New Member

Hi,

My name is Fred. I live in Europe and recently purchased a 1985 XJ 700 X Maxim with the 20 valve engine.
It is my first Yamaha, I had a Kawasaki KLR250 and 650 and GPZ900R in the past.

The previous owner had not used it for 4 years so I only rode it for a couple of times (to find out what needs to be done) before taking it to my mechanic.

He replaced:

-battery
-spark plugs
-front brake pads
-air filter (now K&N)
-engine oil and filter
-cooling liquid

And some more, can't remember what exactly.
I asked him to replace the brake fluid and transmission oil but he said they were fine. I would have liked him to do it but he insisted they were still fine.

He encountered some problems. Apparently some fool had been working on the bike in the past and re-assembling it with some parts missing in the carburetors and front brakes. We had to buy these parts as well.

Just went to pick it up and drove home. While the engine seems to run okay (it was pretty bad before it went to the mechanic, especially when cold, it would hesitate badly until warm) I am not too happy as each time I release the throttle to change gears, the engine's RPM drops way too slow.
It takes over 10 seconds after releasing the throttle for the engine to drop to idle, that can't be good. One cannot use the 'engine break' and I suppose it can't be good for the gearbox/clutch to change gears at higher than normal RPM. Anyone know what could cause this ?

Oh yes I forgot to say he did the valves and carburetor synchronisation.
The carbs also went into some kind of special bath, you'll probably know what I mean.
I also purchased one of these :

http://www.ebay.com/itm/Yamaha-XJ700-XJ ... 0a&vxp=mtr

They asked me whether the exhaust system was stock I said yes.
Regarding the air filter I said I was going to put in K&N.
Regarding altitude I said sea level (Netherlands is about sea level).

However my mechanic did not do the modification, as someone at a motorcycle shop told him it was a bad idea.
I was not too happy as I was afraid the engine would run on the lean side with the K&N air filter and stock carburetors, but it doesn't seem that way when driving home.

Anyone have any experience with these Sigma jet kits ?
Anyone know what could cause the slow dropping of the RPM after releasing the throttle ? I'm a bit depressed right now

I think it idles slightly too high so I'll adjust it, the manual says 1050 RPM it's a tiny bit higher than that I believe, right now.

Thanks for reading !

 

Welcome aboard Fred!

I have owned one of these X in the past and I'd say they are very fun to ride when properly tuned. Their very special valve train requires special attention though, and combined with the necessary carbs balancing and colourtuning, may get you feel mad sometimes before you got them to run fine.

You could count on experienced guys (I don't consider myself as one of them) here to tell you what to do first. To adjust your idle per the manual is a good start. Does your throttle cable operate freely, does it return quickly back in place when released? Check down there at the carbs rack if the throttle lever operates at the same speed as the cable.

 

Thank you, checking the cable would be a very good idea to start with.
There was too much free play in the throttle handle and I asked my mechanic to reduce that. Since the problem was not there before, this could very well be it. I'll have a look. Maybe some grease needs to be applied somewhere for smoother movement. I am not much of a mechanic myself but I can ask my father to have a look with me some time.

 

The throtte handle itself may be sticky, it had happened once on my other Yamaha, and it caused the same situation you are experiencing.

But if you have both of free play and hanging idle, I'd lube the cable first. Do yourself a favor and go buy a can of PJ1 or something similar (don't use WD40 to lube your cables, they will do fine on a short term but they will soon turn more sticky than before).

 

I don't think the handle sticks as I turn it back myself when changing gears, but there might be something with the cable. I will have a look.

What do you think about the jet kit ? Should I mod the carbs or leave them stock ? Is it safe to leave them stock while having a K&N air filter and risk having too lean a mixture ?

 

asvrt,

Welcome.

Gary

 

Think I'm going to buy a new throttle cable while I'm at it.

 

The major cause of a hanging idle is worn throttle shaft seals, cracked boots and bad head-to-boot gaskets (and dried-up vac caps)

Welcome to the site !!

