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Post by cherrymetal on Jan 6, 2009 21:38:27 GMT 1
I've got a strange rattle on my '88 Revere.
It sounds non metallic, and is not consistant. It seems to occur at all sorts of revs and all sorts of speeds, but generally seems to be when the engine is not under load (not when accelerating).
I thought it might be one of the plastic covers rattling that cover the engine mount bolt pivots etc, but have checked them all and removed some and it doesn't seem to be that.
The only thing I can liken the sound to is when I had a Metro with a knackered water pump, it went away when I replaced the pump, does this sound likely on the NTV? I'm hoping not!
Also it does occasionally tend to overheat (not loads but back in the summer was starting to cause me concern), but now the tem gauge seems to have stopped working (any ideas?)
Its got 45k miles on it.
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Post by McF on Jan 7, 2009 0:56:17 GMT 1
Hi Cherrymetal and welcome aboard.
Sorry to hear you have troubles, let's hope they're easily and cheaply fixed.
Your description makes me wonder if the water pump is sound and you have implied as much yourself.
I had a similar problem. Drained my Anti freeze and removed the outer housing of the water pump and found a lot of "loose teeth" rattling around in there.
The impeller blades from the pump had mysteriously sheered off. They are metal (probably mild steel), but were moving around inside the alloy pump body full of water.
You should be able to hear this with the engine running, listen on the lower left side of the bike, perhaps get an accomplice to rev the engine a little while you're listening. to isolate the sound, you could place the end of a long screwdriver against the pump body, put your thumb across the end and then place the outside knuckle of your thumb against the bone behind your ear (honestly - this works!)
The pump is fairly obvious, on the left side of the engine. Follow the lower rubber hose on the left side of radiator down, it goes into a chromed pipe, which then enters the pump.
If you think this is the problem, it will need replacing - at the very least over winter, remove the "loose teeth".
The book says "drain the oil first". As the Water pump is driven from the rear of the oil pump. There are two seals on the water pump - one to keep the water in the cooling system, the other to keep the oil on the engine. If you are careful and can keep the bike leaning towards the right, you can do this without draining the engine - BUT BE CAREFUL!
The drain bolt is in the pump body, there should also be two bolts holding the body halves together plus two other bolts which secure the pump to the crankcase. Check Haynes Manual (if you have one), or post back if you need a diagram.
Drain your system (circa 1.6 - 2.2 litres), either capture the coolant for re-use, but ideally drain and discard (sensibly) and refill later with fresh. You will need your tank off to refill, so best to remove it before you start and remove the pressurised filler cap to allow air to enter the system.
Remove the pump, then split the two halves. If your pump suffered the same fate as mine, the impeller will now be a small conical shape, the "teeth" will be curved bits of metal that were once the impeller blades. They were nothing fancy, just simple vanes that gave the water a push. There was plenty of room in the impeller chamber and if someone was a competent welder (most likely gas) I'd even say they could be welded back on.
However, the pump is otherwise sealed and the impeller cannot be purchased on its own. A new pump is damned expensive (>£100 if I recall). A breakers yard is a good option. I sourced one with a pump for circa £30. I'm not sure what other bikes have a compatible pump.
If you reassemble the pump, it's most likely that you will need a new rubber gasket. Easily available from your main stealer (who will probably have to order in) for less than £5.
The Temp gauge may be related, but not directly. The sender unit is in the thermostat housing (under the fuel tank, where the pressure cap is).
With winter temperatures I wouldn't expect to see much movement of the needle. Can you see any when you switch the ignition on/off?
The temperature sender works by regulating the current FROM the temp gauge to earth. I forget which way it is configured, but the easiest way to check it while you have the tank off, is to remove the wire (a single bullet connector) with ignition on and see if no earth at all changes the position of the needle.
Then connector the loose bullet connector directly to a good earth and see what the needle does.
My guess is that the sender should improve conductivity with temperature (as it gets hotter - more current goes to earth), therefore, a direct earth should show as overboiling.
Have a look and report back then we'll see what steps to suggest next.
