ZRX1200 Carb Conversion

[IanDMacDonald]

I ended up pulling the head and ran a bead of Permatex The Right Stuff on the underside and on top of the head gasket. I DID find that the top banjo bolt for the oil supply line was loose and likely the source of the oil leak, but I was not willing to take a chance.

Head is back on, and I'll finish up tonight after class to see if the oil leak is fixed.

Pulling the plugs, I saw that 3 of the 4 were very lean (white plugs). I'll try a 3/4 turn out on the idle mixture screws to see if that'll enrichen them.

[IanDMacDonald]

Welp, I dusted it with AP flour and got it hot. It seems to be from the back of the head, near the rear head bolt. The bolt is tight, so I know it's not that. Odds are, I'll need to pull the head.

Should I pursue a leakdown test to confirm it's the head gasket? I can spray the cylinder head with soapy water? But, i presume doing this on a cold engine may not reveal itself?

[Radioguylogs]

Yes, sir. I found the post. V-Star 650. Nice guess!

It's in your footer/signature.

[IanDMacDonald]

I'm going to clean it off real quick, dust it with flour, and take it around and see if I can find the leak.

[IanDMacDonald]

Perhaps a V-Star 650?

Yes, sir. I found the post. V-Star 650. Nice guess!

[Radioguylogs]

It's not a V-Max tensioner, but some other older Yamaha model. I saw one of my older posts where I mentioned it. I have the ACCT area RTV'd to death, so I don't think it's from there. I really do think it's from the head gasket. It infurtiates me, as I thought I was done.

Perhaps a V-Star 650?

[Bonz]

The fact it's running like a champ is awesome. That's a blessing to count.

Years ago I put a new head on the ZRX 1200. I forgot the dowel pins connecting the head to the block. Tightened everything down, but I could see something wasn't right. That head wanted to Slither around too much when I was tightening down the bolts. Yeah, that was a night of frustration yet satisfaction when I did it right lol.

[IanDMacDonald]

What are you running for a cam chain tensioner? I’m running one from a 550 Vision. I had to slot the top mount hole for it to fit. It created an opening into the engine and it leaked. It took a very long time for me to figure that out. I thought it might be the head gasket.

It's not a V-Max tensioner, but some other older Yamaha model. I saw one of my older posts where I mentioned it. I have the ACCT area RTV'd to death, so I don't think it's from there. I really do think it's from the head gasket. It infurtiates me, as I thought I was done.

[jetmechmarty]

What are you running for a cam chain tensioner? I’m running one from a 550 Vision. I had to slot the top mount hole for it to fit. It created an opening into the engine and it leaked. It took a very long time for me to figure that out. I thought it might be the head gasket.

[IanDMacDonald]

Got it running like a champ. Put it all back together (airbox brackets completed). However, I cannot get ahead of a bad oil leak. I cannot ascertain where it's coming from, other than the head gasket. I may need to pull it all back apart and use some sealant between the head gasket and the head.

[IanDMacDonald]

Got the ZRX carbs back on. Runs like a raped ape. So, maybe I'll leave it alone.

I have an oil leak from somewhere, so I ran a bead along the front where the cylinders meet the head, along with the ACCT area. I retorqued the head again to 30 Ft. Lbs., thinking it needs more torque.

Next up is pulling the clutch basket again, and swapping one from the parts bike. Then, fabbing new brackets to mount the airbox.

[IanDMacDonald]

Update is in the post below.

[Bonz]

If it pulls good at higher rpm, and doesn't bog down or lay down, the mains are good.

[IanDMacDonald]

Looking forward to the second round with the Keihin 36mm carbs.

Yessir. Pulling the Mikuni's off tomorrow, and reinstalling the Keihins. I'm contemplating ordering larger mains.

[Bonz]

Looking forward to the second round with the Keihin 36mm carbs.