Low idle Engine cuts out on no throttle - oh, tyre clearance Q too

Hi folks - looking to join the club with a purchase of a nice clean XJ650 (US Import to UK), the bike rides sweet and condition backs up low mileage - fires up on first press of starter button, but after 30 secs or so of no throttle the revs (set at around 1200rpm initially) slowly begin to drop until the engine cuts out.

Also happens after engine has been warmed up. A little choke seems to help. The bike has only seen around 1000 miles over the last 5 years or so. I've read these bikes tend to idle quite low, would the above issue be a common one which should be easy to solve?

Also, the tyre is standard fitment (130/90/16) - but the LHS of tyre tread seems to run perilously close to touching the swingarm. Again, I've read this as a fairly common issue - but how much clearance should there really be? We are talking no more than credit card thickness gap here.

 

I will tackle the tire c!earance issue.
The 130 /90/16 tire is correct. But there should be more clearance. Approx 1/4 inch or more.
Make sure the correct spacer is used between the final drive and wheel.
Maybe Dave can jump in here with a measurement for the spacer?

~Ghost

 

Regarding your low idle, what color are the plugs? Have you tried adjusting the idle speed up a hair?

 

Havent had a chance to check the plugs - did tweak the idle speed on viewing though. At first seemed to solve the problem, but after leaving bike running for perhaps a further minute, it then slowly but surely dropped its RPM until it eventually cut out.
Fired up again, first time with a tiny bit of choke. As mentioned, pulls away clean and runs fine.


*EDIT* for clarity - this is a potential purchase bike, I haven't paid for it yet.

I'm unlikely to be able to check spacer width on rear wheel. If it did turn out to be an incorrect spacer am I likely to be able to easily source a replacement?

 

It sounds to me that your mixture is maybe just a hair off. Take a look at the plugs (or better yet, post some pictures) so you/we can get an idea which way it needs to be adjusted.

 

Mixture eh? Well that would be a good (and simple enough) result.
I'm mainly keen to know if this was more likely to be a costly fix, or not. I appreciate its impossible to be certain - but if the described fault had you guys all gritting your teeth then i'd feel more inclined to be worried!

 

The petcock could have crud plugging it up I.E. it is starving for fuel ,the float bowls can fill up , but after a few minutes of running level drops lower and bike can die . My guess look in tank-rust or dirt? Carbs probably need removed and cleaned ( taken to the Church of clean ) the Petcock checked , make sure fuel line is not kinked slightly
Agree with Drew-uth maybe mixture screws 2.5 turns out from soft set is good starting point. Another possibility is you have a slight vacuum leak usually carb to intake boots. Try a little carb cleaner sprayed around them see if idle increases or boggs down. Good luck.

 

Great advice, thanks.

Tank looked pretty clean inside, was recently sprayed and I think flushed/treated at that point. I've read the petcock renewal thread on this site so would be keen to give that a try. A full on carb clean would probably be a good idea as a matter of course.
I did wonder myself if there could be a leak around the intake boots as the engine idle was reducing so smoothly, i wondered if it could be (lack of) vacuum issue.

Any more ideas on this rear wheel/swingarm/spacer deal?

 

Agree with Mi Ghosts reply about measurement ..do you have a manual ? ( if not recommended ) there are 2 spacers I don't recall off the top of my head , I think one is longer than the other, but I'd have to look at my bike .

 

No manual as yet (one included with purchase should I proceed). Could someone kindly link me to the parts in question? I'd like to get a brief understanding of position/orientation/access to said spacers.

 

http://www.yamahapartsnation.com/oemparts/a/yam/500421c2f8700209bc7873a9/rear-wheel

 

The long spacer would be on the final drive side.

~Ghost

 

So going by that diagram, could it potentially be that the flange spacer (no3) is missing? I'd imagine the spacer (no2) is almost certainly present otherwise the wheel wouldnt have been able to be installed.

Ah yes, I believe I recall seeing that clamped to the RHS of swingarm. I guess that it slides over the fat end of the axle?
I'm trying to visualise what would be required to essentially bring the entire wheel over toward the RHS by a few mm.

Again, what could be the worst case scenario im facing here?

