Help! XJ650 starting issue

I have an 83 650 Maxim and it has issues starting. It only starts if it has already ran that day or if i give it a jump. If it sits for a day, it will start just barely but 2 days and it cranks and cranks but never starts. I have already pulled off the carbs and meticulously cleaned them twice in the last week. Starting fluid doesnt help either. Only a jump start helps. My spark plugs are only 6 months old and i checked and they arent fouled. Im thinking it might be a problem with the coils... any insight or further tests i should do?

 

How old is the battery?

 

6 months old. Saturday i tested it with a multimeter and it read about 12.8 volts. When i hit the starter it dropped to about 10.9 briefly and started. But today it cranked for about 2 minutes and never started until the battery died.

Edit: Oh and while it was running, it read 14.5 volts. So it looks like its charging just fine.

 

if it starts ok ,jumping from another battery, and you're sure the battery is a good one (you could have it load tested ).then maybe there is something pulling the battery down , over a couple of days
if you have a multimeter with a amps range on it,
remove the battery +ve ,then attach the meter leads positive to the positive battery post, other to the lead.
see if there's a reading with everything switched off,
if there is current flow, then the battery is being drained.
do that check first, then we can go from there
stu

 

Another possible issue is low voltage in the ignition circuit caused by a defective fuse box. If you still have the original fuse box, then it needs to be updated or repaired regardless of whether it solves this problem or not. Here are a couple of links for replacing it. The first thread mentions there is a bit of a fitment problem on the 83 maxim


http://www.xjbikes.com/forums/index.php?threads/how-to-install-an-aftermarket-fuse-box.6350/ Unfortunately the pics are gone from this link


http://www.xjbikes.com/forums/index.php?threads/electrical-fuse-box.41848/#post-367960


http://www.xjbikes.com/forums/index.php?threads/xj550-fusebox-replacement.20809/#post-422459


Do you have a service manual? If so, it will give you the specs for checking continuity on the ignition coils and caps. IIRC the primary resistance is 2.5 ohms, and the secondary resistance is 11.o Kohms. If the caps are in place 1 and 4 are 5K so should read about 21K from plug 1 to 4. 2 and 3 have 5K caps also, so with the caps in place 2 to 3 should measure about 21Kohms also. Tolerance for the coils is 10% for the primary and 20% for the secondary.

 

Sorry, im not very familiar with using multimeters. My knowledge on them is limited. So i need to detach the positive battery terminal and put the pisitive lead on the battery terminal and the other lead on the detached lead? What setting would I have to set the meter to?

Edit: I just checked it and its nott being drained. There was no flow between the battery terminal and the detached lead.

I have already converted to blade type fuses a while back.

Sorry, i didnt quite understand what im measuring the resistence between. Between plug boots 1 and 4 should have a restence of 21kohms?

Edit: I checked the resistence between plug boots 1 and 4 and got a reading of 28.8 Kohms. Between 2 and 3 , i didnt get any reading in any of my resistence settings. So that means that the ignition coil is bad right?

 

Setting would be set to DC amps, most meters are like the photo below. Note that most are limited to 10 amps, so as Stu noted, do not turn the key on while performing this test. You stated the hookup correctly.

You should get a reading on 2 and 3 similar to 1 and 4. However, check again and make sure you are touching the metal up inside the spark plug caps that contact the plug. Since the bike runs OK once it is started, you wouldn't really expect this to be open. If it is indeed open, then time to isolate.

The spark plug caps have a threaded prong that screws into the center of the coil wire to make an electrical connection with the coil wire. The spark plug caps can be gently unscrewed while pulling on the wire and the cap (30 year old stuff) to check them individually, and to check the coil without the caps. Each cap should measure 5 Kohms +/- 20% from the threaded prong to the metal up inside the spark plug cap that connects to the spark plug.

To check the coil gently place the leads into the center of the coil wires where the prong on the spark plug caps screwed in, this should give you a reading of 11 Kohms +/- 20%.

If all the testing seems to check out, then clip approximately 1/4 inch from the end of the coil wire after verifying you have sufficient length to do so. Then screw the cap back on while pushing the coil wire and spark plug cap together. Re-check continuity to see if you now have the 21 Kohms.

The reading for 1 and 4 at 28.4 Kohms is technically out of spec. Most likely the spark plug caps are out of spec. You can check these also just as above.

Also, just to be sure, when you cleaned the carbs did you make absolutely certain that the enrichment wells in the float bowls were not clogged?

Edit: Spark plug resistance tolerance from 10% to 20%

 

So I pulled the coils and plug caps and tested everything. Here is what I got:

Both Primary coils were 9.1 ohms
1&4 Secondary resistance (no caps): 11.64 Kohms
2&3 Secondary resistance (no caps): 11.74 Kohms
Cap 1: 5.6 Kohms
Cap 2 was strange. At first it read 14.88 Kohms but then it jumped up drastically until it no longer registered on the highest setting. Now I get nothing no matter how hard I try.
Cap 3 was similar.
Cap 4: 8.07 Kohms

Replacing the caps gave me 28.4 on Secondary 1&4 and infinite on on 2&3

So it looks like I definitely need new plug caps.

Also, what are the enrichment wells?

Edit: I did some research on the enrichment wells. I did not actually know about them. I sprayed through every jet I could see in the carbs but apparently this one is very tricky. Which jet is it exaclty? The thread that I found no longer has pictures...
Looks like the rack is coming off for a third time this week! Oh boy... Anybody have any ideas how to clean it out without buying that specialized bit? I was thinking maybe a paper clip could do the job?

 

Which bit, the JIS screwdrivers? Get a hand impact tool and some penetrating oil, it will pop them all loose, and replace them all with common Phillips, or even better Allen head screws.

