All Things Moto! Dirtbike Forums

Go Back   All Things Moto! Dirtbike Forums > Dirt Bike - ATV - Suspension Forums > 4-Stroke Dirt Bike Bike Forums

Reply
 
LinkBack Thread Tools
  #1  
Old 07-04-2018, 05:12 PM
Novice Class
 
Join Date: Jun 2012
Last Online: 07-14-2018 12:36 AM
Location: socal
Posts: 82
Default 2007 yz450 stopped working.

     

First of all happy fourth of July everybody. I went out for a ride at some fireroads . The bike was running great the first 7 miles of rocky trail. I was going up a trail when the bike turned off .

I checked the bike and tried to kick start it for a few minutes and could not get it to start. Rode down a few hills trying to bump start it and I had no luck.

Luckily a friendly rider stopped and pulled me up the hill 5 miles out of the trails. During that time I kept trying to bump start it and was able to start the bike once . It ran for a few minutes and died again and I could not bump start it anymore.

What do you guy think happened , has this ever happened to any of you guys? Is it any easy fix ? what should I check first ? Thought I'd ask you guys first before I take it to a mechanic. Thanks
Reply With Quote
  #2  
Old 07-04-2018, 06:31 PM
ATM! Pro Class
 
Join Date: Jul 2011
Last Online: Today 10:39 AM
Location: Benton, LA
Posts: 4,903
Default

Now those are big questions with no knowledge of the bikes history....
How long have you owned the bike?
When was the last rebuild?
When was the cam chain replaced?
How many hours on the engine now?
Are you using fresh gas?
Do you have spark?
Are you getting fuel to the carb?
Is the carb delivering fuel to the engine?
Are the valves in spec?
How old is the spark plug? What does it look like?
Have you ohm'd the coil? If so, what were the readings?

Paw Paw
Reply With Quote
  #3  
Old 07-04-2018, 08:17 PM
Novice Class
 
Join Date: Jun 2012
Last Online: 07-14-2018 12:36 AM
Location: socal
Posts: 82
Default

Hi pawpaw thank you for the reply I have had the bike for about 5 years . The motor was completely taken apart and put back together about 4 years ago. I had the piston and cam chain changed about 3 years ago .
I am unsure of the total hours, I don't have an hour meter and bought the bike used.

I'm using fresh gas, I am getting fuel to the carb, valve lash was checked when the piston and cam chain were replaced. Spark plug was changed about 3 years ago . I rode it two weeks ago through the same trails and it ran fine and don't race the bike . I just use it for trail riding. thank you.
Reply With Quote
  #4  
Old 07-04-2018, 08:23 PM
ATM! Pro Class
 
Join Date: Jul 2011
Last Online: Today 10:39 AM
Location: Benton, LA
Posts: 4,903
Default

3 years is a very long time to go without checking and replacing worn parts.
You have a lot of work to do.

Paw Paw
Reply With Quote
  #5  
Old 07-04-2018, 11:41 PM
bjunior's Avatar
novice
 
Join Date: Feb 2012
Last Online: Yesterday 11:02 PM
Location: dallas tx
Posts: 844
Default

3 years is a long time on any spark plug.
Reply With Quote
  #6  
Old 07-05-2018, 02:41 AM
Welcome To ATM
 
Join Date: Dec 2017
Last Online: 07-05-2018 02:41 AM
Location: dangtan291990
Posts: 1
Default

Lưu ý khi chọn đồ lót thể thao nữ
Các chị em ng*y nay, bên cạnh việc công việc v* gia đình, cũng đã quan tâm rất nhiều đến việc bảo dưỡng nhan sắc v* tăng cường rèn luyện cơ thể, giữ gìn sức khỏe thế chất. Để chăm sóc những người thân yêu, trước tiên các n*ng cần biết chăm sóc bản thân mình. Các n*ng có đủ khả năng t*i ch*nh để lựa chọn mua sắm áo lót thể thao thoải mái để trang bị cẩn th*n cho mình khi đến phòng t*p, tuy thế để đạt được hiệu quả luyện t*p như mong muốn, bạn cần chọn được một chiếc áo ngực thể thao phù hợp, đảm bảo giá trị s* dụng của nó th*t hiệu quả nhé.

Chúng tôi chia sẻ với các chị một số lưu ý khi mua áo lót thể thảo:

– Chất liệu:

Các chị tránh chọn những chất liệu quá co giãn, vải mỏng, vì s* dụng sẽ nhanh bị biến dạng, bị giãn ra. Hãy chọn chất liệu cotton thoáng v* thấm hút nhé.

