R1100SS High Compression Engine

cliff j randall · 11-21-2001, 05:12 PM

Hi folks........We are almost done re-building my SS utilizing the High Compression pistons from SanJose BMW and Lennie's 6 degree advance cam sprockets. Here is something interesting that we found; the cylinder volumes were not the same, close, but never the less, not equal. One cylinder was 1 cc larger than the other, so we milled the head down to make it equal, approximately 4/1000 then removed another 4/1000 from both heads for a little more compression. The trick here is not to go to far or you can get into trouble with the cam chain tightener not able to take up the new slack, and or detonation on a large, big twin combustion chamber.
John Parker of Budd's BMW in Oakville Ontario Canada is doing the engine work for me. John is a master mechanic, a perfectionist with engines, a champion flattracker on weekends and a great guy! John has his own machine shop at home where he has worked the 1100 heads over big time, he found many areas in need of improvement. John also balanced the HC pistons by polishing away weight to match them up. This makes a world of difference when the motor is on the boil. I will be attending the shop, just as soon as Lennie's sprockets arrive, and will take digital pics of the new motor, before assembly, so you all can see the work.
I expect to see 105-110 rwhp and 80ft/lbs of torque when we hit the dyno in the spring. It's winter here in Canada.
Cheers,
Cliff

lennie · 11-21-2001, 08:59 PM

Cliff,

Posted the sprockets today via EMS. Should be there in 2 to 4 working days.

Regards,

Lennie

Addie · 11-21-2001, 09:05 PM

Cliff,

Your post is once again a sign of how interestingly closeknit the worldwide biking community is. You're upgrading your S using parts and technology from different parts of the world. What's a ball park cost for this project? I am really interested as I am not too far from San Jose BMW and I've heard that Lennie was coming out with these cam sprockets. Sounds like the next step for my bike, too. Thanks for sharing the info.

cliff j randall · 11-22-2001, 03:33 AM

The cost of the motor work complete, will be approximately 2,500.00 Can or 1,600 US.
The total cost of my R1100SS project is now 35,000.00 Can, or 22,000.00 US.
Cheers,
Cliff

roger albert · 11-22-2001, 05:30 AM

Hey Cliff,

you're a braver man than I. Everytime I start adding project costs up, I get frightened or depressed.

I wanted to clarify one thing. You mentioned the cylinders being off 1cc. You did mean the cylinder volumes, not the head volumes, right?

You also mentioned milling the head on one side (presumeably the higher volume side)
Did you mean the head was milled, or was the cylinder milled to match the cylinder volumes?

Just trying to understand the procedure.
Thanks for any add'l feedback

regards
roger

cliff j randall · 11-22-2001, 08:10 AM

Hi Roger........The cc difference was in the heads. So we milled the bigger one 4/1000's to match, then milled them both another 4/1000's to grab a little more compression. I suspect we will have approx. 12.5 to 1 on the motor when built. This will produce the added torque, in conjunction with the HC pistons.
We did a deck height measurement of both barrels, with the stock pistons in place and with each piston set at TDC. Both were equal.
Cheers,
Cliff

JeffD · 11-22-2001, 09:06 AM

Too much pressure she's gonna blow! Just kidding hope it holds together but I recall reading when the S first was being developed there was trouble with the higher compression but I can't rember the specifics.

cliff j randall · 11-22-2001, 09:20 AM

"Scotty this is the bridge, more power. But captain, she won't take it I tell you"........Turn it up baby, I want 110hp and 80ft/lbs of torque and I want it now!
Don't worry gang, the SS can hold it, Me, my team of John Parker at Budd's BMW in Oakville Ontario and Chris Hodgson of San Hose BMW are all confident of that.
I hope they have the airstrip open next summer at the big rally in Trenton Ontario. I would love to wind this baby up for all to see and hear........Trust me, you'll weep openly at the sound of this motor on the boil.
Cheers,
Cliff

Rapt · 11-22-2001, 09:40 AM

I dunno about having the airstrip open, but I look forward to hearing her run...

cliff j randall · 11-22-2001, 10:12 AM

Open the strip for 15 minutes Rapt.......Call it a special guest appearance!
Let's have some fun.
Cheers,
Cliff

jclark · jclark's Garage

>....Trust me, you'll weep openly at the sound of this motor on the boil.
>Cheers,
>Cliff

Ooooooooo....
Get it recorded w/ first firing it up!

jeff
also thinking about 110(ish) horsies.....

