What is your safe temparature for this motor'
Thanks'

i have mine at around 220. but it depends on where ...

have running mine with 1/2L 5% and 1L O'D 20%, then turn it to race run, compare to Spec II the XZ had more bottom power and great top speed , i ran it about 95 to 100F and with a RP6 plug, OS t-1050 pipe, will try RP7 plug next time.

I ran it on State Title with stock plug (RP6) and T-1050. Heaps of bottom end power compare with Speed-I and Speed-II. Especially with T-1050, it makes the XZ sing! But so bloody thirsty!!!

yep, the temp i ran with have had arround 5m15s run time so next time i will test if RP7 can help a little more.

what restrictor do you use? I seem to be able to get more than 6 min all the time using RP6 and 1050

you mean the insert of the carburetor? 5.5 i have 5m45s+ on a Spec II with P7 plug and T1050 pipe, so i must try to squeeze them out.

Does this engine come shimmed for 20 or 30%? If I run 20% does that help with run time?

Thanks

30%, as the manual said, remove the 0.2 when using 20% i'm try to have more run time too

how many shims come with this engine?

never mind post above
saw the pics, appear as .3 for shims (1 .1 & 1 .2)

besides sage and os1050 pipe, what other pipe is suitable for a technical short track?

thanks in advance

I had a lot of success with the Hec pipe from Harmony models

For longer tracks I use
the Mugen Pipe 2501

have you tried novarossi pipes and header?