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Discussion Starter · #1 ·
1968 650 fresh rebuild. Running tri-spark ignition, tri-spark dual coil, brand new stator and rotor, no battery, but had a battery hooked in during this initial start up attempts. I set the ignition up at 38 degrees before tdc. I triple checked the cam gear timing before putting the cover on. I just set the valves last night.... I tickled the carbs 15 different times with gas coming out, I have spark at both plugs, but it will not fire. I even tried alittle starting fluid with no luck. I think I hear alittle air leaking out around the spark plugs.... but not much. What do you guys suggest?
 

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air leaking out around plugs or at head gasket? have you checked compression?

screw the idle speed screws in a good couple turns to start then you can back them off once it fires up. air screw 1.5 turns out.
 

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Making sure your slides are open. Try holding the throttel open alittle . You can run a Tri spark without a batttery? I dont know much about them but seems weird for an EI.
I think you need the battery. Check wiring, charge battery to 12+ volts. Turn on key, see how much voltage drops.I know when you eliminate some of the stock wiring you need a good battery to fire,a lot of this stuff won't fire on low voltage.
 

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Discussion Starter · #5 ·
ya I tried with the throttle open alittle.... ya they are able to start with only like 8 volts or something like that. But I am using a battery now to try to get it running. I think around a plug that was helicoiled, a put alittle copper sealant around the washer and put it back in, I dont hear anything anymore. Ya I have my screws set as wes describes them. I actually just got it to start backfiring.... atleast thats more than what it was doing
 

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Discussion Starter · #7 ·
Do I need to have the engine on the compression stroke on 38 before tdc on the timing side when I set my ignition? And would my intake valves being set wrong do this? I have an intake cam out of a 750 and it says to set the valves at .006 were the 650 says .002 I wasnt sure what I should do so I set them at .004
 

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You don't have to have a battery with an E/I all you need is a good alternator and a battery eliminator charge unit or a capacitor in line.
you only need to set ether piston on 38 degrees before TDC, an Tri-spark E/I is a single spark ignition and fires both plugs at the same time as do most E/I ignitions.
you need 3 things to fire up. correctly timed spark, gas and compression, you are missing one. and it's likely compression. Do a compression check.
.004 will work for valve gap, all you really need is just a gap when the motor is hot.
And just out of curiosity you say you used a 750 intake cam in a 68 motor. the 750 cams don't have a breather hole in them so how is your engine going to breathe?
 

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Discussion Starter · #9 ·
I actually had asked you about this before.... I made a breather for in the timing plug hole for the crank. I mean I think everything is good but when I just crack the throttle as I kick it it will only backfire.... I am gonna try a compression test I guess.
 

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I actually had asked you about this before.... I made a breather for in the timing plug hole for the crank. I mean I think everything is good but when I just crack the throttle as I kick it it will only backfire.... I am gonna try a compression test I guess.
ok that will work, now verify the compression and get it timed right and you should be able to ride soon, backfiring indicates bad ignition timing or bad cam timing.
 

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Discussion Starter · #11 ·
well I am pretty much 99 percent sure the ignition timing is where its supposed to be... I followed every step to a T. the cam timing may be it but I am not sure. let you know about the compression soon
 

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Discussion Starter · #12 ·
well I bought a cheap compression tester and both cylinders went up alittle over 90 after about 4 kicks..... the gauge on it held the air in so I hooked up a different gauge that would let it in and out. And it only leaked a few psi after about twenty-thirty seconds, I am going to contribute that to about five different fitting points and no teflon on the gauge threads itself. So compression seems good. I read in another thread tony that you said the 750 cam fits the cam wheels the same as a 650 cam. Well thats how I have it set, so I am pretty sure that is good to go. I have had the motor at 38 degrees before tdc about ten different times every time trying to reset the ignition..... every time the same thing. ugg I am stumped
 

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the cam wheel can go on the cams in 3 different positions, the correct one is the keyway lined up with the wheel setting mark.
you could use a timing plug pin to find 38 BTC but the 68 motor is a little weird, some have a normal timing plug in the top valley and a normal notch on the crank that indicates 38 BTC, and some have a timing plug under the engine near the front of the bike with a crank notch there at 38 BTC, and none in the top valley.
so the best way to get close to it is put the piston at TDC by feeling it through the spark plug hole and then by turning the rear wheel in gear backwards until the piston goes down 3/8" backwards. that is 38 degrees before top center. then make sure you have the ignition dot lined up with the Counter Clock Wise hole one on the ignition plate.
 

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Discussion Starter · #14 ·
I did put the keyways inline with the timing dots so I am pretty sure thats good. The motor does have the top timing hole and I have turned the motor up to tdc and then rotated it down alittle more to get my plunger timing tool to stick in the notch. I ligned the magnet rotor up with a correct mark on the brain and did exactly what the instructions say. It just doesnt make sense. I have fuel, I have compression, I have spark, my cam timing should be right, and my ignition timing has been followed word for word. I read a quote from wes saying 750 intake valves should have play of .08 is this right? Mine are set at .04, Would this make any difference? I tried rotating the ignition either way on the pillar bolts and it does not start no matter where I put it.
 

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no 4 or 8 thousands isn't the deal killer. I would not set them at 8k that would be a real noisy top end.
you say you rotated the motor a little more...which way backwards or forwards?
 

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Discussion Starter · #16 ·
i want to thank you so much tony.. Did you ever do something for the first time and it seemed so difficult but after you figure it out you want to kick yourself. ha i dont know what the other notch in my crank is unless its like you said for another plug in the motor? But i took your advice and put it at top dead center. Then I put a drill bit in and marked it with a sharpie measured three eighths of an inch rotated the engine backwards, and reset the ignition rotor and the thing fired second kick! Wow what a great feeling too bad its so late i only let it run for a few seconds. Woo
 
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