Sprag Clutch - Demystified

Hi,

To start this thread with the correct mindset about CI engine bulls (like mine), lemme make this very clear:

" Bullets break down. Bullets get back up again. It just gotta be with a person who is patient and knowledgeable. "

Now if you have been following my posts or have seen my bike, it's a no-brainer to guess this baby (forgive me for saying this about the Bull which enjoys a macho status in India) is taken care of well. Well.. just to brag a bit more about our relationship, lemme say we take care of each other well, through thick and thin. It never gave up on me during any big rides and I return the kindness by taking care of its needs at the right time. Actually, it's quite common if you consider any biker who loves riding. There, I said it :D

Last Year:

Now before the eyeballs start rolling, let's get back to the topic; Sprag clutch. Well, I got to know about it a year back when I was trying to switch start the bike for going to work. There was this loud (relative, to other noises I usually hear from the bike) 'clang' from the engine (wasn't sure from where) when the switch didn't really start the bike. Though knowing bullets are an ancient tech, a noise once in a while is nothing new. But a metal-hitting noise was a bit too much for me to ignore. So I called up my mech and got to know it could be the starter gear and its nothing to do with the engine. That was a relief. So I decided to continue with my day and get that noise checked once I get some free time.

During the next servicing, I got the following update from Sami (my previous mech):

The starter gear (that's what my then mech referred to it as) slipping mechanism is faulty and the noise comes when the engine backfires. So every time I switch to start (or even kick) and if it causes a 'kick back', the crank is trying to rotate the starter gear backward (which should ideally rotate in only one direction and slip in the other). As the slipping mechanism is not working, the starter gear is rotating during kickback. It has to be replaced, however, I can continue using it and in case of a breakdown, kick start can be used.

Upon searching online for more details on the sprag clutch I came across the following post which made some sense to me:

Royal Enfield recommends 420ml of oil in the primary case(clutch case). While this is the right amount of oil for a CI/AVL Bullet without an electric start, it is insufficient for Bullets with electric starters. The reason is the fact that bullets with electric starters need more oil to lubricate the sprag clutch bearings and gear assembly for the electric start. 

Bulleteers in the UK and the USA have been instructed by their dealers to use 1 liter of oil in the primary case since a large number of sprag bearing failures have been attributed to lack/insufficient lubrication. So, the Bulleteers abroad have been following this advisory with good results. 

As far as my little knowledge goes, Royal Enfield India for its part has not circulated this advisory in India either through the dealers or through any means of communication, amongst the large number of owners who own electric start-equipped CI/AVL Bullets. 

I had a word with a well-known and highly respected Royal Enfield dealer and mechanic from the US of A, who strongly advised the usage of 1 liter of oil in the primary case. Hence, I thought I'd let fellow bulleteers know about this as this could save many sprag clutch/electric start failures which otherwise could have resulted due to the lack of sufficient lubrication.

Note: This advisory does not apply to the Unit Construction Engined(UCE) bullets.


I brought this topic up with Nandan (my mentor in bullet maintenance, whom I approach occasionally when I need to know the engineering-centric explanation for certain bullet behavior, which is usually beyond a mechanic's cup of tea), and here is what he had to say:

What is good for preventing jamming, will be bad for gripping.
The sprag itself has to grip in one direction &  slip in another.
The clutch has to grip well, or else you may as well buy a 100cc bike
with mileage-problems!
And even with small amounts of oil in the bike, it leaks.
In my opinion, extra oil is too much headache for a very small problem!
The best way is to avoid the starter and learn to kick-start the bike.
You can buy an ignition unit...the OLD model TCI, which did not skip a
spark like the new models.
It will make starting even easier. This unit can be kept as a spare.


After the above discussion, I continued with my rides on my bike, and other than occasional 'clangs' nothing really happened. 

Last Month:

I was looking for a new mech (as the old one is no good for my work anymore), and I came across Nizam from BSK. Very humble guy and currently the chosen one to put their hands on my bike. Even he told the same fear of a defective sprag clutch. Better to remove it for my Ladakh ride or replace it completely. However, he would still have a look at the clutch during servicing and let me know of any hope of repairing it.

Yesterday:

As part of some fabrication work getting done for my fuel tank, I was speaking with Imran (a well-known bullet mechanic who also travels with groups as a support mech). Even he suggested removing the 'sprag clutch' for the trip and using a kicker. That's the safest thing to do and commonly done by other CI bullets as well. Apart from that he was quite impressed with my bike's looks and the condition of the engine ;)


Reference Links:
The best and simple description of detecting known behavior of a bad sprag:

http://www.royalenfields.com/2012/06/royal-enfield-sprag-clutch-starter.html

Parts Diagram of Sprag Clutch Assembly:

Picture of the spare parts:

http://www.bulletwala.com/index.php/vintage-royal-enfield-genuine-new-sprag-clutch-assembly-560042.html#.U8S5C_mSxdU

So I have decided to remove my sprag clutch assembly for my upcoming ride to the mountains. I will try and record the removal process for my own reference.


Cheers!!,

Sid

Leh - if wishes were motorcycles..

