xj750 mid max been sitting up and abused way too long

I just got a hold of a early 80's model xj750 mid max with the yics motor.

This little gem has been sitting up for quite some time and just from the looks of this beaut shes been abused pretty badly. I can get her to start up pretty easily, and she idles and revs up okay enough (though once i rev her up and release the throttle, the rpms linger then slowly descend, not immediatly like my previous girls)

another odd problem is while riding her down the road, i have good power off the line, but once i get into the higher rpms in second gear and above i loose a lot of power and i begin getting a lot of sputtering sounds, almost like the bike is only runnin on two cylinders.

im curious the check list and order i should start checking, cleaning, and adjusting, I'd like to go to pod filters to open up the inside of the frame, but ive read a few different threads saying that they were difficult, but can find no explenation as to why. I also read on another thread that i cant just go adjusting the carbs for pods, that i needed to check other things in certain order to ensure its in tip top shape before going to pods.

Ive had a couple bikes previously to my mid max, but none that needed so much love. Im really looking forward to the challange, but im trying to find a good starting point. hopefuly some of you can help me.

 

You need to address:

Valve shim clearances
Carbs thoroughly cleaned and rebuilt
sync and colortune
check all wires, connections, etc.... I'd recommend upgrading the fusebox
total brake system clean/rebuild/replace shoes and pads
replace tires
thoroughly clean the tank

The symptoms you give are normal for the condition, but when you get it all cleaned and back in spec, you're going to be surprised with what these can do.

Now, make sure to put the year of your bike in your signature. I assume that when you say mid max, you mean a xj750 Midnight Maxim. That's a pretty nice find.............

Glad you found us! You'll never leave.............

Welcome to the Hotel XJ-fornia............................

dave

 

"They stab it with their steely knives but they just can't kill the beast"

 

"We are all just prisoners here, of our own device"

 

Touche!

 

First bike I ever owned was found in a dumpster too.

Turned a wrench, spent a few dollars.

Rode it for 3 more years before I left it NEXT TO the dumpster 1 year after that. It was the elite 50 in my signature.

 

First bike I ever owned was found in a dumpster too.

Turned a wrench, spent a few dollars.

Rode it for 3 more years before I left it NEXT TO the dumpster 1 year after that. It was the elite 50 in my signature.

 

Pod filters and CV carbs have issues because CV means "constant velocity" and pods don't provide that.

Like HogFiddles said, valves, carbs, brakes. Then worry about mods; if you start cutting into it before you get it running you might not.

 

Well, i pulled the carbs out. Im in the process of cleaning them really throroughly. Is there a thread or a good place to look to get help with the shims? this is the first time ive had to go this deep in a bike and its gonna be a lot of learning. lol.

 

This little gem of a walk through will help with the valves.

Try reading In the Church of Clean for tips on cleaning the carbs.

Explore the site. It's a treasure trove of information.

 

Another quick tip: Shortcuts make for short rides. Take your time and do the job right. You'll be glad you did.

 

YET ANOTHER QUESTION. Where can I find the stock specs for my bike? Stock jets, shim clearence, etc?

 

In the service manual! If you don't have one yet...get one!
You're going to need it!

 

Click here and scroll about 1/5 of the way down for information on jets.

Valve clearances are .11~.15mm for the intake and .16~.2mm for the exhaust.

Click on the XJ Forever link on the top right of every page and you'll be able to find almost any part you'll need.

 

Carbs are clean and bike is running much better than before. Wayyyy better. Now I'm having a problem with idle. Idles at 4 grand. Idle adjustment screw does nothing. Choke does nothing. Very frustrating to say the least.

 

I wonder if :

-one of more Carb butterfly springs are too tight
-have you running-synced the Carbs
-have you checked for vacuum leaks

Dave

 

You most certainly have a vacuum leak. If I were to guess I would say the throttle shaft seals.

Here's a walk through. You have to keep in mind you're dealing with 30 year old stuff here and rubber doesn't stay real soft and supple over those time frames. Unfortunately you'll have to pull and split the rack, but keep in mind, subsequent times become easier. I found this out the hard way too.

 

I actually fixed both of the previous issues! Haha. Bikes running even better. I do now need to do a running sync. With the yiks motor, what's the best way to do this at home? I've seen many videos about using a little home made set up with a couple vacuum lines and some liquid etc etc. y'all likely know about it. Is this a functional system for the yiks? Better ideas?

 

The BEST way it to order yourself a carbtune unit. They run a bit over $100 bucks , but you'll never have trouble with it, you can tune everyone's bike near you, and you can take it to carb clinics with you...... Everyone will think you're a god.

Dave

 

dang. i was hoping to get it tuned up tonight. will that system work with the whole yics synchronization bar thing?

 

http://xjbikes.com/Forums/viewtopic/t=2132.html

http://xjbikes.com/Forums/viewtopic/t=4191.html

 

I have the Morgan CarbTune Pro, I use it a lot and LOVE IT. I also have a YICS tool and ever use it. I'll start the next round of volleys by saying that in my opinion you don't really need to use it.

Dave

 

I made a two cylinder balancing deal. How should I pair the carbs up. 1/3 then 2/4 then balance the pairs?

_________________
Current Scooter: 1983 Yamaha 750cc Midnight Maxim (rat bike project)

Past Scooter:
1991 Suzuki 750cc Intruder (bobber project)

 

1/2 then 3/4 the 2/3

 

im looking to buy new clutch levers and master cylander assembly. Ive found them at a decent price on ebay and things, but i wanna make sure i get parts thatll definitely work. What specs do i need to know?

 

and how do i buy things from the xj4ever link? or is it to just give me part numbers

 

You have to ithe PM or e-mail in your order.

The bottom of the first post in section A:


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