 

No, Those spacers are internal to the wheel and hold the bearing spacing. They will not affect the side to side spacing.

http://www.yamahapartsnation.com/oemparts/a/yam/500421c0f8700209bc7873a2/drive-shaft
The spacer I am talking about is (#42) in the top left corner. This will be approx 45-50 mm in length. I do not have one handy at the moment to get an accurate measurement. It goes inside the drive flange (#7) and fits tight to the inside if the final drive housing. This spacer should stick out from the drive flange a little bit (2-3mm).

And
http://www.yamahapartsnation.com/oemparts/a/yam/500421c2f8700209bc7873a9/rear-wheel
(#27) By the end of the axle shaft. This look like a thick washer maybe 8-10 mm thick and will go between the brake plate (#12) and the swing arm.
The axle shaft will bottom out on it leaving the fat section in the swingarm to be clamped down.

If everything is in the correct place you will just have room to slide Space #27 between the brake plate and swing arm before sliding the axle shaft through the complete assembly.

Here isa pic showing the axle shaft and spacers. The tube spacer is #42. The washer next to the nut is spacer #27. The washer in the middle is just a washer that goes on before the nut.

Worst case is as the tire warms up from normal use. The air inside heats up and expands causing the tire to swell a little bit. If your as close as you say. The tire will start rubbing the swing arm wearing out the sidewall of the tire. At speed a worn sidewall could blow out. I am sure you can guess what happens next!

~Ghost

 

You are a legend, thank you.

So, if I get the wheel apart and it turns out everything is already set correctly, what next?..

Is there flexibility in the set up in order to set the wheel position accurately?

 

• Depending on brand of tyre, clearance can be as little as 4mm upto 10mm

That being said the tire will not get wider at speed but get taller.
And due to the fact it's shaft drive alignment will not change as it could with a chain drive bike

 

Does the tire have rub marks on the side?
If not then just go ride.

 

Yeah I figured the tyre would probably get taller, I wondered if lateral flex during cornering could be an issue.

I checked tyre closely, it still had a sharp edge at its widest point, I had to loon hard for any signs of rubbing - there was a small patch that could arguably be said to be a very slight rub. Otherwise it seemed fine

 

I could really use some help here. My rear tire is rubbing on the final drive side. I have all the spacers you show in your picture, and they all look just like that. But, when I pull the wheel out, no other spacers are in there.

Am I missing a spacer- the spacer mentioned going between the final drive and wheel- Part #146-25315-00-00 (#3 in the schematic) Unless that spacer is living in between the wheel bearings (and I don't see it there) I don't have anything that looks like that one.

 

But, in looking at this guide... http://www.xj4ever.com/rear drum brakes.pdf

I see no mention of any spacer aside from the long cylinder one. I am lost...

Edit- looks like the spacer part # above goes in between the two bearings.

 

Which brand, and model of tire?

 

Flange spacer (#3) is a thin stamped steel piece that slides over the bearing spacer (#2). You will only see it if you remove a bearing. The purpose of the flange spacer is to keep the bearing spacer centered inside the hub. It does nothing as far as side to side spacing.

~Ghost

 

I just read the same document and was interested to read the section that states:

I'm yet to remove my rear wheel but am wondering if this 'spacer tube' could be the cause of my (and potentially your) tight tyre/driveshaft housing spacing?..

Would be great if someone could shed some light on this component and how it is adjusted accordingly.
My guess is that slight a lateral tweak of this tube could pull the wheel alignment over towards the RHS slightly (thus clearing the driveshaft housing).. No idea how it's adjusted though.

 

There should be no lateral (side to side) adjustment to the bearing spacer. The bearings will sit flush with the outer edge of the wheel hub.
If any of the bearing, or wheel spacers is incorrect the axle shaft will not tighten properly and the wheel will slide from side to side.

What size, and brand tires are mounted??

~Ghost

 

What is Len referring to then when he states ''leave it there, we don't want to throw off the wheel alignment'' ?

The picture and comment from the link seems to suggest that the tube is accessible without removing the bearing, and affects the wheel alignment if 'not left alone'.

In my case, I have a Continental 'Blitz' 130/90/60 and as you can see here, the tyre is pinch holding a cable tie in place against the swingarm:

Also, you can see here that the tyre leading edge appears to have rubbed marginally against the swingarm at some point:


I am about to head down shortly to remove the rear wheel and check rear brake shoes for first time, having just had a pre-inspection I noticed that the axle appears to have been engaged slightly too far before being tightened:


The cotter pin is missing and as you can see, the entire pin 'hole' isn't fully visible. I wonder if this is potentially enough of a reason to cause the gap spacing issue?

