High head temps

I have posted about this before but am still concerned.

Puch maxi with stock cigar exhaust and opened up stock airbox. Changed the main jet to 58 (I think). Seems to run OK with a hint of 4 stroking at wot when cold but goes away when warmed up. Head temp was 340 today after running WOT on flat ground with an OAT of 60deg F. Timing is set at 16BTDC. Did a plug chop today with a new plug and it appeared light brown/ normal. Would leaking seals cause a head temp to be higher than normal while the plug looks like its not running lean? Went to a local ped shop today to get some jets and they said the a basically non kitted 50cc Puch should run 275-300.

Tom

Re: High head temps

340 does sound a little on the high side. I would think that leaking seals on the intake side would cause you to run lean and you would have seen that in the plug chop. a leaky head gasket or bad piston would cause a power loss if not actually cooler temps I would think seeing as your never seeing the high cylinder pressures. a leak in the exhaust would again cause you to run lean and you don't appear to be doing that. My personal guess might be timing or poor spark.

Re: High head temps

Overpriced Parts /

Tom Hale Wrote:

-------------------------------------------------------

> I have posted about this before but am still

> concerned.

>

> Puch maxi with stock cigar exhaust and opened up

> stock airbox. Changed the main jet to 58 (I

> think). Seems to run OK with a hint of 4 stroking

> at wot when cold but goes away when warmed up.

> Head temp was 340 today after running WOT on flat

> ground with an OAT of 60deg F. Timing is set at

> 16BTDC. Did a plug chop today with a new plug and

> it appeared light brown/ normal. Would leaking

> seals cause a head temp to be higher than normal

> while the plug looks like its not running lean?

> Went to a local ped shop today to get some jets

> and they said the a basically non kitted 50cc Puch

> should run 275-300.

>

> Tom

That is so not true they should be around low 300f

Not 275 f but ya your little too hot and a leaner atomizer will make it worse

14.5 degrees btdc will drop temps a lot

Re: High head temps

Ya, the timing is right around 16deg BTDC.

I did remove the head gasket as per the service letter from Puch to convert a 1.5HP to a 2 HP along with the couple of holes drilled in the exhaust pipe.

I may replace the head gasket to see if that helps.

Tom

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