E: Engine Power Arc Ignitions
- Thread starter Oldhaven
- Start date
I recon that bike doesn't have any pistons in it and Gleniman has just added a soundtrack to the video!
Now I have to make a third video, this time with me standing on the kicker! 
Glen
Glen
My engine definitely does not spin over anything like that Glenn. I am starting to think I have higher compression pistons or something else maybe hanging up the engine. The compression bumps are quite hard, can't kick through them. There is no "carry on" when I kick it, not so much either with the plugs out.
I will get you to try next time we are out - buy you a few cold ones if you can replicate how you kick start yours, and a bottle of top shelf if you can arm start it..
I will get you to try next time we are out - buy you a few cold ones if you can replicate how you kick start yours, and a bottle of top shelf if you can arm start it..
If there is no 'carry on' when you kick it over with the plugs out then there is something wrong. Nothing to do with compression ratio. etc. Has the engine done lots of miles so that it is free? If you turn it over by hand with the plugs out are there any stiff places? Valves hitting pistons, the piece on the valve stem hitting the lower guide etc are things to look for. Hand turning the engine will feel harder in some places rather than in others due to valves lifting etc but there should be no really hard spots.
Motor was built 20yrs ago, about 17K miles in that time. I have only recently acquired the bike form Quebec last Sept Engine noted by local experts here as "very quiet" so no evidence of valves hitting as such.
I remember when I first started it after it arrived - I added new oil etc, it immediately squeaked for a bit, sounded like it was dry - the fuel had been drained so it couldn't have washed the cylinders - I added oil down the cylinder, front rockers and have never heard it since.
I have ridden 500 miles on it, some quite spirited, seems to go very well, no smoke. I wonder if there could be some damage to the cylinders or valves - but that would normally be evidenced by noise and smoke.
I remember when I first started it after it arrived - I added new oil etc, it immediately squeaked for a bit, sounded like it was dry - the fuel had been drained so it couldn't have washed the cylinders - I added oil down the cylinder, front rockers and have never heard it since.
I have ridden 500 miles on it, some quite spirited, seems to go very well, no smoke. I wonder if there could be some damage to the cylinders or valves - but that would normally be evidenced by noise and smoke.
Jim, the twin point/twin coil ignition makes this bike very easy to start, it only seems to need a rollover at very low rpm to fire up.
It may well be the mileage factor makes rollover easier. It's done about 60,000 miles since John McDougall fitted new liners, 8 to 1 low expansion pistons, Honda chrome rings and new upper valve train with RD valve springs etc. On measuring bore wear last year, there was virtually none.
It showed less than 1 thou total taper in the cylinders. Hastings ring Co recommends reboring at anything over 12 thou. So I need to budget for a rebore somewhere around the 720,000 mile mark
As far as ease of kickover, I seem to recall that it was about the same old same old right after the rebuild.
I did gain 2 mph on Dyno hill!
Your bike may well be higher compression.
My other Rapide is 9 to one with just 4,500 miles since everything new.
It does require a bit more effort, in part due to compression, but mainly because the single point D ignition does not seem quite as willing to light up as the twin point twin coil setup does. It can be arm started as well, just takes a bit more push.
Glen
It may well be the mileage factor makes rollover easier. It's done about 60,000 miles since John McDougall fitted new liners, 8 to 1 low expansion pistons, Honda chrome rings and new upper valve train with RD valve springs etc. On measuring bore wear last year, there was virtually none.
It showed less than 1 thou total taper in the cylinders. Hastings ring Co recommends reboring at anything over 12 thou. So I need to budget for a rebore somewhere around the 720,000 mile mark
As far as ease of kickover, I seem to recall that it was about the same old same old right after the rebuild.
I did gain 2 mph on Dyno hill!
Your bike may well be higher compression.
My other Rapide is 9 to one with just 4,500 miles since everything new.
It does require a bit more effort, in part due to compression, but mainly because the single point D ignition does not seem quite as willing to light up as the twin point twin coil setup does. It can be arm started as well, just takes a bit more push.
Glen
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I don't think you get very far if the pistons are hitting valves, making the engine hard to turn over and start.
Peter, it can be fairly subtle. It is often not the face of the valve hitting the top of the piston cut outs. It is the edge of the valve just hitting the side of the cut out on top of the piston, sometimes only by thous. I have generally only discovered this after dismantling the top end of various bikes. Same with the ET35s on the valve stem. A thou is enough to cause trouble but if the engine is spinning then the inertia of the flywheels can take it past the contact point. I always enlarge the diameter of the top of piston cut outs and make sure that there is clearance on the valves by getting to maximum lift and then levering up the tappet end of the rocker to make sure there is clearance.
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