need help with a $400 GT380

[Ser_Jorah]

sorry for the wall of text

This is my first bike, bought it for 400 bucks. not running. from what the PO said he bought it about 2 years ago and it ran but hasn't done anything with it since, so its been sitting. We started with a carb clean its cleaned up fairly well, nothing looks damaged. wont start. its leaking alot of gas when we get it back together from the overflow on the carbs. finally track down the cylmers, turns out we had the jet pins(?) upside down and the pointy end was against the float. get that fixed. changed the spark plugs, they looked okay but the cylinder chambers do look quite dirty but the spark is fat and blue. try to start it without the airbox on, it still wont turn over but now we are getting some smoke from the exhaust and it backfired a couple times. we put the airbox back on and it wouldn't even backfire or smoke.

so at this juncture im looking for help as to what to check next. i haven't adjusted the air mix screws or anything yet. would the engine be running to lean to turn over? it seems like its close to going but just doesn't want to go. new battery as well that we charged full. any help would be appreciated, pictures included. one picture has a circle around a missing part, the boot covering the carb to the throttle linkage(?) would that boot not being on there cause problems? havent changed the oil yet either.

GT380

Edit: if i can avoid a complete engine tear down at this point that would be nice. but if its gotta happen then so be it.

[jaybob]

The next thing I would do is clean and adjust the points. The clymer manual should have a procedure for you to follow. Sound like it may be rich also from the carb clean. Did you take out all of the screws when you cleaned the carbs? Start with the pilot jets 1.5 turns out.

Also turn you petcock to "ON" instead of prime. That is a vacuum petcock , does it have 2 hoses going to it? It should, one for fuel and 1 for vacuum.

The missing boots on the carbs should not prevent it from running but can let in extra air and dirt.
here is a link to a carb manual.

http://www.3cyl.com/mraxl/gt/manuals/su ... /cover.htm" onclick="window.open(this.href);return false;

[Ser_Jorah]

>clean and adjust the points

i may have failed to mention i havent done anything mechanical besides change the oil on my car a couple times. where would the points be located. i can take more pictures and ill be back to pick your brain some more if you dont mind.

>Did you take out all of the screws when you cleaned the carbs?

yeah there was some thick gunky build up on pretty much every inch of the carbs. i would have to assume the pistons had the same crap on them. we cleaned everything in the carbs they actually dont look bad.

the petcock does have 2 hoses we had it on prime because nothing was coming out on the on setting. didnt know it was vacuum thanks for that.

last question for now before i try this stuff, is it okay to put pod air filters on?

[jaybob]

Yes you can run pod air filters. The foam UNI filters work best. The Kind with a plate on the back end do not work so well because or air reversion on your 2 stroke.

You are in luck....Member Scorch is fixing up a 380 similar to yours and has documented many things with photos including the points, they are under the small round right side engine side cover....here is the link.

I myself run an electronic ignition in an GT550

http://moto-dude.com/gt380_repairs.htm" onclick="window.open(this.href);return false;

If you have a clymer manual that should help also. If not get one

[diamondj]

There's also a factory manual here:

http://www.3cyl.com/mraxl/gt/manuals/gt380man/index.htm" onclick="window.open(this.href);return false;

[Scorch]

Hi Ser Jorah,

yeah, you are only a few steps behind me. I had a perfect running GT380 a couple years ago. When gas started appearing out of the overflow drains on one of the carbs... read the rest.

I would think the timing is still ok, if the bike was running before. But the PO may have done something to it and got it out of time, so it probably would be worth the trouble to check. GT Keith posted an excellent description of the timing process here: viewtopic.php?f=2&t=3031" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; Look for his post with pictures.


You have to drain the transmission oil and remove the clutch cover, to do that remove footpeg, rear brake lever, and the kick starter lever. There are six of seven screws holding the clutch cover on. TWO of them are behind the points plate, so you need to remove the three screws that secure the points plate, slide it off the shaft and let it hang, to get to the two hidden screws,


Lesson 1: DON'T turn the engine over using the kickstarter with the cover removed, there's a spring behind it and it's a pain to get into place.

With the clutch cover off, you can also check the health of the small nylon gear that drives the points cam.

Lesson 2: You should remove the magneto cover on the left side of the engine to rotate the crank (four screws), if you need to turn the engine over in order to align the marks


.

