New xs400 problems.

[Onetype]

"Check the charging voltage, at 2500 RPM is should be around 14.5 volts, if it's less than that it's not charging. Likely culprit would be the regulator, but there are a series of checks to be sure".

So I did that and it was at around 12v but wouldnt go up anymore no matter how much throttle I gave it. I let it idle and it dropped all the way into the mid 11's before I shut it off...When I was re-wiring the bike the first time the connector for the rectifier fell apart so when I re-wired it I had to guess which white wires to connect to eachother, since there were 3 of them all the same color I didnt think it really mattered.

Update: So I pulled the connector off my other bike and swapped it all over. My question now is do I need to be worried that I screwed something up? I cant start it tonight since its too late but Im going to fire it up tomorrow and hope it all works.

 

[drewpy]

sounds like the voltage regulator, not the alternator, if you have the electro mechanical one, you can adjust it.

It is charging just not enough.

there is no specific connections to doing the white wires.

 

[Onetype]

Well bummer, I was hoping that would solve it. Neither of my regulators are adjustable, tried swapping in my spare (I thought it was the rectifier at first) and it didnt make any difference. I wouldnt be suprised if they were both bad though since both bikes originally had wiring issues. I tested one using this method in the manual. I didnt get a reading at all, but it seems they are under the assumption that I have the regulator that you can adjust so im not sure if it still applies to mine.

 

[Onetype]

Charged the battery last night, rode it around the block. It went above 13v once. Im going to clean all the connectors as much as I can and check the wires behind the sprocket cover again before I order a new rect/reg single unit.

 

[drewpy]

battery does need to be in good condition to charge it. sounds crazy, but that what the system needs.

try a good battery first before laying out for a new regulator!

 

[Onetype]

I understand the need for a good battery as a start. I honestly dont know how old this one is, it came from my brothers bike when he bought it. I pulled it off the charger at 13v and hooked it up to the bike and left my meter on it while i put everything back together and it started to drop before I even started the bike. Im going to see if I can borrow my buddys new battery and test it.

I had originally posted this but changed it because it might have nothing to do with anything. The right side spark plug wire/cap is letting current through it, as in if you touch any part of it you get a good shock.

 

[Onetype]

Alright swapped batteries. Its only wanting to run if I start it on full choke now and the idle soars. It looked like I was getting plenty of volts though it was hard to tell because I kept having to shut it down pretty quickly. Im going to order the 50's right now and some new wires and caps while im at it.

 

[lhaolpa]

Before buying a regulator,check all connections that you can find,cleaning and treating with dielectric grease.This includes grounds and positive connections,and plastic multi-wire connectors.I've remedied several strange problems myself by cleaning these things. lha

 

[Onetype]

Alright its been a while since I've had time to mess with this thing and I was waiting for some parts to come in. Put in #50 pilots, new wires/caps and new bowl gaskets. Started up fine, idles fine (I dont have a working tach so I cant tell what rpm) but once I hit the throttle it didnt want to return to idle. The mixture screws were at 2 turns out, tried at 3 as well.

Alright a few questions:

1. Do I need to be adjusting them as its running?
2. I think there may be a small exhaust leak near one of the manifolds, would this cause problems?
3. Which direction on the mixture screws does what?

It seemed to run better when I had them turned 1.5 out but still not right. It seems to get worse the warmer it gets.

 

[XSLeo]

On your charging, if the feild windings in you alternator or the stator windings are bad, then a new regulator won't fix the problem. Before spending any money you should test the system. Your repair manual will have the correct procedures to test your system. Don't guess and throw money at it, that never works. Test and get the right parts the first time.
Now on your carbs, set the mix screws at 2 out. Get the bike warmed up. With it at idle short out one plug so it runs on one cylinder, back off the idle speed untill it runs as slow as it can.
Now on the running cylinder, turn the mix screw in untill it stumbles. Back it out until it gets the highest idle speed. turn it out 1/8 turn.
Repeat on the other side. Now with both mix screws set adjust for an idle speed of 120-1500 rpm's. If you have vaccum ports in the carb holders use a homemade manometer. Fancy word for 15 feet of 3/16 inch clear hose with a few ounces of an easy to see fluid, I like tranny fluid. And a stick. Search for it.
With it hooked up, bike at idle adjust the sync screw between the carbs to get the fluid level in the hose even left to right.
This will probably fix the high idle problem unless the throttle cable isn't sticking.
Leo

