I’ve been rebuilding bikes now for a while, but never a 4 stroke, they intimidate me. Recently I got adventurous and bought a 250f and 450f (twins) for cheap. On the 250f I rebuilt the top end, 3 intake valves, new timing chain and the goddamn thing won’t start. I will say, you sir give me inspiration to actually keep chugging along on these bikes. Thank you for your videos
If those are original titanium valves and not stainless replacements, then they shouldn't be lapped in like you suggested that you have. The titanium valve have a coating on them, and lapping removes it. Once lapped they'll eat through them in short timeframe, with valves needing shimming thinner and thinner.
Agreed but it depends on the manufacturer. On early model Yamaha YZ’s, the manual specifically says to lap in the valves and they are titanium but as a rule of thumb, you are correct. The valves on this bike had been replaced with steel valves.
Hey Rooster, Do you have a link to the specific valve cutter you're using here? Is it the Neway? Getting ready to purchase it and want to get a good one.
Just bc I have 300 plus hours on my head does that mean it could be worn ? Am I better off buying a used head with way less hours or just work on the head I already have ? 13 kx450
It’s definitely worn but it certainly depends on your style of riding and your maintenance. If you were on the limiter all of the time you wouldn’t have over 300 hours. It’s not a simple answer unfortunately. I would tell you to follow your manufacturer recommendations for disassembly and inspection but I’m also of the mind of if it’s not broke, don’t fix it…haha
I’ve been rebuilding bikes now for a while, but never a 4 stroke, they intimidate me. Recently I got adventurous and bought a 250f and 450f (twins) for cheap. On the 250f I rebuilt the top end, 3 intake valves, new timing chain and the goddamn thing won’t start. I will say, you sir give me inspiration to actually keep chugging along on these bikes. Thank you for your videos
Thank you for your kind words and for your support!
WOW I know why I have the pros do this kind of work and now I understand the high costs of head work. Impressive video
Thank you for your feedback!
If those are original titanium valves and not stainless replacements, then they shouldn't be lapped in like you suggested that you have. The titanium valve have a coating on them, and lapping removes it. Once lapped they'll eat through them in short timeframe, with valves needing shimming thinner and thinner.
Agreed but it depends on the manufacturer. On early model Yamaha YZ’s, the manual specifically says to lap in the valves and they are titanium but as a rule of thumb, you are correct. The valves on this bike had been replaced with steel valves.
Thanks for imparting this knowledge to us. Another great video!!!
You’re welcome and thank you.
Hey Rooster,
Do you have a link to the specific valve cutter you're using here? Is it the Neway? Getting ready to purchase it and want to get a good one.
Wow, so sorry I missed this comment. Yes, it is a Neway cutter set. KM2563 is the kit I have. I bought it secondhand because it’s extremely expensive.
Just got my 2005 honda crf450r goin an my exhaust pipe wuz glowing red not long after the first start up
If you were riding hard, it is not uncommon for them to get red hot. If you were just putting around and it was glowing your jetting is too lean.
@restoroosterohv it started glowing red hot on the first start up from fresh engine rebuild
Just bc I have 300 plus hours on my head does that mean it could be worn ? Am I better off buying a used head with way less hours or just work on the head I already have ? 13 kx450
It’s definitely worn but it certainly depends on your style of riding and your maintenance. If you were on the limiter all of the time you wouldn’t have over 300 hours. It’s not a simple answer unfortunately. I would tell you to follow your manufacturer recommendations for disassembly and inspection but I’m also of the mind of if it’s not broke, don’t fix it…haha
Awesome video, thank you..
Thank you for your feedback.
Hey Rooster,
Hey!