5 replies to this topic

[honda_tlr]

Think I know the reason for the TLR not running right , the first problem , the first piston ring was cracked , so was in 2 bits ! and the seccond problem , both valves appear to have hairline cracks in them !!
No wonder I couldn't get a the spark plug a nice colour !
Here is a picture of one of the valves, had a quick file at it and it does appear to be a proper crack, not just a casting mark!



On the pluss side m at least the head is now nice and clean





Now then , were is the best place to buy a set of piston rings and 2 new valves from? How much are they going to cost ? (about)

[max1956bikes]

i have never heard of a crack in valve i think its a casting mark.you will have to get gaskets as well.try your local honda dealer

[honda_tlr]

max1956bikes, on Dec 31 2007, 05:03 PM, said:

i have never heard of a crack in valve i think its a casting mark.

No, it is a crack.

[PeterB]

Usually valves would only crack around the seat area, never seen any cracked across the valve surface. Cause of valve seat cracks are down to insufficient tappet or valve clearence or ignition timing too advanced or a very lean mixture creating overheating. The plug would indicate this. Also, if the valve timing was set incorrectly. As for new ones, try your Honda dealer and if none available look for similar sized ones, either new or from a wrecker.
Bye, PeterB.

[swooshdave]

Would pre-detonation (pinging) crack a valve?

But more likely a manufacturing defect. Probably isn't still under warranty.

[ask greeves]

Your cracked valve is probably down to the production process, mass produced valves are usually two piece, welded together. 20 years of stopping and starting, with the metal being heated and cooled has probably released the internal stresses, your lucky the head of the valve didn't come detached from the stem. Gordon Farley M/c's keeps a good selection of Honda parts.