XJ700 Maxim X problems from new member

Hi,

This is my first post so here goes. I'm from the UK and last month bought an XJ700 Maxim X from the usual auction site, its a real nice looking machine and very comfy, just after purchasing I noticed a slight drops of coolant appearing around the bottom of the clutch case so have ended up replacing the mechanical (Something I am used to doing on my Honda CX500 which uses the same size seal) and resealing the O' rings and replacing the gasket, in doing this job I thought best to remove the fuel tank, but when it came to refitting the fuel tank I couldn't remember quite how the hoses went back on. After looking at the parts diagram I think I have them on the correct way but the one that I think is the vacuum hose had a bolt stuck in the end and didn't go anywhere.

So now I'm baffled as the bike will only run with the petcock in prime position and the seems to run uneven between tickover and about 2000rpm, before taking the tank of it still was uneven but would run with the petcock in the On position. Please tell me where this vacuum hose should be connected to and any ideas as to why it should be uneven at lows revs would be very much appreciated



I also own a XJ900S Diversion, a CX500A and an SV650 so you could say I like my bikes

 

If the vacuum line is disconnected, it will only run on prime. Prime is a free-flow setting on the petcock that bypasses the vacuum side if it.

 

Sounds like the PO had a problem with the pet cock & bocked the vac' line, if you are going to run on PRI suggest you fit an in-line manual fuel tap.

 

Welcome aboard Longway. Nice looking X with the gold accents.

The vacuum line should be connected to the petcock as shown below:


The petcock may need a rebuild and maybe only works on prime. Hence the reason for the PO to plug off the vacuum line.

As far as the rough running at lower speeds, it sounds like the carbs could use a thorough cleaning.

Tony

 

Thanks for the reply's, can you tell me where the vacuum pipe connects to the bike from the Petcock, also the previous owner claims the carbs had new air inlet rubbers fitted and the carb's ultrasonically cleaned, my guess is, for them to do all that work, this was an ongoing problem for PO, what I cannot understand is why it would run before with petcock in the On position and now it won't, especially since it wasn't even connected to anything but a bolt stuffed in the end of vacuum pipe. The uneven running isn't a great issue as once its revved out of the low revs it seems OK but would be nice if it could be sorted, I'm wondering if the carbs need balancing or could it be something simple (Hopefully)

Tony, unless its the angle I'm looking at it, the petcock on mine looks different to the one in your photo, please photos below, I'm guessing the 2nd photo showing the red blanked off outlet from carb body could be where the vacuum pipe should be connected

Picture Petrol feed pipe



Picture 2 Vacuum Pipe blanked off with bolt

 

First, that doesn't look like a stock petcock... it's been replaced.

Second, the "vacuum pipe blanked off with a bolt"... I don't see a bolt, but it looks like a red cap of some sort. On the #2 carb, you say? You've got a California X... at least the carbs are.

Is there a black canister sitting behind the right-hand side cover with two hoses coming off it? If so, is there a hose barb coming off the bottom rear of the tank?

 

The pipe coming from the the left side of Petcock has been blocked with a small bolt at the end, not sure about the red cap, my thoughts were, is this where the vacuum pipe should be connected? there is no Canister behind the RH side panel and no hose coming off the bottom of tank. Not sure about the carbs

 

Took the liberty of editing your picture:

The vacuum line off the #2 intake (red arrow) is what is supposed to be connected to the petcock. Where does that go to, and is the end on that plugged if not connected to anything?

Next, the petcock you have on there now is not original, and may or may not work in the on and reserve positions. You should do yourself a favor and get a replacement that matches the original if it doesn't work.

Also curious to know if your bike is a California model? Does your serial # start out with JYA1LT00? The reason I ask is that the second (blue arrow) points to a vacuum signal fitting that is specific to the fuel vapor recovery system. The big issue is not that it is capped off, just that your fuel tank cap may not be vented and will not allow fuel to flow properly if that system has been disabled.

 

xHondaHack has sharp eyes and is sniffing up the right tree here.................

 

Here is the new petcock I fitted on my X a few years ago


Big outlet for fuel line, small outlet for vacuum line.

 

Thanks for the info xHondaHack, I will report back when I've had chance to have a look

Looking at the prices for replacement petcocks, I'm hoping this one will be OK

 

All is becoming clearer for me now, this machine is a California Model as the number on the Frame starts with JYA1LT00, and when I've raised the tank up I can see my mistake, I've missed the vacuum pipe and left that dangling and put the vent pipe from the rear of the tank (which has been blanked off with a bolt in the end of pipe) onto the Vacuum point on the Petcock.

As for the fuel cap, since the ignition key opens the fuel cap, I'd say its the original cap, could this the cause of uneven running at low revs? I doubt it but what do you Guys think, should I change it?

