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Old 10th August 2011, 13:18   #31
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Default re: Honda Unicorn losing Engine Compression - HELP

I've got a few questions to all unicorn owners who have had compression problems.

What distance do you ride everyday?
I mean do you use it for short trips, say less than 5km at a stretch?

and

Do you idle your bike and warm it up during first start of the day?

I think I know why this has happened with very little kms in the odo.
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Old 10th August 2011, 14:51   #32
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Default re: Honda Unicorn losing Engine Compression - HELP

Quote:
Originally Posted by sharanvenu View Post
I've got a few questions to all unicorn owners who have had compression problems.

What distance do you ride everyday?
I mean do you use it for short trips, say less than 5km at a stretch?

and

Do you idle your bike and warm it up during first start of the day?

I think I know why this has happened with very little kms in the odo.
I travel about 36 kms (to and fro) a day since the last 4 months. Previous to that it was about 20 kms a day.

I normally don't idle and warm up the engine in the morning. Mostly would start it using electric start and for most part with choke ON.
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Old 10th August 2011, 17:00   #33
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Default re: Honda Unicorn losing Engine Compression - HELP

I'm using a 2006 model Unicorn. As far as I've seen from my experience, Unicorn engine needs a gentle warm up. And I've noticed that to reach the operating temperature, it takes at least 5km. So for people who ride less than this at one stretch, its better not to use Unicorn. I have seen couple of my friends' Unicorns having the same problem while I was in college. The hostel in which we stayed was around 2km away from the college and that was the distance the bikes used to run at one stretch for a period of 3 or 4 years. Both of my friends have scrapped the bike. My bike is still going good. It still gives me a mileage of 55-57 kmpl consistently in Hyderabad city.
I've maintained the bike's warm up regime very religiously. I usually do a 90 second Idle on the first start(it's been electric till date. I've had to kick start my bike only twice in 5 years. Need for choke is confined to winters) followed by 1st km run keeping tacho under 3k mark before I rip open the throttle. I've covered 60k km so far without any sort of engine issues.
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Old 10th August 2011, 22:29   #34
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Default re: Honda Unicorn losing Engine Compression - HELP

HI all.

This issue was reported by me a year back and I was adviced to go for engine related work. I didn't trust the Honda guys and suspected a mere deposit of carbon in the engine.

Yes, my work place is just 4kms from my home and my bike would not do more than 20 kms a day. This happened for almost four and half years before this happened.But remember no white smoke was visible from exhaust.

I took the bike for Delhi-mussorie-Delhi trip just after that ( around 700 kms in three days), burned all the carbon deposits in the process and since than no issues.I have covered around 9000kms after that and touchwood everything is just fine and the bike would touch 60000kms in few days.

BTW, I was suggested to go for complete engine overhaul with new engine block and new piston and the estimate was around rs 12000 IIRC.
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Old 11th August 2011, 12:33   #35
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Default re: Honda Unicorn losing Engine Compression - HELP

These buggers, the people at Honda Service are keen on doing only one thing : Selling Spares.
I've in fact stopped visiting them since 2 years. The last time I visited Service center, I asked them to adjust my chain. And after removing the chain cover, he said, 'the chain is finished, sir'. 'Wow', I said. He explained to me that the chain has stretched to its max and it cannot be adjusted any further! The bike had done only 35k km back then. I left the place, stopped at another local mechanic, made him take out 2 links from the chain and now at 60k km, the bike is still having the same old chain and sprocket.
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Old 11th August 2011, 14:18   #36
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Default re: Honda Unicorn losing Engine Compression - HELP

I have my bike lying at the service centre. Still undecided on whether to get the engine work done for 20k. The problem is that I cannot start the bike and take it to another service station for a second opinion. Even if I have to exchange the bike, the newer Honda models does not suit me. Dazzler does not have a kick start and has open chain, so not interested. Not keen on getting another unicorn and also the waiting period looks to be long. Not interested in a downgrade to a sub 150cc bike. From the posts in other threads looks like Suzuki GS150R would be most suited to me if I have to change the bike.

Kindly let me know which would be the best option. Fix the bike for 20k or sell it off and get a new one? My daily running is about 40 kms now and I need a bike with good riding posture, 45 kmpl mileage atleast, less maintenance and very less waiting period. Thanks for any help in advance.
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Old 11th August 2011, 16:44   #37
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Default re: Honda Unicorn losing Engine Compression - HELP

I have a sept-2006 unicorn. It's still on the stock chain even after 42.3k km.
The initial fuel flow problem is its trade-mark. The cost of spares are also on the higher side. Last week I bought rear brake-shoe and was charged 225 from a honda dealer. Every mech knows that this non-asbestos shoe is the most useless one and instead suggest asbestos based splendor front brake-shoe.
I have also experienced similar loss of compression situation few times. the motorcyle acts as if its dead, the kicker goes smoothly all the way down and no self too. Luckily it happened very close by my home so I managed to push it back home. I rested it for few minitues and started it again normally.
My only rides are during weekend, But I had made it apoint to ride atleast 20 to 30 km after proper warm up and mild throttle use for initial 5km.

