Hi forum
Chasing my tail on an issue am having with my 76 DT175
It developed a misfire when engine under load
Also erratic and runaway revs
Have changed the stator crank seal but yet to get to the clutch side but it doesn’t seem to be burning trans oil, levels not going down
Have just been checking points timing and noted the points don’t appear to be opening and am now thinking it could be worn cam follower on points
Also if anyone could tell me what the device in pic is?
I think it’s advance regard mech?
Many thanks
J

You are correct on the device in the pic. Provides retarded timing at startup then advances when running. The points don't open very far....012 to .014 of an inch. You really have to watch very closely. On your misfire and erratic revs...it sounds more like an air leak. I'd be looking for a leaking gasket around the cylinder and especially the intake. There are experts on this forum that are more familiar with the smaller bikes and you'll hear more I'm sure. Good luck!

Read the manual... you need to lock the advance open when setting timing.

I agree that runaway is likely an air leak...

Manual is on the list
In meantime though may i quickly ask how you lock advance retard open to set the point gap?
Thanks

Thanks

Piston, rings and gasket on order
And thinking on it I am now pretty certain I saw exhaust gassed escaping from the head so that could well be the cause of the air leak
The misfire started intermittent but is now all the time I think I am chasing two separate issues

The manual is probably in the Tech Library on this forum (see top toolbar) and is free to download - you don't have to buy one.

Yes, manual is in the Tech Library here.

Site does accept donations... it's expensive for owners to provide all this great stuff for free.

yamaha-enduros.com/index.php/community/d...ite-maintenance-fund

If you've not torqued the head properly then I'd expect a loss of compression, maybe it's bad bottom gasket or the surfaces aren't flat. Might be worth spraying some "Easy Start" or "Start Ya Bastard" around the inlet rubbers see if there's a reaction.

Try and fix one thing at a time. "Runaway revs" sounds like an air leak and probably the easiest to fix first off.

With it on retard you'd have to have the flywheel slot a long way around to see them opening. Hold it on advance then set the gap within spec, not over spec, & should be close for timing. But--yes, airleak, had the base gasket on my old husky chainsaw get sucked in or blown out & similar problem with getting higher in the idle revs, no idle just getting faster.

Thanks, to clarify I have to hold the adv/retard on flywheel in open position to set point gap?
Or ensure it’s open before putting flywheel back on?
Sorry dark arts of points completely new to me only ever having cdi bikes prior to this one
D