New owner wondering about power loss in the rain

Hey everyone! New owner of an 81 XJ650H as of this evening!

Couple of questions regarding performance in the rain.

Bought the bike off of a guy in Vancouver who has been using it as a learner bike, but he bought a Harley to replace it. Bike is in pretty good condition, save for a couple of minor issues that I'm a bit worried about. Bike was stored in underground parking for the several months the owner had it, and he was a definite fair-weather rider.

When I took it for a test ride, it was nice out, and the bike performed beautifully except for a bit of guttering in first gear when getting off the line. Owner told me he usually solves this by topping up the oil, so I filled it to capacity with 10w30 (what he had in the hardbags).

On the way home, however, it started to really rain, and the bike got progressively less responsive the closer I got to home. It actually stalled as I got into my driveway.

Sounds to me like one of the cylinders may be missing or possibly even misfiring, but I can't yet tell which one it is.

Bike starts up reasonably well with no choke, but takes a fair amount of throttle to get it to rev high. Once it's revving > 3000rpm, things start to sound a bit more normal. When the bike was warm and dry it was idling at about 2000rpm.

Question is, what can I do to make sure everything is sealed up and rainproof? I'll definitely be riding this baby in all weather conditions (it's my new daily rider) and I would hate to get caught out in the rain with a dead bike.

Also, would it simply be easier to take it to a mechanic and get it tuned up?

Thanks!
C

 

welcome

Try this:

Coils in the rain

Other problem:
Have a look in the suggested faq for a guide to ($5) syncing your carbs which will help. Most people set there carb mixtures between 2.75 and 3 turns out. This is a ballpark figure. Have a search of the forum for more info.

Check for air leaks on intake boots - sprey 'em with WD40 with motor running.

Have a good read of the forums for alot of other info, there are many little tricks, eg alternator brushes and fuse boxes ;

 

Welcome to the site Lefty.
Silly question, what do you mean by "filled it to capacity" - the the top of the site glass or to top of fill plug?

 

Filled to the marker line on the glass window. Overfilled my XS400 once, it was *not* happy for a long time

Update on this, I'm fairly sure it's electrical now, as I just went to start 'er up now that the rain has stopped. Cranked up, ran for a minute or so, then lost power to the point of stall, wouldn't start after that, choke or not. Headlight stopped working too, so I *think* it's the fuse box. Will have to pick up a 20A fuse tomorrow to replace the headlight one and see how it goes there.

I'll check out the coils, kiwi, thanks for the pointer. I'm just chewing through the forums now to find tidbits.

Can't wait to get this bad-boy running smoothly! I've been without a bike for way too long

 

The fuse box on XJ models are notorious for failure. The clips that the glass fuse fits will collect a fine layer of insulating corrosion, and the heat softens the grip of the clip itself. Replace that turkey with a new fuse block. Check your wiring harness for dirty, loose connectors, Pull the alternator cover & check you brushes, Pull the Starter & check them, too. Once you get these electrical issues corrected, If the carbs are clean, it should run like a train!

Dan

 

New fuse block, check!

I'll see if I can borrow a workshop for a couple of days and get the wiring pulled apart and cleaned.

Thanks for the input!

 

Well, after tinkering for a while, I'm fairly sure it's not the fuse block, though I will replace that for sure. Looks like someone's already started, the clips on the headlight fuse were broken off and someone's replaced it with an in-line fuse cup, I may just do the same for the other three fuses. I pulled each of the wiring harnesses apart, gave them a quick clean, and put them all back together just to make sure they weren't corroded, but it hasn't made any difference to starting or running.

I'm leaning towards coils right now, as it's difficult to start... and even when it does start, it runs OK at >4000 rpm for a couple minutes then fades out to stall, then is difficult to start for a while again. I put a trickle charger on it just to top the battery back up from all the cranking I've been doing, so I'll let it charge for a couple hours before trying again.

Am I way off in thinking it's the coils? After reading through the forums (at length, man there's a lot of good info!) and seeing a thread about XJs that don't like to start, but *almost* catch when letting off the starter button (which I'm going to go find again and read more thoroughly), I did notice my bike doing that.

Whew!

 

Lefty, it could be coils, it could be poor connections someplace in the wiring harness, and it could be a low battery also. These bikes crank over really well on low voltage and leave very little for the coils to fire properly. See what happens when you get her charged up!

Here's a great link full of electrical info on the XJ's.....
http://www.geocities.com/MotorCity/Speedway/7795/

 

That doesn't sound like coils to me. Sounds like carb bowls running empty, then bike will run again when they refill. I'd make sure plenty of fuel is coming down the fuel line. Also might want to have a look at the screens on top of the float valves.

 

Well, it seems to be figured out now!

The neighbour from across the way heard me cranking my poor new baby and came out to lend a hand.

Through much fiddling and testing, it turns out it runs fine on reserve, but badly on main, and the spark is weak.

Weak spark we fixed by jimmying the broken fuse clips for the ignition fuse (next weekend I'll replace the damn fuse box), which didn't seem broken but were and were giving a bad contact when the bike was vibrating.

Bad fuel seems to be the culprit for running on reserve, so I'll take the tank off tomorrow when it stops raining, drain the fuel, and replace it.

She's close, I can feel it!

 

Oh, and next payday I'll take it in to the local bike doctor and have the carbs rebuilt and resynched. I don't have the tools or the patience to do it myself yet

 

Well, took her out for a blast today, and it looks like she's good to go!

I put in a tank of high-grade fuel, and am letting the crappy fuel burn off on short rides. Seems to be making a difference, as she was reluctant to start in first gear for the first half of the ride, but towards the end the power was coming back and I didn't have to slip the clutch so much. It was only a 30km ride though, as I don't yet trust her not to die on me in the middle of the city.

One more ride today if the rain stays away, and then I'll ride it to work tomorrow!

 

Pull the tank, drain it, remove the petcock. I bet you find a bunch of junk in the filters & crannies of the valve itself. Clean them carefully with a soft brush & carb cleaner. Clean the tank. If it has surface rust inside, get some Muratic Acid from the hardware store, make a sealing plate for the petcock hole and pour about a pint in. Leave the cap off, and very carefully slosh the MA around inside. (Rubber gloves, old clothes, eye protection, outside upwind from the fumes, use a fan) Put some baking soda/warm water solution in to neutralize the acid. Pour out, rinse thoroughly, the dry with a hair dryer for an hour or so.

You'll feel better knowing your fuel tank is factory fresh again.

Dan

 

If you aren't using a tank lining kit, I would recommend diluting the muriatic acid a little bit with water. It will etch into the metal, and could cause rust where there was no rust before.

I used Muriatic acid full strength before I used my por15 liner kit, and it worked BEAUTIFULLY! I have used it lots of times in the past on old rusted car parts.

 

A couple of thoughts also:

Our TCI's (ignition module) are also prone to moisture related failure - they don't even have to get wet, just damp air can do it. The bike will die, and not fire again until it's dried up. Doesn't sound like your issue, but something to keep in mind.

As Dan said above - cleaning the petcock is a good idea too. And you might want to think about installing an in-line fuel filter -- many of us have to avoid the whole bad-fuel or crap in the gas problem.