Backfire?

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r97

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Ok, so I was starting to trouble shoot my motorcycle today and after spraying carb cleaner in the intake I cranked it over. Eventually I got a banging/popping noise from the rear carb. I looked over at the carburetor and saw all this thick fog/vapor in the venturi, and that a small copper tube seemed to be covered with a white/green powder (could it have flash oxidized or something?). I wasn't watching the carb so I do not know if any flames shot out.

What would something like this be telling me? How can I fix it? If it is just a backfire I feel a bit silly asking this, but better safe then sorry no?
 
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Ok, will do, have been meaning to check/replace them anyway (bike sat under a porch for 2 coastal new england winters and summers :ack2:)
 
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Indeed it is, its in so so shape, but I have big plans for it, and it doesn't seem bad mechanically, so for $300 with the service manual, I'm happy.

Just did an oil change, but once I get it running I will be cleaning the whole thing, replacing cracked rubber, coolant, oil, filters, and tidying up the electrical. As long as I don' need to split the case, or remove the heads and it runs, I'm a happy camper.

Here are the specs,
http://www.bikez.com/motorcycles/yamaha_xz_550_s_1983.php

And the pictures,






It seems as though Yamaha buried the spark plugs deep into the heart of this machine, so getting them out wont be easy (none of my spark plug wrenches fit....), but that's a job for tomorrow.
 

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Any idea what kind of shape the carbs are in? I acquired a 1983 Honda VF750 Interceptor a while ago and the carbs were full of snark. No big deal, except the fact that the diaphragms are done, and hard as he// to find replacements. I was even thinking about building a new intake manifold and using a 1 or 2 barrel car carb. Might lose a few ponies, but... I'm a cheapskate...

EDIT- Shaft drive, eh? Nice! Gonna drive it as is, or molest it for a project?
 
devino246

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Man, thats a nice find.

toystory_4wd said:
Any idea what kind of shape the carbs are in? I acquired a 1983 Honda VF750 Interceptor a while ago and the carbs were full of snark. No big deal, except the fact that the diaphragms are done, and hard as he// to find replacements. I was even thinking about building a new intake manifold and using a 1 or 2 barrel car carb. Might lose a few ponies, but... I'm a cheapskate...
Click to expand...

A car carb:roflol: That would be interesting to see, to say the least. I guess you would have had a make the intake so the carb sits level. What would you have done about an air filter?
 
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Just looking down the venturi they look pretty clean for how long they have been sitting, the accelerator pump also works perfectly. The outside is oxidized a bit, but not bad. And of course I wont know the condition of the carb, or fuel pump internals until I get it a bit closer to running.
 
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devino246 said:
Man, thats a nice find.



A car carb:roflol: That would be interesting to see, to say the least. I guess you would have had a make the intake so the carb sits level. What would you have done about an air filter?
Click to expand...

Oh, probably a K&N filtercharger, or maybe a 5" Edelbrock or something.
 
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devino246 said:
Man, thats a nice find.
Click to expand...

Yeah, I guess searching since April finally paid off! If your looking for a bike definitely put up a wanted add, I was given pictures of this about 3 days after doing just that.

Plans as of now are to start working my way towards something like this, :devil2:. I'm planing to go all out, but getting money for it will slow things down a bit.


 
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r97 said:
Yeah, I guess searching since April finally paid off! If your looking for a bike definitely put up a wanted add, I was given pictures of this about 3 days after doing just that.

Plans as of now are to start working my way towards something like this, :devil2:. I'm planing to go all out, but getting money for it will slow things down a bit.
Click to expand...

Aww, your gonna tear it apart? I assume you didn't get a title with it then?
 
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Yeah, I hate tearing it apart too, but I will most certainly do some "100% mandatory testing" (not just riding it for fun if my parents ask) before taking it apart ;). It has no title, I have no license, and my parents would never allow me to use that as a commute vehicle. I'll get a motorcycle to ride someday.....

EDIT: Going to be scary riding the thing, It weighs just under 4 times as much as I do!

EDIT2: Just saw toystory's edit, yes shaft drive. I will mount the engine 90* from where its at now and run a sprocket on the output to a homemade reverse box.

Was really a nice bike, If only I could keep this bike and get an engine for my buggy.... If I chose to keep it as a bike I would have a llllooooonnnnnggggg restoration process ahead of me. Decisions, decisions, maybe the rents will lighten up a bit once they get used to a bike in the garage...
 
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Yeah, that's a lot of power and weight for guys like us. Way back when my Interceptor was running and my buddy owned it, I took it for a spin. Something like 86hp. Spooky. At the time, they were at the forefront of sportbikes. Here's a pic as I got it. Rather similar, actually...
 

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r97

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Yeah, that bike looks really similar, nice looking! HAHA, with me at about 135lbs(?) and nearing 6ft I'm pretty thin, and I'm only 14!?

Perfect starter bike for me would be one like that Honda NX250 I found before, except nicely restored. I'm going to need to just get over the fact that I want to keep the bike, will use it in my buggy, and then by a more suitable motorcycle to ride if my parents ever let me.
 
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I still beat you both. 6' and 135lbs:D You should see me shooting a 12ga shotgun:roflol:

Am I the only one noticing that attached pictures are showing up as thumbnails and filenames?
 
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Benjo said:
how do you plan on fitting a sprocket to the shaft drive?
Click to expand...

Plan is to take the engine side splined u-joint fork and cut it down (on a lathe if i can find one) so I can weld a hub or a sprocket to it. Haven't decided if I want the extra support bearing yet, I will decide once I find out the shaft dia.
 
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