74 GT380 no start. Need help.

[Rickybigblock]

So bought a 1974 GT380, and have been working on getting it running. So far I have replaced the oil line for the CCI, and have rebuilt the carbs (L) with a kit provided from the previous owner. After the rebuild I ended up buying new intake boots, because the old ones were rock solid. After replacing those, I installed the rebuilt carbs, and attempted to start the bike...No luck. Took the plugs out one by one to check for spark, no spark. So removed the points cover and found out the old nylon gear for the points cam was junk. Replaced the gear after aligning the two alignment marks, I attempted to start the bike again. Still no start. All three plugs have crisp sparks but still no dice. Bike seems not to be getting fuel. Fuel flows freely from the tank to the carbs, but still seems the bike isn't getting fuel. So im on here looking for any help. Im currently running pre-mix in the tank until i feel safe the air in the oil lines have bled out. I've replaced mostly all the items that come in a rebuild kit, except the slides and emulsion tubes. Mixture screw was set at 1 1/4 turns. Im just lost at this point.

[Vintageman]

Did you save all your oem parts you replaced with carb kit parts? For example if the Jet needle did not need to be replaced the OEM parts are better. But still should start


Are the plug tips dry after trying to start proving no fuel?

If you drain the bowls via drain screw at the bottom of the bowl, you should get a significant amount of fuel draining.

If you have filter off, carbs slides up spray a tad of your premix into the carbs. It should run for a moment.

Next would be to look at electrical (timing by measuring piston height versus points opening), plug/wires swapped, cylinder compression (hole in pistons, stuck rings) or Crank seal(s) real bad/wasted (hand over carb mouth and each should have good suction per cylinder)

[Rickybigblock]

First thanks Vintageman, I did save the OEM parts. When I checked the plugs they were wet, not soaked but wet, i was also able to drain the bowls which did appear to have plenty of fuel stored. I was able to spray some premix through the carbs into the cylinder heads and it was able to run, and rev for a few. However I did not check the point timing, i alligned the contact points the same way they came off and trusted the previous owner. And I didn't check compression with a gauge but the kickstarter does have what seems like adequate pressure on my foot as i kick. Any further ideas with that knowledge?

[Rickybigblock]

Might have to download the carburetor service manual and start all over again from step one, and then go from there.

[PHPaul]

First thanks Vintageman, I did save the OEM parts. When I checked the plugs they were wet, not soaked but wet, i was also able to drain the bowls which did appear to have plenty of fuel stored. I was able to spray some premix through the carbs into the cylinder heads and it was able to run, and rev for a few. However I did not check the point timing, i alligned the contact points the same way they came off and trusted the previous owner. And I didn't check compression with a gauge but the kickstarter does have what seems like adequate pressure on my foot as i kick. Any further ideas with that knowledge?

The bolded statement leads me to believe that the timing is at least in the ball park and you have adequate compression. Therefore, the issue almost has to be carburetors. Double and triple check float height. Seeing as the plugs are damp, my first suspicion would be flooding and drowning the spark.

[Rickybigblock]

Thanks PHPaul, I will check the float heights again to be honest I never pulled out my slide ruler because i was in the "must rush before snow comes" mode. But i do appreciate all the ideas you guys are bouncing of me. It was silly of me to rush through the process. I will tear em down again tomorrow and I'll fill you in on my results.

[yeadon_m]

Ricky,
If the motor has sat for a considerable time, its worth removing the three blanking plugs at the front lower section of the crankcase to allow any excess two stroke oil to run out, then replace them.
These are vestigial threaded holes for the recycling system fitted to earlier models, and deleted along the way on GT380s. Sometimes the oil tank / pump / lines leak-by and lots of oily mess can collect in the crankcases. In extreme cases, there is a risk of hydraulic lock on start up.

On getting it running, I'm with Vintageman and, assuming you have a new, fully charged battery, its probably carbs. When refitting dry carbs, I prime with fuel for one minute while tapping the float bowls in turn to allow the floats to lift up and shut off fuel flow. Then turn on ignition and kick it a few times with the choke lever still down (ie off). Then usually, flick up the choke lever to on and one more kick and it'll go. If I start cold kicking with the lever up, for some reason I often find it harder to start.

Good luck!
Mike

[Rickybigblock]

Thanks mike, i was wondering about how to drain the excess oil for i had heard of such but didnt know 100% where and how. I will try all of this advice and go from there. You guys have been a big help.

[Rickybigblock]

Well I removed the three plugs on the bottom of the crank. Some oil came out of all three, but nothing that looked to alarming. I also removed the carbs again and set and checked every setting to match that of the carburetor service manual. I also bought brand new plugs just to be picky. My petcock, and manual on/off remake crap the bed so i used one of those porta-tanks that look like a iv drip, let the bowls fill up and started kicking with choke off (down) after a few kicks i flipped it up and tried again... No luck, not even a hint of life. I bought a compression gauge and i plan of checking that tomorrow just to put myself at ease when it comes to that. I this point im about ready to drop a couple hundred on some refurbished carbs from across the pond. I honestly don't know anymore. Maybe I'll replace all the connections coming from the battery and maybe give it a charge again, it was new when i put it in about a month ago.

Ideas?

[yeadon_m]

Ricky,
Frustrating for you. Not yet clear what the main issue is - compression, spark, carbs.
What voltage do you see across the terminals with ignition switch on and the run/stop switch set to Run? (the coils draw quite a current and if the battery is sub-par the voltage can fall too low to make good sparks).
After a month, especially if its a traditional lead/acid battery and also if its been drawn upon for a while, I'd expect it to be at risk of being sub-par.
Cheers,
Mike

[Rickybigblock]

Mike,

Yeah I plan on getting a jump box or going out and buying a "better" battery. I've never been a fan of maintenance lead acid batteries, even though the bike is from 74 I'd still prefer a modern battery. I'm taking the day off from it for today before a blow a mental gasket. Next post I'll post all my findings. Thanks again for all your help, sometimes forums are full of people who post anything but... helpful information. You guys have been great.

Thanks

[ConnerVT]

Hey, if you can't get it started, I'll take it off your hands for $100. Much cheaper than therapy.

See? I can be helpful.

[Barry S.]

Get somebody to tow you with a mower or something to see if it will hit. Carbs can be picky, sometimes clean looking is not clean, passages inside carb body hard to clean out.

[titan performance]

So it fired up on all pots when you squirted fuel into the backs of the carbs? Check the pilot jets are clear. You'll have to remove them to see, as they are small.

[rngdng]

Well, I can tell you that if the choke circuits don't work, you will likely never get it started. At this point, I would squirt fuel into the plug holes, put the plugs in, and kick it. If it spits, you KNOW it's a carb problem. I am betting that the pilot circuits, and choke (richening) circuits aren't clear. Good luck.



Lane