CM250T 1981 cam timing

226 Views 2 Replies 2 Participants Last post by Hawkeyefxr, 10 d ago

Hawkeyefxr

Discussion Starter · 13 d ago

Have been here before for this model. The manual i have is for a Cm200, 185 and 250.
I have got the seized bolts out and have been reassembling it.
Come to the valve time and the manual i have seems a bit awry for the 250.
Manual says:
1. Have bike at TDC
2. Have the square notch in the end of the camshaft towards the carbs
3. Have the marks on the cam cog level with the top of the head (horizontal)

Trouble is the bolt holes are about 90 degrees out, if i line up the the marks left by the cam cog by the camshaft the notch is at 6 o'clock (facing down in the head)

I know i could carry on with the assembly, then rotate the engine two complete revolutions and see if everything is free.
Have included pictures hope fully in sequence with with the way i set it up from the book

See less See more

Save

1 - 3 of 3 Posts

PoiPio

· #2 · 11 d ago

Just go with left cam lobes down. If sitting on the bike, left is left.

You have left piston at TDC on the left side.

The sprocket is timed correct in the photos, so in theory the cam should lineup with the sprocket holes.

As far as I know with the Big4, every cam are lobes down on #1 cylinder to time the crank, or you'd be 180° out of cam timing.

Save

Hawkeyefxr

Discussion Starter · #3 · 10 d ago

Yea I went that way in the end, have rotated the motor several times and the vales not not tangle with the pistons.
I have the Honda shop manual but things get vague when you get to the 250cc. The torque figures i am guessing are the same as the 185cc as there is none shown for the 250. And it is low but then again it is a fine thread.

Save

1 - 3 of 3 Posts

CM250T 1981 cam timing

Hawkeyefxr

Attachments

PoiPio

Hawkeyefxr

Top Contributors this Month