1991 Honda Nighthawk 750 giving smoke on the right exhaust also where to find...

N

Nico

New member
...a starter relay? I will be writing the question in detail so that someone is able to answer accordingly. I wanted to know a couple of things. I am thinking of buying this 1991 honda nighthawk 750 and went to seller's place to inspect it. It has 35,000 miles on it had not been cranked since august. The battery was dead so we jump started the bike. Seller had put a scorpion exhaust on the right side and the left one was stock exhaust. I noted that there was a combination of steam and smoke coming from the scorpion exhaust. When I asked the seller about it he told me that it is normal as the bike was being started after sometime. He told me that this happens on his 2002 CBR 900 too. He said that once the bike heats up it will be gone. I actually doubt it because it is not supposed to be like this. Although the smoke was not that heavy and it was only coming from the right exhuast, I feel that this is either due to weak valve seals in either or both of the two right cylinders or it may be because of weak rings on either or both of the cylinders.

Now when I inserted my finger in the right scorpion exhaust I could see the black carbon on my finger. This to me is the initial stage of weak rings. I know this much that I can check the spark plugs and find out if the plugs show any deposit or are black. Any suggestions by keeping this in mind that the left exhaust is stroke and never showed any signs of steam and smoke.

Also while cranking up the bike for the second time I unfortunatly flipped the polarity on the battery and it burned the starter relay on the bike. Can anyone tell me where to buy the realy and where can I spot it on the bike.

Lastly what would be a fair price on this bike with or without the problem mentioned and if I go for the certification will the smoke thing me addressed by the inspector.
 
The exhaust system should have a collector that joins the headers coming from the engine, then splits into 2 again for the exhausts. Having different exhausts on each side should make no difference to the running of the bike. When cold starting and the air is cold, my VTR also appears to "smoke" from 1 side more than the other though no one has ever been able to explain it. Once the bike has warmed up, it evens out. Maybe its just a Honda thing. If the bike had bad valve seals or rings, it would smoke continuously. See if you can do a compression test on the engine but I would bet that its ok

Unleaded fuel always leaves a black residue in exhausts. Quite possibly, you couldn't put your finger far enough down the standard exhaust to feel it.

The bigger issue I feel is "Why does he have only 1 aftermarket exhaust?" the obvious answer to me is that he has dropped the bike on that side and was too tight to buy 2 new cans. Check for damage elsewhere on the bike.

Sorry, can't help with the relay or the price
 
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