Just another XJ owner

Hi everyone, I just thought I'd introduce myself. I'm just another proud owner of a motorcycle; my 1st street bike; a 1983 XJ750MK, the Midnight Maxim. Its a pretty neat looking bike, of course you all know what it looks like.

Although I'm not happy to report that it seems to be running way rough. I believe its the carbs. But not sure.

Well happy to be here, it is a total relief to find a site all about yamaha XJs. Man, this has to be the best site ever, right when I was giving up hope and thought I'd never find anything on the internet about my motorcycle. I even went to Yamaha dealers and even they couldn't provide any info. Well you'll be seeing me around, posts and what not. Ride on!

 

Welcome to THE XJ site.

You'll find what you're looking for to help get your bike running great.

And if not, at least the good humour and helpful assistance will make you feel better while it running rough!

 

We can't have an '83 750 Max running rough ... if that's the same ride as I got!

What's it doing?
What have you done to it?
Can you wrench or do carb cleaning and tuning?
.........

(Fill-out the "Signataure" section of Your Account with your Bike's Thumbs!
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1983 - XJ750MK - Total Miles - Stock or Mods - Main Problem (short)

 

Thanks for the warm receptions.

I just got the bike 3 weeks ago and haven't had much time to wrench on it. It sputters and bogs down when I start it, as well as when I ride it.

I have not done anything to it other than make the proper checks, i.e. oil levels, spark plugs, brakes, clutch and brake adjustments, blub replacements, pretty basic stuff. But the mian problem is the sputtering and bogging down. I'm pretty sure its the carbs. I juist strated wrenching, but can do basic stuff.

 

Yer in the right place

Now we gotta know everything

Plug condition, air filter cond, when does it run best or worse.

You should try some Seafoam

 

well the plugs are just fine, me and my father took a look at those and they were just right. I haven't checked the air filter yet but I should be safe and buy a new one because its been sittin for awhile and hasn't been ridden but 600 miles. And the guy who I bought it off of put them on.

It runs pretty bad all the time, sometimes it doesn't even want to start. I mean, you can tell it wants to start, but it just wont. It fires and everything, it just doesn't want to stay running. I have to keep it on PRI in order for it to run and stay running, but if the petcock is in the ON psotion, it'll fire, but wont start. If I remeber correctly, the man i bought it off of said that if I take the seat off and spray some ether into the airbox, it'll start right up, but I shouldn't have to do that just to start the darn thing.

It just sputters and bogs and won't start. The plugs are fine. What could it be besides the carbs?

 

Well, the reason I asked about the plugs is, there should be some telltale sign of the problem from looking at the plugs.
One may be wet or sooty or maybe even 2 or 3 could be messed up.

Think about it if the engine is running rich then the offensive holes should have sooty or wet spark plugs.

The plugs should give you a clue!

unless you arent able to run them long enough.......or....maybe the fuel is not reaching the cylinders.

Is the fuel filter clean? Is the screen on the inside of you tank plugged up?

If everything were good then it would be running good.

 

You make a vailiant points. I'll have to check next time I run it. I'm kind of at a disadvantage, the bike is at my old mans house and he's in Indiana since I purchased it out there.

Although, I do remember that when I purchased the bike, it ran long enough to get it home. I shut it off, then couldn't get it started agauin, no matter how long I tried. It smelled like it was flooded, so I waited about 20 mins and tried again, nothing. It wouldn't start. So we checked the plugs, they were a tanish color, all 4 of them, but I didn't notice anything sootish on them. Hmm, this might be a bigger project than I anticipated..

 

YEP when I had a carb that flooded I tried to let it set too.....
once that baby got flooded it wouldn't dry off even if the other 3 were running and up to temp.

I could tell because the pipes coming out the head were all hot but that one.

A tap on the carbs might jar a hung float free but I'd be careful, that metal can break real easy!

From all you've said it sounds like a flooded problem. If that hole dont run it wont make soot, just smell like raw gas and be wet.

Good Luck

 

Thanks Hvnbnd, I'll try everything I can in order to get this machine to run right. I'll let everyone know how everything turns out!

 

You need to have the Carbs ~~> CLEANED!

Everything.
But especially the:

Starter Jet Circuit.
Fuel Bowl Metering Jets to the Siphon Tube Reservoir, Siphon Tube Openings, Enrichment Valve Fuel Passages, Enrichment Valves Fuel Outlet.
Back-flush with Carb Cleaner.

When all these guys are CLEAN ... You can throw the Can of Starting Fluid away!

 

That starting fluid will ruin your engine after a period of usage.
It will strip the oil film off the cylinder walls, exposing them to abnormal wear.

 

These are all great tips fellow XJers! Does any one have any links on how I could get pictures of the carbs and where everything is labled. So I know how everything goes and I have a reference point?

 

Hey XJBiker! Congrats on your "new" bike!

I think you should be able to find a good tutorial if you search the forums. Click here: http://xjbikes.com/Forums/search.html

 

Thanks for the link edgar67, I'll try it and see what I can find!