Finally its running right on PODS and nearly straight thru's

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

Gawd...at last...

After months of experimentation at the end of winter till where we are now..nearly start of summer, I finally have this thing set up right.

Basically anyone contemplating using POD filters or after market, or "none design to spec" exhaust systems, think LONG and HARD before you take this on.

y first order with XSshop. in Germany resulted in the supply of some EMGO POD Filters. Without the prior knowledge of how BAD this product is, I did everything I knew to do as an experience bike rebuilder to make the thing run right. Nothing worked.

Then after fixing this problem with some new decent POD's, I had a paint job and the ally from the metal flake ended up in my carbs PAST some less the adequate filters..and it was still in mystery land.

THEN...it became a apparent that my carbs on my 78SF were from a 77 model. And all the internals were completely mismatched.

So after fixing all these problems I ran one size over pilots and two sizes over mains. High Octane gas, and a slight timing advance. Still terrible. I played with advance retard, high octane, low octane, additives. Surely one size over pilots couldn't make it this bad...WRONG! :-). The pilot screws are effectively less than a half possibly less than a quarter size in total adjustment. The local dyno operator told me this, and believing him finally got me where I needed to go.

This weekend I lost my temper. And rebuilt the carbs to the exact spec of the standard bike including the pilots. I opened the mains up to 123. From an apparently rare setup of 112.5. I cleaned and replaced everything. 123 was the closest I could get at the time.

RG made a valid point about top quality very fine micron filters. Basically put you guys with bad tickover..YOU NEED THESE.

I had used all the 97 Ron fuel by this time and was again using 95.

Today I had the bike running so unbelievably well by going back to 100% standard, I thought I'd press my luck and set the timing back to standard. I took my strobe to the petrol station and with a few allen keys (boyer) I set up the timing to standard bang on and added the 97RON fuel at the same time. (I don't recommend changing more than one thing at once normally).

Put it this way, I rode down the road, and took a couple of junctions and about 2 miles down the road (when the high octane was in the carbs?) I opened the throttle and the bike ripped my arms out of the sockets and tore arse off down the road....(or as best an XS650 could do that Smile

)

The bike is crisp, fast, responsive..the way it should be.. At last.

Its worth noting that the dead cylinder method is a big help, but you need to keep at it and refine it down getting it close each time. You think you might have it right, but then you can hear one cylinder leading the next..keep at it.

When you have a non standard inlet and exhaust setup, you can get it running right. You MUST have back pressure in the exhaust system and you MUST get the jetting right. Always start from standard before you make assumptions like oversizes you dont need. Especially in the pilot circuit.

an ..serious this thing actually goes!

I just wanted to add that in my view xsjohn is right..but my view is that its standard setup is too hot in comp for standard octane fuel, you either lower the compression and adjust the valve timing, or run a higher octane fuel. My experience running highly tuned motors two and four stroke tells me that high octane fuels run cooler.

Running high octane gas in a standard XS motor defiantely reduces heat and vibration!

What Happened to 650rider.com?

Yamaha xs650