Bump start 426 with Decomp?
Posted June 03, 2004 - 06:00 AM
Might be a silly question but I have never attempted it due to fear screwing up valves.
Yes I know about the 450 cam mod
Posted June 03, 2004 - 06:17 AM
Posted June 03, 2004 - 08:14 AM
Posted June 03, 2004 - 09:27 AM
Posted June 03, 2004 - 09:51 AM
Stumpy- I'll give that a shot this weekend. That doesn't harm anything by doing it that way???
Posted June 03, 2004 - 02:55 PM
Pull the clutch, pull the decomp lever, shift 2nd or higher, and let the ckutch out as it rolls. You'll hear the compression being released through the exhaust system. After the engine is turning (2-4 cycles)ease off the release and it should pop off pretty happily.
's what we all did way back in the day.
Rememeber, the comp release holds one of the exhaust valves off its seat, so it's "less than cool" to go yanking on the thing at any speed above idle.
Posted June 03, 2004 - 04:27 PM
Thats what I was looking for, thanks
Now I'll only bump start it when I'm good and pissed
Posted June 04, 2004 - 08:55 AM
Posted June 04, 2004 - 07:00 PM
When you realize what it does (lift an exhaust valve), you can understand that it will temporarily increase your valve clearance from 0.2mm to over 1mm. Fool around with that at higher speeds, and it's pretty much like banging on your cam with a hammer.
Besides, the decomp in a four stroke will not produce the braking effect that top cylinder releases do in two cycle engines (diesels included). The internal dynamics of the two are entirely different.