Now it's engine time

[(RIP) Kaister]

The best way to 'pep' up older motors is to increase compression and improve gas flow.

Putting in a big bore has the same effect as upping the CR if the heads are kept the same - more volume squished into the same head space.

if the pistons and bores are ok - spend the money on headwork.
I would only go for a slightly bigger inlet - leave the ex valve alone.

port and polish, 3 angle valve cut.

If that all works then a longer duration cam, not higher lift would be step 2.
The valves on the airheads are known for falling off, so banging them down from a greater height won't help.

longer duration will mean the springs can stay the same too.

You could skim the flywheel too depending on wether you want a bit more get up and go or leave it if you like cruising

http://mailer.fsu.edu/~jroche/road_rod.html

 

[cookie]

i'd leave the engine standard. fettle the suspension and brakes then ride it harder.

 

[Shep]

Well that seemed to rattle a few sabres in the smoking room

It's a 1000 so i'm not sure where the idea it was a 800 came from, i did mention initially that any work would be mild in nature.

I'll not be going the twin plug route, past experience has led me to feel its a bit of a lottery, some work well but the majority realise very little difference in performance a half a horse here or there is not going to be noticed, the positioning of the extra plug is the problem it needs to be spot on, no point in just chucking a threaded hole in it in the easiest place in the area with the most meat that would be pointlessrolleyes

I'd only change the barrels if I had issues with the original bores

I'm certainly not going to lighten the flywheel, cos that won't get me what i want.

I feel a set of slide carbs might improve the feel of the bike, the CV carbs feel a little 'remote' IMO. But a pair of dellorto's would have to be cheap and also I could fit them at any time its not an advantage to have the engine stripped.

Shep

 

[England-Kev]

Well that seemed to rattle a few sabres in the smoking room

It's a 1000 so i'm not sure where the idea it was a 800 came from, i did mention initially that any work would be mild in nature.

I'll not be going the twin plug route, past experience has led me to feel its a bit of a lottery, some work well but the majority realise very little difference in performance a half a horse here or there is not going to be noticed, the positioning of the extra plug is the problem it needs to be spot on, no point in just chucking a threaded hole in it in the easiest place in the area with the most meat that would be pointlessrolleyes

I'd only change the barrels if I had issues with the original bores

I'm certainly not going to lighten the flywheel, cos that won't get me what i want.

I feel a set of slide carbs might improve the feel of the bike, the CV carbs feel a little 'remote' IMO. But a pair of dellorto's would have to be cheap and also I could fit them at any time its not an advantage to have the engine stripped.

Shep

So it would seem that you just need to improve the gas flow then, and then fit a Dyna coil conversion, the Dyna makes a huge improvement to the bike in standard form, and has been the single best thing I have done to my R80ST

 

[Shep]

So it would seem that you just need to improve the gas flow then, and then fit a Dyna coil conversion, the Dyna makes a huge improvement to the bike in standard form, and has been the single best thing I have done to my R80ST

Go on then what's a dyna coil, a souped up ignition coil set up? Where are they from?

Shep

 

[John Armstrong]

Go on then what's a dyna coil, a souped up ignition coil set up? Where are they from?

http://www.airheads.org/content/view/283/98/

But if yours is working why change it? Might be worthwhile fitting a new BM coil plus leads ....

 

[(RIP) Proff]

Go on then what's a dyna coil, a souped up ignition coil set up? Where are they from?

Shep

I think Robs got a couple spare Shep.
They DO make hell of a difference in reliability and are smaller than the original.
Look at Thunders thread and you'll see them on Artic Storm................

 

[Rob Farmer]

It's a 1000 so i'm not sure where the idea it was a 800 came from, i did mention initially that any work would be mild in nature.

It was the mention of the Siebenrock kit.

Just fit high comp pistons in yours if it's a 1000 and the early airbox. The standard airbox works very well on the 800 but restricts the 1000. You can pick the early airbox and starter motor cover up for around £20 for the pair.

 

[England-Kev]

I got mine from Motorrad Elektrik (sp) in the US, the kit is an easy fit....

Here is the kit as it arrived

I only live in Reading if you need to have a look..

 

[Roger Chatterton]

I bought my 100GS PD already fitted with coils as above, twin-plugged, Seibenrock kit, gas flowed, and with Mikuni carbs, plus a few other mods. Runs a treat, and very smooth, and pulls well too.

Interested in the earlier airbox idea -hadn't heard of that.

But, can highly recommend the twin plugging and higher comp pistons etc. I can't say it has made it a whole lot faster, as I don't know what it was like before the bike was modified , but it's fast enough for what I want.
All the work was done by Andrew Sexton, so happy that it was well done -also stiffened up the front forks and more.

 

[Rob Farmer]

Roger,

I spent a whole load of time and money on Dyno runs. We couldn't get enough air into the engine using the standard airbox. I fitted an early RS airbox and filter out of frustration and the problem simply went away. To bring the jetting into line I ended up with 170 main jets 2.68 needle jets and the needle on the top notch. Strangely the standard airbox worked perfectly on my old 80 g/s and the jetting was spot on all the way through the range.

Bam Bam spoke to HPN and they told him to make the standard air box 1cm higher under the filter to transform the breathing. Thats correct isn't it Cain?

There's clearly a volume issue on the engine side of the filter on the 1000cc engines with 40mm inlet ducts. Fitting the early airbox transformed my bike.