Can you double-check your carb sync with a long tube (1/4 inch) and a bit of tranny fluid??

FYI - you have no "transmission oil" to change, but you are expected to renew your brake fluid and final drive fluid at home, this weekend !

 

Thanks, it's nice to be here.

I'm still hoping it has something to do with the cable as it wasn't so when it went to the mechanic and he did adjust the free play on the cable and now the problem is there. We'll have a look.

The only thing my mechanic mentioned would be good to replace at some point would be the 4 rubbers going from the air filter to each carburetor. They are stiff.

Yes by transmission oil I was referring to final drive fluid.

I'm sorry I'm not very technically skilled so the "can you double check your carb sync etc etc etc" is really chinese to me

 

Welcome

 

Thank you for welcoming me to all that have.

 

http://www.marktplaats.nl/a/motoren/ond ... ousPage=lr

Would these be what my mechanic is referring to when talking about the 4 joints between air filter and carbs ?
Would they fit my XJ 700 X Maxim or only non-X models ?

 

Welcome aboard from a fellow dutch guy Great bike you got there as well. I recently picked up a '86 XJ700X Maxim

There's a map here http://xjbikes.com/dfmaps.html , not many dutch people on it yet though.

 

Yea, that looks like the joints between the airbox and the carbs. Yet, they look taller than they are on my bike ('86 Maxim X). I'm sure someone here can tell you if they fit on your bike.

 

I think it may be different, ( the airbox tunnels ) though I'm not sure. I have the 86 xj700s, and it is not the same as your 700-x. Yours is a watercooled, 20 valve motor, where the 700s is a 8 valve air-cooled motor.

I also think the carburetors are different, 700s being hitachi, and the 700-x is mikuni, so the air tunnels may be very different.

Hope that helps, and welcome to the club.

 

Hi Darthraider.

I wonder whether the air-cooled carbs are the same as the X carbs.

 

I'm pretty sure some of the experienced guys here could dig in their cross-reference parts database to make that clear, but I don't hink that the carbs or air boots of an X would fit any other XJ, maybe they are the same of a Fazer of the same year, but that's about it.

 

I'm sorry I missed your post.
Thanks. I will look into it.

 

ha, i wondered about that =).

Good luck.


To help out others, to help you, you may want to include your location in your profile, so we can see where you are, in case someone close can help, plus put your bike / year / etc. in the signature, so we know what you have.

 

Welcome aboard Fred!

I want to start by mentioning the air-box rubber boots are specific for the X models. They are a different length and diameter as compared to the ones used on the air cooled models.

Secondly, the carbs are specific as well. They are Mikuni BS33's and are used on the 85 and 86 700/750 X's.

I see that you are getting some help from your mechanic and you'll have to consult with them and verify that the items supposedly taken care of are actually done, such as the valve clearance adjustment and proper carb cleaning.

With that, replace the throttle cable and make sure you lube it first. While you at it, disassemble the throttle, clean and re-lube it. Make sure it moves freely when you reassemble it and snaps back when released.

A more difficult task would be to check for any vacuum leaks, especially at the intake (where it meets the head), and the throttle shaft seals. Sometimes the carbs are soaked when cleaned and this damages the seals. While not as critical, replace the air-box rubber boots as they need to be pliable and crack free.

With those things checked, you can move on to a jet kit and a K&N filter to help with overall performance. Be aware of the fact that the jet kits don't come with pilot jets. With that in mind, you're at low altitude and I would make sure you have the 37.5's (as some of these carbs have 35's-very lean). You could possibly need to move up to the #40's with the K&N?. Also, it's critical to make sure you Colortune after syncing the carbs, then check the plug color after a high RPM run. It will take some work to get the carbs dialed in with a jet kit and tuning, but the results are well worth it.

Tony

 

I was told that vacuum leaks at the intake could be traced by pointing a propane tocrh (not lighted) close to every carb while the engine is running, if the RPMs get higher , there is a leak.

