New bike

Hi,

I just got my first bike, a Maxim XJ750 1983.

It had some issues with the carburator which were fixed. However, my idle RPM is around 2.5k - 3k. What is wrong with my bike? I figure that it is way too high.

Thanks for your input.

Turboninjo

 

Carburetor? There are four of them. What were the issues? What was fixed? You may only need to adjust the idle screw. You might have to do a vacuum sync. How are the valve clearances? Since this is your first bike, there are many things to check to make your bike safe and running top notch. Remember, it's 30 years old. It helps us to help you knowing some history about the bike.
BTW, welcome.

 

The engine should idle at 1100 RPM. The idle speed adjustment knob is between the #3 and #4 carb (accessible from the right side of the bike).

Please go over what you've had done to the bike so far. There are a number of maintainance items that have often been overlooked for many, many years. Those items need to be cought up on before you will have a motorcycle that is safe and healthy.

 

You're in for an interesting journey! Turned me into parttime mechanic and still wrestling with it. Fun, exasperating, strange, fun, say what, so that's how it works, frustrating, fun.

More time working on it than riding it ....... but hoping that is about to change.

 

I got the bike a few weeks ago. After 15 km, the engine stopped and would not start again. I changed the Spark plugs and it started again, only to stop 5 km later. I got it working again with new plugs and got it to the garage. I noticed my idle was too low ~500RPM. I told the mechanic all this and he went around and changed my filters and found some problem with the carburetor(s) (it had pieces inside that were moving, I'm not sure what or why).
When I took my bike home, it was fine when I drove, but I noticed that the RPM was too high.

I will check that adjustment knob.

Thanks!

Edit: I just took it out, the idle was fine. I drove a bit and at some point, at a red light, the RPM went up to ~2.5k and stayed there everytime I stopped until I came home. Any tips?

 

Tips:
Get a manual.
Get some metric wrenches and JIS screwdrivers.
Rebuild full brake system ( front and rear).
Don't let anyone else work on it - you and only you will rebuild items to meticulous detail.
BE meticulous.
Meticulous = safe and reliable.

Plan on spending at least $800 more dollars.
Ask ALOT of questions here.
When I joined I knew "righty tighty, lefty loosy" and precision measuring.
There are people here that are more than happy to provide you with answers to guide you to a point of having a safe reliable ride.

 

Amen.

You have a lot of work to do; and "the shop" has no clue, honest.

If they did, and they were honest, they would have told you that what needs to be done to the bike will run you about $3000.00 in THEIR labor (or more) and sent you on your way.

But they didn't; and the bike isn't fixed. No surprise.

YOU are going to need to fix it; if you keep riding it in its current state of "tune" you will kill it.

Sorry, but this and the above advice is right on; you're going to need to spend a few Loonies in the process.

We're here to help; but there's no "quick fix." And you'll need that manual.

 

Hi guys,

I do indeed feel that the shop cannot know for sure what the problems are since they're not the ones riding the bike. You must be right that I have to be the one to do it.

I do have the owner's manual and a few tools (including those JIS screwdrivers and metric wrenches).

Now, concerning the bike. After I took it out yesterday, I tried starting it an hour later and nothing would do. This is the third time this happened to me. I tend to believe it has something to do with the fact that my RPM goes up after a few KMs. As in, when the engine gets hot, things go ham. I was told that it might be the air filter that is faulty. I'll ride it today until it heats again and will remove the air filter just to see.

Thank you for helping me out.

 

It's not the air filter.

Don't go back to those same "mechanics". They suck.

 

I went out just now with a few biker friends. They took a look at my bike and they thought that my problem was that I let my "choke" on too long. This coupled with the fact that my air filter (which I took out to see) was filthy was the reason I was having troubles. The gas/air proportion was too high and I probably flooded the engine.

As for the brake system, I will get to it this week. I will start by opening the rear brake. It seems quite simple actually. Is there anything I should on the lookout for?

 

The owners manual only has basic information in it...you will need a factory service manual for your bike......plus time & money......trust us.....do it right...& you will be rewarded in the end....

