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Can we identify the root cause of valve/seat failure?

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Guys,

If you don't mind, answer these questions and send the answers to me in a private message or email : acguy@peoplepc.com

I will in turn do an analysis on these factors (and I know there are probably more), but for now, let's see if there are any big factors or interactions in the list.

1. What class of rider are you (A,B, C, etc..)?

2. What type of fuel do you use and why?

2A. Do you mix fuels? If so how?

3. MX or Offroad riding?

4. Do you ride in the putt, putt range, or rev to the limiter to get your power?

5. What type of air filter and oil do you use?

6. Does your bike have stock exhaust or aftermarket? If aftermarket, what brand?

7. Is your jetting kind of lean, stock, or rich?

8. When you idle your bike after riding, how long do you allow it to idle before shutting engine off?

9. What did you ride before you got this bike?

10. Have you replaced any parts in your top end?

11. What specifically did you replace, and after how many hours of operation?

12. If you never replaced any parts, how much approx. time is on your engine (in hours)?

13. What is the average temperature where you ride?

14. What is the altitude where you ride?

15. What is the humidity level where you ride (approx = low, mid, high).

16. Which bike are you reporting here? CRF250 or CRF450?

Thanks

Bob

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1. C moving up to B

2. VP 110 mixed 50/50 with premium (I was pinging with just premium so needed some more octane)

2A. See above…..

3. Hare scrambles racing, supermoto racing and trail riding

4. I would say overall I am in the mid RPM range. I have only hit the rev limiter like twice.

5. PC Racing air filter with twin air filter oil. When its dusty I also use filterskins.

6. Dr.D with quiet core insert.

7. Perfect, nice golden brown burn throughout the powerband.

8. About 10-15 seconds.

9. Honda 50, Kawasaki KX80, Honda CRF230, Suzuki GSX-R 750, Triumph TT600

10. Just the rt hand intake shim.

11. After 25 hours I replaced the shim because the valve started closing up.

12. I now have about 30 hours on it.

13. On average its been in the hi 80’s, lately its dropped down to mid 60’s.

14. Anywhere from 5000 to sealevel.

15. mid

16. CRF250X

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1. What class of rider are you (A,B, C, etc..)?

B

2. What type of fuel do you use and why?

Usually pump gas

2A. Do you mix fuels? If so how?

No

3. MX or Offroad riding?

MX

4. Do you ride in the putt, putt range, or rev to the limiter to get your power?

Use all the powerband but not the rev limiter

5. What type of air filter and oil do you use?

Twin-Air

6. Does your bike have stock exhaust or aftermarket? If aftermarket, what brand?

FMF Factory4

7. Is your jetting kind of lean, stock, or rich?

JD Kit

8. When you idle your bike after riding, how long do you allow it to idle before shutting engine off?

Not long at all

9. What did you ride before you got this bike?

YZ250F/YZ250

10. Have you replaced any parts in your top end?

Yes

11. What specifically did you replace, and after how many hours of operation?

Valves after 40 hours then again at 50 hours. Dusty.

12. If you never replaced any parts, how much approx. time is on your engine (in hours)?

13. What is the average temperature where you ride?

78

14. What is the altitude where you ride?

+200

15. What is the humidity level where you ride (approx = low, mid, high).

mid

16. Which bike are you reporting here? CRF250 or CRF450?

CRF250

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1. What class of rider are you (A,B, C, etc..)?

A

2. What type of fuel do you use and why?

Premium unleaded pump gas

2A. Do you mix fuels? If so how?

No

3. MX or Offroad riding?

Both

4. Do you ride in the putt, putt range, or rev to the limiter to get your power?

mostly mid, rarely hit rev limiter

5. What type of air filter and oil do you use?

Stock and NoToil w/ NoToil oil

6. Does your bike have stock exhaust or aftermarket? If aftermarket, what brand?

PC 496

7. Is your jetting kind of lean, stock, or rich?

Stock

8. When you idle your bike after riding, how long do you allow it to idle before shutting engine off?

Not more than a minute or two anytime

9. What did you ride before you got this bike?

10 yr thumper owner

'02 YZ250F, '00 YZ426F, '98 YZ400F, '96 XR400

10. Have you replaced any parts in your top end?

No

11. What specifically did you replace, and after how many hours of operation?

Checked valves at 30 hrs, were within spec

12. If you never replaced any parts, how much approx. time is on your engine (in hours)?

45-50

13. What is the average temperature where you ride?

80-100

14. What is the altitude where you ride?

2000

15. What is the humidity level where you ride (approx = low, mid, high).

low

16. Which bike are you reporting here? CRF250 or CRF450?

CRF250R

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1. What class of rider are you (A,B, C, etc..)?