And when you go to put the clutch cover back on, you want the Left timing mark to be aligned to show through the small window at the bottom of the timing plate.


.

A pulled back view, the window just below the shaft and the brown fuzzy pad.


.

Sounds harder than it is, really. Don't hesitate to ask for help, that's what this forum is for.

[Barry S.]

You may need to really clean the carbs again paying attention to the pilot jet and main jet. They have tiny passages or holes in them that gunk up from old gas sitting in them for years. It's hard to get them clean, carb cleaner blown thru them or a tiny wire can clean them out, won't run if not clean. Don't worry about the pistons being gunked up, not a problem.

[TLRam1]

Soak your carbs in Berrymans.

[Coyote]

Hmmmmm. You say it backfired? If so, the timing is way out OR the plug wires are crossed.

[Ser_Jorah]

okay first thanks for all the help ill narrow this down one way or another.

ive checked the points and they looked clean and the contacts looked smooth and hit even. last night we changed the 2 stroke and regular oil. the oil pump was a little off so got that adjusted. checked the carbs again jets are spotless as far as i can tell. took out the baffles on the mufflers and cleaned those off while waiting for the oil to drain.

tried to start it same thing. once or twice it would backfire which by that i mean it would make a LOUD ass crack noise just once. other than that it just would not turn over. opening the throttle a little didnt seem to change anything. we were getting smoke puffing out of the mufflers so something is going on.

on the advice of a thread i think i found on this site we took the plugs out and put a dab of 2 stroke in the cyclinder heads and cranked it a couple times to get the pistons lubed. still nothing.

edit: coyote - from what i could tell between scorchs teardown and the clymers the timing seems to be okay looks clean stuff is lining up where it should. the plugs have been kept in the same position from when we got them ill check the manual make sure they are right but they should be.

i attempted to get a compression tester, but they were sold out so ill get that in the next day or two.

one other thing while we were trying to start it we noticed the quick connect for the battery was (what seemed to us) was quite hot for a cable. also noticed the headlight was dimming after about 20 or 30 minutes of trying to start it. if were getting battery drain that fast could it be an alternator issue or something of that nature.

scorch your trailblazing has made my life 100 times easier thank you for documenting your troubles

i cant think of anything else we did atm its hard to keep track of all this stuff from not knowing what any of it was a week ago.

edit 2: some random pictures of the points and muffler baffles and me blowing on the oil tank to get the thing to drain faster.

[Barry S.]

If somebody has tried to turn the motor with the bolt on the end of the crankshaft on the points side it may have ruined the plastic timing gear. If it is bad you would probably get a little pop every now and then when trying to crank it but it wouldn't run.

[jaybob]

How do you know the timing is lining up where it should? Can you explain what you did to verify timing? Check the timing gear as barry said and then let us know.

Read through this thread on timing issues and procedures

viewtopic.php?f=2&t=3031" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;


You may need a dial indicator and a multimeter to get the timing just right.

[Ser_Jorah]

>If it is bad you would probably get a little pop every now and then when trying to crank it but it wouldn't run.

this sounds like the exact problem.

by checking the points i made sure they they were clean as someone had said to check for burrs or pitting and they were smooth and hitting evenly. i checked to see if the timing marks were lined up and it appeared they were it looked the same as the pictures scorch put up. so ill be picking up the tools i need this weekend to actually time it. so far ill be getting a feeler gauge, a dial indicator, and a multimeter. is that everything i would need to get that set up?

[Ser_Jorah]

where can i get a nylon gear if i need it?

[cyclebuster]

pull all 3 plugs. put number 1 plug back in the wire on the head where you can easilly see it. put your finger on the hole and have someone kick it over. It should have so much compression that the air feels hot. at maximum compression that plug should fire. not before, nor after. if its firing right on top of compression, try the other 2. I would pull all 3 plugs, put it in first and tow it with the lawn tractor, in case anything ugly is in the crankcase. IF there is old gas, and oil in the cases it cannot run. it cannot suck air. if it does run it will explode instantly from the oil trying to compress beyond the strength of the rods.. this happens A LOT. tow it some. see what sprays out the top! i had one spray crud, oil, gas, etc for 10 minutes in 1st . made a huge mess, but when it quit spraying crud, we put in gas, fresh plugs and rode it all summer.