CR 390 exhaust port question

[vmxrider]

Husky expert help needed. Is it normal for the exhaust port to be eccentric to the exhaust flange recess.? With the flange fitted there's a step on one side where the spigot meets the port. Can't be good for gas flow. Pretty sure it's a '79 model with the thicker liner.
 

[Lozza]

Husky expert help needed. Is it normal for the exhaust port to be eccentric to the exhaust flange recess.? With the flange fitted there's a step on one side where the spigot meets the port.Can't be good for gas flow. 

Great for making HP though. Removing the step will remove HP. The No2 mistake in the amature tuners handbook. Great that Husqvarna was onto that one ages before Japan Inc.

Here is a quote fro the now world famous ESE tuner thread

Monday Jan 21
 With pipe properly mounted and an adaptor turned up to match the exhaust port in the barrel (25mm) to the pipe header (32mm) - a bit more hp (8.1hp I think) but the powerband was narrower and moved up the RPM range. Initially this adaptor had a sharp step in it from the smaller diameter up to the larger diameter.
 
This is where it got interesting. A suggestion was made to smooth out the step in the adaptor and try it again. Instinctively, this seemed likely to produce a positive result. In fact it wasn't. The result was worse in every respect. There was less peak power and the powerband was narrower!

[PEZBerq]

No its not normally as pronounced as your photo shows. Can't see it being much of an issue though.  There is also a step where the exhaust slips over the adaptor flange when the pipe is fitted.

The 390 has awesome power as you probably know anyway.  Unless you are Heikki Mikola it probably wouldn't make any difference.

BTW its the first time I have ever seen a cable guide off the forks fitted to the frame down tube for the clutch cable. Quite unnecessary unless your frame flexes a lot! Zip tie would be better I reckon.
 

[vmxrider]

The 390 has awesome power as you probably know anyway.  Unless you are Heikki Mikola it probably wouldn't make any difference.

BTW its the first time I have ever seen a cable guide off the forks fitted to the frame down tube for the clutch cable. Quite unnecessary unless your frame flexes a lot! Zip tie would be better I reckon.
 

More than enough power , and not about to do anything about the step, just a bit curious

Never really given the cable guide any thought, been there since I've owned the bike, does the job.