QuestionFirst off you've answered questions of mine before and done it real well - and free - so thanks, a lot. Now, I picked up a 98 VMax with 20,000 miles in absolutely showroom condition about two weeks ago. She started up fine, didn't drip any oil and ran perfect on a test ride. On the two-hundred mile ride home, though, I noticed a problem - when the temp gauge is over the halfway mark she'll die at idle, and you know how VMaxes heat up in traffic. I took her in to the shop and my mechanic found that the airbox was full of oil so he cleaned her out, changed her oil, and synched up the carbs. It's a little less of a problem now, but in traffic and heat she will still die eventually, after maybe a minute. The fan comes on fine but I'm thinking of picking up one of those low temp fan switches and some Water Wetter for the radiator. Also, I got a pair of Supertrapp Megaphones with the deal, which had previously been on the now-stock bike. Maybe the bike's still tuned to the old pipes? She hasn't been jetted, I know that. So what do you think? Does it sound like the carb and if so, what am I looking at? Thanks in advance, and I look forward to your reply. Keep up the great work.
AnswerHi Tony,
Welcome back, Sir. Thanks for the compliments.
As always, I return tech files by email. You'll have to reply to this with an email address as requested to receive the tech files.
I suspect the carburetors will require tuning to correct air-fuel mixtures.
I suspect the engine overheating problem is related to air in the cooling system.
Cooling systems are designed to be air-free. Air in the system lowers the boiling temperature of coolant. Improper ratio of coolant also lowers the boiling temperature.
Use a tool such as MityVac's AirEvac tool anytime the cooling system is opened to air (with the exception of simply removing the radiator cap for visual inspection).
I'll send carb tuning tech files to your email addy. You'll have to figure if the carbs need tweaked or not by reading the appearance of the spark plugs. I'll include tech files on reading plugs, too.
The first thing is to check cylinder compression. This will determione the condition of the engine (sealing properties of the combustion chambers). Follow with a leak-down if compression is not within service limits as outlined in the service manual.
Next, check and adjust valve clearances. I cannot remember if V-Max and Venture valves are self adjusting or not. Duh! In any case, compression and valve clearances must be within specs for carbs to function properly.
After the above has been performed, purge the cooling system of air. I think this step will fix the problems you're experiencing. This step requires acquiring the purge tool ($90), draining the system, and then re-filling the system.
Respectfully,
Mark Shively