Thanks xHondaHack for helping me understand this machine and its history

Here's photos of my findings

Vacuum pipe now in its correct place



Vent pipe from tank now in it correct place, this is blanked off with a bolt




Fuel Cap - should I change this, not sure if this is vented

 

IF the gas cap is not vented, then you cannot block off the fuel tank vent line............otherwise the gas tank will "vacuum lock" and fuel won't flow.

Vented cap or not? You'll need to remove the lock mechanism cover plate to know for sure:

http://www.xj4ever.com/gas cap.pdf

See page 7 for all the details.

 

BTW, very nice looking bike!

 

Just fired her up and seems ok now, uneven running better too. Weather is good, no work, and I have full permission from missus so going on a ride out over North Yorkshire Moors to Whitby, round trip of about 160 miles so will give it a good test today

 

Good to see you've connected the line in the right location. You'll still have to verify that the petcock works properly in each of the ON, PRI, and RES selections.

And, if the cap holds vacuum, it will not let fuel flow after a minute or two. I know an inaugural ride is tempting, even if the missus gave clearance, but you want to make sure it's not going to starve for fuel and end up running too lean.

Plus, the brake system should be thoroughly gone through before hitting the road.

Tony

 

Sorry Tony, but I'd already set off before your post and have gone and clocked up 180 miles, (Brakes have been well checked over and had new pads previously) averaged a little over 60 mpg and the bike, well I just love it, handles real nice with the 2 new Avon tyres I put on, and the engine pulls like a train with no evidence of the Tank holding vacuum, and no leaks from around the clutch cover and water pump.

Why don't they still make these bikes

 

Guess they don't put ethanol in you're gas do they? Glad to see you enjoyed the trip and made it back without incident.

And, I suppose manufacturers stopped making this type of bike because it doesn't fit into any of the hottest selling categories. They are very unique being a cruiser with a sport bike engine, and have a few shortcomings.
But, now that you have the pleasure of riding one, you'll be hard pressed to let it go.

Tony

 

Nice bike!!

 

I think they do but I always try and good quality high octane fuel in, makes a big difference to economy

 

If you have a Calif. model, and you have the Calif. carbs, check behind the right side cover....where the tool pouch would normally be....you should find the 'charcoal canister' with the extra tubes from the carbs going to it. From there, there is one tube going back out of the canister---THAT tube is the one that goes to the gas tank vent tube.

It was an emissions thing that vented fumes back into the tank where they supposedly condensed back to gas and then, of course, being burned as fuel.......

If your cap is NOT a vented cap, and you still don't have any problem with vacumm lock in the tank, then i'd highly suspect that your cap-to-tank seal is dried out and not sealing anymore which now allows air to enter the tank that way and avoid the vacuum lock.

dave

 

The canister has been removed and the hose from tank blanked off, not sure about the cap, need to check that out

 

Only way to know is if you disassemble it. If you go that far, you may be better off just getting a new "Standard" cap with the check ball and swapping over your lock cylinder so you can keep all your locks the same. That way you have a new tank seal, and it's vented as well.

Tony

 

Or, if you want to keep the original cap, then un-blank the hose to the tank and put a tiny air filter on it.

 

I don't believe the thing is venting *into* the tank, guys.

Looking at the factory manual, the little nub on the bottom of the canister is labeled "to atmosphere". I get the idea what's happening is that the airflow going through the #2 carb is creating vacuum in the line leading to the canister; that in turn creates vacuum in the line leading to the tank vent. Vapor is pulled out of the tank, through the canister filter, where the big bad petrochemicals are magically removed, and what's left is vented out the bottom.

 

That overall, sounds more logical---- except that drawing even more vapor from an otherwise sealed compartment would create even more of a vacuum .

Hmmm...... Hafta think on this more

 

Yeah, that occurred to me later on today at work. Non-vented cap and all.

On mine I have the California carbs and the emissions canister... but not the California tank. (Yet it came with the non-vented cap. Had to replace it. Go fig.)

 

nice looking bike; gold inlays on the grab rails and rear brake plate and gold brake calipers - cool

 

I now have a replacement cap, the original had some pitting anyway, just need to figure out how to swop the lock if its possible. May not be as the replacement is not original so maybe different fit

 

PS the bike is running spot on now

My next decision is wether to strip down amd get frame blasted and recoated or just enjoy the bike as is

 

Oh, it's very possible. Did it with mine when I changed caps.

Your Gas Cap And You

You don't need to go about rebuilding the cap in this case, but you'll see about how to pull out the lock plug. Maybe clean and lube the thing while you've got it out.

 

Beat me to it Schmuk.

Just make sure you have the key in it when pushing out the lock cylinder as shown. That way the pins are retracted.