Hello All! i have a wierd(to me) problem with a friends 77 naked. i will tell it all, first we had a carb problem so i did a single carb and manif like mine except i used a holley 1bbl from a 62 rambler and after a main jet change, works great!, however it was still down on power but not near as bad as the stock carb set up as they were in dire need of service! away they went! so we ran a compression test and sitting on the bike,left front cyl had 70lbs of compression,left rear had 150lbs. this bike has 38,000 miles. as i pulled plug wires at idle, all made a big drop in rpm except the left front that made zero diff? OK, pulled the head's,it looked like we just caught the head gasket starting to fail on the sealing ring, not blown but getting ready to go. OK!i thought to myself,i pulled the heads (both)apart,lap job on all the valves,seat and cut job looked good,new seals on cam's and valve stems, head gaskets,belts and started it up.. same crap?? All good pulling the plug wires 1 at a time and still left front cyl dead! he has a dyna unit but i dont think that is a problem as the cyl on the other bank,same coil is fine?? So i have a old 80 1100 parts bike and i took the coils and plug wires from that one and wire it up.. NO CHANGE?? Man? I just have no idea?? I have another dyna unit to try on it but i feel it is a waste of time as the unit only triggers a coil not a ind. cyl. Any one here had any thing like that? by the way, now the cranking compression is around 160 in all the holes :help:
77 gl1000 engine missfire
- Thread starter sgq700
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Pulling plugs like we do on a car engine can be mis leading on these engines with it's wasted spark design.
I'd pull all the plugs out, pop them into the plug boot and lay them on the grounded head. Crank over and check for spark that way. How do they look?
I'd pull all the plugs out, pop them into the plug boot and lay them on the grounded head. Crank over and check for spark that way. How do they look?
Have you considered taking the heads and swapping side off course the canvas would need to be swapped to keep the ignition the same... if the pressure comes up on the left front and drops on the right rear you may have a warped head..
I have done both heads and have a crisp blue spark? If i had the stock ign,it would be like a bad condenser? Has me stomped!! :shock
btw,i surfaced the heads when i had them off with a plate glass and emery cloth)
btw,i surfaced the heads when i had them off with a plate glass and emery cloth)
- Joined
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- Messages
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- 243
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- Van Nuys Ca.
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- 1983 Interstate
2018 KLR 650
2018 BMW S1000 RR
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What do the plugs look like?
Is the weak one wet or dry?
At this point I'd be looking closely for vacuum leaks maybe?
How about a pic of the manifold and carb setup.
Is the weak one wet or dry?
At this point I'd be looking closely for vacuum leaks maybe?
How about a pic of the manifold and carb setup.
when we took it apart Dan, the plug looked new,the combustion chamber and piston looked new(washed clean with fuel foe about 1500 miles) and when i put it back together tonight,brand new proper NGK's and even moved them around? ??
The manif is a carbon copy of the 1 i did for my bike only used a different carb. i'll do some pic's tomorrow. No vac leaks, we checked that long ago when i did the conversion. Great throttle and drops down to 800 rpm idle instantly
ok if compression up on all ... its going to work ... there just no reason it shouldn't...tim to ckect for that runner on the cylinder for leaking air ...on the manifold setup up ... seems only thing left not mentioned......just read the new post go through all things again ....
slabghost
Well-known member
Try new plugs and look real close at the plug resistor caps. :builder:
It's just crazy!! I think i will have 3 beers and give it thought for the rest of the night...
Yep, new plugs and a different set of coil's and wires with end's from a 1100
slabghost
Well-known member
could swap plugs and see if the problem follows the plugs but I'm betting its a resistor cap.
i have done that twice with the same result?? Mabey it is a gremlin playing with my head!
slabghost
Well-known member
plug moved no difference? Put on another set of resistor caps on that side from the 1100 maybe.
i used the entire secondary ign system(coil's wires and res.caps)from the 1100! I must be tired and missing something minor? Tomorrow is another day!! fuel pressure and fire all present! Dang it!!
Check for a plugged or collapsed exhaust header. Or some kind of blockege in the intake runner. Even spark, even compression, single carb - even mixture...what else could it be? Unless this is an April Fool's joke!
slabghost
Well-known member
+1 :good: very possible especially with double wall headers. Picture of one was just posted not long ago.[url=https://www.classicgoldwings.com/forum/viewtopic.php?p=113772#p113772:13yveafv said:
Great Thought! I never even looked at the pipes,just bolted that stuff back on! won't be too bad as it has sporty muff's on it so no cross over pipe.. Thx Much!!
Hey Steve!! Great Call.... i finally got back to my pal's 77/1000 and i couldn't blow air thru the front cyl on the left side exh header. Thank You Again Sir!!
wow great its amazing how many times this comes up