– Kiểu dáng:

Hãy chọn những kiểu dáng phù hợ với thị hiếu thời trang của mình, đồng thời phù hợp với môn m* bạn luyện t*p. Nếu l* Yoga, hãy chọn những kiểu đừng quá rườm r* cách điệu, hoặc với các cô n*ng mũm mĩm, hãy chọn cho mình một chiếc áo lót thể thao kiểu dáng đơn giản v* sẫm m*u.

– K*ch cỡ:

Các chị em chọn cho mình chiếc áo lót thể thao vừa mặc, đúng size của mình, tránh quá rộng sẽ gây ra những tình huống dở khóc dở cười v* không bảo vệ, nâng đỡ được bầu ngực, cũng không nên mặc áo quá ch*t sẽ gây khó chịu trong quá trình luyện t*p.

– Mút áo

Nên chọn những dạng mút tam giác, có thể l* tam giác đứng hoặc tam giác nằm, vì sẽ ôm trọn khuôn ngực, dễ d*ng t*p luyện hơn, đặc biệt l* ở các b*i t*p v*n động mạnh.

– Áo phù hợp với vóc dáng của các chị em, đúng chất lượng m* nh* cung cấp cam kết v* phù hợp với từng môn thể thao m* các chị luyện t*p

+ Không gây k*ch ứng da, an to*n trong mỗi buổi t*p

+ Giá trị s* dụng được lau bền, tiết kiệm được chi ph* cho bạn v* thời gia để bạn liên tục đổi áo lót thể thao.

+ Giúp bạn tôn được vóc dáng cơ thể, thấy rõ những đường nét để có thể đưa ra lịch trình t* luyện chuẩn xác v* th*ch hợp.

Hy vọng với những lưu ý trên, các chị em sẽ chọn được cho mình một chiếc áo ngực thể thao phù hợp để luyện t*p hiệu quả, luôn giữ được sức khỏe v* vóc dáng khỏe khoắn, xinh đẹp nhé.
Reply With Quote
  #7  
Old 07-05-2018, 06:34 AM
ATM! Pro Class
 
Join Date: Jul 2011
Last Online: Today 10:39 AM
Location: Benton, LA
Posts: 4,903
Default

English please...

Paw Paw
Reply With Quote
  #8  
Old 07-05-2018, 09:39 AM
Novice Class
 
Join Date: Jun 2012
Last Online: 07-14-2018 12:36 AM
Location: socal
Posts: 82
Default

The bike did bump start once and ran fine for a few minutes then died again . And would not turn on anymore by bump starting. I did notice that the bike was easier to kick over with the kick starter. But also still would not start.
Reply With Quote
  #9  
Old 07-05-2018, 10:32 AM
ATM! Pro Class
 
Join Date: Jul 2011
Last Online: Today 10:39 AM
Location: Benton, LA
Posts: 4,903
Default

So you lost compression. Time for a tear down and inspection for damaged parts.

Paw Paw
Reply With Quote
  #10  
Old 07-05-2018, 12:30 PM
Novice Class
 
Join Date: Jun 2012
Last Online: 07-14-2018 12:36 AM
Location: socal
Posts: 82
Default

I checked the valve lash the intake valves measured at .005, .005 and .007. The exhaust valves measured at .013 , .013. It seems like one of the intake valves is a little out of spec the intake valves are supposed to be at .004 to 006. Both exhaust valves are way out of spec when they are supposed to be at .008 to .010 . I thought the valve clearances are supposed to get tighter when worn down what could cause increased clearance?
Reply With Quote
  #11  
Old 07-05-2018, 03:24 PM
ATM! Pro Class
 
Join Date: Jul 2011
Last Online: Today 10:39 AM
Location: Benton, LA
Posts: 4,903
Default

My books shows .007" for intakes and .011" for exhaust.
If valves streatch or are sinking into the head seats they will in fact get tighter over time.
Exhaust valves mostly wear the valve guides and don't change that much.
The fact that nothing has been checked for at least 3 years is just crazy!
Do the tear down as I would expect you to find many issues. Bad cam chain, worn piston and rings are at the top of the list.

Paw Paw
Reply With Quote
  #12  
Old 07-05-2018, 07:29 PM
Novice Class
 
Join Date: Jun 2012
Last Online: 07-14-2018 12:36 AM
Location: socal
Posts: 82
Default

Took the top end apart and scrubbed the head to remove carbon build up. I then put water on top of all the closed valves and blew compressed air into each valve. All of the valves had some bubbles come through . Can I lap the valves to seal then? What do you reccomend I do? Also the spark plug is not showing any spark.
Reply With Quote
  #13  
Old 07-05-2018, 08:22 PM
ATM! Pro Class
 
Join Date: Jul 2011
Last Online: Today 10:39 AM
Location: Benton, LA
Posts: 4,903
Default

You can't lap these valves. They will need to be replaced and the seats cut.
You will need to find the reason for no spark. Ohm test the coil. If ok, then move on to the stator. Don't forget to test the kill switch also.

