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Should i break in my new valves?

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Just put in new Titanium Intake valves and seals on my CRF250R and got the seats cut but didn't change the springs. Should i be doing a break in or running it through a heat cycle on first start up or can i just ride like normal???

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On 9/2/2017 at 7:13 AM, Aymen said:

 

Just put in new Titanium Intake valves and seals on my CRF250R and got the seats cut but didn't change the springs. Should i be doing a break in or running it through a heat cycle on first start up or can i just ride like normal???

 

Nothing special to do for break in.  Let it warm up and as long as the seats and valve faces are matched up and not leaking it will be fine.  Why not change the springs? To be honest thats one of the most critical parts of the valves train and also one that takes the most abuse. I would highly recommend changing springs if they have more then 40-50 hours on them. Also with the seats being cut did you check valve spring pressures?  When the seats are cut the valve goes up in the head farther and takes spring tension off the valve alittle. The spring can be shimmed if needed. Hate to see you float a valve if spring pressures where never checked. 

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Unfortunately im a teen with a very tight budget, and although i'd rather spend that extra 50 getting new springs and spring seats. I really dont have the money.. theres still pressure on the spring though, maybe ill get some new springs in if i can rack up the money somehow :/

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2 hours ago, Aymen said:

Unfortunately im a teen with a very tight budget, and although i'd rather spend that extra 50 getting new springs and spring seats. I really dont have the money.. theres still pressure on the spring though, maybe ill get some new springs in if i can rack up the money somehow :/

You dont need to replace the spring seat they tend to not really wear out. You can get all 4 new springs for around 30 bucks. Springs have a certain free length they need to be and once they are squished beyond that length you really risk floating a valve and possibly destroying that motor. If a spring is weak and barely able to keep the valve following the cam then one good over rev and you have a chance that valve will float away from the cam and the piston will come back up and smack the valve and either break the head of the valve off and drop it into the cylinder and you will trash the whole motor. 30 bucks could be what saves you from a 1000 plus dollar engine repair. New valves and cutting the seats and putting the old valve springs in is about like putting a new piston in and using the old rings. 

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Is there a way to measure if my current springs are any good or not?

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4 hours ago, Aymen said:

Unfortunately im a teen with a very tight budget, and although i'd rather spend that extra 50 getting new springs and spring seats. I really dont have the money.. theres still pressure on the spring though, maybe ill get some new springs in if i can rack up the money somehow :/

The reality of owning a high performance race bike,

what you don't save up / spend on regular and preventative part replacement

may end up costing much much more to repair later on when something fails, beyond what you will be able to afford to repair.

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Your service manual should have all the specs.

As an example, the CRF250X manual says about 0.035mm shorter than standard length is considered out-of-spec.

Edited by mlatour

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8 hours ago, Aymen said:

Is there a way to measure if i need to replace my springs???

Yes you can measure the length of them and see if they are still in spec. The down side is ive seen springs measure just fine and few hours later a coil wind break due to fatigue of being compressed thousands of times. In all honestly the 30 bucks can save you a grand or more of problems if those springs have alot of time on them. What year 250 is it and i can tell you what they should measure. 

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Yes you can measure the length of them and see if they are still in spec. The down side is ive seen springs measure just fine and few hours later a coil wind break due to fatigue of being compressed thousands of times. In all honestly the 30 bucks can save you a grand or more of problems if those springs have alot of time on them. What year 250 is it and i can tell you what they should measure. 



Its a 2004 crf250r

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Do you have any past history on this bike (engine overhauls) ?

For all you know those could be the original springs with millions of cycles on them.

 

As mentioned earlier, when refurbishing a high performance engine,

despite the added costs, many parts are simply replaced preventatively to avoid  

a potential failure that would cost much more to repair (perhaps more than the value of the bike)

 

Timing chain / tensioner or piston ever replaced ?

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Piston looks amazing, and crosshatching on the cylinder looks like it was done yesterday. Thats all i really know, no info on weather the springs where ever changed

If i was to pull the head off again.. would i have to get another head gasket, just put this one on 2 days ago and bike hasnt been started yet..

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23 hours ago, Aymen said:

 

 


Its a 2004 crf250r

 

 

Intake is 38.5 mm

Exhaust is 42.1mm 

You will need to check them with a set of calipers and dont compress it at all checking the length. Im telling you though you are money ahead just putting new springs in it with it being a 04. Especially if you just put new valves in and had the seats cut. 

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Intake is 38.5 mm
Exhaust is 42.1mm 
You will need to check them with a set of calipers and dont compress it at all checking the length. Im telling you though you are money ahead just putting new springs in it with it being a 04. Especially if you just put new valves in and had the seats cut. 


Alright ill check the clearances today and let you know what they are, is there a certain tolerance?? Like +\- 0.5mm?

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9 hours ago, Aymen said:

 


Alright ill check the clearances today and let you know what they are, is there a certain tolerance?? Like +\- 0.5mm?

 

No tolerance, if they are under that service length they are shot. If you are going through the hassle of removing the head and removing the valves and springs i would just order the springs and be done with it. I realize you are on a budget but if 30 bucks is out of your price range to possibly prevent major engine damage and possibly injure your self if it would granade on you at the wrong time then i would say you just need to sell the bike till you can afford the basic stuff. 

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No tolerance, if they are under that service length they are shot. If you are going through the hassle of removing the head and removing the valves and springs i would just order the springs and be done with it. I realize you are on a budget but if 30 bucks is out of your price range to possibly prevent major engine damage and possibly injure your self if it would granade on you at the wrong time then i would say you just need to sell the bike till you can afford the basic stuff. 


Will be ordering springs in today
I thank everyone for there efforts in helping me
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Intake is 38.5 mm
Exhaust is 42.1mm 
You will need to check them with a set of calipers and dont compress it at all checking the length. Im telling you though you are money ahead just putting new springs in it with it being a 04. Especially if you just put new valves in and had the seats cut. 

My intake measures at 39mm dead

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Intake is 38.5 mm
Exhaust is 42.1mm 
You will need to check them with a set of calipers and dont compress it at all checking the length. Im telling you though you are money ahead just putting new springs in it with it being a 04. Especially if you just put new valves in and had the seats cut. 


Should i still change them even thought they are long enough and in spec????

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3 hours ago, Aymen said:

 


Should i still change them even thought they are long enough and in spec????

 

If you already have them out i sure would change them. Especially if there is a change they are original springs. Ive seen then coils break on springs in spec before 

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