 

[lhaolpa]

Turning the screw out richens the mixture.The exhaust leak should be remedied,but should not cause any problems in the short run,probably a bad gasket or loose nut.Check the adjustment,oiling of throttle cable. Check the butterfly seals as they will leak air,causing problems.The slides will stick as well and cause a rich mix and with air leaking in,it will stick at a high rpm. Using 400 or finer and W-D 40,smooth out the slides and the bores,and while you're at it,check the diaphragms. lha

 

[Onetype]

Thanks for the replies guys. When you put it that way it sounds damn simple. Guess I will need to see if I can get one of these tachs to work.

 

[WulfgartheBlack]

About that oil:
It seems that engine oils have changed formula since our bikes were made. When our bikes and the world were younger you could use the same stuff in your two-wheel as you put into your four-wheel but newer cars use a lube that doesn't protect all the parts in our little engines and they don't sell the old type any more - for gasolene cars. In addition, the new stuff could mess up our wet-clutch.
Now you could go to the motorcycle shop and get 'special motorcycle oil' [$$$] or do some research and get away with a few bucks to spare. Here's one site - there are others but they say pretty much the same thing:
http://www.calsci.com/motorcycleinfo/Consumables.html

Do some research - save your engine, your clutch, and some money.


BTW: A gallon-and-a-half is way too much oil - probably gas sneaking past the petcock and carbs. 2 Litres [a little more than two quarts] looks to be the standard amount of oil for these machines. Mine has 2000cc cast into the metal right beside the oil filler hole.

 

[Onetype]

Now on your carbs, set the mix screws at 2 out. Get the bike warmed up. With it at idle short out one plug so it runs on one cylinder, back off the idle speed untill it runs as slow as it can.

Ok so Im in the middle of trying to get this thing buttoned up today. What do you mean by short one side, pull the wire off the plug while its running? Just want to make sure I know what your talking about so I don't mess anything up.

Off topic but here is a recent picture, its been a while and I have changed quite a bit. It has come a long way, looking forward to when I get to slap a plate on it.

 

[XSLeo]

What I did was make an adapter that screws on the plug then the cap plugs on the adapter.
Now with a jumper from ground to the adapter, this shorts the spark to ground so the plug won't fire.
Some spokes use the same thread, use a spoke nipple and a piece of spoke to make the adapter. I drilled and tapped some aliminum and threaded a nail the right size. Threaded the aliminum pice on the plug, screwed in the nail put the cap on the nail.
On some coils, unplugging the plug wire can hurt the coil.
One thing you can do is after it warms up shut it off unplug the wire on one side, ise a jumper to hook the plug wire to ground, then restart the engine.
Leo

 

[Onetype]

Thank you for the clarification. I know it sounded like a dumb question but I do remember reading that you can damage the coil, so better safe than sorry.

On another note, it does seem to be running pretty damn good right now. I still dont have a tach so I can only guess at what to set my idle at by ear.

 

[drewpy]

Ok so Im in the middle of trying to get this thing buttoned up today. What do you mean by short one side, pull the wire off the plug while its running? Just want to make sure I know what your talking about so I don't mess anything up.

Off topic but here is a recent picture, its been a while and I have changed quite a bit. It has come a long way, looking forward to when I get to slap a plate on it.

note, is that new fuel delivery system vented?

eventually no fuel will flow if the space the fuel was in isn't replaced by air! then you will get high revs from low fuel in the bowls.

 

[Onetype]

note, is that new fuel delivery system vented?

eventually no fuel will flow if the space the fuel was in isn't replaced by air! then you will get high revs from low fuel in the bowls.

Haha, ya I cut a big hole out on one side. This is only temporary until my manual petcock gets here. For some reason the petcock on the tank wont flow any gas, took it apart and cleaned it and still nothing.

 

[xschris]

Even with it on prime?

 

[Onetype]

Let me re-phrase that. I can get gas to come out of it but not enough. Prime barely works, RES seems to be the best but the flow wont last very long. When I try to run the bike off the tank I can't even get enough gas to fill up the in-line filter. I also tried to drain the tank a few weeks ago and it stopped flowing and it was still like half full. This may be normal but i'd rather opt for something simpler.