New bike! Plus a question...

[LJTurtle]

Hey all,

After passing my MSF course a few weeks ago and doing some flip-flopping between bike choices, I found a 1991 Honda Nighthawk CB750 in the classifieds for $3200. The guy was the original owner and it only had 3700 miles on it! I rode the bike and it stuttered a lot, and there were pinging noises in the gas tank. I offered him $2500 on Thursday and he accepted! Against all my better judgement I rode it the 35 miles home expecting it to die at every intersection, but it made it home fine. The performance of the bike improved greatly (it had been sitting with gas in it for 10 years!), and after pumping out the remaining old gas and giving it some higher octane, it has been running like a champ. I've ridden it another 100 miles or so over the weekend with no stalling or other problems.

My question is, should I still take the bike in to the shop this week even though it seems to be doing fine? From the original state the bike was in, I was told by people on this forum that the bike would need carb work. I'd really like to save the money, but if I'm doing damage by running it I better do it now. Are there any additives that help clean carbs/old engines? Also, I have been riding on the original, 15 year old tires. They both have plenty of tread, but the front has quite a few cracks in the tread wells. The front looks like it needs to be replaced, but can I get by with the original rear tire for a little while? And finally, where should I get my tire(s) replaced? How long does it take a mechanic to replace tires, and how much does that cost?


P.S.: Does anyone use Marvel Mystery Oil in their bikes?



Thanks!



~LJ

[ZooTech]

For the love of God, replace the tires tomorrow!

As for the carbs, try running a few tanks of gas treated with SeaFoam through the engine and see how it does. The bike did a ton of sitting around which is pretty much a death sentence, but you may get lucky.

[Bachstrad37]

Hey, glad to hear you got the Nighthawk! I figured it was old gas.

As for cleaning the carbs, I wouldn't worry too much about it. Ordinary gasoline comes with some detergents already in it. Just concentrate on getting some miles into the bike so that the old stuff gets completely flushed out.

I would; however, worry about the tires. Get them replaced the first chance you get...both of them. Most shops I know will mount and balance your tire if you buy it from them. You can ask them to do a quick once over to see if anything obvious is out of whack. And if they do spot something, ask them how much it'd cost for them to repair it. Some people on this board is very good at assessing costs for all kinds of repair. Some are actually professional mechanics. I'd start up a post if you are curious.

Oh, and more thing - Do an oil change. Chances are, the previous owner didn't bother with the oil change. It's very easy and will give you a starting point on when you should plan for the next change.

[LJTurtle]

What do you mean by death sentence? The bike is running well now, is it going to have a catastrophic failure or something?




~LJ

[ZooTech]

What do you mean by death sentence? The bike is running well now, is it going to have a catastrophic failure or something?

I found a 1991Honda Nighthawk CB750...and it only had 3700miles on it!

What I mean is, 3700 miles is not something to be excited about. That's a BAD thing! I'd be happier if the bike had 37,000 miles on it, since at least then I'd know the owner used it, maintained it, and gave a crizzap about it. Sitting around with bad gas in it will dry up the engine seals and very well could lead to a catastrophic failure, such as a blown head gasket or costly transmission leak.

I'm not trying to be a wet blanket, I'm just bringing a little reality to the discussion. The bike needs to be looked over very well by a professional to make sure the brakes are functional (most likely need a fluid change) and everything else is up to snuff.

[Bachstrad37]

He's relating to your tires.

Bikes are extremely reliant on good tires. Unlike a car, bikes have only 2 tires. Bike tires flex and bend much more than a cars' tires because your bike depends on your leaning in order to steer.

Don't compromise on tires. Get the best you can afford. It's the only thing keeping your arse off the pavement.

[LJTurtle]

Thanks for the help bachstrad37. What's the name mean? A 37 member string ensemble playing Bach on Stradivarius instruments?

So if I buy the tires from a shop they will put them on for free? Cool. Maybe I can keep it under two bills then.

The oil was changed last fall and had less than 10 miles on the change when I bought the bike. Should I change to a synthetic in a few thousand miles when I change it, or just do what my manual says?










~LJ

[m1a1dvr]

Very nice bike. Congrats. And yes. Dont skimp on the tires.

[ZooTech]

Change the oil now. Oil doesn't like to sit around any more than tires do. If the seals are good and the engine is healthy, switching to synthetic would be a good idea.

[Bachstrad37]

You'll want to change the oil asap. Oil starts going bad once it goes into your crankcase. So with time, it just loses its protectant properties eventhough you aren't even running the bike.

As for your choice of regular dino oil or synthetic, it's entirely up to you. It's around $60 for synthetic while the dino stuff runs around $30 each oil change. There's all kinds of "debate" which is better, but it's really not a debate - synthetic is better. The question is really about how much you're willing to shell out for synthetic. However, the mineral (dino) oils are catching up with the prices of synthetics due to recent increase of oil. Myself, I'm switching to full synthetic on my next change. The KEY tho, is regular oil changes. Unless you have access to free oil analysis, stick with what the owner's manual recommendation on interval. I've got mine set for every 2,000 miles or 3 months. You can do it as earlier than what's recommended of course. Your wallet will hurt a bit more, but your bike will last nicely.

Thanks for the help bachstrad37. What's the name mean? A 37 member string ensemble playing Bach on Stradivarius instrument?

You've got the sport right (music), but you're in the wrong ball park. I'm an amateur musician. I play a Selmer Bach Stradivarius trumpet with a 37 weight bell. It's a pretty common model. The Harley of motorcycles if you will...