Another ER5 thread

[imbezza]

Hi All, just got back into riding after about 8 years off since I sold my 600 bandit. I'm now on an Er5 which is a surprisingly nice albeit simple bike and despite being a 98 plate is in pretty good nic with 24k on the clock.

I've only had it 3 or 400 miles and during that time it's mostly been spot on but once or twice it's bogged down at 6k rpm, like it's on a limiter, and it just will not rev higher. Whacking the choke on full returns the full rev range to me. In the past few weeks it's gotten worse and now if I open the throttle quickly it tries to stall on me, and won't go over 4k when it does this and this happens at idle/neutral and when riding. In neutral I can ease up to red line without issues but not when riding The bike starts perfectly on the button without choke first time every time, seems to idle OK, battery voltages seem OK and battery is holding charge for weeks. From the symptoms my (very) simple mind is thinking it's fuel/air related and is either getting to much air, or not enough fuel. which is possibly why the choke solves the problem (except at traffic lights when I just sound like an idiot idling at 4k with an embarrassingly loud exhaust - pending db killer ). Fuel efficiency has been around 45mpg which seems about average so I don't think it's running massively rich, although my kids say it stinks

The bike had a carb rebuild from the previous owner last year with a stage 1 kit, has a blueflame exhaust system, air box/crank breather delete with filter on the crank breather, and an RF900 gravity tap, but is otherwise stock as far as I can tell.

I gave it a new filter and oil when I got it, and I've got a carb rebuild kit so I can replace the diaphragms, jets, and gaskets with OEM sizes so I can use my Haynes manual for adjustments. I'll be replacing or clipping the lines to try and remove any possible vacuum leaks and will replace the in-line fuel filters - which look ok but in case they are blocked. I've also got a tap rebuild kit coming for the stock tap which I'm planning on replacing the gravity tap with so I don't have to turn it off every time I park. I'll be adding an in-line switch after the tap so I can turn it off for longer breaks in riding - just in case as I know these are prone to fail.

At this point I don't necessarily care for the exact cause of the issue, as long as one or a combination of things resolves it. That might be a stupid way of looking at it but I just want to get back on the bike and ride!

I'm fairly new to motorcycle maintenance, although I did all the standard oil/pads/sprockets/filters on the old bike, and the steps I'm taking so far are based on a lot of googling and other threads on this forum and others. Is there anything else I should be looking at sorting as a precaution whilst I have the bike in bits? Or even am I jumping to carbs too quickly and is there something else I should be checking which might be more likely to cause these issues before I do the carbs?

Any help appreciated, I'm sorely missing the ability to ride with the weather we've had down south!

Bez

[Nobby the Bastard]

As it's mostly okay and clearly is sometimes failing when it should be on the main jet, I will ask why the previous owner felt the need to clean the carb.

I'm inclined to think that there's shit blocking the jet. Does it have a fuel filter?
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[imbezza]

The last owner put a stage 1 kit on it - I don't know if he had issues with it before but that's the only info I have so either it had issues before or he wanted to upgrade it (I don't know why you'd put a stage 1 on a 50bhp bike ).

Thanks for your quick reply btw, tis appreciated

There is a filter under the tank and fuel filters in line on both the reserve and main lines, which I intend to replace whilst I'm working on the bike.

if it is main jet I suppose I have to take the carbs off anyway, so my plan to return to new/stock spec parts would I think be a fix? if the float needles and jets look OK is it worth trying a blow through with compressed air before replacing it all, or should I go for broke so I know what's in there is new and clear?

[stinkwheel]

No mention of the air filter?

If it's sucked lumps of disintegrating air filter material into the power jets, they are a bastard to clean and that gives the result of refusing to rev properly between about 4 and 8k RPM but running fine outwith that range.

So does it have a manky and disintegrating or suspiciously new air filter?
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Nobby the Bastard]

I'd start with replacing the fuel filters and then look at whether anything else is limiting fuel to the carbs after a second look at the symptoms.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[imbezza]

Cheers both. Air filter was basically new when I got the bike and I replaced it anyway when I got it. I’d like to think it was because he was fixing up the bike and added the stage 1 - he seemed genuine and it might be wishful thinking which is another reason why I was thinking of replacing the lot.

The current fuel filters look ok but I’ve got some on order so I’ll try them first and if no joy I’ll carry on with the carb internals.

