Since '02 xBhp is different things to different people. From a close knit national community of bikers to India's only motorcycling lifestyle magazine and a place to make like-minded biker friends. Join us

Axor
Magazine
Castrol Power 1

Check the helmet from inside.

Our Partner

Announcement

Collapse
No announcement yet.

Need advice on few issues on my Honda Unicorn

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
  • #1

    Need advice on few issues on my Honda Unicorn

    I am a first-timer on this forum, so please bear with me if i make a few mistakes . Own a Honda Unicorn 2nd Gen (with stickers), its a 2007 model and has completed around 12,600 km. I'll just enumerate the problems that i am facing one by one:

    1) There is a sudden increase in engine noise when the bike touches around 6k rpm. As if something is rattling or grinding vigorously . I know the engine noise does increase as we increase the throttle but it used to be linear before and not a sudden scream like it is now.

    2) The front part of the bike (Handle+Forks+Front Wheel) starts vibrating at speeds greater than 70 kmph. I had met with an accident more than a year ago and my front rim had lost its original shape. I claimed insurance to repair the bike, so it seems the mechanics just hammered the rim back into shape. I feel the slight deformation of the rim might be causing the wheel to vibrate at higher speeds but there may be several other reasons.

    3) The manual recommends replacing the spark plug after 8k kms or 6 months. Mine has exceeded both, so i was wondering whether it is time to replace them now. I know that spark plugs can last quite long, so i am posting a few close-up photos of the spark plug. The experts here can analyze it better than me .



    Some of the black material on the center electrode seems to have eroded leaving behind that white strip.



    Its very difficult to quickly diagnose faults in the unicorn as it is so smooth and refined. I have experienced a drop in performance since i bought it but there may be several other factors at play. So i thought i can sort them out one by one.

    In the process i'll also start understanding my bike better than before
    Tags: None
  • #2
    Query Approved.
    :)

    Comment

    • #3
      Speed is a joy but roads are not race track. Keep speed in your limit and always Drive safe...

      Comment

      • #4
        Thanks !!

        Thanks a lot for the quick response . I was planning to take the bike to my regular mechanic. But in my experience, they don't change any settings on the bike unless you tell them do so. So i though it best to get a diagnosis done from the people here . Now i have a few valid points to argue with the mechanic and get the job done from him.

        I'll get the front rim checked at a reliable place. Replacement is not an issue, if a part is irreparable then i am willing to get it replaced to get back my old uni .

        About the valve clearance and cam-chain, i think its best left to the mechanic to do that. But i think valve clearance should always be adjusted when the engine is cold, that means I'll have to leave the bike at the mechanic's place for some time.

        For tuning the carb, do you mean i have to adjust the fuel screw for that ? I need a little help for locating the screw as i haven't been able to find it yet. Idle screw is very easy to find, but i dont know on which side of uni's carb is the fuel screw situated. AFAIK uni uses a keihin carb, but haven't been able to find any useful info on the net for it.

        And yeah the spark plug gap is a bit bigger (According to manual should be 0.8 - 0.9 mm). I used a camlin scale to measure it and it clearly exceeded 1 mm. I need to know the precautions to be taken while bending the side electrode, i found it a bit brittle and hard to bend so didnt screw around with it .

        Comment

        • #5
          Himansu.. not only in unicorn but in all other 4 stroke bikes these problems occur. Very often the sound is create due to Valve settings, Worn Timing Chain and main thing improper oil circulation within the moving parts.
          Must be checked with a Unicorn Service centre.

          The wobbling you face above 70 kms may be mainly because of the RAZOR balls and the cone. Faulty Rims may be a reason, also check your wheel Bearings and your Tyres

          Spark Plugs lasts long but their performance will be reduced day by day resulting in poor mileage and performance. Never hesitate to spend on it
          sigpicTame the Road........

          Comment

          • #6
            Ok, i forgot to mention one detail about the spark plug. The pics above only show one side of it. On the other side of the plug, the porcelain(insulator) wasn't that dirty. What should i make out of that ?

            Unfortunately i don't have a pic to show it as I'll have to remove the plug from the bike again to take a snap of it from the other side .

            Comment

            • #7
              i dont think there will be any engine oil fouling
              its a four stroke

              Comment

              • #8
                AFAIK the whiter ur sparky its on the leaner side
                and more blackish or more carbon deposition its runnin rich
                i say get ur valve clearance checked by a good mechanic preferrably in the showroom , a reputed one
                dont meddle with ur carb iirc it has a throttle sensor or something i wudnt touch it
                with ur wobbling issue get all ur cycle parts checked ..

                Comment

                • #9
                  IMO, the mixture is perfectly fine, only that the spark plug has never been taken out and cleaned even once that's why it looks like that..everything lasts long if you care for it, even your spark plug would have if you had cleaned it every service..but it's ruined now and you need a new one..try changing the spark plug and you will see a difference in vibs and smoothness although i don't disagree with loose tappets..i also own a second gen uni 2006 wid stickers..

                  blackening of spark plug is perfectly normal, only that it shouldn't be very deeply black..you will know the difference if you see both types of plugs, normal and rich mixture, side by side.

                  one side of plug getting dirty is normal, it represents the side which faces the direct combustion flame..also that proves that you didn't once remove the plug from it's original position
                  If U haven't Seen GOD, U haven't gone fast enough

                  Comment

                  • #10
                    Many Thanks to all For your Inputs !!

                    Yeah, you guessed it right !! I have never removed the spark plug before this. I used to think these service centers are supposed to do the job, but i always had a hunch that they don't so i have started gathering info to do some basic maintenance myself . The only thing i used to notice is that they change the oil every service. But now that i have started using synthetic (Agip 5W40 Racing) even that is out of question. I Really like these oils, They outlive minerals any day !!

                    Ok, back to topic at hand. I got the bike checked from a head mechanic at the showroom. This has got to be the most embarrassing reason ever encountered for vibrations. The leg guard was loose and so it used to vibrate dependent on the engine revs . He just tightened the bolts and voila !! the bike was back to its signature silent roar again .

                    This was silly, how couldn't i notice the leg guard vibrating. Must have happened when the bike fell during the accident. I wish i could find the guy who hit my front wheel again, have to face these problems all because of his fault .

                    About the wobbling issue, he said bearings are ok as there is no free play in the wheel. He told most probably its the fault of the front tire. He needs to check if the bike is wobbling after fitting with another wheel. I'll leave the bike at the showroom on Monday morning as i need it right now.

                    I have a pic of the right hand side of my bike. Need to know if i am looking on the correct side of the carb.



                    Thanks a lot shubhanker for your feedback. Its always good to get an opinion from someone who owns the same bike .

                    Comment

                    • #11
                      fuel screw is on the other side of the carb..the default setting is 2.5 turns out..
                      ur always welcome..
                      If U haven't Seen GOD, U haven't gone fast enough

                      Comment

                      Previous template Next
                      Working...
                      X
                      © xBhp.com 2026. All rights reserved.
                      Designed by xBhp