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Slash five engine performance parts sources

Posted: Mon Oct 04, 2010 4:15 pm
by Frog
Well, after 114,000 miles of great motoring (40k mine), my dear 1973 R75/5 is ready for some top end attention.

I pulled it apart and look it over closely with Bob Grauer.

We determined that it needs the heads rebuilt, first over pistons and a cylinder bore. I also will replace my lifters, as a couple are showing some pitting. So that is my basic investment.

But, I cannot help but think about opportunity to do a little more while I am in there. I am not a purist about keeping everything stock. I also love riding this bike. I tend to ride it on the more spirited side. I was recently getting killed on the long uphill runs, by other R75/5’s.

Bob and I started talking about making some modifications. As I understand, you touch one part and you need to do others as well.

Here are the things that we discussed:

1. 336 cam-It sounds like a nice performance upgrade, especially when combined with a higher compression set up. My understanding is that this combination will retain the bottom end torque.
2. High compression pistons-Maybe go up to 800cc
3. Dual plug-sounds like a must for our current fuel options and a high compression motor
4. 36mm Mikuni round slides

I am running an epco stainless exhaust.

I am studying the option of staying stock, versus this path. Do you have any thoughts?

More importantly, do you know a source for these items?

Thanks in advance.

On another note, I will be installing case savers soon. I will document and post back.

Re: Slash five engine performance parts sources

Posted: Mon Oct 04, 2010 4:23 pm
by Garnet
If your thinkin of going 800cc check out the 50110 pistons at the bottom of this page: http://www.motobins.co.uk/displayfinal. ... le=PISTONS

The price is right.

Re: Slash five engine performance parts sources

Posted: Mon Oct 04, 2010 4:32 pm
by Garnet
"4. 36mm Mikuni round slides"

Might be a bit too much. I have little fact to go on, but generaly the closer you stay to stock carb size, the more tracatble your outcome. And round slide 34s are all over fleabay. I have a set of 32s and cables that I haven't had the time to sort yet. Going up to a cammy 800 I doubt if the 32s will do you.

Re: Slash five engine performance parts sources

Posted: Mon Oct 04, 2010 5:50 pm
by Frog
Garnet wrote:"4. 36mm Mikuni round slides"

Might be a bit too much. I have little fact to go on, but generaly the closer you stay to stock carb size, the more tracatble your outcome. And round slide 34s are all over fleabay. I have a set of 32s and cables that I haven't had the time to sort yet. Going up to a cammy 800 I doubt if the 32s will do you.
Thanks Garnet. I do have to do some homework on the size of the carbs. 34's might be the ticket if available.

Re: Slash five engine performance parts sources

Posted: Mon Oct 04, 2010 7:26 pm
by gspd
Frog wrote: We determined that it needs the heads rebuilt, first over pistons and a cylinder bore. I also will replace my lifters, as a couple are showing some pitting. So that is my basic investment.
That's all I would do to it if it was mine.
At least it'll then keep up to the other 75/5's
How's the timing chain?

If you really want it to honk, get a used 1000cc engine from a wreck, don't waste your time souping up a 750.

Re: Slash five engine performance parts sources

Posted: Mon Oct 04, 2010 7:33 pm
by Garnet

Re: Slash five engine performance parts sources

Posted: Mon Oct 04, 2010 9:59 pm
by Max Headroom
I'm grafting a late model R80 top end onto our R75/5 toaster. Nikasil barrels, late rockers, conrods, pushrods, the lot. I've already machined the barrel spigots to clear the crankcase.

The aim is for smooth quiet running, and reliability. Performance is already adequate.

Re: Slash five engine performance parts sources

Posted: Tue Oct 05, 2010 12:42 pm
by Garnet
I LOVE spending someone else's money.

http://www.bmwbayer.de/index.php?page=product&info=54

Bolt on 64 HP.

Edit: click on the little English flag on the right.