New here andbjust picked up a decent 01 600 off a fella i think needed to reup on his dope content. Anyways when you start the bike up it wants to rev up to 9k rpm's and just hang there. Im thinking there is a major vacuum leak. Engine doesnt smoke and has a slip on yoshi. He rode it to meet me and it seemed to run ok for him. Any advice on the problem would be appreciated
When you rev the engine does the exhaust smell rich? Like its not burning fuel? Sounds like it could be bad spark plugs. FYI it's easy to ride these bikes normally not going over 9k rpm so how do you know it was really okay to begin with? How many miles on bike and when was the last time they were changed? Probably well overdue.
Are bad plugs going to cause the bike to rev up to 9000 rpms and hold there steady? I only ask because with other mechanical things a vacuum leak can cause a high idle
As to yoir question of running rich i didnt really smell a rich smell of fuel. Also i know you can ride them without hitting the 9k rpm mark. It didnt do this when he was riding it so it must be just an at idle issue and not under a load issue.
You didn't tell me how many miles on the bike. Also how stock is the bike? Is there a custom air filter on the bike? It could be a vacuum leak, but it could be a lot of things. Is your gauge cluster acting funky? Like flickering or the needle acting whacky? If you have a custom filter I would check ur air box and the connections. Also i would check ur carbs/lines going around it start the bike and try and find air escaping with a little spritz of wd40 or water. The easiest thing to check is see if the bike is running on all cylinders. If u have a heat temp gun that's the best or just spray water on the headers and see if any stay wet or just boil the water off, indicting a misfire. Spark plugs could cause this issue and a lot of the times overlooked, but it could also be a loose air filter plug/adapter or ur carbs/lines.
A vacuum leak does sound likely. Check the vacuum hoses between the intake runners and the IAP sensor. Also check the condition of the sensor, especially if you see FI flashing on the dash. Another possibility might be just a very badly adjusted idle speed, possibly raised to make up for some other problem.
Thxs for the tips fellas and the bike has 23k miles on it. I really couldnt pass it up for $1000. As to it being set to idle high i dont think thats the case because it has started up at normal idle speed and then just ran up to 9k. I will pull the tank and check hose connections etc. I havent checked to see if it had an aftermarket filter but i will do so. What i dont get is while its under a load it doesnt run like this. If you ride it it runs normal until it isnt under a load.
Small vacuum leaks, such as rips and cracks in hoses, do tend to affect engine operation more under throttled conditions. Consider this: if the cylinder is trying to ingest air though an almost closed throttle plate, with barely a crack open, there'll be a big vacuum and it'll draw almost as much air from a crack in a vacuum hose, which, after all, is comparable in size to the opening afforded by the throttle plate. Under open throttle operation it's much easier to draw air through the throttle plates, so the amount of air drawn from any hose cracks, will be negligible in comparison, as will be its effect on fueling.