Confused by part number on discovered NOS exhaust collector

A buddy found a NOS Yamaha exhaust collector stamped 4G0-5. Would this happen to be for the 550 Maxim/Seca?

My part number cross-reference doesn't come up with anything that short (although the collector part number contains 4G0-xxx...-5 or something like that.

 

It sure will.

Model prefix 4G0 is the prefix for the original, home-market XJ400. A LOT of the parts on your Seca have 4G0 prefixes.

A quick check of the fiche shows the 550 Seca HEADpipes and collector as all having "4G0" part numbers, only the mufflers are 4U8's. http://www.yamahapartshouse.net/oempart ... 50rh-parts

The numbers stamped on the other exhaust components are like that; just the prefix-dash-a single digit. For instance your headpipes say 4G0-1, 4G0-2, etc. The collector is pipe #5.

Jump on it. <expletive deleted.>

 

Re: Confused by part number on discovered NOS exhaust collec

Thanks Fitz. I thought it might be.
This is actually part of that batch that I IM'd you about some time ago (asking for your help coming up with a list of spares to watch for). My buddy wasn't able to do much with my parts list, as the boxes and boxes of parts aren't well organized. I'm going to have to go with him myself to spend some time looking for specific parts I recognize, THEN compare the part numbers. I'll see what I can find.

 

Re: Confused by part number on discovered NOS exhaust collec

Okay, so my friend from work took me to this old, remote junkyard he found, where they've collected cars, motorcycles, snowmobiles, buses, etc., etc...

We were able to browse through all the dusty shelves "upstairs". It was one of those places so dark and dingy that the fluorescent lights only seem to glow about a foot below the fixture. Glad we had flashlights. Plenty of NOS Yamaha pistons... but none for the XJs. Basically, I just had to look through hundreds of shelves looking for something familiar to the XJ, then look for a part number to match the list I brought with me.

After all that, I ended up with the exhaust collector this thread is about (my buddy had hidden it under a shelf to save it for me), and also scored the no. 1 and no. 4 head pipes -- also NOS. One has the aluminum finned collar, one does not. All three items are not pristine, but they are unused and can be cleaned up well. Oh: I got all three items for $30!!! Woohoo!

So do you guys think I should ditch the 4-into-1 header I've had on my Seca since I've owned it (12 years or so) and look at finding the 2 and 3 headpipes, and use all this to go back to a 4-into-2 system? Will the seat-of-your-pants performance be that much better? I know that the 4-to-1 systems were touted to be lighter weight, thus "faster", but I haven't experienced the OEM setup.

 

I can tell you that the performance IMPROVEMENT when I got rid of the Kerker 4-1 that came on my '81 and went back to a full stock system was dramatic.

 

Re: Confused by part number on discovered NOS exhaust collec

I was afraid you were going to say that.

Now I'm going to have to start sniffing around Ebay more.