 

Buy a new air filter, check to see if your choke was on.
If not, look to see when the choke attaches to the carbs and see if its "Hanging" (If its pulling the plungers up juuuuust a little)
After you get that done and it still doesnt ride very good you need to do
Valves,
Carb clean,
Sync,
Colortune

And that'll get you started

-Chris

 

I will receive my air filter tomorrow.

I went for another ride and while I'm riding, there does not seem to be any problem. However, it's when I have to stop at a red light that my engine reminds me of its faults ~ 2.5k RPM.

I take off my choke early now but nothing seems to have changed.

Friday I'm going for a longer ride, I'll probably get to know more.

I'll keep you posted.

 

You MUST dis-assemble and THOROUGHLY clean the carbs, read the thread called "in the CHURCH of CLEAN"

Then, check and adjust valve shim clearances.

Then go through the brakes, both front and back, pay close attention to the backs for delamination issues.

NOW....your mechanic WAS CORRECT. There ARE some moving parts inside the carb. The slide assembly goes up and down, the float and the float needle go up and down, and the float pivot can move slightly back and forth, too.

Other than that, your mechanic is whacked. very generally speaking, MOST shops have no clue what to do with these bikes......the bikes are too old for them to comprehend--they can't hook up a computer to it.

Start at ground zero, and learn your bike.

As we say with older snowmobiles, "Ya gotta wrench if you're gonna ride"

Dave F

 

Thank you all so much for the tips

It's nice to know that so many people share this passion!

 

I got my new air filter.

I took my bike out for about 120km. After a few kms, the idle was reaching 2.5k RPM. By the end of the ride, it reached 3.5k RPM.

I sure do not keep the choke on for long. I checked to see if it was stuck or something, and the movement seemed fine.

@SLKid: What do you mean by "hanging"?

Thanks!

 

He meant check to be sure one of the enrichment plungers isn't "hanging up" or not closing fully (being held up/open just a tad.)

That being said, we've already told you what needs to be done. Just changing the air filter won't "fix" your issue; nobody expected it to. You have some work to do.

-Service the carbs and accurately "wet-set" the float levels.
-GET THE VALVES IN SPEC.
-"Bench" sync the carbs, re-install on bike.
-Running vacuum sync with YICS blocked.
-Mixture tuning, using a ColorTune (or other less precise methods.)

Study your manual, then dig in. Ask questions.

Again; there is no "quick fix" for your issues. The bike needs its maintenance caught up. Period.

 

So it's like the fellas told you- it's not just the air filter.

Your machine is 30+ years old, it needs love. That love must come in a specific order if you want the right results, otherwise you're just wasting time in a flamboyant fashion.

Step 1: Valves. Everyone always goes straight to the carbs if they're having issues, but the valves and their exact distances and timing controls what the carbs do, so if you neglect checking them, you're gunna have a bad time. CHECK YOUR VALVES.

Step 2: Pull the carbs and clean em. Religiously clean. Cleaner than a monk's soul. It's called the Church of Clean.

Step 3: Bench sync your carbs so all the butterfly valves are in sync.

Step 4: Check and adjust your float levels.

Step 5: Running vacuum sync.

That will get you started. Failure to follow the order, or halfassing any step, will end up with you being in square 1, just more confused. Don't waste time, do it right, don't trust any mechanic (seriously), and learn to do it yourself. You can do this. We can help. But we can't help if you don't try to help yourself.

Whereabouts in Canada are you? I'd be willing to road trip and come help you out if you're in BC.

 

I'm in Quebec city, a bit far from BC

 

A bit of a drive. And I can't speak french or deal with your weather on a regular basis, so you're on your own

Fitz laid it out for you. You can do this. It won't be a quick fix. But it will be worth it!

Don't believe me? Fitz also wrote a great thread on quick fixes...

 

Salut Turboninjo

Je suis entre Montreal et SHerbrooke. J'ai deux frères à QUébec.

 

Si t'es en visite et que tu veux faire un petit tour, fais-moi signe!

 

Vérifies dans ta boite de courrier je t'ai envoyé un message.

 

What is the best way to find a manual? Is it Amazon where it's listed at 89$?

Edit: I found a CD version for 11$. That should do the trick. I'll print out the pages I need when I need them.

Nevermind my question