Linhia valve clearances and shortcut By 4950cycle (Read 339 times)

[4950cycle]

BTW, The Linhia manual says 0.08mm-0.10mm intake valve clearance, 0.16mm-0.20mm for exhaust valve clearance. Translation for us Yanks is .003 inch -.004 intake , .006 -.008 inch for Exhaust . No wonder us Linhai engine driven scooter guys and gals have to adjust our exhaust valves so often. The typical valve clearance specified by your friendly neighborhood scooter mechanic is .005 - .006 of an inch. for the exhaust. Couple that with the inferior valve seats that recede as miles go by and you have to adjust the exhaust valve sometimes every 500-1500 miles. That is " WAY TO MUCH WORK "       To have the privilege of riding a scooter around. Especially with all the body work that needs to be removed to do it. So turns out it is perfectly OK to adjust your exhaust valve out to .008+ inch clearance. Stay under .009 inch. It will shorten your duration if you go to big. This should maybe double your ride time before it starts stalling at stops needing the valves adjusted again.     PS I have a JCL MP 250 A just like a Roketa-54 (Linhai engine) scooter and I have made removable access panels so I don't have to take my whole scooter apart to adjust my valves. Just turned a 2 day job into an hour and a half. Working on and off of course on the 2 day thing. Best thing I ever did !

[4950cycle]

Please, no lectures. I've been running larger than spec tolerances on my Linhia now for a couple of years with no ill effects and incredibly little if any power loss. And much more ride time in between valve adjustments on these Yamaha clones minus quality valve seats. In fact I run about .006 on intake and .008 on exhaust. I've tested my power on same road, same conditions with my valves set at .004 intake, .006 exhaust and then at .006 intake, 008+ exhaust and have virtually same acceleration and "may" loose 1 mph top end per my gauges. Sorry, It's just the way it is. And now I have finally been vindicated by this scooter repair manual I spoke about in my post above. When I started handling my valve adjustments this way back in the scootdawg days everyone told me monsters would eat me if I did it this way. And I would be sorry

[crwford]

I look at everyone who's always talking about valves and adjustments. My 3 Zodiacs 2 of which have 5,500 miles never had valves done why? Because day one I did a compression test all 3 tell me 175-180 so every 3,000 mile I pull plug and check compression still 175-180 PSI as far as I'm concern it tells me nothing has change and changing oil regularly is also a must I use Amsoil yes I pay a little more for oil but I don't screw around adjusting valves. Only problems I ever had were vacuum cracks on rubber intake, maybe a small hose cracked lose some vacuum. Buy the way every trike I have is still stock even the plugs. I'm old school my school teck teach always said think first and test and use common sense, throwing parts to fix isn't the way. And by not wasting time my wife and I ride more we had the trikes 14 months

[4950cycle]

Sounds good, Glad you are having a good scooter experience. On our, I say our because I am not the only one who got one of these Yamaha clones with a substandard head. The valve seat recedes as time goes on . Making us have to at least adjust the exhaust valve way more than normal. Not that easy to do either. We can't make it go away even with impeccable high quality maintenance. There is nothing we can do but install a brand new Name brand Yamaha 250 Majesty head AFAIK. People that got a 250-300 Linhia powered scooter with one of the good heads (maybe came from a better maker than other heads over in China) don't understand what the big deal is. Their bikes don't give them any trouble. I guess you and your wife are one of those. Or you have a CF Moto (Honda clone) powered scooter to which this does not pertain .