Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

Well what you are looking to do I suppose is increase the counterweights on the crankshaft right? I highly suggest you do not modify it. Increasing the counterweights could possibly become much more of a hassle than good. A lot of factors go into the development of these crankshafts as to how the fit into the engine and how they are spaced for its lubrication and for optimum performance the counterweight has to be perfectly balanced. I believe you would end up having to modify the area surrounding the crankshaft accordingly as well.

RE already uses heavier crankweights and hence the vibrations and the famous "thump". Going bigger will result in bigger thump, more load on the smaller pistons, load on the starting motor and a slow motorcycle. Could possibly even destroy your engine completely if you get it wrong.

How ever there is one way though,... drilling the weights and filling it with denser moltel metal or so... I'm not sure... You might have to check it out.

or just Don't do it :P

Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

This is a very tricky job. It was possible for the older cast iron bullets, had done it for my bullet too. But regarding the UCE engine I cant comment much but I had heard an engineer from RE giving the mechanics a talk on this topic. He said that the trick of installing a heavy crank for the UCE should not be tried. They may their own reasons. But if the crank casings and bearings are the same the then it worth trying cause I don't think any one has tried this stuff yet or else there would have been some one answering your question.
And your going open your engine completely and fitting it again it may not have the exact precision of the factory fitted engine.
Good luck with your project :thumbup:

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Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

The closest reply in the context . Yes as many said you are right, fiddling with crankshaft in the UCE engine is definitely not a good idea which can result in less benefits but more issues.

BTW you said you have changed crankshaft in for your CI bullet. Please throw some lights.

What was the initial weight and what was the weight of the changed crankshaft?
Which Bullet, which model?
What was the technicality involved and what crank change required what else to be changed/modified?
What all changes/improvements/issues you experienced after changing the crank?
And did it make the thump more prominent?

I am expecting a detailed reply from you as it might not be 100% in context with my query of UCE engine crank change but would definitely help many Bullet fans/owners/lovers as I see many have this question surfacing in their mind sometimes in their Bullet's life.. Can I change the crank to heavier one?

BTW looks like I am not going to move ahead in my project

Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

Digression
The lighter crank of the stock engine weighed 7.5 kgs. The heavier crank weighed around 10.2 kgs. Had to xhange the timing side shaft as it was a crank of a ci 500. Also changed the bush to brass. There two types of heavy cranks one of the 500 and the second of the g2 engine bullet aka made in England. The latter's almost impossible to find. If you happen to lay your hands on one you should be considered lucky
My bullet was a 2001 standard. Sold 6 months back.

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Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

You did not answer all of my queries like thump factor, difference before after etc.

BTW Interesting. The new UCE Bullets comes with crank weight of around 9.5 kgs and UCE standard with 10.2-10.5kg crank weight, that is why they say the UCE bullet already has a heavier crank and they are not all time low on that aspect .
But isn't this interesting, everything is same but still UCE Standard's crank weight is more than other UCE bullets (talking about 350 cc UCE only) that means the crank can be made heavier. Also the heavy crank effect of UCE standard can be easily felt, it easily pulls on 4th gear at the speed of 32-35 unlike other UCE Bulls which start lugging at the speed of 35 on 4th.

Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

Thump increases but top end is bad and yes it lugs
I have seen the crank of the UCE it looks identical to ci crank.
I have ridden both uce std and electra didn't feel the difference.
Waiting for my tb500

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Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

What model is your enfield?? An experienced mechanic told me that by adding an extra gasket/packing you can lug at 25km/hr in top gear on the older Ci bulls. Have to verify this. And then try it

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Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

Mine is 2012 UCE Classic ... Extra packing and chug at 25 on top gear? now this is something I never heard of

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Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

I was kind of puzzled on hearing this. Have to confirm this though.
But I think you can go for the heavy crank because the crankcase is the same for all UCE models including the 500. Only blockpiston and head is bigger in case of 500.

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Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

Is this true that Std 350's crank is heavier than other 350 Bullets? RE site says so..

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Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

yep the crank is heavier on the std 350 uce ,it runs the crank of the 500

Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

Do you know the exact weight?

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Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

Very interesting topic and one which I have been fascinated about in the past. As far as Crank weight goes and this is all hearsay, with a bit of hands on experience, The G2 350 bullet had the heaviest Crank at about 12KG, they were assembled in India up until 1968. After this with the closure of the Redditch factory in England, Enfield India started manufacturing 350 bullets in India. From 1970 to about 1980 the crank weight was reduced to about 10+KG. Again sometime in the early 80's it was reduced further by 2.5KG. this is why most mechanics recommend the 80's Bullets for its pickup and FE. Now to the question of Thump, Crank weight has little effect on thump.
For twenty odd years I was obsessed with the perfect thump. What I have found is that the thump is determined by 1. Exhaust pipe. 2. Valve seating. 3. Timing. (Points that is)
A heavy Crank helps you chug along in a high gear at low speeds and helps you set an incredibly low idle.
hope this helps.

p.s about the extra gasket, by increasing or decreasing gasket height, alters a 4 strokes compression ratio.

Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

Hmmm... Actually the biggest factor for thump is massive torque at relatively very very less RPM. I never heard about valve seating and ignition timing for that, can you throw some more light on how does these two affect the thump?

Btw: which Bullet you own now?

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Re: Can crankshaft be changed to heavier one in the Royal Enfield UCE Bullet

nope, i dont