Rapt · 11-22-2001, 11:38 AM

Well except for a couple of "military" fields most all the runways locally are grass... I doubt you'd want to try a top speed run there...

However.... I may know of a private and secret location where a run MIGHT be possible. I have to scope it out and see.

cliff j randall · 11-22-2001, 01:38 PM

God dame it, I'll do it!.......I'll get all drunked up, strip naked and ride the SS, full blast, thru the town of Trenton on Saturday night! Let the bastards try and catch me.
Cheers,
Cliff

brad black · 11-23-2001, 01:26 AM

just gotta love the nude pissed idiot on a motorbike routine.

brad

cliff j randall · 12-10-2001, 12:50 PM

Hi guys......Dropped by Budd's BMW today and photo'd the finished headwork anf high compression pistons etc. I'd love to print the pics but I don't know how. If anyone can help I will galdly send them to you for posting. cliff@randallsearch.com
Cheers,
Cliff

Rapt · 12-10-2001, 01:01 PM

Cliff you can email them to me. IF you haven't got my email address someplace just send me a quick note via the profile mailer and I'll reply in the next hour or so. Then you'll have it.

I'm presuming you mean making the images so they can be posted here.

Photography and digital imaging is something I do as a sideline (kinda like Roger's motorcycle mechanics bizz).

cliff j randall · 12-10-2001, 04:16 PM

Hi guys........James Horne kindly agreed to post the pics, I'm assuming they will arrive shortly.
Here is what we did. Regarding the stock head, a substantial amount of smoothing was completed to attempt to move the intake port deleivery over to match the exhaust port exit. In stock form the valves don't match up. The stock head has a metal rise around the valves, I don't know why, John removed it. The valve seats were re-cut with 5 angle cut, as opposed to 2, which is stock. This is important to make sure that all the compression you build, stays until you require the exit.
The intake and exhaust ports were cleaned of all stock casting irregularities or flashings.
The high compression pistons were milled to remove any unnecessary bits and matched to weigh. They were the coated with a special silicon on the sides for slip and a heat coating on top. Apparently the heat coating helps direct the heat up, not into the aluminum piston.
As I mentioned earlier, the heads were matched for volume because they were off by 1cc. We also removed 4/1000's of an inch to bump the compression a little more.
Well was it worth it? Don't know actually. I get the bike back next week and if this unseasonably warm weather holds here in Toronto, I'll go for a ride and let you know.
Fundamentally the process was done to increase the compression which in turn will provide more torque and resultant hp. How much, I don't know, however I am looking for 105 hp and 75-80ft'lbs of torque.
Cheers,
Cliff

RC51DRAG · 12-10-2001, 05:22 PM

Hello I'm new to the board and it's refreshing to see another gearhead that loves to tinker with their toys. I would be very interested in seeing and hearing your bike next summer. When exactly is this rally in Trenton and is that Ontario or Michigan? Also what kind of rally is it. As you see from my signature I have a RC51 and have done similar mods to mine as well. My next bike will be a R1100S since this was the only other bike I was interested in and would be a fine stable mate for my RC. What I do find interesting is how you will yield more torque than mine. I'm not doubting it simply because while mine is a v twin and does have a lot of torque as a consequences of this configuration it still has the majority of it's hp in the top end. As a comparison i make 137.9 at the rear wheel @ 10,500 rpm while I have 78 foot pounds of torque from 7,500 to 9,500. I'm definitely interested in some of the modifications that you have done to the S. Is there another post where you have them all listed or better yet do you have a site where they are listed. I know sooner or later once I've acclimated to the S that tuning it will be my next goal.

cliff j randall · 12-10-2001, 05:46 PM

Very kind of you to write RC, I appreciate the courtesy. Trenton is in Ontario, near Shanonville race track. The mods to this bike are extensive. Why not send me a personal e-mail at cliff@randallsearch.com and I'll give you a breakdown and a pic of the SS.
Top of the season to you,
Cliff

Rapt · 12-10-2001, 06:41 PM

Well here thay are... Sharpened and resized.