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Discussion Starter #1
This here beauty is a 1978 XL175. It is in need of some rebuilding and i was hoping you might be able to help me with a problem. For a while it was starting but would only idol with the choke on. If i shut the choke of it would stall and if i hit the throttle to much it would stall. I clean out the carb a few times and blew some air through every hole i could find. There was a plug in the intake near the floaters but that didn't do much of anything once i got it out. eventually i got it to rev a few times and then after stalling it again with to much choke all of a sudden it wouldn't start at all. I checked inside the carb and on my work bench and all the parts are where they are supposed to be. I have decent compression and im getting a spark. It was running before with out the battery but just for the hell of it i tried it with a battery and it still wont start. I am lost to as of what could possibly be wrong.

Thanks
Bob
 

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Jack of all Trades, Master of None
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If it won't idle w/out the choke on, that's indication that it's sucking air from some other location. Most likely the carb to intake gasket area.

Buy new gaskets or cut your own w/ gasket material and try that; and make sure the gasket surfaces are good and clean before trying the new ones. If that doesn't seal then use goop- not a lot, just a thin bead will do.

Give that a try and see what happens. Also, do you have an owners manual for the bike? That should explain how to adjust the air/fuel screws and synchronize them. The stalling while trying to throttle could indicate a misadjusted throttle cable.
 

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Discussion Starter #3
If it won't idle w/out the choke on, that's indication that it's sucking air from some other location. Most likely the carb to intake gasket area.

Buy new gaskets or cut your own w/ gasket material and try that; and make sure the gasket surfaces are good and clean before trying the new ones. If that doesn't seal then use goop- not a lot, just a thin bead will do.

Give that a try and see what happens. Also, do you have an owners manual for the bike? That should explain how to adjust the air/fuel screws and synchronize them. The stalling while trying to throttle could indicate a misadjusted throttle cable.
I've had a look at all the gaskets there are no cracks but one has a little bit of the rim of it missing on the inside, it doesn't look serious but its also kinda hard to check if your fix would work when it wont start. But i am planning on rebuilding the whole thing, so gaskets are something that i will eventually be replacing. I just wanna get it running and take it out on a little ride before its all rebuilt. How would i check if the throttle cable is miss adjusted? I'm pretty new at the whole motorbike thing. I dont have a manual but i really need one lol. I find it pretty weird that it was running and and idoling then all of a sudden it wont start at all. I found some one else having similar problems and it was a timing issue. Do you think that could be the case with me?
 

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Jack of all Trades, Master of None
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217 Posts
It could be timing. Have you checked it? Make sure you're on the #1 compression stroke to get an accurate reading. I'm not specific to the 175's, but I ride a 73 CB350 and the timing mark will line up once for compression and once for exhaust.

On the note of timing, what's the condition of the points?

One thing you might try is to use starter fluid. Not a lot- spray some into each carb and turn it over. It should fire but probably won't run. If this is the case, then it has to be a fuel delivery issue, whether it's starving for fuel or is running too lean to start at all. I understand you may have cleaned the carbs but the fuel/air mix could still be off.

As for the throttle cable, check for slack near the connection at the carb(s). If there's no slack, turn the throttle and watch the carb. If the lever the cable is attached to moves as you operate the throttle, the cable is adjusted correctly. But if you operate the throttle and the cable moves afterward, the cable needs adjustment. The adjustment should be mounted on the carb.

Again, if you have an owners manual, all this info and how to procedures should be in it.

Keep us updated.
 

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Discussion Starter #5
The points are not in very good shape they will need to be replaced i might get a chance to take a look and try a few tips tomorrow.

Thanks
Bob
 
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