Last edited by sulivan : 11th August 2011 at 17:05. Reason: to add point
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Old 11th August 2011, 17:17   #38
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Default re: Honda Unicorn losing Engine Compression - HELP

I too have a 2006 model Unicorn and experienced the same issue of stalling quite often. It was like a choke and I have throttle more to get back the life. When given to the service centre, they informed its due to mix of water in the petrol and they have also drained and cleaned the tank. They even showed me the can in which they have taken the petrol from the tank and I can see more than 60% water. Dunno how it entered the tank.

Now my engine is running smooth. Since this seems to be a unicorn thread, i have some queries. Couple of days back, when I throttled, the accelerator cable snapped. Called up the service centre and they told they dont have a stock of the cable and asked me to fix it from a local mechanic. No where in my vicinity I am able to get a cable.

Can I purchase a cable from other brands like CBZ/Pulsar/Karizma?
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Old 11th August 2011, 17:26   #39
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Default re: Honda Unicorn losing Engine Compression - HELP

Not sure about it, but ask your mech if its suitable since unicorn cbz extreme and its like, all have same skeleton.
My mech who was chief mech with HH for more than 10years discovered similarity with certain parts with HH and HMSI in ther scooters and motorcycle range, like front brake shoe of splendor(Rs 120) is same as unicorn rear shoe(Rs 225)
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Old 11th August 2011, 17:31   #40
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Default re: Honda Unicorn losing Engine Compression - HELP

Quote:
Originally Posted by dre@ms View Post
Can I purchase a cable from other brands like CBZ/Pulsar/Karizma?
You can go with a CBZ Extreme's cable. You wont have any issues.
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Old 11th August 2011, 17:44   #41
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Default re: Honda Unicorn losing Engine Compression - HELP

Quote:
Originally Posted by ash_g View Post
Kindly let me know which would be the best option. Fix the bike for 20k or sell it off and get a new one? My daily running is about 40 kms now and I need a bike with good riding posture, 45 kmpl mileage atleast, less maintenance and very less waiting period. Thanks for any help in advance.
Pal, why don't we get a second opinion regarding the engine issue? I think there is some serious mistake in the Service Center Guy's diagnosis. And besides, 20k is about half the current market value of the bike. Forget the Battery, Chain etc which he recommends to change, for the time being. If you can get it fixed for at least 15k I suggest you to keep the same bike. And one more thing, the above said half engine change for suzuki small cars cost just Rs.35k or so. So I guess we have some room for bargaining. Check with a reputed local mechanic and then take a decision. Vehicles with half engine change done usually live a normal life afterwards. So no need to be put off or have a feel of riding with an overhauled engine.
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Old 27th August 2011, 11:58   #42
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Default re: Honda Unicorn losing Engine Compression - HELP

@ ahs_g
So what did you do with your bike finally?
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Old 6th September 2012, 10:56   #43
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Default re: Honda Unicorn losing Engine Compression - HELP

Guys, I have been haunted with this Compression problems on my Honda Unicorn 2007 (alloy wheels model).

I had the values replaced in the year 2010 when one fine day there was no compression and had no choice but to show it to a roadside mechanic, he opened and showed me the values which were bent.

Now in this year in Jan 2012 i felt the bike is losing power when i accelerate little hard and almost comes to a still and fails to start after that. The kick rod becomes loose which is a clear sign of compression failure. Took it to a local mechanic who services my bike regularly. Said the valves have to be replaced. Got them replaced and the bike started showing the same signs after a week. Initially it runs well but starts becoming sluggish after 20 km of continuous running when trying to accelerate. Took it to the mechanic again who gave me the bike after one day saying the replaced value had a manufacturing defect and it has been replaced FOC. Now i am facing this problem since past week and really worried about it. I need your advise on the below questions :

1. Is this compression problem common for all the initial alloy wheel models ?

2. Should I take it to the Honda Service center ? I am only worried that they will over-charge me, the same components will be used by any local mechanic too.

3. Do the valves need replacement after 40 K ? In 2010 when the valves were bent I was told the reason as no engine oil in my bike. I agree that was the case as i didn't get the bike serviced for 6 months as i didn't use it and was out of station.

I am planning to show the bike to my old trusted mechanic who used to take care of my Yamaha Rx 100. Need your advice, this is bit urgent so that I can plan my weekend for this task.

Cheers !
Abhi
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Old 13th September 2012, 11:22   #44
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Default re: Honda Unicorn losing Engine Compression - HELP

Took the bike to Pratul Honda at Kondapur today morning. The service adviser started the bike and gave full throttle, smoke started coming from the exhaust and he immediately said it needs a engine overhaul. Bore, piston, cams bearings all need to be replaced. Gave a quote of 12 k approximately. Asked him why do the bore piston need to be replaced just for 44 K, he gave a blunt answer that these parts age after 45 K. Will take the bike to my trust worthy RX 100 mechanic this weekend and get it checked.
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Old 10th October 2012, 19:13   #45
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Default re: Honda Unicorn losing Engine Compression - HELP

Finally, my bike is back to life. Gave it to my old mechanic who used handle my RX100 ten years back. He test drove the bike and said the piston, valves, cam chain need to replaced.
Attached is the details of the parts replaced along with the cost :


The ride is as smooth as a brand new bike. I am hearing a lot of grinding noise, seems that the chain set needs to be replaced too. Will be doing it in few days.

Can anybody suggest a good synthetic oil for unicorn. I am planning to go for it during the next oil change. Please help.
Attached Images
 

Last edited by Abhi_abarth : 10th October 2012 at 19:16. Reason: Some additions
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