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Post by Buzzin (^_^) on Jan 7, 2009 9:56:36 GMT 1
May I suggest a simple check first? Check the coolingfluid level first. The tank at the side of the bike is an indication, but just that. Get the tank off, open the pressure cap, the fluid should be up to the cap. If not, fill the system to the max, let the engine run a while and refill (to let the air escape) If there is to little fluid in the system, the tempgauge won't work either. This won't explain the sounds you hear, but if you're opening it up anyway, it might be worth checking... A few notes: - Keep in mind that the first Reveres had a slightly different waterpump to later (even revere) models. The haynes manual says the older models have a seperate drainbolt on the waterpump, the newer ones just use one of the mounting bolts for draining. - Like said above, always fill from the top, under the tank. The small resevoir on the side of the bike is an overflow tank, and cannot be used for filling the system. - I would always recommened new coolant, for two reasons: 1. I asume you didn't replace it before, and it might be old 2. having had problems, you never know what is floating around in the old fluid, it can cause all sorts of troubles if not replaced. I got 5L aluminium friendly unmixed BMX coolant, just mix with water and add, it wasn't very expensive (once you realise it will last forever...). Another thing that just popped into my mind: If the thermostat is stuck in open position, the engine won't warm up (even with enough fluid and working pump) and the gauge won't move either. Only way to test...let the engine run while stationairy for a long(ish) time. Eventually it should warm up a bit... (I currently have this problem on my car) And if none of that works....you can still replace the waterpump  |
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Post by McF on Jan 7, 2009 20:54:22 GMT 1
The small resevoir on the side of the bike is an overflow tank, and cannot be used for filling the system. For a little further clarity, the small white plastic bottle is an expansion tank. It does a very important function, far more than just overflow. When the cooling system heats up to operating pressure, the contents expand. The pressure cap spring opens and allows the coolant to "overflow" into the expansion tank. When the engine cools down, negative pressure is caused inside the coolant system and it sucks back coolant from the expansion tank. To maintain the right balance, it is important that the coolant level in the expansion tank is maintained inside the marks on the plastic bottle - when the engine is cold. I had terrible problems with my system (on the engine I still have). I spent hours trying to figure out how the coolant gets back into the system and then "found" the shiny metal centre on the rubber seal of the pressure cap will move against spring pressure "into" the system - thus allowing the coolant to get back in. Agreed with Buzzin ref Thermostat, and add - if you think that is a problem, with thermostat stuck open, water will be allowed to circulate directly into the radiator - check temperature of top hose (right had side), if that is feeling warm early, water is getting past the thermostat. Even with the stat open, I'd still expect to see the temp gauge moving though. Interested to hear your progress |
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Post by cherrymetal on Jan 10, 2009 10:21:58 GMT 1
Thanks for the info, I'm gonna try and have a play this weekend, time and weather permitting!
So do I fill from the expansion tank or direct into the rad? I've always topped up the expansion tank in the past.
I'm pretty sure there's something wrong with the gauge rather than it not warming up properly, because it always feels (and smells) like its plenty warm!
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Post by Buzzin (^_^) on Jan 10, 2009 17:07:57 GMT 1
Always fill up from the top (under the fuel tank) filling up the expansion tank won't fill the system properly. Fill all the way to the top, run the engine for a bit and refill to top (the air escaping makes the level drop) I hope the problems are minor and easy to fix |
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Post by cherrymetal on Jan 31, 2009 20:10:04 GMT 1
Well, I think I've diagnosed half the problem!
I went to top the water up (from the top of the rad), put a load in then ran it to circulate and get rid of the air etc
Uh oh!! Water all over the floor! It seems to be leaking from the small pipe that joins the two cylinders in the middle of the vee.
Anyone else had the same problem? There seems to be two o'rings (that I guess I'll have to replace) on a little collar thing.
So this probably means I've been running the bike almost dry (silly boy, I know!), which would account for the temp gauge not registering (it seemed to register a little when I put the water in), and it overheating.
I just hope I haven't killed it?!
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Post by rj2para (Bisto) on Jan 31, 2009 22:47:41 GMT 1
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Post by cherrymetal on Feb 1, 2009 10:19:40 GMT 1
thats the one!
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Post by McF on Feb 1, 2009 10:33:34 GMT 1
That's the one I think Cherrymetal is describing.
Rubber O rings will be an "interesting" condition by now and are most likely reason for a leak in this area.
Replacing will be fiddly with the engine in the frame, but should be straight forward if you have plenty of spare change for the swear box ;D
Cooling system operates at 1 bar (about half of the pressure in your tyres) when the engine is warmed up. I presume you don't get a leak at first?
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Post by cherrymetal on Feb 1, 2009 14:47:59 GMT 1
Done!
I managed to get o rings from my local car parts shop, 18mm x 2.5mm for anyone else who needs to know!
It is fiddly, but got there in the end.
Filled back up with water, and ran for 10-15mins, and the temperature gauge now works again! I'll top up again when its cooled down, and keep an eye on it.
Now to find out what that rattle its....
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Post by rj2para (Bisto) on Feb 1, 2009 15:34:54 GMT 1
;D
Great News.
look out rattle here he comes.
Roger.
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Post by McF on Feb 1, 2009 20:05:09 GMT 1
Done! It is fiddly, but got there in the end. Excellent, well done. How much in the swear box? Does the rattle increase in noise when you throttle off, but reduce when you throttle on? If so, it sounds like the rattle I had from the previous bike. I was convinced it was from the oil pump chain, there is a huge amount of play in it and no tensioner. It is a fairly simple job to look at the chain - remove the right hand (Clutch) crankcase cover (needs oil drain and exhaust header pipes off), you can reach behind the clutch basket to see the chain, but to remove the chain requires the clutch off. Other sources could be the little ends, but I'd say they were more likely to get noiser with load. Big ends and Main Bearings make more of a rumble |
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Post by cherrymetal on Feb 7, 2009 11:11:23 GMT 1
Swear box was pretty empty, as I had my 3 year old watching me!
It doesn't seem to be effected by throttle openings, there seems to be a pattern in the rattle, it always seems to happen at 50mph, which is strange, because it doesn't happen at the same revs in other gears??
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