[Bhud]

Just a general note of caution on ER5s, as I rode mine to the point of major engine failure, many years ago. They are nice and they handle better than people think, but maintenance is absolutely crucial on those bikes. Don't listen to anyone who says they're bulletproof, because they definitely are not. They're just the water-cooled, electronic ignition successor of some very primitive twins from the 70s. A big improvement on them, but still those are their roots. Check everything - not just fueling. Check valve clearances, cam timing, carb synchronisation and compression first. If those are all good, go on to fueling.

[redeem ouzzer]

[Robby]

Before pulling anything apart, turn off the fuel at the tap and drain the carbs into a cup - there is a drain screw on the bottom of the float bowl. See if there is any water in the fuel. If there is, drain the tank on reserve and you should get rid of it.

[stinkwheel]

[Bhud]

[sickpup]

[stinkwheel]

[to v or not to v]

could always try putting a fuel additive in the tank. something like wynns formula gold.
its cheap and simple and may clean out some gunk in the system.
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current bike Yamaha Thunderace.
Moto Guzzi V7.

[imbezza]

Hi All. Thanks for the comments and debate! Taken me a while to get to the bike but I started taking it apart to check the carb and noticed the previous fuel filters had no crud in them as they were blocked at the top with rust and crud from the tank, which it turns out was rusted like mad and the fuel lines were blocked.

Tank has been cleaned out and rust removed, new filters, new fuel lines, new vacuum hose between petcock/carb, and fuel flows nicely out of both lines. Tap repair has been done and the tap works and fuel flows under vacuum.

But - it still doesn't work.

Now it's back together it won't run past around 4k. Both cylinders are firing but the right one seems hotter (both are hot), and I've noticed the oil has gone down a fair bit. It feels like it's dropping a cylinder or still suffering from fuel starvation.

It still starts on the button every time, without choke, revs fine when in neutral or not under load (on centre stand I can run through the gears and full rev range). As soon as I get it on the road it's OK to around 3-4k and then just nothing. if I try to accelerate it will drop to 0rpm and will stall if I don't let off the gas. It's very slow but will just about sit at 30 and will rev past 4k slowly but without any gain in speed and it's not happy about it.

The leads and coils look fairly new but I'll be testing them as best I can with a multimeter and I've not yet done the carbs as I wanted to sort the rust first. Are the carbs the next go to?

[stinkwheel]

Carbs are probably a good place to look. On the KLE above, the needle valves had both gone tits-up due to what I assume was the ethanol in the fuel. They were stuck initially, then started sticking in and on a couple of occasions stuck out causing a fuel leak which on one occasion flooded the airbox and caught fire but self extinguished.

Replaced them with viton tipped ones and the problem went away. Give those power jets a good blow through too.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[jeffyjeff]

You probably have constant-velocity carburetors on that bike, in which case the diaphragms should be inspected for possible leakage. You might do what you can to check the exhaust temperature on both cylinders when it acts up. Your problem might be traced to one cylinder or the other. Once you get that sorted, it would be a good idea to synch (balance) the carbs. Not difficult on that bike, being a twin.
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History shows again and again how nature points out the folly of men - BOC

[imbezza]

Thanks both. So I took the carbs off and worked through the service kit and found a fair number of mistakes from the previous owner...

The crank case breather was attached to the bolt head - not the opening in the case

many screws had been rounded off, couldn't even get a screwdriver to grip and had to be cut to a flat head and replaced.

The main jet on carb 1 was completely blocked and the float bowl full of crud.

The main jet on carb 2 was part blocked and the float bowl full of crud.

Both pilot jets were completely blocked and would have been letting zero fuel through.

This is the best one - The fuel mixture screws from the dyno kit had been installed and should be screw-spring-shim-oring. The previous owner had left the old springs/shims/o rings in!!! I found the stock springs under the dynojet ones, and at least two disintegrated orings on each side, so the mixture screws weren't getting anywhere near and would have been letting tons of fuel through!!

Somehow, the guy landed on the perfect combination of issues to block all fuel from one route, and permit all fuel in another, to make a rideable bike when I test rode which was somehow starting on the button every time

Anyway, full carb rebuilt including diaphragms, new plugs, new air filter, HT lead resistance checked, idle and mixture adjusted correctly, crank breather in the right place, and proper fuel filters in place and she's now sweet as can be. I've also put a longer baffle in which makes it bearable, but I'll probably baffle it further with some wadding as I don't need the world to hear me coming on my 500.

Wasn't until I rode it after fixing the issues that I realised how much it was underperforming beforehand. Now the components of the carb are new I'll only be running on e5 or better, so hopefully this will last me some time.

Due an oil replacement, coolant top up as I spilt loads bumping in and out of the workshop, and a new indicator as I broke one, and hopefully I'll be back on two wheels!!

Cheers