Running on one cylinder... Honest opinions

So I got a "Bobber" late last month from a guy that said he bought it and didnt ride it much. He said that he ran a compression test and all cylinders were within spec gave me some bullshit numbers but I dont remember anymore. He said the carbs have been cleaned and synced recently as well. Well I just got it back from the shop today after putting a new voltage reg, tci, stator, and a whole new minimum wiring harness. Well it still doesnt run it will run in neutral but will only let me ride it in gear for about a mile and then it dies and wont start or run in gear again for quite a while. It WILL start and run forever in neutral. The shop also told me the bike is only running on one cylinder the rest are all so full of oil it fouls the plugs and its spitting oil from my exhaust. I belive this is most likely because it has pods and straight headers and had never been re jetted. I just bought a used set of carbs off ebay for $50 bucks but its pointless to rebuild re jet and sync with a bad motor. SO... my question is what should I do in this situation??? part it out, sell it whole, or take the time and spend the money to fix it? I live in a apartment with minimal space for anything. All I need is some honest opinions???

 

Really, you should start with a compression test - I'm sure there is a "Sticky" somewhere. At least this should help you decide if it is worth spending more money.

I don't think I would take a bike back to that shop!

The fuel problem could be related to a vacuum being formed in the gas tank - try taking the cap off and listening for a hiss.

My old XJ600 had 48000 miles on it so these engines are built to last and will tolerate quite a bit of neglect - unfortunately, it sounds like you have one in need of TLC!

 

I will give it a shot and I dont know how to do a compression test but I will look into it.

 

+1 on the compression check. That is a first step to decide if its worth fixing.
I am not an expert on these bikes (yet), but I would suggest you take a look at the side stand switch. These bikes won't run in gear with the side stand down. There is a switch that detects the side stand position and if its loose or making intermittent contact, it might explain the shutting down mysteriously while riding.

 

The results of Compression Testing will let you know what condition your condition is in.
You can perform the Test yourself.
You need a Compression Test gauge.
(Some AutoZone Stores let you use theirs if you leave a License or Deposit)

You need a Fully Charged Battery
Pull all the Plugs
Un-Plug the "Black Box"
The Throttles will need to be Wide Open.

Google:
Compression Test and learn what the results will indicate.

 

KumanK a compression test is very easy to do - trust me on this one.

Go to the auto parts store and get a compression tester $20 (they also rent them). The one I picked up had 12mm, 14mm, & 16mm adapters. Almost certain on your bike it's 14mm. Unplug the TCI harness, pull your plugs, screw in the compression adapter, open the throttle all the way and crank it over about 4 or 5 times or until the needle doesn't rise anymore, record your numbers for each cylinder.

I know you are getting frustrated and tired of this, but don't let it get you down. Either it can be fixed (most likely) or you can recoup your money by patiently selling what you can.

Did you ever put any sort of muffler or pipe on your headers? Unfortunately I believe you are suffering from what happens when someone sets out to modify these bikes (not you) and doesn't do it the right way. If you change intake, exhaust, wiring, suspension, etc. it MUST be done correctly and there isn't much wiggle room there.

That bike shop is a joke. Don't go back to them and give them any more of your money. Your bike CAN NOT run on 1 cylinder-it just won't do it. Try disconnecting 3 of your plug wires when you've got it running and see what happens. They are lying to you-and they are clueless.

Modifying a bike like yours requires compensating for EVERY change that's been made. You have more air entering your carbs, much less exhaust backpressure and who knows what else is different that is throwing it all haywire.

Your best route now is determine the TRUE condition of your motor, then if you decide to fix it - one by one compensate for the changes. Like for example you need some exhaust backpressure because that's the way these engines were designed and you can't just modify the design away. Hope this helps you.

 

ony be careful about the loaner compression gauges I got 3 babck to back loaners and they were all crap. if you get crazy low numbers its most likley a bad whacked out gauge. I got one from harbour frieght for 19.00.
and yeah it would not run on one cylinder they are idiots.
Also yes your engine is 14mm in the plug hole, pug number BP7ES the "B" denotes 14mm
Far as the pods-- good luck with that if it were mine Id find an airbox and mod a cover out of diamond pate to fit the bobber look-but thats just me
get the gas out of the oil fast though like yesterday

 

I had my engine shut down on my 82 650 Maxim, turned out to be the kickstand safety switch. If you have oil coming from your mufflers you may have stuck or broken oil control rings. This may not be reflected in a comp test, because oil control rings do little for compression.

 

wow lots of great info guys I really appreciate it, I will go down and buy a compression tester and check that out hopefully it will turn out better than what I expected and be a simple fix without having to pull the motor and all that fun stuff. The PO obviously neglected the bike maintenance wise, and even more obviously he didnt take the time to research proper mods and spend anytime on this site. Thanks again for the help I will let you guys know what I come up with.