Paw Paw
Reply With Quote
  #14  
Old 07-06-2018, 12:15 AM
bjunior's Avatar
novice
 
Join Date: Feb 2012
Last Online: Yesterday 11:02 PM
Location: dallas tx
Posts: 844
Default

Get a 2 stroke
Reply With Quote
  #15  
Old 07-06-2018, 10:24 PM
Novice Class
 
Join Date: Jun 2012
Last Online: 07-14-2018 12:36 AM
Location: socal
Posts: 82
Default

Not exactly sure how to check stator cant find anthing on the process in my manual. Has anybody tried caltric valves ?
Reply With Quote
  #16  
Old 07-07-2018, 06:06 AM
wFo250's Avatar
will fall over
 
Join Date: Jun 2004
Last Online: Today 07:42 AM
Location: NTX
Posts: 3,489
Default

Quote:
Originally Posted by bjunior View Post
Get a 2 stroke
And then dont maintain it for years and see how that works out.
Reply With Quote
  #17  
Old 07-09-2018, 11:42 PM
Novice Class
 
Join Date: Jun 2012
Last Online: 07-14-2018 12:36 AM
Location: socal
Posts: 82
Default

Checked the stator and it is not reading any ohms on all the connections. Was planning on maybe trying different cams.
What are some good cams to add more low end power to the 07? Do I need to change both cams for this? Any one ever have the crankshaft fail on a yz450 around this year?

Also since the intake valves are still in spec is a little bubbles blowing throw the valves ok? I am putting water on the valves and blowing about 150 psi right under the valve . Is this an accurate way to check leaking valves? Or is the pressure excessive?

---------- Post added at 10:42 PM ---------- Previous post was at 10:38 PM ----------

Would the loss of spark make the bike easier to kick? Trying to figure out if the stator and compression failed at the same time. The bike had the oil changed every two rides and new oil filter every 4 rides. Air filter changed every 4 rides . Piston was not changed because it was hardly ridden for a few years. Radiator fluid topped off after every ride.
Reply With Quote
  #18  
Old 07-10-2018, 07:20 PM
wFo250's Avatar
will fall over
 
Join Date: Jun 2004
Last Online: Today 07:42 AM
Location: NTX
Posts: 3,489
Default

Wait your putting water on the chamber side and blowing air past the springs? If so, the air will lift the valve.
Reply With Quote
  #19  
Old 07-10-2018, 10:51 PM
Novice Class
 
Join Date: Jun 2012
Last Online: 07-14-2018 12:36 AM
Location: socal
Posts: 82
Default

Yes I blew the air underneath the valve with an air gun with extension with my air compressor fully charged at around 150 psi with water in the chamber. What is a more a more accurate way to test valve leaks ? Also would a bad stator with no spark make this bike easier to kick over? Thanks
Reply With Quote
  #20  
Old 07-11-2018, 01:05 PM
gusco's Avatar
Expert Class
 
Join Date: Apr 2013
Last Online: 07-17-2018 09:14 PM
Location: South Texas
Posts: 967
Default

A no spark condition will not affect the way the lever feels as you kick it over. Loss of compression will.
Reply With Quote
Reply

  All Things Moto! Dirtbike Forums > Dirt Bike - ATV - Suspension Forums > 4-Stroke Dirt Bike Bike Forums


Bookmarks

« Cheap yz250 | - »
Thread Tools


Similar Threads for: 2007 yz450 stopped working.
Thread Thread Starter Forum Replies Last Post
2007 yz450 5 gear problems tundrabeagle3 4-Stroke Dirt Bikes - Yamaha 7 11-20-2014 04:44 AM
2007 yz450 leaks oil tundrabeagle3 4-Stroke Dirt Bikes - Yamaha 2 07-29-2014 09:04 PM
CR250 07 Fork rebound stopped working MrPilipsi 2-Stroke Dirt Bikes - Honda 0 04-28-2013 11:36 PM
bike stopped at mid rev! HELP!!! ridered88 2-Stroke Dirt Bikes - Honda 7 10-14-2008 12:32 PM
KTM250rm393 stopped by cpl mondays ago cr-manp4l General Discussion 3 04-23-2005 12:33 AM


All times are GMT -6. The time now is 01:13 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright ©2002-2017, JDub Consulting, Inc. All Right Reserved.