 

These should be 2.5 ohms, but it is easy to get fooled by the meter or poor contact with the terminals when checking low resistance values. To start, short your meter leads together and make sure you get a reading very close to zero ohms. Typically you should get like .1 or .2 ohms with the leads shorted. Now check the primary side of the coil again making sure you have a good connection with the metal spade terminal inside the connector. Subtract the number from the shorted leads to get the true resistance of the coils. For example, shorted leads were .2 ohms, primary coil was 2.8 ohms, so coil primary is 2.8 minus .2 = 2.6 ohms.

I would agree. Some of them can be rebuilt / repaired, but they are not very expensive and I would just go for new ones.
Len (Chacal) is a great source for parts for these bikes, not only do you get the right part quickly, but also great advice when needed. Email him at info@xj4ever.com

That was a great thread by Gamuru - hopefully someone knows him and can get him to upload the pictures again. They were probably linked to a photo bucket account or such that expired. Here are a couple of pictures that might help:





Also make sure that the feeder tube that extends into the well when the bowl is attached to the carburetor is clear.

One thing that works quite well is plucking one of the strands from a parts cleaner brush and using it on these small holes. Also, unless the carbs were really dirty the carb cleaner and compressed air should work. Also, it is not a good idea to use any metal device to clean the small orifices as they can scratch the surfaces and affect the air / fuel flow rate - particularly the jets.

How far did you go on the carbs? Did you break the rack? I think most of the members here would recommend that the 30+ year old throttle shaft seals should be replaced to avoid tuning issues. If you decide to do that in the future:

http://www.xj4ever.com/hitachi throttle shaft seals.pdf

 

9.1 ohms is the real value that I get every time I measure it on both coils. Thats at the connectors and ar the soldering points as well.

Edit: My multimeter has a resistance of 0.7 ohms so I guess the real primary resistance is 8.4 ohms.

I already ordered some new NGK caps and they should be here tomorrow. Hopefully they will help quite a bit.

As for the carbs, I already cleaned them twice about 8 months ago when i got the bike (it wouldnt go above 45 mph and i found crystals growing in the carbs). I broke the rack back then and dint plan on doing it again at the moment. Maybe when summer rolls around ill have time to replace the seals after I shim my valves. But im going to open up the carbs again today and check the enrichment wells while im waiting for my new caps.

Thanks for the help and advice! I update soon with how my enrichment wells looked and how the resistance is looking with the new caps.

 

Where is the exit for this feeder tube? I cant find it...

 

rooster,, I'm impressed how you put up pictures with the little dialogue boxes, how do you do this, do you use some photoshop programme or summat.
stu?

 

As with most computer questions there are a lot of ways and programs to add a text box to a picture.

I just use Microsoft Excel 2007:

Insert a standard JPEG picture using the Insert Ribbon
Add the text boxes and shapes to the picture using the Insert Ribbon
Select each object by holding the Ctrl Key or the Shift Key and left click each object
Right click and select group
Right click the picture and select copy
Right click within the reply pane on xjbikes and click paste

 

So now i have cleaned the enrichment wells and the feeder tubes. I have verified that carb cleaner passes through all of them easily. Tomorrow i will get the new plug caps and see if it starts better

 

So i tried starting it today and im still having the same issue... any more ideas guys?

 

have you checked and wet set the floats? have you checked the compression?

FU

 

+1 on FtUP on the compression and wet set of the floats.

Reading back through the thread I did not notice any recommendations on valve adjustments ( Where's bigfitz52 when you need him).

So have the valve clearances been checked recently?

The 9.1 ohms is way out of spec. Are these stock coils?

 

After reading through all the discussion, I'm going right back to the top and will say you need a new battery.

Dave Fox

 

Compression tested and i got 125, 124, 124, 125. That was done cold and i didnt do it with a squirt of oil.
I cant adjust my float level properly because all of my drain screws are stripped.
The coils are stock.

 

Pull the carbs and get those screws out. Post up a pic of the damaged screw heads and we can advise on the best way to remove them. Do you have a handheld impact driver?

Without the float levels set correctly you will never have a good runner.


Edited to remove brain fart. Carry on. Nothing to see here...

 

you can wet set the floats without removing the screws, but you need the carbs off the bike.
using a plastic jug shaped to the outer size of the bowl , fill the bowl and measure the level from the carb body, to the fuel level.

if you need more info on how to do this just say
stu

 

You mentioned that when the bike is running the battery reads 14 volts. Does it drop right away to 12 volts or is it overnight? Would it be possible that your battery is being drained while sitting for a while? If that happens often you may have a bad battery with not enough juice to get the engine going.

 

+1. You need to get those screws out and replaced.

Gary H.

 

Would it really be a carb issue at this point? It only starts off of a jump or if it has already ran recently. Starting fluid doesnt help. So that tells me that it isnt a fuel issue or am I wrong?

I was planning on getting those scews out and doing a wet set but I dont have a garage so I was hoping to wait until summer.

 

Running is one thing. Once you have that solved you will have to be able to get it running well. Work at the bike's pace, not yours.

 

Have you gotten another battery yet?

 

Not yet, they are a little hard to come by around here. Im looking.

 

Batteries Plus should have one . . .
Seattle should have at least one of those stores . . . .

 

Walmart, Napa, Advance Auto Parts, Autozone, etc......

 

I work at Oreilly's and I found one in the system after some digging. I just have to order it in.

 

O, O, Ooooh.......!

 

Update

I replaced the battery and now it fires up like a champ! Thanks everyone!

 

Ahem-----cough cough itoldyouso cough cough. Oh, sorry.... Just clearing my throat

 

Do you get a discount? you may have just gotten more popular!

 

Just a little discount. But im only working there for the time being. Dental school starts up in the fall.

 

Geez..... It's like pulling teeth to get a battery around there!