Pistons and crank balancing

I concur with Lothar..the chokes on my Dells were very generous and once the engine fired up. get that choke OFF.  Dropping the choke jets for #60 from #70 made a significant improvement in cold starting and manageable enrichment.

I still get off that choke almost immediately when the engine is running. #60 choke jets eliminated any plug problems too.

And Clem if some used Laverda HC pistons have value to you..you can have a set of first oversize 75.4mm HC pistons. No charge.  Top ring lands are fractionally out of spec. Skirts and piston pins are fine. Just let me know.

I just swapped out those 1975 HC pistons for some Ross 77mm HC slugs. Very nice results. I had to use a very thin home-made cylinder base gasket to get the piston squish right. Engine pulls like a freight train with Axtells, a flow-ported head with Wolfgang's big bore downpipes and a beautiful big bore collector.

Laverda-big-bore-collector21fee8adb596c13c.md.jpg
 
thanks for the offer but I doubt that I would ever use pistons that had been "previously" owned and everything I do is with 80mm bores.
but thanks its a generous offer, the likes of which I get quite often!
CLEM
 
Rusty Spokes said:
I concur with Lothar..the chokes on my Dells were very generous and once the engine fired up. get that choke OFF.  Dropping the choke jets for #60 from #70 made a significant improvement in cold starting and manageable enrichment.

I still get off that choke almost immediately when the engine is running. #60 choke jets eliminated any plug problems too.

....


.... and a beautiful big bore collector.
Click to expand...

Standard jetting might be on the rich side; to much choke makes it to rich and just "piss" out the spark on your cylinders (especially, if the float level is also to high and/or other components are worn out like needle jet/needle...). The fact that matters is: to rich on starting = you will have issues with one or more plugs. So - on an originally set up carb-system that works fine else, I would not pull choke completely. On my bikes, it is mostly enough to have it opened 2/3.

Regarding the collector: take a look into the collector and check how they are made inside. I had a similar one from Keihan and it caused the engine to stop reving beyond 6250 revs. Changing it to a 3-2 (instead of 3-1-2) setup improved the situation and gained/freed up the missing 15HP at Top-End...
 
The Keihan one is not similar at all.
I have one of these (from Wolfgang) on my bike, work of art.
The transition stages are tapered very nicely compared to a Keihan, and the system I have revs as high as I want it to.
 
Collectors...

Whichever you end up with, the most important thing is to get your G-Spot finger working and check the insides. I've not seen a single one that didn't need internal dressing. Badly cut (or over long) raw pipe edges facing gas flow, nasty globs of weld, etc.  Easy horsepower liberation.
 
Laverdalothar said:
Changing it to a 3-2 (instead of 3-1-2) setup improved the situation and gained/freed up the missing 15HP at Top-End...
Click to expand...

What does a 3-2 look like?  Does it go straight from the headers into the 2x splitter?
 
Paul H said:
Collectors...

Whichever you end up with, the most important thing is to get your G-Spot finger working and check the insides. I've not seen a single one that didn't need internal dressing. Badly cut (or over long) raw pipe edges facing gas flow, nasty globs of weld, etc.  Easy horsepower liberation.
Click to expand...

absolutely correct, exactly my findings on the Keihan one... it looks similar as the one above but is just stupidely made...
 
Piranha Brother 2 said:
What does a 3-2 look like?  Does it go straight from the headers into the 2x splitter?
Click to expand...

almost yes. I posted a pic of it several times here I think, I'll try to find it and will repost

Here you go:

Jota-Sammler01.JPG
 
in my book that is still a 3-1-2
its just that the common part (1) is not the extended and flattened 50mm pipe that we are familiar with, your one still has a "mixing" chamber at the end of the three front pipe headers, which then has two much longer single pipes (chamber release) leading to whatever cans you fit, I have seen it before, I admire your work.

What I had a few years ago was exactly the opposite, my collector was big enough (width wise) to cover all three header pipes, it was in fact made from a split tube which formed the left and right edges of the collector with approx. 80mm of flat sheet on the top and bottom, the front then being arranged to take the three stock pipes and the rear likewise to take the two stock cans. This proved very successful horsepower and torque wise, especially in mid range but totally slaughtered the fuel economy, not as in a little bit , but as in GONE BIG TIME, it was cheaper to run my V8 Range Rover!
CLEM
 
You must log in or register to reply here.
Back
Top