 

Yes, that's a great way to check for vacuum leaks.

 

Thanks for the great feedback. Will let you know once there is something new to mention. I'll check my profile, see how I can indicate my location.

 

My bike is in the garage and I haven't used it since monday.
Is it normal that it still smells ?

I've purchased this for final gear fluid, hope that's okay ?

http://www.autopartsplus.be/media/catal ... 830080.jpg

I can use DOT4 instead of DOT3 for the brakes, right ?

 

Depends what it smells like. Pizza?

Dave

 

Depends on what you smell? When I parked it in the garage, my garage would also smell as if the engine 's been running for about 5 minutes with all windows closed.

 

Hi and welcome from Denver, CO

Massimo

 

Hi Massimo.

It doesn't smell like pizza, I'm afraid
I guess it smells like gasoline, more or less.
Maybe I need to wash the bike with some soap, see if the smell returns.

 

We adjusted free play of the throttle handle/cable to the max and the RPM seem to drop better now. Didn´t replace the cable as we haven´t got it yet.
Throttle handle spring seems fine as the handle returns well, and at the other end of the cable it returns strong as well, so cable doesn´t seem to be worn.

Replaced final gear fluid, the fluid was old and dirty.
Also adjuster idle speed a little.

Motorcycle drives pretty well now, I don´t believe the mixture is lean, engine does not heat up too much at all.
There´s one strange thing though, while driving I hear some kind of whining sound, it´s frequency appears to be speed-related, not RPM-related, I believe.
When speed drops below approx 10 / 20 mph, the sound abruptly stops.
I wonder what that could be. It´s definitely some kind of whine, more or less like some kind of siren.

Otherwise the sound of the 20 valve engine is incredibly cool above 4000 RPM. I´d compare it to the sound of a 6 cylinder race car, though it´s sound doesn´t really compare to anything, quite unique. Love how smooth the engine is around 6000 RPM.

The front brakes have been worked on by the mechanic and they function, strange thing is I can´t press the handle in for more than a couple of millimeters. I am not used to that.

 

Sound like your speedo needs some lubing.

 

The cable ?

 

No, the input shaft bearing - dribble a few drops of synthetic motor oil, and spin the "square cable receptacle" with the gauge inverted.

Also lube the cable.

 

Okay thanks.
So what do I have to do to have access to the input shaft bearing ?
Unbolt the speedometer ? I'll have a look, can't be that complicated ?
Hope IO don't have to disassemble half the dash or the 'highway window' that was mounted by a previous owner.

 

Mechanical instrument tech: http://xjbikes.com/Forums/viewtopic/t=15303.html

As for the brake lever: there should be an adjusting screw in the lever for where it makes contact with the plunger in the master cylinder. If you back this out a tad you can adjust the point at which the lever "engages" the brake and give yourself a bit more travel.

 

Thanks again.
We partially disassembled the speedo and did some lubing, the cable too.
There's snow here right now so haven't tested the bike yet.
I was thinking, if the sound's still there, I'll disconnect the cable from the speedo, just to be sure whether it's actually the speedo or something else.

 

I took the bike out for a ride and the speed-related whining is gone, thanks !

Strangely, I sometimes hear a (different ?) soft whine when accelerating for a short period of time. For instance, if I drive at a constant speed in say 3rd gear and then accelerate, I hear some kind of noise. It reminds me of the sound the cars with superchargers make in my race simulator on my Xbox ?

Also, the fuel indicator light is flashing now ?! (Plenty of fuel in the tank)
It's not a huge problem but slightly annoying.

Otherwise, these bikes are fun to drive !
Is braking power generally poor on these bikes ? My mechanic replaced the front brake pads but I am not very impressed. He did not replace the brake fluid as per my instructions, though he said he had it tested and it was fine. It's probably very, very old though as the previous owner did not use the bike for 4 years.

 

That soft whine you're talking about is probably the distinctive sound of the Maxim-X. Been there, heard that!

