Shop Talk | Tech Questions & Answers

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Tire trouble

**I have a 2007 Yamaha V-Star 1300 Tourer with 21,000 miles on it. The first two rear tires I replaced with the OEM Bridgestone Exedra G722, with which I got a respectable 8000 miles of tread life. However, the last tire I had installed is ready for replacement after only 4000 miles. **

Since my riding style hasn’t changed (no rapid or hard acceleration nor skidding to a stop), how can there be such a difference? The service manager of the local Yamaha dealer said the tire may have been in a warehouse for a few years prior to installation on my motorcycle and this may cause premature wear. What are your thoughts?

Victor LaPrade
Dixmont, ME

_Although you didn’t specifically state that the tire in question was also a Bridgestone G722, I’m going to assume that it is. Unfortunately, without being able to examine the tire I can only speculate as to what may have happened. First I’d bet good money that the tires age had nothing to do with it. Tires tend to harden over time so even if the tire was older than dirt, it wouldn’t have cut its life span in half; if anything there would have been a marginal increase in mileage. However, inflation and load have a huge impact on tire life so if the bike was heavily loaded, for instance if you did a lot of two up touring after the new tire was installed, then the wear may be appropriate. _

_My other thought is that your tire gauge may be suspect; again without examining the tire, I can’t tell if under inflation was the culprit, but it might be worth checking your gauge just in case. Lastly, although it’s a long shot, you may have inadvertently had a tire with the wrong load range installed. I’m not sure what load ranges the G722 comes in, and the Bridgestone catalog wasn’t particularly revealing, but double check the tire load range. It’s stamped on the tire sidewall, and it should be at least a 71. Anything softer and the tire would be prone to premature wear. _

They all shrink in the cold

Question: Two different bikes with very different engines—both seeped coolant out of the engine while the bike sat unused in the garage, but it only happened after the bikes had more than 25k miles and only when the temperature got below 20 degrees Fahrenheit. Why? Do I need to get the head gaskets replaced? How much would that cost?

**A few years ago, I owned a 1985 Honda Shadow with a liquid-cooled 750 V-twin. I owned it for 5 years, from 8K miles to 29K miles. In the last two winters of ownership, I would find small amounts of coolant had come out of the engine between the cooling fins where the head gasket is. This would only show up after cold days when I wasn’t using the bike. When spring came around again, the leaking stopped and the bike ran just fine. **

**Now, I own a 2004 Royal Star Venture with a liquid cooled 1300 V-four. I’ve owned it for 3 years from 6K miles to 35K miles. Last winter, it seeped a few drops of coolant out of the base of the cylinder where the head gasket is, but only after very cold days sitting in the garage. No evidence of leaking during the spring, summer, or fall. Now, this winter, the seepage has increased to the point where there was a small puddle on the garage floor after days of single digit temperatures. When temperatures got above 25, I rode it again and didn’t see any coolant until the bike sat unused and the temperatures dropped below 20 again. **

I do general maintenance, but I’m not the kind of guy who would tear apart an engine.

Russ G.
Via email

_Are you sure the leak is coming from a gasket surface? When there’s a drastic temperature change it’s not uncommon for coolant hoses and fittings to leak. These are known appropriately enough as “cold leaks,” and typically go away as soon as the engine temp increases. This is one reason why traditional rubber hoses and worm drive clamps are being phased out by silicone hoses and heat shrink collars, so the first thing I’d do is double check all the radiator hoses as well as any sending unit that’s threaded into the block or head, and any gasketed or O-ring joint. If the leaks are definitely coming from the head gasket I’d retorque the head before going any further and see what happens. You can always replace the gasket if the situation worsens. _

I’d also recommend changing the coolant on a bi-annual basis to replenish any lost additives; degraded coolant can have a deleterious effect on gaskets, O-rings and aluminum blocks and I’d also recommend adjusting the protection level to at least 20 below, which will provide an extra margin of safety.

**To the point **

A friend of mine added a NOS kit to his Harley. Would my Vulcan 1500 be able to handle that without other modifications needing to be done?

Scott Daly
Via email

While the bike could certainly handle the installation of a Nitrous Oxide kit, I’m not sure what would happen the first time you pressed the button, but I’m sure it’d get your attention. My suggestion, should you decide to install “juice,” is to contact one of the many guys that offer such services and see what they recommend. My best guess is that at very least you’ll need to install some sort of fuel module and beef up the clutch.