Anyone near Tewksbury that knows howto rebuild a top end ?

[danny86]

I'd like to learn myself and would like to know if anyone could come down and help/show me howto rebuild a top end. Obv I'll pay for the help.

I have a 2005 RMZ450.

Thanks

[Awesome]

What do you need to do specifically? New piston and valve adjustment? Will the head need to be machined? Valves? Guides?

[danny86]

TBH bud Im really new to the mechanics of dirtbikes. I hear frequently I need to re build the top end of a dirtbike every season. So whatever that entails

[Awesome]

TBH bud Im really new to the mechanics of dirtbikes. I hear frequently I need to re build the top end of a dirtbike every season. So whatever that entails

Start with checking valve clearences, if you keep them in spec you won't damage the head and valves and have to dump real money. As far as pistons, it's not like a 2 stroke, so you don't have to replace them anywhere near as often. Is the bike hard to start? That's a good indication that they're tight/too tight and you're looking at a hefty price.

[Sheppo]

on checking valve clearances. If you do your maintenance there is no reason to tear down a dirt bike every season. Especially when you are not racing it. Note the hours on the engine and go from there.

[Awesome]

If you don't know how to check clearences let me know and I'll see if i can swing by and walk you through it. It's not hard.

[Sheppo]

The RMZ isn't bad at all.

[DBB]

I recently checked the valves on my 09 CRF250R and this is what I found.

They're fucked. Feeler Gage doesn't fit the intake or exhaust valves at TDC.

The manual mentioned something about the valves "sticking" which would give irregular clearances even though they are adjusted properly.

Anyone ever heard of this?

[Awesome]

I recently checked the valves on my 09 CRF250R and this is what I found.

They're fucked. Feeler Gage doesn't fit the intake or exhaust valves at TDC.

The manual mentioned something about the valves "sticking" which would give irregular clearances even though they are adjusted properly.

Anyone ever heard of this?

Does it run? I'm guessing you're doing something wrong.

[Sheppo]

I would double check that you are at TDC and go from there. Something isn't right, wrong gauge, not at TDC...

[DBB]

Does it run? I'm guessing you're doing something wrong.

Ya it runs great.

[Awesome]

Ya it runs great.

Then you're def doing somethign wrong.

http://www.thumpertalk.com/forum/sho...d.php?t=179775

[DBB]

I would double check that you are at TDC and go from there. Something isn't right, wrong gauge, not at TDC...

I did double check both of those things and even had my buddy double check as well.

hmmmmm...

[lrrs313]

I did double check both of those things and even had my buddy double check as well.

hmmmmm...

You're most likely one rotation off. Spin the motor one more revolution of the crank, you'll probably find much better results. If they're beyond repair, the bike won't start for shit. The valves may need to be adjusted (different shims) but Hondas usually don't go out more than a couple thousandths in a season.

[DBB]

You're most likely one rotation off. Spin the motor one more revolution of the crank, you'll probably find much better results. If they're beyond repair, the bike won't start for shit. The valves may need to be adjusted (different shims) but Hondas usually don't go out more than a couple thousandths in a season.

I think that must have been it. I just checked the valves again and they are fine. I thought once the marks were aligned that was it.

Whoops.

Thx guys.