[Roy L.]

Thanks axman.
Yes, it would seem something has not been right with it since new.
I took the fuel injector off last year and gave it a good clean. It looked just fine.
My mileage (kilometerage?) is great. I can do 100km with around 3ltrs - or in US money: 75 mpg.
My buddy the farmer who's keeping my bike in his barn can do a compression test, so I guess that's the next logical step.
There's a good guide to that in my manual.

I wish I'd asked this question in April - about 6 years ago!

[gashousegorilla]

   Simple stuff first.  Dumb question time here .... .     BUT , how sure are you about your speeds  Roy ?   Did you compare your speedo reading to a GPS ?   Perhaps with an app on your Phone  ?    I think most people would be shocked at the difference.     Enfield speedo's  are not known for being the most precise instruments .... particularly on the earlier UCE's.     Some are good , some are slow and some stick high and some swing wildly at times  and Some break internally and etc. . Greasing the speedo cable also can make a world of difference... 

[Roy L.]

Hi
My clock tends to be way too optimistic at low speeds. There are many electronic speed display signs round here near schools that show you your speed as you pass - they're nearly always in 30 or 40kmh limit zones to encourage drivers to keep their speeds down. When I pass them I'll have just short of 10kmh on the clock more than the display.

The accuracy of the speedometer improves at higher speeds. I've been on rallies where they pay strict attention to road speeds and when in an 80kmh zone (it can do it !!) that's exactly what I had on the clock.

My buddy at the farm will be doing a compression check for me hopefully this week, so I think that's a good place to start.
I'll get back with those results asap.

[heloego]

My 2012 UCE is running with the stock header, free-flowing exhaust, and EJK system (no O2 sensor) left at stock settings.

Keep in mind that anything interfering with the air flow will adversely affect your performance at higher power settings. Verify you have normal flow by checking your filter/intake for full functionality, exhaust port and header inlet,even the silencer for blockage of some kind.
I had a similar problem losing power and couldn't get it to go past 80kmh unless I was going downhill full throttle. After MUCH troubleshooting that even had the guys here stumped, it turned out the problem was blockage at the exhaust port/header where I had applied too much exhaust paste during maintenance. The stuff expanded with the heat and closed off the flow about 80%! Once cleaned and re-assembled she's a happy RE. 

I now use high temp silicone sealant. Period.

[Roy L.]

Great reply heloego, thanks!
You just disconnect the 02 sensor?

[GlennF]

Great reply heloego, thanks!
You just disconnect the 02 sensor?

He has an EJK which replaces the stock EFI controller with a programmable one.

[axman88]

We assume from your comments, RoyL, that your machine has fuel injection and a O2 sensor?  The ones for Europe and USA were set up like that, whereas bikes for the Indian market, and perhaps Indonesia had EFI, but with a "look-up" table type of ECU computer and no 02 sensor.  The ECU can be reprogrammed anyone with the Royal Enfield software, (dealers), and there are aftermarket controllers available.  Also, it isn't uncommon for people to replace the entire EFI system with a carburetor.  The 350s for India only still have, and manage to meet BS IV emmissions standards with, carburetors.

It's never hurts to say exactly what equipment you have on your bike, when asking for advice.

Since your bike quite possibly came from the factory with the issue you described, it may be particularly difficult to diagnose.  It's unfortunate that your local dealer is no longer in business.

Taking it step by step, and verifying each component will ultimately find the problem.  I don't know any way to test the ECU computer, but every sensor can be checked, and REs are quite simple mechanically, as motorcycles go.

You may want to consider investing in a carburetor, simply as a diagnostic tool, even if you prefer EFI.  One nice thing about these Indian bikes, all the parts are quite cheap, via Ebay or Amazon, from suppliers in India.

[gizzo]

I can sit on 120 kmh all day on my B5. Top speed is an indicated 140kmh but it is probably actually more like 130 kmh accounting for an overly optimistic speedo. Still even 130kmh is vastly faster than 80kmh.

Same here on my '14 Continental GT.  38,000km and always been ridden "sporty" like. 120 all day and tops out at around 145, verified by GPS. I can't help thinking something's not right if the OP's bike can't pull 100.  Maybe cam timing is way out or something. Or, might just be an unlucky bike.

[Ove]

As I understood it, you have two problems?
1. Vibration at/above 80kmh
2. Lack of top speed performance

For 1. factors such as the balance of rotating components and the tightness of mountings may be at play
For 2. A compression test seems a good 1st step. De-Coke may be due, but doesn't explain why it's always been this way. Air, exhaust or fuel flow may be worth checking, timing too? Something that can persist for long mileages without failures. A dyno run will tell you if engine output is the cause. Other causes, giving the effect of reduced power might be worth looking at, such as binding brakes, tyre pressures, bearings, but these would most likely have corrected themselves or failed by 20,000+ kms. 

Maybe check they didnt put a 350 in by mistake! 

[Roy L.]

You're all extremely kind with these suggestions and help. Thanks!

Yeah, it's a European spec model with an 02 sensor and fuel injector.
I'm not going to bother sticking a carburettor on it. It's too much messing about.
I have a feeling that Heloego might have nailed it with the blockage diagnosis as his former problem sounds just like mine.
But for now I'm just going to wait on the compression test result.

I've just uploaded a video for your viewing pleasure!
https://youtu.be/du5wH0Kmwok

BR
Matt

[gashousegorilla]

    If you haven't already Roy, take a look at your air filter and your whole intake track as well, and see how dirty it is.    Here is why....  the air boxes on those bike's have TWO hose connection pubs on them.  One is at the front right side of the box... this is where the crank case vent hose connects to.    And there is another hose connection pub at the bottom of the air box.    It is difficult to see unless you are looking for it or if you take the whole air box out.   THAT one I have found open , with nothing attached to it.  And a Filthy Throttle body and intake to go along with it !  That lower Pub connection is pointing down towards the chain...    I really don't know why it is there ?   Maybe just as another option to attach the crank vent hose two .    I see no other purpose for it.    But anyway... if either one of those hose pub connections ARE open ,  that air being pulled into the air box will be un-filtered .  It will by-pass the filter and go right into the intake.

[GlennF]

I think the significant point is the bike has a 40% lower top speed than it should for a 500 and it vibrates at 80 kmh when (given the sprocket mod) it should actually be just cruising along at a bit over half maximum revs.

You either have a 350 or something is seriously amiss.

[gashousegorilla]

   And unfiltered air could wreak havoc on the intake valve and seat as well as the ring seal over time .   I think a simple compression test as a first step is a good idea...

[axman88]

Thanks for posting the video Matt.  I wouldn't be surprised if some of the guys in here could diagnose most engine problems from a short video with audio like that.

Does anyone else think that the valve clatter audible in Matt's video was a bit more than should be expected, or is that about normal?

[Roy L.]

More great advice, thanks gents.

As the bike's not here, sadly I can't check any of these things right now.
I'm confident though that with all your help, I'll get this sorted out.
As I mentioned, my buddy's going to check the compression and then we can take it further.
I hate to rush him as he works 14 hrs a day every day, but I'll drop him a gentle reminder at the weekend.

Cheers from a sunny South Finland