Turboed kx valves
- Thread starter goodtogo
- Start date
SS all day. Ti Wears on out stock bikes to fast. add boost. even faster.
What air fuel mixture are you trying to maintain during high boost, high load scenarios?
Just wondering if its burnt up or just floating around and drilling itself into the head?
How long was the turbo on before this happened? . I didn't think the kx bd kits have been shipped yet.
Just wondering if its burnt up or just floating around and drilling itself into the head?
How long was the turbo on before this happened? . I didn't think the kx bd kits have been shipped yet.
G
goodtogo
Member
I have had it out for 6 rides , I have a custom built kit that I made for the kx
G
goodtogo
Member
Ya that's what I was thinking thanks
I have a CRF450X... probably the most famous bike for eating valves. I just send my head to fastheads for service. I was going to get SS valves from somewhere else until I saw the option for berrylium copper seats with titanium valves. I can't find anyone who's had it done that doesn't love it, but I'll be the judge after I get it back.
They claim they last longer than SS valves in the stock head, we'll see about that. Should have it back this week to take it out and try it.
They claim they last longer than SS valves in the stock head, we'll see about that. Should have it back this week to take it out and try it.
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Hbmtr
Well-known member
1 thing to remember about turbos and exh,valves is heat.usually head rebuilders will use different valve and seat angles on turbo heads.Heat from the exh. valves gets absorbed thru the head when the valve is closed.One thing that helps this is a intercooler to cool the incoming intake charge.
I am sure you know any time you compress air it heats up and that alone creates once again another problem.One thing that concerns me on the turbo charged bikes is the advance curve on the timing end of things. My exp. is mostly from the marine/boat performance tuning.
I know i am running a cp 13.5 to 1 piston in my 07 crf 488 stock was 12 to1 but compressing an intake charge plus high comp. piston and a steep ignition curve sounds like a recipe for a short lived engine.plus lets not forget about detanation.Are you running race fuel?
I am sure you know any time you compress air it heats up and that alone creates once again another problem.One thing that concerns me on the turbo charged bikes is the advance curve on the timing end of things. My exp. is mostly from the marine/boat performance tuning.
I know i am running a cp 13.5 to 1 piston in my 07 crf 488 stock was 12 to1 but compressing an intake charge plus high comp. piston and a steep ignition curve sounds like a recipe for a short lived engine.plus lets not forget about detanation.Are you running race fuel?
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goodtogo
Member
I am running Vp c16 @ 9 pounds with zero signs of detonation. I am going to run a fresh top end and see what happens we are really in the unknown area here. I have a spare motor I will stud up and run a low compression pistion after I get my stock motor setup dailed in. I have 3 450f,s I am building so it will be interesting to see the issues that come up.
I ran the piss out of my prototype Boondocker KX 450 at 12 to 14 psi last year and had no valve problems at all. I think you have a heat problem with the design of your kit. Can’t say for sure. I do know that turbo bikes with no inter cooler can run intake temps well over 200 degrees and with inter cool my bike ran at a consistent 60 to 80 degree.
G
goodtogo
Member
Cool good to hear, now that I looked back I had over 150 hours on those valves I should of changed them out at the start of the season and my intake temps are so low it won't even melt the snow off my intake so I think I am okay until I turn that boost dial up thanks for the info,now u got me thinking about 14 pounds 
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Hbmtr
Well-known member
very good to hear on the race fuel.150 hrs 0n a head is getting on the edge for a rebuild,not sure how many of those hrs r boosted but it sounds like you have your basics covered good luck