 

That is not a cotter pin hole. The hole is for a drift or punch to fit into for axle removal. What I think I see is the telltale of an axle nut (opposite end of the axle) that has been over tightened.

 

Likely to cause any lasting damage?

 

Now I can see the problem!
There is far to much of the axle shaft pulled through the swingarm. The complete hole plus approx 3/16"-1/4" of the axle shaft should extend outside the swingarm.

The spacer that is pointed out in the brake write up is the spacer between the wheel and final drive (Spacer #42). If that is not in place or has been changed it will cause exactly what you are dealing with. It can easily get lost when pulling the wheel off if you are not aware that it should be there.

I am going to take a wild guess based on experience that you will find yours missing. The good news is that it is the exact same part for all xj650, and xj750. So it should be easy to find a replacement.

~Ghost

 

My tire is Michelin Commander II 130/90 16.

The amount of tire rub is similar to the above picture. I do have the final drive spacer and it looks like the part in the picture showing the axle "skewer."

There is no side to side play in the bearings, and they look like the bearing spacer is in there. All of the bearings are sealed bearings and look newer than 1981. Brakes have also been replaced.

When I took off the rear wheel, I found the axle nut torqued to a LOT LESS than 77 ft lbs- maybe 20-30. Still, rubbing the final drive side.

Using the pinch bolt to space the wheel out isn't going to help, right? If I torque to 77 ft lbs, I will just be pulling the swingarms closer (assuming the pinch doesn't slip) until I bottom out the spacers, right?

I have no idea what to do here if this is non-adjustable but yet I don't have enough clearance. It seems the only way to fix would be to do something like washer the final drive spacer out a few mm.

 

I also have the Michelin commander II tires on my xj750j and i haven't experienced any problems at all since day one

 

From XJ PARTS CATALOG, SECTION L: AXLES, WHEELS, TIRES

Spacer #27: Right side
HCP4803 OEM rear wheel axle shaft COLLAR, for all XJ650, all XJ700, all XJ750, and all XJ900RK, RL, N/FN, and F models. This is the 5mm thick spacer washer that is fitted on the right side of the brake backing plate (all models except XJ900RK) and on the far right end of the axle shaft (XJ900RK models).
$ 6.95


Spacer #2: Inside wheel hub
HCP4751 OEM rear wheel center hub SPACER TUBE this 2-1/2" long tube spacer fits into the wheel hub, and the HCP1795 flanged spacer ring fit onto the right end of it. For all XJ550 Seca, XJ650, XJ700, and all XJ750 (except XJ750RL models), Each:
$ discontinued

HCP21015 Aftermarket rear wheel center hub SPACER TUBE this 2-1/2" long tube spacer fits into the wheel hub, and the HCP1795 flanged spacer ring fit onto the right end of it. For all XJ550 Seca, XJ650, XJ700, and all XJ750 (except XJ750RL models), Each:
$ 21.95

Flange Spacer #3: Slides over spacer #2
HCP1795 OEM rear wheel axle shaft FLANGED SPACER RING, for all XJ550, FJ600, XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models. This is the incredibly thin flanged shimming washer on the right side of the spacer tube, behind the right side wheel bearing. A necessary part and one that is easily damaged during bearing removal or forgotten during replacement. NOTE: the original "spacer flange" is larger in diameter than this replacement, but the original is trapped in a secondary dwell cut into the wheel below the bearing pocket on the right side. The replacement does the same job; however, it needs to be installed further onto the spacer tube so that it misses the "land" for the original and just does its spacing off the inside of the casting itself. Then it works fine. It's only there to make the tube line up with the axle.
$ 3.95


Spacer #42: Left side
HCP12325 OEM final drive output/wheel clutch hub SPACER TUBE this almost 3” long tube spacer fits on the wheel side of the final drive housing, into the splined clutch hub on the left side of the wheel. If this spacer is missing, you will not be able to align the rear wheel properly side-to-side within the swingarm. For all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models. Each:
$ 12.95
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Check the wheel bearings to make sure they are flush with the outer edge of the wheel hub.
If the wheel bearings extend outside the wheel hub then it is possible that the center hub spacer (#2) and the final drive spacer (#42) may have been switched.. This would cause the wheel to be shifted towards the final drive.

~Ghost

 

All of that is there.

Wheel bearings- Brake side is flush. Final Drive side the bearing is a few mm inside of flush- I think because it is a sealed bearing and thus no oil seal.

