. you wouldnt think it was the flywheel as i had a new one installed a year ago. bad batch of fuel?? it was from a failry big BP an is 98. spark plug? dunno its a new plug?

Which model PE?
Pop the magneto cover, clean the flywheel shiny and new - now you SHOULD be able to find three little slits in a row. Pop the plug out, kick it over until the piston is highest. now look at the little slits on the flywheel.. where are they? Also, in the centre at the shaft, undo the nut - do you see the big key slots lined up? If not, it is going to have to come off.

Luke
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Offline Hoony

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Re: backfires on start up.
« Reply #5 on: October 07, 2011, 07:41:52 pm »
the stator winding maybe breaking down possibly?
« Last Edit: October 08, 2011, 06:53:08 pm by Hoony »
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Offline Doc

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Re: backfires on start up.
« Reply #6 on: October 07, 2011, 10:02:12 pm »
I'd go for the obvious first. Change the plug, sus out the plug cap, clean the carb, drain/replace the fuel, check the woodruff key on the magneto hasn't sheared as Adam said, make sure the wiring isn't grounding or rubbed through under the seat or tank, or the killswitch.
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Offline PE MAN

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Re: backfires on start up.
« Reply #7 on: October 08, 2011, 08:39:06 am »
going to try my best today to get it going today.... its got me stumped because everthing is new... or in tip top working order... but obvioiusly not... ah well... wish me luck guys... when i find out what the problem is ill let you all know... cheers
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1980 SUZUKI RM50
1980 SUZUKI PE400

monaro308

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Re: backfires on start up.
« Reply #8 on: October 08, 2011, 02:29:03 pm »
As all of the above,start with plug first but it does sound similar to what i had with the pic-post above and maybe try another cdi off another suzy if you have one and it should tell you straight away.
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Offline PE MAN

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Re: backfires on start up.
« Reply #9 on: October 08, 2011, 03:34:12 pm »
reckon i have found the problemo... its the stator. seemed to have spark before. why i thought it might have been timing. wires are fairly daggy comming off stator. so i jiggled them a little. now no spark at all. checked with multiple cdi's. multiple coils & multiple plugs. nothing. so i am putting it down to that. now flywheel must come off. sounds fun. but at least i know what it is now. i hope!
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1980 SUZUKI RM50
1980 SUZUKI PE400

Offline LWC82PE

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Re: backfires on start up.
« Reply #10 on: October 08, 2011, 07:07:07 pm »
Flywheels are not easy to come buy so make sure you use the right puller, but when you use it, dont screw the 3 M6 bolts all the way through so that they hit the coils.
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Offline PE MAN

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Re: backfires on start up.
« Reply #11 on: October 08, 2011, 07:30:13 pm »
yea leith i know how hard they are to come by, an how much new ones cost too...  :/ i wont be touching it with out the right puller. so ill either get one off ebay or make one up... so dont screw the the outside bolts all the way in. thanks for the tip... an thanks everyone for their input. much appreciated. now back to the bat cave.
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1980 SUZUKI RM50
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Offline Freakshow

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Re: backfires on start up.
« Reply #12 on: October 10, 2011, 07:07:43 pm »
sold a guy a PE250 stator a while back, he drilled it to fit on a PE400 but he still couldnt figure it out, even cuttign the lighting coil off. i think, any how he should still have the coil, stator,and CDI if you interested i can ask how much or i can pass on an offer for you

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Offline PE MAN

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Re: backfires on start up.
« Reply #13 on: October 11, 2011, 07:24:18 am »
thats ok freak show. if it comes down to it ill just take my stator in to get it re wound & restored.
i have recently heard about pvl ignition systems. seems interesting to get rid of the flywheel all together. an run a internal rotor. only thing is i am not to sure if they make anything for the pe400. i know they make one for rm 250 T. an i know the pe400 was based on the 250 motor.
can anyone give me some advice. will the rotor fit on my crank? will the stator fit over an will the bolts line up with my crankcase?
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1980 SUZUKI RM50
1980 SUZUKI PE400
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