Z1OwnersClub GB

Hi can anyone recommend (a good engineer) my gpz1100 unitrac head appears to have very worn valve seats. I can no longer get a valve clearances required. It also looks like someone has shaved the tops of the valves to overcome this issue. I don't want to bin the head as there now getting rare.
Thanks

Try Chris Tombleson at Grumpy 1260

Buzzard is our man for cylinder heads I know he is very busy right now

There's a few options to reclaim your head.
Either go the whole hog and fit new valves and seats (not a hard job for any engine re-conditioners or competent home mechanic.) or simply fit bigger valves and re-cut the seats.
The latter is the most common fix and the main reason most zeds get them fitted rather than for performance gains.
Fitting bigger valves puts the valve seating area on to the un-worn wider radius of the seat which should get your clearance back and put the shims back in the thick end of the range.

Hi do you know where I could get the over size valves?

APE or Manley etc sell them.
Either get them direct from the states via Pitstop Performance or Z1ENT etc or over here from one of the performance shops, Debbens etc or probably from Saisie and then of course there is always EBAY.

i don't know if it's compatible,but i have an 1100b1 head (complete) although it might be a 1000j head in my shed that i could live without if it's of use ? was previously in a good running (crashed)bike about 1991 about 16,18 000 miles as i remember..i understand the uni has uprated cam's and the 1000j (998cc)has slightly larger valves than the 1015cc z1000 but i don't know offhand if it's a match.. if so let me know.. mark

I'm sure you know....but the unitack head has different combustion chamber shape...which is why it's sought after.

Doubt the J head would be a good alternative.

i didn't know that Garry.never had a unitrack cheers

thanks Gary i know now you've told me. not much help at all.

Thanks for your help chaps

8 Valve Mark wrote:thanks Gary i know now you've told me. not much help at all.

Sorry. the first post was about a unitrac head....didn't spot the conversation had moved.