Running Lean and Re-jetting.?

Question

I think I need to re-jet. Here are my symptoms:

1. Unresponsive Acceleration at times.
2. BIke backfires. Burps.
3. RPMs drop slowly when the bike is rev'd.
4. Poor gas millage

Thoughts?

I bought this bike used a couple months ago. I DOES have an aftermarket V&H exhaust.

Answer 1

I'd say greg nailed it. The RPM should drop off quickly when you throttle off.
When the R's drop slowly along with back fire this sounds like an intake leak.
Take a look at your spark plugs, the ceramic portion that surrounds the electrode should have some color on it . A gray to a medium tan color should be present.
If the plug is white ,you are very lean, likely due to an intake leak.
Here's an easy way to test for an air leak:
1) Go to the auto parts store and get a can of brake cleaner with a skinny red nozzle.
2)Using the throttle stop or a helper hold the RPM's at about 1500.
3) Spray a small amount of brake cleaner at the union of the intake and the head one at a time for each cylinder and where the carb.(s) join the manifold.
4) If the idle stumbles or drops or the bike dies, that indicates brake cleaner has been sucked in through an air leak.

Once the air leak is repaired, check the plugs for color again .At that point you can decide if jetting is needed.

Answer 2

It sounds like you're running rich, not lean.

I had a similar problem with my bike. The previous owner had an aftermarket exhaust, intake and had bigger jets installed. Before I bought it, they put the stock exhaust and intake back on, making it run rich since it still had the larger jets in. I installed stock jets, and it runs perfectly fine now.

Answer 3

before you change any jets you may have to look for another problem,have you change any part of the bike recently? you may have an exhaust leak or inlet manifold leak. check for other problems before you change jets,and if you have to it would be best to have it done with the bike on a dyno to get the best performance.

Answer 4

if you have not changed to exhaust system sounds like you need to clean out all,or should say replace all filters and make sure your lines are clean,clean out the carb or carbs,make sure you have no bad gas,if you have not changed anything it should not need to be rejetted at all,also make sure your air filter is clean and not stopped up,check your plugs,if they are 'black' you are not getting enough air,but sounds like you need a new gas filter

Answer 5

You need a tune up. plugs, carb sync, and new air filter.

Answer 6

what did you do/change before this started?