Couple things about my new XJ

So I bought a XJ750 maxim last week and this is my first motorcycle. A couple problems I have been having.
#1 sitting at a light it idles at 1k and starts dropping and roughly around 500 has the tendency to just stop. I am hoping a 1/3 of a can of Seafoam in the gas tank (recommended to me on another forum) but do you guys think I am going to need something more major?
#2 The power also doesn't seem like it is up to par. At idle the headlight and other lights are fairly dim (until I up the RPMs). I should probably put a voltmeter on it to see where it is at idle and where it gets to with a little throttle but my question is whether this is a common occurrence or not.
#3 When I received my insurance the bike is listed as a 1982 Yamaha XJ750H R Standard X. Can anyone help me decipher that?

 

1- it sounds like your carbs are in need of tuning. if you have a plugged pilot jet, it will do this. frankly, sea foam might help but it will not help remove crud that is in your bowl and sucking up to the jets.
2- these bikes will not keep the lights bright at idle. the alternator will not kick on till about 1850 RPM
3- http://www.motoverse.com/tools/vin/yamaha.asp

see if that helps.

 

I'd recommend checking your battery fluid levels and putting it on the charger for a couple of hours and see if that makes a difference. It may be time for a new battery.

 

Welcome to the site!

Sounds to me like you should do a rebuild on the carbs (search the forums for a Carb Clean walkthrough by RickChroMatic (may have mispelt)). Basically you can't go wrong doing a rebuild on the carbs and it can really help things out, just make sure you take the time to do it right. I would also recommend that you inspect the brake lines, pads for general wear and the rear shoe for delamination as it seems to be an issue on older bikes. Actually while your at it you might as well flush your brake fluid.

It sounds to me like your eletrical issue is caused by a bad battery so you might want to check that out. I recommend slapping it on the charger over night then taking it into a local tool/automotive store that will test the cranking amps of the battery to check its condition.

I think if you go to the xj4ever section of the 'supported vendor' part of the fourm there is a thread on deciphering your serial numbers to double check the bikes info (very good to check both the engine and the frame).

 

#1: unfortunately, yes. That was a bit much seafoam, you need to hold it to about 1oz. per gallon. Most likely you are going to need to pull the carbs and clean them thoroughly.
#2: The alternator on the XJs doesn't begin to make full power until above 2000rpm. Below that rpm you are on the battery, so the answer to your question is yes. Fully charge the battery; have it load tested at your local auto parts store. XJs need a healthy battery.
#3: See the "VIN" section here: http://xjbikes.com/Forums/viewforum/f=23.html to "decode" your VIN and tell you exactly what you have. You can't trust insurance papers or even the title at times.

How many miles are on the bike? The best "general" advice I can give is to get yourself a book, factory preferred, or the XJCD. Go through the "maintenence" section, item by item and leave nothing out.

You need to IMMEDIATELY check your rear brakes before you ride this bike any more: http://xjbikes.com/Forums/viewtopic/t=15874.html

 

bigfitz you just saved me a question. been working on 750xj i had bought. a lot of starting in the garage turning off and on. wont start now never had a problem before just had to turn the key. now i suspect the battery needs only to be charged. did not know that about the charging system at 2000rpm. good to know.

 

fatman, a lot of short rides will drain it too. I went through it with mine.