Hi all,

I have just acquired a bike that needs some attention and have some very basic questions that hopefully another air cooled four stroke trials owner and respond to...

• What engine oil is best for my bike (viscosity and mineral / semi-syn / synthetic) 10/40W??....
• What fork oil is best for my bike (viscosity) 10W??
• Should I mix a valve protection additive with my unleaded fuel?
• Is 91 octane unleaded the best fuel to use?

Thanks

 

Mal

 

I would think 10/40 would be the right grade, and mineral or synthetic wont matter too much,

Synthetic might not emulsify with water that gets in as much as mineral will, if that's of any concern. Two sides to that; 1 if the oil stays separated then lubrication isn't compromised, 2 Water will be harder to remove at oil change time, ( a concern because of corrosion ).

Fork oil is a matter of experimentation to find what works for you. My preference is 5W in both my Gas Gas 320 contact, and my KT250. I like shocks on the softer side to stop small things bumping me off line, so I can worry about the "big stuff" (NB Big Stuff varies with rider, mine, ...not so big). Also at trials speeds (generally) soft will help keep the wheel in contact with the ground, which = grip.

Fuel, high octane = slow burning, Good if knocking (Detonation, or Pinking) is a problem. High compression will need high octane.

Typical engines will get more power from 91 than 98. Make sure timing and sparkplug are spot on, rings, bore  and valves are in good nick (compression check a good guide to this) and try 91. If it knocks when hot under load, change to 98.

As for valve seats and guides, I have no idea if Honda used hard seats and guides back then or not, sorry.

 

 

Honda used hardened seats back then, no worries. 

Thanks guys for your answers - they are a great help.

1. Guys anyone know the engine oil capacity?  (1976 TL250)

Having fresh oil marke near impossible to read the dip stick!

Edited August 11, 20188 yr by 82desmo
More info

Sorry no idea. but carefully remove dipstick and lay it on some newspaper or bog roll and the oil will show up. Worth a try at least.

Hi Still Trying,

I must have done this a dozen times and I am still not confident - different results every time and so hard to see with amber oil on the dipstick

You would think that somewhere there will be a specification...

Thanks mate.

make sure the dip stick is dry before, will make it easier to see where its wet

Yes I have been doing that.

Problem solved, I got hold of a service manual which states 1.9L capacity.

Thank you for your input.

Sorry this is so late. Get a stick (clean) and mark the stick with the bottom of the thread and the full line. Put it in the sump up to the thread line, pull out and presto easy oil level indication. Second time will be a little less clear. Or you could use any similar thing as long as it is clean and not likely to leave bits behind.