Did any other bikes have different length spacers with similar diameters? The guy I bought this bike from had a few he was working on, perhaps he got the spacers mixed up? I don't really know what to do here aside from getting a longer spacer.

 

Exactly what I have been trying to say! There are different lengths in these hub spacers.

Check the length of the hub spacer (#42). It should be almost 3" long as noted above.
If it is shorter than 3" it is the wrong spacer and needs to be replace with one of the correct length.

~Ghost

 

Ok, so the washer and thin outer spacer are both present:



And I have the long spacer present:


But the long spacer butts up against what appears to be another press fitted spacer that is almost flush fitted at the end of the drive shaft/diff housing:

You can also just about make it out from the inside of the wheel, looking right down the axle hole:


Is that the shorter spacer (#42) and has it been wedged in there correctly or incorrectly? I'm completely guessing that the long spacer (#2) should actually reside in its place and press up against the axle nut washer?
If so, should I attempt to drift it out? (and from which direction?) and where does the bugger actually go?

I am probably completely wrong in my assumption. I just don't see reference to this wedged in spacer anywhere.

 

The long spacer in the final drive is hub spacer #42. It should be almost 3" (75-76mm) long.
The short piece wedged in the hub is press fit in place and should not be removed.



~Ghost

 

I'm confused because on this diagram: http://www.yamahapartsnation.com/oemparts/a/yam/500421c0f8700209bc7873a2/drive-shaft
#42 is clearly shorter than #2 on this diagram:
http://www.yamahapartsnation.com/oemparts/a/yam/500421c2f8700209bc7873a9/rear-wheel

I'm pretty sure we are talking about #2 here?
At least, #2 (labelled 'spacer') matches your description, and is what I have in the rear hub. I can't see where #42 (labelled 'collar') fits into the equation. Sorry if I'm barking up the wrong tree!

 

Can I request some more specifics on the specific length?

A tape measure reflects my spacer is about 2.75"

 

I have one on order to get an exact measurements.
Based on the measurement from the XJ parts catalog quoted above. Your spacer is 0.25" short.

~Ghost

 

Would finding and adding a shim/spacer of the same diameter not solve the problem?

In my case, every component appears to be in place, but the axle just slides in too far. If I added a shim of, say, 10mm - the axle would theoretically end in the correct location - or am I missing something?

Edit* on reflection, this would probably push the wheel off the final drive hub. I'm stumped as to how my axle is able to be inserted 'too far'. I can't envisage how my issue can be solved as moving the spacing would affect the hub/wheel interface.
It's almost as if the wheel offset is incorrect. Can anyone offer suggestions to a fix?

 

The drawings are not to any scale. Size comparison between different drawings will not work.
The parts list will only give you a general location and vague idea what the part should look like.

For the nitty gritty technical details you need to find another source if the description does not clearly state (yamaha is good for this).
I got the length from the XJ4ever parts catalog (a trusted source). The technical details on the parts available through XJ4ever have been developed over years of handling these parts.

Your missing that it takes every piece in the correct location, and correct size. If you look at every piece (bearings, spacers, brake plate, drive hub) you will notice that each has a certain thickness or length. The thickness or length of all these parts when assemble together create a total length measurement. This total length measurement is what determines the location of the wheel/tire in the swingarm. Different bikes have different total length requirements. It is very easy to get parts mixed up if more than one bike is being worked on (which I believe is the what happened with anachronism's bike). Or if you are not aware that the hub spacer needs to be a certain length.

http://www.yamahapartsnation.com/oemparts/a/yam/500421c2f8700209bc7873a9/rear-wheel
Starting with the axle shaft you will notice that the shaft has a step cut into it that catches the 5mm axle shaft collar (#27). The axle shaft collar sits against and catches the brake shoe plate (#12). The brake shoe plate then catches the right wheel bearing (#4), Which then catches the bearing spacer (#2). Followed by the left wheel bearing pair (#5 & #6).

http://www.yamahapartsnation.com/oemparts/a/yam/500421c0f8700209bc7873a2/drive-shaft
At this point you pick up the final drive and hub spacer (#42). which passes through the driven gear to catch guide collar (#5)(this is the short spacer in your pic of the final drive).

Once the washer and nut are attached and tightened down the axle shaft pulls against the axle shaft collar pulling everything together to form a solid tube along the axle shaft. The only piece that can change is the hub spacer(#42). If the hub spacer is shorter than it should be it allows the axle shaft to be pulled farther into the swingarm. In noting that your axle shaft was pulled in to far. It directly points to the hub spacer being to short.