Hi there,

If wishes were motorcycles, I would be riding one right now around some of the most beautiful and exotic routes of Europe or cruising through the American state highways or crossing our country border to catch up with our friendly neighbors like Nepal and Bhutan, or riding up north to one of the highest motorable roads on this planet. Well, maybe they(wishes) are (motorcycles), provided we strongly believe in them and we are ready to put in our best and not look back. I am trying to do exactly that and the one wish I am after at this moment is not only to experience the route via Khardung-La but to enter the beautiful valley of Kashmir on a motorcycle. Well, it's not the first time, that motorcycle has been a positively dominating factor in my plans of traveling. There was a time when I skipped every single opportunity to visit Goa, especially when it was just not acceptable for an earning youngster like me, who loved beaches, to say no to a place like Goa. But then there was this wish of mine to enter Goa on a bike for the first time. It took me time and quite a bit of effort to make than happen back in 2009. Since then the next item on the list has been Leh. However may be the desire to make it happen wasn't as strong as my reasons (of why I can't do that), that I could never pull it off. The closest I could ever get was in 2013 when I took some steps to en-quire and plan a bit about it. Then before I know it, the whole dream faded into the oblivion of "job switch, leave approvals, and not being able to put together a team of inspiring/inspired individuals", just not to be brought back to life again. As an individual am quite determined and it was a failure on my part, not being able to keep a promise I made to myself. This realization kicked me hard the day I went ahead and informed my manager that I won't be taking the days off in August. This was sort of an official closure of the possibility of the ride. I felt bad and I knew this ain't it. The possibility of the 2014 ride actually started that very moment. Sometimes one needs a hard kick on the butt to get started. I wish there were better (read milder) alternatives, but am afraid, probably there aren't any:)

I did a couple of rides last year, which kept me warm up to the thought of this big ride. The ride to Leh wasn't only about riding through the exotic locations, it was about capturing the experience in the form of a documentary on camera. My bull is a gift from my dad and I would love to share our trip experiences with him and mom. Why should the thrill and excitement be only with us privileged ones (yes I feel so!) who ride. We earn it anyway, but the joy doubles in sharing and inspiring others. This not only inspires people to ride but on a broader perspective, it inspires everyone (even me!) to dream big and to make it happen. Really.

"life is too short to play small".

It took me ages, of a certain way of being, and a lot of friction with my mediocre surroundings to develop a strong belief in my dreams. All I can say to you all who have big dreams is to start now. Regret of a life half lived is more painful than death any day. So you have a choice now to start living the life of your dreams, where even occasional failure is much more satisfying.

Well.. there I got a bit philosophical (an inseparable part of me anyway!). Now let's delve into one of the most interesting bits of the ride, yes it's 'the planning' :) I am not opting for any guided tours, it's not for me I feel. I love to try things on my own and setbacks (if any) are just learning experiences that I use to get to the next level. And after all, how could I miss out on all the butterflies in the stomach I enjoy when I put together a plan for a ride and be the first one to visualize the whole experience well before it happens. Then of course the responsibility is to pass on the joy to fellow riders. Nah I don't see it's going to change anytime soon. So here I am in the planning stage of this ride.

This time there is this one friend who is as excited and determined as me, Sriki. There was a time we were neighbors and my bullet was the only common topic we used to discuss when we crossed each other in the parking area of the building. Then he had to use a bull as his daily ride and since then we have done quite a bit of trip together. Being a person who is interested in getting into defense services, one can expect a lot of maturity and determination from Sriki, and he is no exception in this regard. That makes me get along with him quite well, as I can be straight (and at times brutally so) with him and he sees the point being made than my way of expression. All these qualities and his passion for riding made him an obvious choice for such a ride.

Currently, bullets (especially older CI bulls) rule my fancy. So the riders are in touch with ride RE bikes. But honestly speaking there are now more bullet owners in my vicinity than any other bike owners, but the irony is, still it is rare enough to come across true riders/travelers who are larger than the brand of their bikes. It's actually not RE (the company) that inspired the motorcycling fraternity in India, it's those people who chose to use an RE motorcycle for their travel and adventures, are the ones who inspired the next generation of riders (myself included). Hats off to them, and we feel proud as we carry the baton.

Now considering Sriki and myself, it's just two of us. One of my original choices was my best bud Abhi, who got married last year and I don't think it's a good idea to put him through learning a motorcycle (yes he doesn't ride daily until last year) and riding to Leh at this point. Initially, I was only looking forward to a crew size of 3-4 so that I can manage the group and do the necessary shooting for the documentary. But slowly few good friends wished to join in and now we stand at a group size of 6 and I don't wish for it to grow beyond this (though there is still a pending request from another candidate who is a colleague of one of our riders).

I have the experience of blogging (and not completing it!? Goa trip:P ) for a few of my earlier rides. Taking those into consideration today I thought let me just get down into writing about the experience of conceptualizing, planning, and causing this ride. For me to go through sometime down the line as well as fellow bikers to plan theirs. Hence this post. Going forward I will (try and) write posts more frequently, sharing as we prepare ourselves in terms of bikes, equipment, accessories, and any other preparations. Also may use certain hashtags/labels to categorize them for easy reference.

On my bike, there is quite a bit of thing to be done. Currently am planning my budget for the most important/necessary fixes/mods. As I have other financial commitments, it's going to take a lot for me to save for this ride. But nobody ever said it was going to be easy, all I know is it's going to be awesome!!

Until my next post, keep riding and stay safe.

Cheers!!

Sid