Rocket Sprocket Review

[Soliton]

I did an installation of Lennie's Rocket Sprockets on my bike last night and for anyone considering it here is a mini-review.

First up I had better give you an idea of how I use the bike. It is an everyday ride. Rain hail or shine it takes me to work. I live in Canberra so the roads are 80-100 km/h all the way with the occasional roundabout and 4 sets of lights over a 25km distance. That being said, slow downs do occur on a couple of sections. On the weekends the same bike goes spinning out in the country and that includes dirt roads. So it is an all rounder. I am happy to give the bike some stick on the open road but around town I ride like your nanna (but at, or just above the speed limit). My preference is for the engines torque curve to sit in the low to medium rev band.

The Installation
If you aren't good with a wrench don't do it. The instructions that come with the sprockets are "minimalist" and even the better guides, that have been written by folk who have done the job, miss at least one of the pitfalls (that said, thank you all very much for your instructions they were still brilliantly helpful). I had a car mechanic and a BMW Master motorcycle mechanic with me and we still hit a snag. I had the engine stripped down (valve covers off, timing chain sprockets off and left hand throttle body removed) when the guys arrived at 17:30. The job was done (finished tested and mostly cleaned up) with about a 45 min dinner break by 21:30. 4 hrs. If I had been on my own there would have been blood and tears.

Issues during installation.

Cam chain tensioners.
On the right hand side although it is easy to undo it wouldn't come out. On my bike at least the header pipe prevents it from going fully free. We did the job without taking it out, just loosening it.
On the left hand side the throttle body must be disconnected and getting out the tensioner is a bit of a bugger. A bigger and more comprehensive tool set might have helped but in the end a 16mm ring spanner upside down did the job.

Getting the old sprockets off the chain.
Harder than you think and make sure you have a magnetic probe. We did drop the sprocket into the engine and ended up getting it back with a bent coat hanger.

Getting the new sprocket onto the chain
Getting the new sprocket onto the chain is fiddly and getting it on in the right position is more fiddly. The solution seemed to be to get it on, and then "walk" the chain around the sprocket to get the timing marks to line up with the marks we put on the chain that indicated where the old sprocket had engaged.

Getting the sprocket pin to engage the cam.
The lobes of the cam can make the cam rotate slightly when it it is not engaged with the sprocket. For some reason this seemed to be a particular issue on the left hand side. We screwed the new sprockets loosely in place without the retaining washer and when it was correctly seated undid the bolt and put on the washer.

Left hand side issues
The timing marks on the sprocket were correctly lined up with the paint marks on the chain but rotating the rear wheel showed that the timing was now "off". It would get to a point and lock and the arrows on the chain would not come to the correct (perpendicular with the ground) position. The guy in the crew who "had a BMW clue" suggested that on the left hand side because of the tensioner arrangement it is possible to misalign the chain at the bottom of the engine when the chain is loose meaning that when the sprocket is re-installed at the top it will look rich but be one or two teeth out. Once again we walked the chain around the sprocket and this fixed the issue. The big lesson here is make sure everything works by just rotating the rear wheel before any electricity is applied anywhere.

Performance differences.
The obvious difference is the much greater feeling of confidence and surety at low revs. The engine just pulls away and feels very snappy. I tried letting the clutch out gently with no throttle (idle only) and was able to pull away from a standing position. I don't advise doing that as a matter of course it was more of a test. In the 0-50km/h area (low speed city traffic) the bike is far more tractable and would sit all day at 40km/h at 2000rpm. The advantage here is that throttle changes at this point deliver a far more "gentle" power and don't jerk the bike around when riding at lower speeds.
At 3000rpm the bike will now do anything. Roll on the throttle and you are off. The sprockets have transformed the bike as far as city riding goes and haven't had any negative effect on the type of country riding that I do.
The feeling is that between idle and about 5000 rpm the bike has become a bit like a turbo-charged tractor/rocket combo. Tons of low down grunt and when you hit 4000 rpm it really sings. i wouldn't feel any need to push it must past 5000 except occasionally to keep it free of carbonisation.

Economy changes.
I haven't had the chance to fully test any economy changes. It will need a couple of tanks of fuel to give an accurate measurement but the bike is much happier at lower revs and this means that lower gear riding is an absolute possibility. This should have a positive effect on the economy.

Pre-ignition ?
Sometimes advancing the timing can pre-dispose the engine to pre-ignition. Using either 91 octane with 10 ethanol or 95 octane I have not seen any symptoms of this issue. ( I did recently water torture the engine and was definitely seeing it prior to that treatment.)

Would I recommend it?
If you use your bike as an all rounder and like tons of tractable torque in the low to medium rev range....ABSOLUTELY. If you are sports rider who wants the power deliver in the medium to high range and regularly push the engine in the 5500 - 7500 rpm range I would think about it.

Thanks to Adrian and John who did way more than help. Without their assistance it would never have happened in one evening.

Soliton

[lennie]

soliton,

I read your email and I can only say that you need to complete one side at a time.

