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Old 01-22-2014, 10:25 PM   #1
ImaginativeFig
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Join Date: Jan 2014
Location: College Station, Texas
Posts: 138
Multi-problemed bike (electrical + ???)

I don't even know where to begin... I have a 2003 GZ250 with 8,046 miles on it that I suspect is having multiple problems. It broke down back in October when I was on my way out to the Texas Renaissance Festival, then some friends who work out there said they'd see what they could do, but they were busy and only got around to ruling out a couple of things before the Fest was over. By the time I got it back it was finals, then I went back to Oregon for winterbreak, so my bike's been sitting around worsening.

The current (haha) most pressing issue is that the battery is losing charge super fast. I had a friend come over to help me poke around at it and he brought a tender over, the tender would charge it up, then we'd stop it and watch the voltage plummet about a tenth of a volt per second. It would always slow down eventually. Before we hooked up the tender, the lights would turn on and it would try to start, but various times after that the lights were barely visible. I started following the service manual trouble shoot guide for battery running down quickly
  • I have no accessories
  • The current between the negative lead and negative terminal was 0.24 mA (which I understand to mean that the battery isn't leaking)
  • I couldn't measure the charging voltage since the bike won't start...
  • I started to try and check the stator resistance, but it got dark and I called it a night

In addition to that, I've got a fair amount of oil on the cooling fins, much like kongje did in his thread "Source of oil leak?" It looks like the respondents to that thread said to tighten the exhaust bolts (I guess these are the same "EXHAUST PIPE BOLTS" mentioned in the periodic maintenance section of the service manual?) and there was a bunch of talk about gaskets and o-rings which were variously disputed... but would a leak there cause oil loss when the bike isn't running? I could have sworn I had oil back when my bike broke down, but I don't appear to have any now (yes, I checked with the bike upright, I even leaned it to that side.) I haven't noticed any fluid spots of any sort under my bike, where could the oil have gone? :confused:

Other than that... the bike doesn't go. Even when the battery seems to have a charge (lights turn on, and start-y noises happen [my friend said it sounded like it was turning over]). Spark plug's new, carb's been cleaned, I believe my Rennie friend said something about spraying starter fluid somewhere and it not helping. His conclusion was that I needed to do a compression test, but I guess first I should get my electric system in order... right?

I'd really like my bike to be running when my next job starts in 2 weeks... do y'all figure it would be more likely to happen if I sent it to a shop or can I try to fix it on my own (/with help from more knowledgeable, better tooled friends). My fears with sending it to a shop is that they might take a long time to fix it (since they have other bikes to deal with) and/or, they might cost so much that I can't afford it (I'm tight on money until this job starts up)... my fears with attempting to do it myself is that I might mess it up and/or have to send it to the shop after all anyway.

Sorry for being super long winded. Conciseness has never been a strong point of mine.

Actual Problem and Lessons Learned
(So someone coming on this thread later doesn't have to read all of it [spoiler alert])
The actual problem keeping the bike from starting was that the cam shaft had snapped in half. This was found after running all the basic easy tests (new gas, check for spark, etc), I checked for compression with a compression kit borrowed from the mechanic down the street, found it wanting, checked to see what the valves were doing, they weren't moving at all, checked to see what was up with the cams and found the problem. Pictures of that mess on pg 14. Suspicion is that the break was either due to shearing force caused by parts not moving right because of low oil, or perhaps due to manufacturing flaw.

The battery problems described above were fixed by taking it in to be charged at the mechanic, we must have failed to charge it correctly with my friend's charger.
Lessons learned: (added as I review the thread)
  • Be prepared for your repair to take waaaaay longer than you expect. Patience really is a virtue
  • Keep up with maintenance (especially, keep an eye on your oil!)
  • If your battery's being weird, get it charged/tested, most places will do it for free
  • Yes it's fine to change oil cold if you can't turn the engine on, it just takes a bit longer and it's harder to tell if you got precisely the right amount in
  • If you have the OEM spark plug tool, never lose it, also, be kind and pass it on to the next owner. To get mine out, I used a 18mm long socket and an extender, but at that point my deal was so long, I had to take the gas tank off.
  • When loosening a bolt, make quadruply sure you are actually turning it the right way, especially if you're getting at it from a weird angle.
  • (Related to above) don't mess up fasteners (bolts, screws, w/e) on your bike. Just don't.
  • The oil drain plug is an M14-1.25 (meaning it's metric, diameter of 14mm, pitch of 1.25, the OEM part is also 12 mm long, stainless steel, with a 17mm flange head) If your bike shop doesn't have it, the auto stores will, don't let them tell you they don't. It's the same as 2009-2012 F350/450/550 Super Duty truck, among others.
  • If you're ever having trouble finding a special bolt like that, get one of the customer service peeps to give you the specifications (particularly diameter and pitch) and then google those and see what else uses it
  • Yes, the starter plunger (choke) should come fairly freely when you unscrew the nut that holds it to the carb, if it refuses, it's probably gunked up and the spring's probably being crappy. I let WD-40 sit on it and eventually worked it out (I have since learned the wonders of penetrating oil and would imagine that would do even better)
  • Buy penetrating oil (I got P'Blaster) and degreaser (I got DuPont for chain and sprocket). Just do it. They're great.
  • GZ250s' gas system is vacuum fed, there is no off switch, but on or res will keep the gas from flowing if you disconnect the hose from the carb, conversely pri will make it flow freely.
  • There is a drain screw on the bottom of the carb, unscrewing it will let gas out the float drain tube so that your disconnected carb doesn't randomly spit gas at you
  • After reconnecting your carb, prime it for a few seconds to re-fill the float...
  • Before you prime the carb, make sure the float drain screw is tightened, unless your floor is thirsty for gas. (Around page 10 are lots of good carb tips that I'll probably need again later)
  • The screws that hold your float bowl on are JIS #2 because Japan hates you. (Getting a JIS screw driver may not actually help you, however, because your carb hates you too)
  • If spark's good, battery's good, the bike's turning over, the carb's clean, and starter fluid sprayed in the air box doesn't make the bike go, check compression (you may be able to borrow a compression test kit from a mechanic if you're friendly and willing to leave a deposit)
  • GN250 cylinder head (along with most other parts) is interchangeable with GZ250
  • Ebay's great and all, but make sure you get and look closely at pics from all angles before you buy
  • When putting the generator cover tighten down the two long bolts that have the cylinder cans around their holes first, just until the cover is sitting on the bike, then tighten all the bolts evenly.
  • When any tightening bolts on your bike, first look in relevant sections for specific tightening instructions, if there are none, refer to the table on page 7-25 (222) of the service manual (the chart is also on page 17 of this thread)
  • If you have odd timing issues after putting the rotor back on, your woodruff key (the metal semi-circle that keeps the slots in the rotor and shaft aligned) has probably come out.
  • When pushing on the rotor by hand, turn the idle starter gear behind it to get the rotor snugged all the way back, then impact the nut on.



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Last edited by ImaginativeFig; 10-05-2014 at 04:57 PM.
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electrical, oil, problems, troubleshooting, won't start


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