Moved from News: UCE information

[Ace]

Okay, I don't have info on the Himalayan or 650 twins because I haven't had either of those engines apart yet. I have quite a bit of info on all the other singles, but it will take some time to write it all. I will add a bit at a time as I have time. Perhaps it might be better placed in a technical thread because there will be a lot of info.

Okay, I will try to be somewhat brief and to the point regarding the various models, starting with the latest models first.

All model years have some common internal engine issues. Mind you, not all have all of these issues, but may have one or some, or maybe even none that are perceived by the owner. But many reports have surfaced and I have personally needed to make repairs/rebuilds in quite a few instances.
Please bear in mind that I am not slagging the brand, because I am also an owner of various Bullets, but I have been around these bikes all thru the model changles, and I report from experience.

First, UCE 500 and GT 535.
These are basically the same engines, with the GT having a few changes for larger displacement.
The #1 reported issue is vibration. This has been shown via reports to have great variation from one bike to the next, and seemed a mystery. Since I have many years experience with previous model Bullets, I knew how the production methods changed along the way. Specifically, the crankshaft assembly methods changed with the AVL engine that came to the US in about 2006, but earlier in India. The UCE engines share a lot internally with the AVL. Anyway, to increase production speed, crankshaft assembly changed from individual 5-piece crankshaft parts that were basically hand assembled and trued, to a different method that was faster. The crank parts were assembled quicker, probably in some type of jig to get them pretty close to true, and then the crank end shafts were ground on a machine to true them end-to-end. The problem with that method was that each crank had its own slight out-of-true condition that was "locked in" by grinding the ends true, but not solving the actual concentricity issues inboard at the flywheels.
As a result, the cranks for AVL onward were only replaceable as a complete factory crankshaft assembly, and not as the individual 5 pieces as the previous Iron Barrel and vintage Bullets had been. We thought the replacement level was strange, and it only became apparent upon close inspection what was being done. This has continued to this day(AFAIK), throughout the UCE lineup, and this is why you hear different anecdotal reports from owners regarding different amounts of vibration from "smooth" to "rattles my back teeth", and recommendations to ride the ones in the showroom and pick the smoothest one. They really do differ in vibration, and there are real reasons for it, but you won't ever hear it from a dealer or certainly not from the factory. The problem is that it cannot be improved without a tear-down and replacement of the complete crank and con-rod assembly as a whole, and even then it is a "crap shoot" as to whether the new one will be better or worse than the one you took out. However, people do ride them with whatever vibration level that their individual bike has, and most just assume that "singles vibrate like that" and never realize what the underlying matters are.

So that is one big issue impacting rider experience, and there are more that I will add below.

 

[Ace]

Next UCE issue is dropping the exhaust valve. I have personally had to fix about 5 of these, and know of quite a few others that went to the junkyard because of it. Not everybody has this happen, but it is plenty common enough to mention it. All my exposure to it were from bikes with relatively low mileage(<6000mi).

The UCE has an issue with the exhaust valve coming apart at the junction of the valve head And the stem, where valves are typically friction welded together in the manufacturing process. I have not been able to determine the root cause, but it is either a QC matter with the valve or the engine runs too hot in the exhaust for their valve production method to handle it under certain riding circumstances. Does not seem to happen to the intake valve.

In any case, when the exhaust valve head drops into the cylinder, it basically trashes the whole innards. The cylinder head gets hammered in the combustion chamber until it looks like the surface of the moon, or worse. Same thing happens to the piston, along with it typically coming apart. Bore gets scored/damaged. Con-rod often gets bent. Big end bearing get trashed. Metal bits all go down into the whole rest of the engine, and need to be cleaned out if a rebuild is contemplated.

The good side is that this failure is not so ubiquitous as the vibration discomfort mentioned above. It is a small percentage of the total UCE production numbers. But is is much more "final" regarding the life of the engine. And the engine may lock up, which means you need to be quick with the clutch to remain upright. The ones that occurred during the warranty period were covered by RE under warranty, so RE stood behind them, which is good.

Not a high probability, but the issue exists. I have not seen any incidences of this on engines that had high performance aftermarket valves installed, either from us or Hitchcocks.

 

[Ace]

Also, UCE owners need to check your automatic primary chain adjusters. They are known to sometime overtension, or they have been known to come out and get caught in the primary drive, causing damage. Some have modified to a manually adjusted tensioner.

Also, when doing an oil change, check the oil passage holes in the gasket surfaces near the pump for RTV occluding the hole, either partially or totally, causing oil starvation conditions. Fairly common to come from the factory with a partial occlusion.

Regarding tapping noises from the top end of the engine, this is not worrisome, but it is nagging because hydraulic tappets should be quiet. Various attempts by many people to fix the factory valve train to be quiet have not been successful. I think it is likely to be slop in the rocker blocks, but I have not proved out that theory. It is not present when our billet head is on an otherwise stock engine, so that cures it, but I am not suggesting a $3k head replacement to cure a minor noise matter. .
In short, unless you just can't stand the rattle, don't worry about the valve train tapping, even though it should be quiet in a proper hydraulic tappet design.

Also, oil level sight glass can be tricky and cause overfilling for newbies, so always park the bike level on the centerstand the same way, and wait a couple minutes before you check the sight glass level.

Power Commander or Dobeck Electronic Jet or Racedynamics system is needed if you make pretty much any change to the exhaust system, or any power increasing mods.

Early C5 models(2009-2010) had handling problems due to frame geometry which were never admitted by the factory, but later years had different forks and larger front wheel to make it better.

The EFI fuel hose is commonly kinked with a tight bend affecting fuel delivery. It can be replaced(carefully) with a better hose in a loop instead of a bend for better results.

The negative battery strap is fairly commonly making poor contact inside the rubber insulator jacket at the battery end. Hard to find electrical problems are sometimes solved by fixing contact inside the battery strap connector end. It looks fine from outside, but not after you take off the insulator material.

I do not agree with the factory tire pressure recommendations. I think they are too low. If you don't think handling is as good as it should be, try some higher tire pressures. I like 28 front /32 rear.

I reckon most here are already aware of the kickstand switch issues and such.

That's mostly all I can think of about the UCE models at this moment.