J-Engine 410cc Thread

Hi guys, after stripping the engne down to get the Hunter ready for installation of the BB kit I've measured the ring gaps and they are.25mm for top 1 and .35mm for top 2. These gaps seem a little tight based on what I'm reading here.

Are these ok or should I gap them a little wider. Not sure of the best method if I have to do that. Any advice is welcome.
 
You are right, just a bit too tight.
I think in thou, I would be happy with 12 and 15 ( 0.3mm and 0.4mm).
A very fine file( like a "points file")
Held in a vise and you move the ring end by hand, be sure to check for burs.
 
You are right, just a bit too tight.
I think in thou, I would be happy with 12 and 15 ( 0.3mm and 0.4mm).
Thanks for the info.

Regarding piston skirt to bore clearance I'm looking to check mine. Should I take the spec from the LS10 motor seeing this is a 410 bore and the piston looks like an RE OEM piston?

I saw a published picture in the LS10 pages where the clearance is shown as 0.015mm and 0.04mm. Then I saw the link to the wassnor info pages and they quote nearer 0.07mm.
 
I would use the RE Himalayan specs, Wossner may be referring to Forged pistons?
 
I would use the RE Himalayan specs, Wossner may be referring to Forged pistons?
It could be they are quoted as performance pistons.

What clearance is aimed for when making the kits? Also I was wondering if there is an engine heat difference between the J and LS410 as the J series is fully air cooled with no oil cooling. I tried to find data on the Jseies for the clearances but I can only find the service limit.

Am I over thinking this?
:)
 
I wouldn't worry about the difference between the 2 engines.
Wossner would be forged alloy and need greater clearance.
The Boring process as done in India is not high tech but perfectly adequate in this case.
The tec would finish off by honing until the piston just falls through the cylinder, I mean just!
If it needs force or doesent fall by itself it would be honed until it does.
I doubt the tec would have the ring set and therefore would not be checking end gaps.
Customers usually don't like to see the small marks left behind by inserting the rings or the ring package opened.
The running in period finishes off the fit.
 
Am I over thinking this?
yes. the 410 outsells the 500 4:1 and none ever had any problems. its not a new kit anymore so my guess would be accumulated 100k km have been driven with these kits. The only seizing we ever had was with a 477 Himalayan kit and that is a forged piston.
 
Back
Top