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About mxdave

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  1. I have an `08 RM-Z 450 that starts right up and runs perfect until it gets fully warmed up (about 15 min.) after that it just feels sluggish and lazy. Cylinder sensor was replaced along with spark plug and cap,coil,fuel pump and filter. If it were carburated it would run like the choke is on. Any ideas or someone with the same problem???
  2. mxdave

    engine problems on my 05 crf?

    I have a 2008 crf250.Its starts easy and runs fine.However,it idles real high then idles down real low until it dies.It will stay running as long as you blip the throttle,it idles high then slows down until it dies.Carb is clean,piston,and valves are new.Any ideas?
  3. mxdave

    2003 CRF450R Overhaul

    I have purchased the Ferrea nitrate coated Valves from Ferrea and they are very good.You said it right when you stated that when done right things will last and offer good performance.I too have built engines that have been on the gate at SX and MX races.My son can tear up a steel ball so I have to know what is good and what is`nt.I never stated that my Valves were the same,but I have used them.
  4. mxdave

    2003 CRF450R Overhaul

    I use the same Ferrea valves as RHC.Call Ferrea (888-733-2505) and ask them about me and my shop. Ron has a nitrite coating applied.I have used them also and they work really well.I have also found that the Faction MX Valves and springs work really well.I have done 650+ heads and have tried different products on our test bikes.I try to give my customers the best products that can give them the longest service.I won`t use anything on anyones engine that I would`nt use on my son or daughters engines.What you want to be careful of is discounted kits offered on ebay.I have had 6 customers send me Valves and springs purchased elsewhere that were not Kibblewhite or Ferrea even though they were packaged as such.After looking at some 2500+ Valves and 650+ Spring kits I know when something isn`t right.I stand behind everything I do 100% when my parts are used.Ron Hamps work and reputation speaks for itself as does mine.Whether you send your head to Ron or me,you can be sure you will get the best possible results for your $$$. Sincerely, Dave MXTIME Inc.
  5. mxdave

    Head Removal

    The question was on the seats,not the porting.I stated the seats were cut differently.The shape or size of the ports was never discussed.Know the facts before you bash someone you don`t know anything about.The customer stated to me he was on a tight budget and just wanted to ride.I then told him the best way I thought he could get back riding without spending alot of $$$.My reputation speaks for itself as being fair with high quality work,I don`t appreciate being ripped by people off the cuff because they are ignorant of the facts. PS - Learn to spell DA
  6. mxdave

    Head Removal

    Good idea replacing cam chain....most people don`t realize that when your cam chain stretches it retards the cam timing.We replace ours 2-3 times a year.
  7. mxdave

    Head Removal

    If you have unlimited funds the most power can be had with Ti valves and copper Berilium seats,however,the Valves must be changed often and the head re-done.This gets expensive unless you ride for ProCircuit.Most people just want to ride and race without having to rebuild and replace every other weekend.As far as performance,only very advanced riders will have the need for the gains they receive.We have all seen the rich kid on the mod bike rip the start and fade to mid pack.I build everything from $6,000 race engines to budget rebuilds.I was just trying to be honest with people and not just after their wallets.Anyone who knows me or has dealt with me will agree.
  8. mxdave

    Head Removal

    The question was on the seat material,not the porting.The only difference in the seats is the way they are cut from the factory.The porting was changed to help complement the duel exhaust.I have seen little gains when putting an `07 head on an `04 model.I have more than a clue,I have repaired 640+ heads with over 400 of them being Honda`s.Everything you read in a magazine or from online know-it-alls is`nt always the way it is.
  9. mxdave

    Mxtime ?????

    Go with OEM
  10. mxdave

    KX250F 2005 Problems

    Check to see if you have lost Valve clearance.You should have .004 on the Intake and .005 on the Exhaust.If there is no clearance(Probably not on the Left Intake) than you need the seats cut and new Valves installed.I would suggest Stainless Steel valves and a spring kit.Have the seats cut and the S.S. Valves lapped in.I`ve got These bikes with 100+ hours on them!!
  11. mxdave

    Someone refer me to a machine shop please!

    No wories Fletch,blending the seats to the bowls means smoothing out the machine markings from when the seats were installed at the factory.The smooth transition from seat to intake runner will give an increase in performance.I do the basic for nothing while I`m de-carboning.Also,when the seats are cut correctly,the 250`s have had the same longevity as the 450`s.Cutting the seat to the correct width and mating each valve to its respective seat is key.
  12. mxdave


    Ferrea Valves and Springs or Faction Valves and Springs.
  13. mxdave

    New Valves for 2005 RMZ 250??

    The Valve seats are the same material used in the xr400 and xr650 The Ti valves are actually the material that is wrong,its not compatable with the seat material or the way the factory cut the seats.Thats why they don`t last.An XR 650 can be ridden to death without touching the valves.Ever wonder why you never heard of valve trouble until Ti valves were used?They can be used but the seats have to be cut differently than with the SS valves.The contact patch must be wider with a Ti valve as the cooling of the valve takes place when its in contact with the seat.Intake valves are larger,there is more mass of material so the cooling process needs suficient area to draw the heat out.CRF 450`s have huge intake valves with a very narrow seat.Thats why the intakes are the first to go,usually the right side as tis is the hot spot of the engine.The exhaust valves are smaller and I have noticed the 45 degree angle on the Ex. is much wider than the Intake.Honda engineers thought the Exhaust side would be the hot spot but they never anticipated the Intakes would have the problems.Performance wise a narrow Intake seat area would have better flow and HP.That is until they start leaking compression then all that extra power goes right out the window.Once you start to lose compression your bike loses low,mid and top end power.You will also notice that it won`t rev as fast.
  14. mxdave

    Got my valve specs, now need some advice..

    Its because with the less clearance between the bucket and cam,the less shock there is when contact is made.With less clearance the cam lobe to bucket transition is more gradual.As the cam is rotating,with .010 clearance the cam lobe will contact the bucket later and at a point further up the lobe of the cam than if set at .004 -.005 Instead of a gradual lift you get a sudden lift which is hard on buckets and cams.Its like loading your bike in your truck with a 3 foot ramp as opposed to a 5 foot ramp - kinda - I`m not real good at explaining but I hope this may make sense to some.Long story short,Go to the minimum side of specs.
  15. Beware of Ferrea kits being offered on ebay.I am one of the largest buyers of Valves and Springs from Ferrea.I would be losing $$ selling them at that price.I have run into 6 diiferent instances of some sort of knock off cheap chinese valves and sub standard springs being re-packaged to resemble Ferrea.The only things in the kits that were Ferrea were the Retainers and Base Plates.Ferrea is aware of these sellers and has no records of selling them Valves or Springs.You might be getting the real thing at below dealer cost,but you may want to find out how they can sell them so cheap.The ones I tested were made from a low grade Stainless Steel and were cut to length and the keeper groove ground in by someone with a machine shop.The Spring Pressure was also inconsistant between the Springs.Call Ferrea and ask them if they know of the seller.They have records of all their purchasers.That would be one way to know if you are getting the real thing.Ron Hamp is also one of the largest Ferrea purchasers,I know they have heard of him also.