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.
 
I thought it was about time I gave my fitting experience with the 410 kit. I hope this will be further reassurance to others considering this upgrade.

After receiving the kit I decided to measure everything for peace of mind and everything was spot on. This was a great learning exercise for me having an expert show me how to do it while confirming what I did. The results were that the liner was very accurately bored with a nice hone cross hatch. Piston to bore clearances were well within spec for the 410, great job guys.

The only thing I had to do was gap the rings as top 1 and top 2 were a tad tight ( 0.2mm and 0.3mm respectively) I opened them up to 0.3mm and 0.4mm. Using the LS410 specs as a reference, this indicates that 0.2mm and 0.3mm is good but I took the advice from Sam and the guys.

Fitting was straight forward enough and took a couple of afternoons to complete the job, and yes I had to re-thread the cam chain a couple of times LOL. I did find in the end that if you keep the cam chain guide fitted you can let the chain just hang and it doesn't seem to come off. One bonus I didn't drop anything into the engine.

Out of interest I compared the weight of the pistons with rings and wrist pin fitted and the 410 was just 35g heavier. Not sure if that weight difference will have any affect on vibration.

I also fitted the Hitchcocks cam at the same time and modified my open air filter cover by fabricating a larger snorkel to cut the noise a little whilst letting as much air in a possible.

The bike started after a couple of cranks and settled into a nice idle after a few minutes. I let it run for 30 mins just ticking over to give it a full heat cycle and ECU reset. After cooling down I restated and give it a few gentle revs, definitely pops a little on decel and the tappets are slightly louder than I remember but I guess that could be the high lift cam as I adjusted them perfectly. After running in for 300 miles I'll check the clearances and head bolt torque again.

Unfortunately I won't be able to ride for a couple of weeks as we're away for a while but I can't wait to try it out on the road.

Watch this space ....
 
Hi guys,

Time for an update with my Hunter 410 kit. Am I happy? Absolutely yes. The bike is great to ride, lot's of extra shove and with standard gearing pulls very well in 5th gear from 35mph right up to 80mph easily. Maybe it'll go further with a 16t sprocket, but I'm enjoying the way it pulls so I don't really feel the need that.

Ive changed the oil twice, first at the 300 mile point and then again at 1000 miles. I also checked the motor with a borescope at both times and it looks really good in there, no signs of scoring or anything.

I'm surprised that there aren't more glowing reviews here because the way the bike is performing this 410 kit is fantastic value for money, especially as I didn't get stung for import duty.
 
Out of interest I compared the weight of the pistons with rings and wrist pin fitted and the 410 was just 35g heavier. Not sure if that weight difference will have any affect on vibration.
no, not with the 410. the 500 has slightly more vibrations but not in any annoying way.
 
Good day everyone. I'm starting the 410 upgrade to my Hunter next week - got already CAM fitted, air inlet modified, free-flow exhaust and Fuelx lite plus bigger front sprocket. Few of you suggested and also followed by this suggestion to run the bike in idle for several minutes after the swap to 410 - does it impact the running in process in any way? Is it safe to the engine?
 
I followed the advice here and ran it at idle without touching the throttle for a full 30mins, then turned it off and let it go totally cold. This procedure is supposed to allow the ECU to adjust it's environmental parameters. This also gives the new bore a complete heat cycle to start the bed in process.

After that I just followed the RE standard run in process, especially for the first 300 miles. Then I changed the oil and bullt up the revs over the next couple of hundred miles.

I changed the oil again at 1000miles and checked the 6 top end bolt torques and adjusted the valve clearances.

Hopefully you will be as happy as I am with the extra torque you will feel. I do notice that the tappets are noiser with performance cam fitted and adjusted to the same clearance as the standard cam. I've had zero issues with the conversation and have also checked the bore with a scope and it still looks perfect after about 2000 miles.
 
Thanks for the answer - got one question - during the swap - do you keep the crank locked during the whole change using the pin like on this picture? Is this the best way to ensure the timing chain and camshaft will hold the position after the swap?

1783498775149.png
 
Thanks for the answer - got one question - during the swap - do you keep the crank locked during the whole change using the pin like on this picture? Is this the best way to ensure the timing chain and camshaft will hold the position after the swap?

You don't need to do that until the final camshaft re-install. Sometimes the camchain will ride up on the crankshaft sprocket as you reassemble the cylinder and head, so you'll need the engine free to rotate to get the camchain relocated. All I did was reassemble the engine and once I'd torqued the head down and was ready to fit the camshaft I rotated the engine until the piston was at the top and then located the pin to lock it. You can easily see when the piston is at the top using something like a kebab stick in the spark plug hole. Then fit the cam as you did when you first upgraded it.

In case you're wondering it doesn't matter which TDC you use on this engine as it has a simple wasted spark ignition so as long as the piston and camshaft are locked, so timed correctly together with the RE tools you're good.
 
I followed the advice here and ran it at idle without touching the throttle for a full 30mins, then turned it off and let it go totally cold. This procedure is supposed to allow the ECU to adjust it's environmental parameters. This also gives the new bore a complete heat cycle to start the bed in process.

After that I just followed the RE standard run in process, especially for the first 300 miles. Then I changed the oil and bullt up the revs over the next couple of hundred miles.

I changed the oil again at 1000miles and checked the 6 top end bolt torques and adjusted the valve clearances.

Hopefully you will be as happy as I am with the extra torque you will feel. I do notice that the tappets are noiser with performance cam fitted and adjusted to the same clearance as the standard cam. I've had zero issues with the conversation and have also checked the bore with a scope and it still looks perfect after about 2000 miles.
Which Cam did you fit?
 
Back
Top