You could just make up another shim spacer to add to the hub spacer to get the correct length, but are you going to remember it in 3-5 years when it is time to change the tires again? Are you sure it won't fall out and get lost when you do? Is the next person going to know that it is in there if you sell the bike? This is the type of cobbled up stuff that always gets complained about that some PO did to the bike.

It is easier and more reliable to just get the correct hub spacer for it. It is readily available and you will never need to worry about it again!

~Ghost

 

Ok, thanks for taking the time to post. It looks like I've been over thinking it.

I'll head down and check my hub spacer (#42) length and fingers crossed (?) it's a few MM short. Trouble is I have to remove my silencers to get the axle out so its not a 5min job..

Hypothetical worst case scenario, if my hub spacer turns out to be the correct length, what the heck could have gone wrong to cause the axle spacing shortfall?

 

While you are at it make sure that the bearings are sitting flush with the wheel hub. The should not extend past it.

~Ghost

 

Ok, both sides bearings are flush:



All components present:


And #42 collar measuring up at exactly 70mm (difficult to capture but verified):
Therefore, I too appear to be coming up 5mm short. Weird how both anochronism and I both appear to have the exact same issue..
Now need to see how fast my local dealer can come up with a replacement part. MiGhost - did you happen to verify the length of your spacer?

 

It is scheduled to arrive on friday. I will have verification then.

~Ghost

 

Got a surprise this morning!
Here are the specs:

XJ650, XJ750 Rear Axle and Hub Spacer specs:

Axle Shaft Diameter: 17mm [4H7-25381-00-00]
Axle Shaft Head Diameter: 22mm
Axle Shaft Head to Step Length: 75mm (3")
Axle Shaft Step to Taper: 215mm (8.5")
Axle Shaft Step to Thread: 224mm (8.625")
Axle Shaft Step to End: 251mm (9.825")
Hub Spacer Tube: 17mm X 23mm X 70mm (2.75") [90387-172A5-00]
Axle Shaft Collar: 17mm X 32mm X 4mm [4H7-25377-00-00]

Measurements in mm unless otherwise noted in ().
Measurements in () taken with common tape measure.
Part #'s in [ ]

We now have a mystery!
Scooby Doo! Where are you?

~Ghost

 

Darn it. I did think it would be strange for someone to refit a spacer tube within a couple MM of the 'original'. I just came back from my local Yam dealer and they sent me away with tail between my legs for not bringing the frame number with me. Kind of glad I didnt now..

I was pondering this earlier. IMO a correctly spaced axle will prevent side to side moment of the wheel, but the hub is a fixed point - so when the wheel is sat on the hub (ie, bevels are meshed) there can be no method of spacing the wheel in either direction as the beveled faces would effectively lose contact, would they not?

So that leaves Several possibilities..
Narrower tyre for one.
Repositioning of final drive gear?? - is there anything built within the rear hub to allow for this?
Spacing of clutch hub? (would affect bearing positioning)
Some kind of swing arm alignment/damage issue?

Most solutions in my minds eye would affect the positioning of bearings etc within the wheel. So I'm currently completely stumped.
Maybe it really does simply come down to this Conti tyre being too wide?.. although, heck, this doesn't explain why my axle can be inserted 'too far'.

So maybe I have an issue with a hidden collar/bearing size/spacing?

 

So I can join you on what appears to be an axle that is too deep. The bike is original, and it has been this way for as long as I can remember.

It is a 750 Seca though, which uses a 120 rear wheel, so I have nearly a 1/2 inch clearance between the tire and the swing arm. I have done all the removals and installations on the rear wheel, so I know a torque wrench has been used in all cases.

The 130 that you have is nearly a 1/2 inch wider, so about a 1/4 inch on each side. Given different tire manufacturers with different dimensions it makes sense that all could be OK, but the 130 tire would be really close.

Can't explain the axle being too deep though, as that hole does have a purpose to hold a spinning axle if need be.. Maybe Hogfiddles could evaluate the showroom in his barn to see if this is common.

 

Thanks for your comment.
Worst case scenario then, could I get away with fitting a 120 tyre? Or perhaps a known 'narrow' 130.

 

Yes.

 

Which manufacturers 130 tyres tend to be on the narrower side?