 

Yes I thought of that possibility. What could cause such a sound though ? Besides the 5 valves there isn't that much out of the ordinary, is there ?

What pressure do you guys put in your front and rear tire ?
I weigh 75 kilograms.
The manual mentions 177 kpa and 196 kpa which is 1.77 and 1.96 bar, right ?
That seems very little. The guy who sold me the bike said this was based on tires from the 80's and that modern tires need more pressure, don't know whether that's just BS ?

And regarding fuel... Over here in my country we have Euro 95 and Super 98, both unleaded, so I put in the 95. Would that be okay ?

 

As for air pressure in the tires, I use to put 32 PSI front and 34 PSI rear, equivalent of 220 and 234 kpa. The numbers you mentioned are too low and would cause the tires to wear faster at best, and even worse might lead to tire overheating and blow up.

Don't know what causes the soft whine, but I remember I haven't heard it with other bikes I've owned.

 

It's the straight-cut primary drive gears. It's known as "middle gear whine" and is a characteristic of the shaft-driven XJ series.

 

Vroom vroom

 

The rear springs have five settings, they are now on the third (previous owner's choice).
I find it too stiff, personally. I weigh approx. 75 kgs which is 165 pounds.
I was wondering what would happen exactly if I'd set it to the second setting, less stiff. Would it affect height of the saddle when no person is on it, my guess is it wouldn't.
However, if I sit on it, would the saddle go down further than on the current setting ? Reason I am asking is in case I'd take a passenger.
I had my mechanic look when my girlfriend and I both sat on the bike, he said it went down pretty far and there wasn't huge clearance between the upper part of the rear tyre, so he advised leaving it to the third setting and not setting it softer.
However, my girlfriend and I broke up so I am riding the bike all by myself, and I do find it too stiff the way it is. But in case at some point I would have a passenger, I'd not want to touch the upper part of the tire.

 

The preload is adjustable for just the reason you describe & the tool should be in your on-bike tool kit, that way you set it to a comfortable setting for solo riding & if you pick up a nice girl along the way just pop the preload back up to 3 (or 4.... or 5, depending on her "figure" lol )

Shouldn't affect the seat height with nobody on it unless the spring is too short, as even on the lowest setting there should be a certain amount of tension(preload) on the springs.

Also, I think the original shocks shouldn't allow the tire to foul the frame even fully compressed. Not 100% on the last point but makes sense in my mind they'd not design it where a big rider could scrape his tire away...

 

Thanks for your reply. I didn't realise adjusting would be so easy that one could even do it on the road. I thought the rear might need to be lifted so that there's not pressure on the spring.

These are the tools I found. Would I need to put the tool indicated by the yellow arrow in the hole indicated by the red arrow to adjust ? Just rotate ? Counter-clockwise, right ? Much force needed ?




I'll soon wash the bike and take some nice pics and add them here.

 

Sure, you can use that tool to perform the shock preload adjustment.

From the picture, you show that you're on the middle setting. So you should rotate the tool to the Right in order to soften the static setting. Doesn't take much force and make sure both sides are even.

When you find a new girlfriend (one that likes to ride), go back to the middle setting when riding two up and that should keep it from sagging.

 

We managed to adjust them to the second setting but it's not something I'd do on a regular basis. The exhausts are a bit in the way and one of the holes got slightly deformed by the force applied . So we inserted two tools for each spring to spread the force in order to prevent further deformation.

I'll make sure my next girlfriend weighs no more than 140 pounds so I can leave it at the second setting

 

I must admit I had no idea the original shocks used that method of adjustment (assuming they are original).

Most bikes use a C-spanner that locates in a castellated ring, my XJ has Koni shocks that use the same idea.

 

Not sure if you had it up on the center stand? That helps take the pressure off the springs when adjusting. Sorry that I forgot to mention that.

 

Yes we did put it on the center stand, thanks.
We managed, that's the most important. But I wouldn't do it very often.