Valve guide problem - Honda CBR250R Forum : Honda CBR 250 Forums
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post #1 of 15 Old 01-04-2020, 07:53 AM Thread Starter
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Valve guide problem

Hello guys,
My bike have cold starting,and when i visited service center,they said my bike have valve guide problem and it cannot be replaced,or else i have to replace the head assembly,and they said they will try to fix it in lathe.
CAN VALVE GUIDE BE REPLACED? OR SHOULD I DO AS THEY SAY? PLEASE HELP
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post #2 of 15 Old 01-04-2020, 01:39 PM
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Probably less money to just replace the entire cylinder head in this bike. Whereas a lot more labor involved to replace valve guides.

Former Factory Test Rider/Technician
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post #3 of 15 Old 01-04-2020, 09:35 PM
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What year? How many miles?

It would be odd to have the guides wear out with any reasonable miles on the engine. The valve seals will usually wear first and allow oil to run down the valve and into the cylinder, which usually makes the engine smoke on cold start.

We replaced a couple valves on one of our Honda singles (CRF150R) and when it was all said and done we probably should have purchased a head assembly that had valves and cam installed at a reasonable price.

If you do need to replace the valve guides a head assembly may be the best bet, but if the engine has a lot of miles I'd probably look for a good used one instead of buying new.
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post #4 of 15 Old 01-04-2020, 11:16 PM Thread Starter
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2015 model,ok guys thanks i will try to get a 2nd hand one instead of new
Bike has only covered 32k kilometres in odo.
Dont know why it worn out so fast
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post #5 of 15 Old 01-05-2020, 11:41 AM
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Quote:
Originally Posted by aruninchoor View Post
2015 model,ok guys thanks i will try to get a 2nd hand one instead of new
Bike has only covered 32k kilometres in odo.
Dont know why it worn out so fast
It would be very unusual to have to replace valve guides at that point.

What are the symptoms you are experiencing that led you to take it in?

I'd be very surprised if worn valve guides were the actual problem.
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post #6 of 15 Old 01-08-2020, 01:42 AM
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Replacement of head costs less. i had replaced entire head of my 250R with authorised CBR mechanic it costed me around 10k. But after replacement there will be vibrations for first 700 to 1k km and don't panic! after around 1000 km your bike will become normal and vibrations free before. I replaced entire head at 31000km on ODO recently last year in month of November. Don't compromise on spares.
post #7 of 15 Old 01-08-2020, 10:37 AM Thread Starter
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Thanks chethan,
Can you please tell me the parts you have changed.and cost of it,i dont trust service center guys here
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post #8 of 15 Old 01-08-2020, 12:37 PM
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Can you tell us the symptoms that drew them to the conclusion that the valve guides were bad?
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post #9 of 15 Old 01-08-2020, 11:40 PM Thread Starter
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Bike will turn off if i let go the acceleration,on morning time,if engine is heated enough then no problem,A missing feeling at lower speed,
Fuel system has been checked and it is fine.they have checked the head assembly and told me valve guides has worn out
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post #10 of 15 Old 01-09-2020, 10:11 AM
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Quote:
Originally Posted by aruninchoor View Post
Bike will turn off if i let go the acceleration,on morning time,if engine is heated enough then no problem,A missing feeling at lower speed,
Fuel system has been checked and it is fine.they have checked the head assembly and told me valve guides has worn out
Can you describe it in more detail?

Not sure how they came up with that diagnosis, but there are other things that could cause what you described.

Did they tell you anything about how they determined it was valve guides?

I'd get a second opinion before buying parts.
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