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Discussion Starter #1
I'm under the engine run in period, this means I cannot cross beyond 5K RPM. I'm experiencing high vibrations when the vehicle crosses 4.5K RPM in 6th gear, while in all other gears, I've almost no vibrations even at 5K RPM. While this is on one side, I also experience a minor 1-2 mm vibrations from the RVM's when the vehicle is in idle (cold or operating temperature)

I'd taken it to ASC this noon & they said they tightened the engine bed bolt. So after tightening, the RVM vibrations has come down significantly (but still some amount is present), while the vibrations is also noticable at 4.5K RPM & 6th gear, but has come down a little bit.

1. What could be the issue? My ASC sucks a big time as they don't have enough training provided by Honda India
2. Is C250R's engine mounted on a rubber or silicon (assuming) mounts on the frame?
3. Any idea what needs to be done to fix this issue?

Tks for any suggestion.
 

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Discussion Starter #5
Ok, so from Vibes, you guys want to turn into engine run in!!! So what RPM are you guys keeping during run in?

May be I want to clarify further - I DON'T WANT to cross beyond 5K RPM!!! Fair enough?

Now, about the vibes? What RPMs you guys experience?
 

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My CBR has 2k miles on it at this point. Here's my take:

It's a single - harmonic balancer and all, it's going to vibrate. In addition, 250cc means the engine is going to have to work harder to produce highway speeds.

I haven't really noticed any low-speed vibration, but I'll specifically look for it tomorrow (Tuesday) morning on the way to work. at 7500-8000, it definitely vibrates - mirrors don't have any detail, noticeable buzz in both the pegs and he grips.

Since tightening bolts seemed to alleviate the problem to some extent, I would have them check it again. The balance shaft shares the same space as the crankshaft, so I doubt it's a timing issue.

Most engines (except inline sixes) have imbalances at some crank position or another. Singles are the worst.
 

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Discussion Starter #7
Thanks a lot Luke. I really appreciate your post.

This morning I noticed something real strange. I was on my full gears with my riding pants & trust me, though there were vibrations beyond 4.5K & 6th gear, they were hardly noticable on my thighs & foot. Don't know why & how it happened. Let me check it one more time when I go home or ride tomorrow & confirm it thoroughly.

Meanwhile, if you can help me notice it for me, there's nothing like it. I'm having my apprehensions due to the changed engine. Tks.
 

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So what RPM are you guys keeping during run in?
None.

Honda don't recommend to stay under any rpm.
It was taken to the redline in each gear on the factory dyno.
Lugging an engine is worse for it than redline rpms.

Don't let it overheat in the early stages - ride for 20 mins than let it cool down, then repeat.

As for vibrations, it's a single, probably about 7000rpm the footpegs etc and feel of the bike become a bit buzzy.

It's a single cylinder, this is to be expected, want smoothness than you want an inline-four cylinder.
 

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Discussion Starter #9
1. How do you define overheat? I only have 3 bars no matter how many Kms I ride?
2. Next on the 20 min break, for how many more Kms (like 500 kms or 1000 kms) should I follow the 20 mins ride & break? Reason I'm asking is because, my office is 35 Km one way & it takes about 45 min in the morning & 1 hour in the evening. So imagine a 20 min ride & break!!!
3. 7000 is acceptable, but my whole question was on 4.5K RPM & 6th gear & only 6th gear. On 5, 4, 3 & 2 I don't have any vibes even upto 5K. Its silky smooth

Tks @Redline for your help :)

Regarding your point on Honda not recommending to stay under any RPM, I'm gradually buying that point. Because the Honda people over here said, avoid sudden accelerations & engine braking, but I can take even upto 8.5K RPM, but gradually. I hope Honda (atleast in India) is eliminating the concept of difficult times in run-in.
 

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Sorry, my points on overheating were for a brand new engine at zero km.

Let the engine warm to riding temp. Ride for 10 minutes, then let it cool down, then repeat 3 or 4 times. But that is for a brand new engine.

Honda were saying not to 'engine brake'? I'd be wary of any dealer telling me that. Maybe they meant 'hard/sudden braking'. Taking a new engine up to a desired rpm and letting it brake back down is important.
 

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Discussion Starter #11
Sorry, my points on overheating were for a brand new engine at zero km
I've now 350+ Kms on the ODO & I guess it should be fine

Maybe they meant 'hard/sudden braking'
Yup; its like you shift down from a 6-7K RPM at 6th gear to 5th & then 4th without even applying front & rear brakes.

Taking a new engine up to a desired rpm and letting it brake back down is important.
Yes, I do this all the time; I shoot upto 5K RPM & then bring down to 4K & then accelerate, without applying brakes.

But I STRONGLY buy your point on lugging than revving. I'll ensure to give a little more RPMs on higher gears than lugging. Tks.
 

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Yup; its like you shift down from a 6-7K RPM at 6th gear to 5th & then 4th without even applying front & rear brakes.
This is called 'Engine braking'.

It is good for a new engine.

Honda recommend no hard/sudden braking - grabbing at the brakes. They don't recommend no engine braking.

If a dealer tells you not to engine brake, I'd be wary.
 

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Discussion Starter #13
@Redline - From what I understand, engine braking is not good for a new engine because it leads to run the engine lean.
 

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Discussion Starter #15
Very high RPM is acceptable. But again, what defines high RPM?

How about the vibrations? We're again deviated from original topic!!! I suspect there's something wrong in my 6th gear.
 

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^ If you're in the redline, downshifting and engine braking probably isn't going to be too good for the bike - pretty much common sense really.

If you think something is wrong, none of us can see, hear or ride your bike, you have to take it to someone who knows about such things.
 

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Discussion Starter #17
^^^ Ok, I take that it happens with yours too, which should be normal for any C250R.

Let me wait to hear for the real report from Luke
 

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i may buy the cbr250 this weekend but now i'm concerned about the vibrations. I own a ninja 250 and have not vibrations and a very stable bike at 90 can you say the same for the cbr250
 

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i owned a honda 250 scooter as my first bike. right around 75 miles per hour the bike got ( for lack of a better way to describe it) squirrly Is the cbr 250 like that or is it as stable as my ninja 250 at higher speeds like 90
 

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When Riding my cbr i do notice some vibration, it is about the same vibration experienced on the ninja (friend owns). I like the cbr much more than the Ninja, it just seems easier and more fun to ride especially on the roads here in WV. I don't think you will have any issues with the vibration.
Remember, It's a 250, expect some vibration at higher speeds.
 
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