Allow myself to introduce...myself. My XJ650 Maxim Chopper

I just bought another bike, this 1981 Yamaha XJ650 Maxim. Picked it up for $240! This first pic is from the night I got it.

I have a couple of pics to post, but in the end, I need to know something...before I pull these carbs off again, I went to fire it up, shot a little carb cleaner in there and it fired with a vengeance! Revved like a friggin' Ferrari! I killed it as soon as I could cause my ears were ringin'! I haven't built the exhaust yet :roll:

Are the larger jets supposed to be on top of the standoff in the bowl, or is that the smaller jet that's supposed to go there. Where, cause I didn't look, are the air/fuel adjustment screws, and I assume the knob in the middle is the idle adjuster?

 

Anybody? I'm not finding anything online to help me fix this high rev start problem. And, as far as I can remember, I need to drill out a brass plug to get to the air/fuel adjustment screws...which on are they?

 

Hey CutandWeld-Welcome to the site & congrats on the good score! Just use search & you'll find answers to your questions. There is an exceptionally good thread on these carbs- I think its called "clunk test". I found out you usually don't have to wait very long for an answer to a question. If you do your own work on your bike you will find XJBikes invaluable. There are many knowledgable and helpful members willing to help guys like us. Best dang site on the internet!

 

Check your carb boots for leaks. You'd be amazed what a headache a little air getting in there will cause, and sync will also help level things out. Get your bike idling and spray some starting fluid at each boot individually. If it revs, the fluid is getting pulled in because you've got a leak. Then hook up your carb sticks and do a good sync before you look elsewhere. Be sure the throttle and choke cables are not reversed also.

 

Thanks guys. I do ALL my own work. And I don't waste any time. I'll check the boots. At first I attributed the high rev to the vacuum hose I left off the petcock...but it didn't fix anything. I'm gonna pull the carbs off and recheck everything.
Links would be nice if anyone has any they bookmarked as "invaluable".
Thanks again!

 

Hey Cut
I was looking at the pics you posted and it got me thinking.....the right side strut is attached to the bottom eye of the shock, right?
In the 3rd and 4th picture your strut is bolted to the lower shock mount on the aluminum diff case, will the aluminum hold up under constant road pounding?
Just a thought, it would be pretty nasty if the aluminum were to snap off.
I've never built a hard tail, but I'm curious as to how much the diff case can handle.
Looks good so far, what kind of welding equipment you using? MIG, TIG, Stick?

 

Just noticed, nice bit of tin work with the German cros and scalloped frame bracing, do you have a plasma cutter too?

 

I did the same thing on an '80 Honda CX500 and it handled it just fine. I've seen other people use braces that bolt to the swingarm bolts where it meets the final drive assembly and then gusset it all up...not too worried, but I have time to add them....might as well.
I use a Lincoln Mig SP175T with flux cored .035" wire. It burns hot enough to penetrate and I've become proficient enough in it to lay some sik beads. I was using hard wire, but it didn't get hot enough on my little machine.
Because I'm 6'7", chopper was not the appropriate route given how short these bikes are. My CX was much longer apparently. My feet almost reach the front axle! LOL.

On another note, I got the carb issue figured. I got the carbs in place with my wife's help, so I didn't tighten the clamps (couldn't keep her from One Life To Live)...the last guy also had the cables reversed. I just put those back where they came from ASSUMING those were done right....guess he did nothing right.

 

I'm an Industrial Welding student in my second year...I have access to the plasma there. Can't bring myself to fess up the $600 to buy a plasma just powerful enough to cut 1/8" when I can spend that on 2 bikes! LOL!

And, thanks.

 

Re: Allow myself to introduce...myself. My XJ650 Maxim Chop

looking good keep us posted did you get it running right yet?