C

2. What type of fuel do you use and why?

LOWERS GRADE PUMP

2A. Do you mix fuels? If so how?

NO

3. MX or Offroad riding?

OFFROAD WOODS/TRAIL

4. Do you ride in the putt, putt range, or rev to the limiter to get your power?

MID RANGE

5. What type of air filter and oil do you use?

STOCK FILTER W/ PJ1 CLEANER/OIL

6. Does your bike have stock exhaust or aftermarket? If aftermarket, what brand?

DR. D

7. Is your jetting kind of lean, stock, or rich?

PERFECT

8. When you idle your bike after riding, how long do you allow it to idle before shutting engine off?

NOT LONG

9. What did you ride before you got this bike?

RM100 25 YEARS AGO

10. Have you replaced any parts in your top end?

NO

11. What specifically did you replace, and after how many hours of operation?

N/A

12. If you never replaced any parts, how much approx. time is on your engine (in hours)?

25 HOURS

13. What is the average temperature where you ride?

70 DEGREES

14. What is the altitude where you ride?

BETWEEN 6,000 AND 12,000 BUT 7,500 ON AVERAGE

15. What is the humidity level where you ride (approx = low, mid, high).

25%

16. Which bike are you reporting here? CRF250 or CRF450?

CRF250X

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Definitely some good data flowing in. I have only a couple of requests: Send me emails to avoid clogging up this board. I know this has been an issue of late.

Also, when you report your jetting, the term "perfect" means what? leaner than stock or richer? And for those that have done valve or top end work, include the following....

What specific component was worn, by how much and describe the condition. What parts were replaced or repaired?

Include any other factors you feel may have led to the wear such as "found filter leaking", dusty, etc...

So far, this information is inconclusive, but I may be able to rule out a few of the factors soon. By all means, if you have modified any part of the top end, please indicate.

My assumption is that these engines are pretty much stock.

Bob

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1. What class of rider are you (A,B, C, etc..)?

A

2. What type of fuel do you use and why?

VP MS 109, Clean burning no carbon bulid up anywhere

2A. Do you mix fuels? If so how?

NO

3. MX or Offroad riding?

OFFROAD Racing, GNCC Harescrambles

4. Do you ride in the putt, putt range, or rev to the limiter to get your power?

Hit the Rev Limiter a few times every lap

5. What type of air filter and oil do you use?

Twin Air / No Toil

6. Does your bike have stock exhaust or aftermarket? If aftermarket, what brand?

Stock X uncorkerd.

7. Is your jetting kind of lean, stock, or rich?

42 Pilot

R needle 3rd

70 leak

152 Main

8. When you idle your bike after riding, how long do you allow it to idle before shutting engine off?

NOT LONG

9. What did you ride before you got this bike?

TM 125

10. Have you replaced any parts in your top end?

Yes

11. What specifically did you replace, and after how many hours of operation?

Approx 500 miles, Valves got real tight. Went with a new R head/cam/cylinder. 3rd piston is in bike also.

12. If you never replaced any parts, how much approx. time is on your engine (in hours)?

13. What is the average temperature where you ride?

70 DEGREES 30 - 90

14. What is the altitude where you ride?

0 - 1500 ft

15. What is the humidity level where you ride (approx = low, mid, high).

Mid/High

16. Which bike are you reporting here? CRF250 or CRF450?

04 CRF250X

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1. What class of rider are you (A,B, C, etc..)? Vet A

2. What type of fuel do you use and why? half & half 91 octane/race gas

2A. Do you mix fuels? If so how? leaded fule for valves.

3. MX or Offroad riding? MX

4. Do you ride in the putt, putt range, or rev to the limiter to get your power? Mid to top end

5. What type of air filter and oil do you use? sock air filter, Bel ray aeresol

6. Does your bike have stock exhaust or aftermarket? If aftermarket, what brand? Thunder Power slip-on

7. Is your jetting kind of lean, stock, or rich?

8. When you idle your bike after riding, how long do you allow it to idle before shutting engine off? 5 seconds

9. What did you ride before you got this bike? CRF 450 '02

10. Have you replaced any parts in your top end? Intake valves and springs, rings

11. What specifically did you replace, and after how many hours of operation? All at 40 hours

12. If you never replaced any parts, how much approx. time is on your engine (in hours)?

13. What is the average temperature where you ride? Right now? 40

14. What is the altitude where you ride? 6150

15. What is the humidity level where you ride (approx = low, mid, high). very low

16. Which bike are you reporting here? CRF250 or CRF450? CRF 250 R, "04

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