XS360 - Hesitation 6000+ RPMS

[JayRock]

I recently acquired an XS360. I have changed the oil, oil filter, spark plugs, and air filters. I synched the carbs as well.

The bike usually idles pretty good, but it seems I have to adjust it frequently. I understand there is some underlying issue here, but it honestly isn't what is really troubling, however any advice would be appreciated reagrding this.

The main problem is with the power up top. The hesitations tend to start around 6000 RPMs. It doesn't happen everytime, but most of the time when I approach or pass 6000 I get some power surges that come and go. For a split second, I will get a surge and then the power falls flat on its face, and then does it again, and again, until I shift which pulls my RPMs back down. On one occasion it hiccupped at about 4500, but that is very uncommon. The bike is very ridable as it is, but I don't have any of the sweet power that I want.

I am guessing this is carb related, but I am not certain. Does does anyone have advice on what I should look at in the carbs that would be causing this problem? If it is something else, please enlighten me.

Thank you for the help!

 

[eric123]

Bike getting enough fuel at those RPM's?

 

[JayRock]

I believe so, but how can I be sure? I run on the PRI setting on the Petcock. I pulled the vacuum hose and capped it at the carb. So ON and RES are just off all the time.

 

[drewpy]

float/sticking float needle or diaphram torn in the tops of the carb

 

[JayRock]

Thanks for the feedback. I will check it out. Much appreciated.

 

[JayRock]

So I have been messing around with the bike and am sure this problem is related to the charging system. The performance changes depending on if the headlight is on or off. Does anyone have any experience with the charging system, and what I should be looking for?

 

[thlillyr]

I just bought a bike and it could not go past 4500 without surging. After lots of tuning and head bashing I pulled the main jets and found out that they were way way to small. One was a 95 and the other was a 100. Worse is they were the wrong brand of jets. I have mikuni carbs. This was greatly impeding fuel delivery. I got the stock size which is 125 for my region and BOOM all the way to 10,000 rpm strong. You might need to rejet your carb or at least clean them if you havn't already.

 

[akronevan2]

I agree with thlillyr, although I have a question as well. How do we rejet the main jets? Can we do them on the bike? Do we have to tear things apart to get to them?

 

[thlillyr]

There isn't really an easy way to rejet the carb. The jets are just screws that pop right out. But you can't get to them with the carbs in the bike. Here are the steps I had to do to get mine out and in again.

1.Loosen O clams on the rubber tubes attached to the carbs.
2. loosen the bolts on the engine block. To reach the top bolts lift the gas tank to give you access
3. Detach the 2 cable. The is easy. Just pull the cable back to realese the black part and then move the cable to the little gap to release the tip from the holder. You should not have to remove any screws to do this.
4. Elbow grease. It will be dificult to push the carbs back and pull them free of the rubber mounts. I found it easiest to pull the front rubber tubes off the carbs first and then they carbs come off the back tubes easily.
5. remove the 4 bolts from each float bowl cover. 8 total.
6. The center large brass jet is your main jet. Remove it using a screw driver.
7. Look on the jet itself. It should have engraved the the jet size. IF they are the original stock jets then you should only have to move up in size 1 or 2 degrees. Each degree is an increment of 5. So if it's a 105 then you should probably get 110 or 115. You delership will have a better Idea than me though. My seca 400 stock is 120 or 125 depending on altitude. Higher altitude = bigger jets.
8. Follow all step in reverse. Tip i found the easiest way to put the jets back in is to attach the reat rubber tubes to the carbs first. Tighen them down tight. Put the carbs in WITHOUT the front tubes on the carbs OR the bike. Once in then put the front tubes back on. Not it is a b@#ch to get them to sit right otherwise. Especialy if the rubber tubes are a little bent out of shape.

Oh and there is no funky trun back half a turn stuff with the main jets. Just put them in and twist them snug. YOU Have to get the same brand jets as carbs. SO if you have mikuni carbs you get mikunin jets. The reason is that they have different shapes that shapes the burn and sometimes different screw threading.