 

Even if you need a valve job or even to do rings/pistons, etc; you don't need to pull the motor.

It's NOT going to be a "simple" fix; the more important question is "how much will it COST and is it worth it?"

The first step to answering that is a compression test.

 

So I did a compression test and cylinder 1, 2, and 3 are pushing 150 and cylinder 4 is pushing 145. But 2, 3, and 4 plugs are coverd in oil. Cylinder 1 is white with almost a orangeish brown tint.

 

So cylinder 1 is running lean, and the others are running way too rich. Since 1 is clearly working, that would mean that 5 is firing somehow, though not well, since it is so oily. 2 and 4 may or may not be firing. Get an extra new spark plug and do a test.....pull each spark plug wire, one at a time, hook it to the extra plug, lean the plug against the engine where there is bare metal to touch the bottom outside of the plug. Hit the start button and see if there's spark at each plugwire.

1 and 3, 2 and 4. If one of these combos doesn't fire, that's probably a bad coil. Easy to replace.

If all 4 have spark, good. Pull the carb rack and do a rebuild. NOT hard to do. Just take your time and do a lot of reading HERE and ask questions HERE. WE are a whole lot smarter and knowledgeable about these bikes than your "shop" is.

Make sure to drain the crankcase oil and put in fresh, along with a new filter. I bet your oil smells like gas down in there too.

The stalling after 1 mi seems to fit that....it would be an "overheating due to thinned oil" condition.

If if were the sidestand switch you wouldn't be able to consistently get that far. It would me more sporatic, or immediate.

It IS possible that there are other relays interfering.... check back through recent threads--there was one where someone said to pull the "gray/red" (?) wire off of the tci and that would bypass all the safety circuits. Just a thought, I've never tried that, but like I said....it was a recent post here on the forums.

Good luck, DON"T get discouraged. We've had worse cases than your's. Your's is easy (relatively). Just hang in there. It's gonna all be worth it when you're riding down the road and able to say "I built this MYSELF".


Dave F

 

Those compression numbers are good news! Just an FYI, I know harbor freight isnt considered the best but they do sell compression checkers for around 15.

 

I'd like to start off with this reply motivated the hell out of me... I will go buy a new plug tomorrow and do that test.

The PO had straight headers and pods so its weird that they would be running rich? Someone said that the oil rings may be blown and that wouldnt reflect much on the compression of each cylinder so thats what I am thinking at this point.

I am in the process of cleaning, rebuilding, and re jetting a spare set of carbs now so that will eliminate that problem once its all done and mounted.

Im going to look into the overheating issue more, the "shop" that had it said they changed my oil as well, maybe and just maybe they were dumb enough to only partially fill the crank case and the lack of oil is causing an overheating issue, which would be a extremely easy fix.

It cant be a sidestand switch because it is a limited wiring harness with only the essentials, so the sidestand and neutral switch arent wired in, the prong on the TCI is not connected to anything so thats ruled out. And the coils are the only part in the elcetrical system that hasnt been replaced.

I was really thinking it was the carbs or some kind of fuel problem but hopefully it is an overheating issue. Is there a certain temp that the bike will just shut off? It only dies when I pull the clutch in and coast from what I have experienced (havent pushed it hard enough to tell).

And I cant wait for the day that I can druise with no worries and have the pride of knowing my work has really paid off.

I tell my dad all the time who rides a Harley Dyna series that my bike runs on blood, sweat, and tears...

 

OK, but good compression numbers don't mean valves that are anywhere close to spec, just that they're not damaged. THAT'S the next step before carburetor muckage occurs.

I highly doubt your "oil rings are blown" if anything is "blown" it's more likely you need some valve stem seals. If the plugs are truly oily that's a more common cause than ring issues. AND easier to fix by a long shot.

 

Rich would be fuel.

I beleive you mentioned oil. Two very dif probs.

R your plugs fouled with fuel or oil?

 

soot and fuel can appear to be oil, check it out. Use your finger tool

 

it seemed like oil but I will check it out again today... and fitz what are the steps to checking if the valves are the problem?

 

I doubt it's oil if the compression is that good. Of course, I'M not there to look at the bike in person.

Do a forum search on how to check valve clearances. It is NOT difficult, just take your time, work carefully, and record all your numbers so you can do the correct math.

I HIGHLY HIGHLY (I'll add one more HIGHLY) recommend that you get the XJCD. That will give you all the info you need for everything.

Now here's a question....I haven't seen what your odometer reading is. Have you posted the miles? If so I missed it. If you're a hig-mileage bike, then you definitely want to check the clearances. If its a low mileage bike, it's not quite as critical......yet.

Keep reporting everything you do, and we'll get you through it!

Dave Fox

 

I have no idea what the mileage is, when I bought the bike it had no odometer, so in that case I must treat it like it is a high mileage bike either way!

I want to purchase the CD what does it cost and where do I get it?


anyone know exactly how much oil the bike needs...?