I have a friend coming over next week and I will have them help me update the instructions done by pheonixtexoma fromt he Pelican board.

From all the feeback in the past, there has only been one set that I know of removed and that was shreddr on Pelican par as he was purely after all the top end power he could get. I still think that was probably not right.

I had cams and a lot of other work done to my R1100S and I still advanced the cam timing the 9 degrees to improve the part throttle response.

I am glad you have the ear to ear grion that I set out to achieve when developing the sprockets.

Regards,

Lennie

[Soliton]

OK, I have taken the bike out for decent run and this is now officially my "best value for money" mod EVER.

I was worried that the bike might be grumpy after changing something like this but it is the exact opposite. It is a ton more energetic from idle to 6000 rpm and above that I can't notice any difference.

It's odd to think that technically by moving the torque curve back I have "reduced" the power (peak torque x revs) because in real world riding the exact opposite is what comes through the bars.

[lennie]

Soliton,

How is the bike now that you have had a lot of time to get used to the rocket sprockets?

Can you give more of a long term report?

[ROXTR]

Hey Lennie, I'll throw my 2 cents worth in. I put your sprockets in a few months ago along with your InDuct. The install took a few hours, maybe 2 hours on the left side and 30 mins on the right side (learning curve). But I won't be taking these things out anytime soon . Granted I've got quite a few mods on my bike, full exhaust, Induct with a UNI foam filter and RS/RT tubes, Dobeck GEN3 fuel controller, IICE Air, and Brisk plugs. But the bike hauls ass . The power is linear all the way through redline (the RS/RT ducts actually helped a lot with that). Your sprockets gave me the throttle response and punch that I wanted. The front wheel doesn't like staying on the ground in 1st and 2nd gear. Definitely worth the money.

[Soliton]

OK,

It's been about 6 months. This is my everyday ride (to and from work 30km) and my scratcher on the weekend.

Fuel economy - No adverse change. (I run 95 or 98 if I can't get it but it seems quite content with 91+10% ethanol)
Power and response - Continues to be right in the spot where I actually use it.

Had I known how well they worked they would have been my first mod. They are truly set and forget and for the vast majority (99.99%) of us who ride between 60 and 160km/h they put the power output exactly where it should have been in the first place. These bikes aren't crotch rockets and i don't know about the rest of the world (Germany autobahns excluded) but I don't have much cause or any safe places to frequently exceed 140km/h.

Currently the bike has an InDuct / K&N and a full open exhaust, and I am thinking of putting a BBPower chip into the Motronic. I doubt the exhaust help the power at all but it sounds magnificent (thanks Neptune.) Like all wobblies it sounded a bit like a sewing machine having unnatural congress with a vacuum cleaner when I got it but now folk can't tell if its a Ducati or a Guzzi.

Long story short...

A couple of hundred bucks and it is a far sweeter and more ridable motorcycle with no down side. For anyone except a boxer cup race type person I would unreservedly recommend them. (You can send me $500 via postal order or paypal)

For anyone who didn't realise it the last sentence is a joke.

I'm newish to this bike (30,00km) but the things I would suggest for any new owner:
1 - A good tune and de-coking ( I water tortured my bike and it worked like a charm)
2 - Snip the stupidly tight cable ties under the yolk.
3 - Check the state of your right hand side throttle body and if it needs it, fix it before the bushing get worn out.
4 - Decent shocks (Wilbers/Ohlins/HyperPro)
5 - Rocket Sprockets
6 - Y-Pipe and a good exhaust. (as an Aussie I should be touting Staintune but I think Neptune from NZ sound waaaay better.)
7 - Some mechanism for modifying your fuel mix. (Chip, Power Commander, Techlusion.)
8 - Replace the tell tales in the dash with LEDs, they are much brighter and it is a cheap and easy job.

If I could find someone in Oz who could do dynamic balancing and perhaps a mild port and polish I might think about that as well. (I will say without reservation that I am an inveterate tinkerer but these are the things that help to make the bike shine especially if it it is getting on a bit.)

I hope this covers it.

Sol

[lennie]

Soliton,

My brother sah a R1150R and after breaking a cam chain tensioner he had it lightened and bnalanced in Brisbane. A mate of mine there cleaned up the ports and it made the bike a whole lot better.

He added new rings, a couple of valves with gaskets and all other items needed for the rebuild.

He alread had the InDuct, Rocket Sprockets, a slip on and an UltiMap chip I sourced him. He also added a cat eliminator that topped it all off.

Once run in he was totally happy with the ride. I had my fist ride after 3 years when I was on the Sunshine coast last December.

If you email me I will find out who did the balancing for you.

[Soliton]

All,

Lennie got back to me and said the following chap can balance a BMW!

Brisbane Engine Balancing Pty Ltd

07 3823 1305

Unit 3 / 83 Redland Bay Road
Capalaba QLD
4157

[lennie]

Hi all. I still have sets of sprockets available for sale so contact me if you want to make your BMW big twin a lot more fun to ride.