Finally got the JE High Compression pistons put in

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Jscobey
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Location: Thousand Oaks, Ca

Finally got the JE High Compression pistons put in

Post by Jscobey »

i got the STD bore JE 11.5:1 pistons on ebay a few months back. its been torture having them perched on my workbench begging me to put them in. it was a bit of a gamble getting the std bore's because i never measured my bores before i bought them. i lucked out and my bores were well within spec and really good shape overall. they were each slightly more out of round at the top where the bore is unsupported but still plenty within tolerance.

i was going to do a full engine rebuild. split the cases, all new bearings, seals, etc... but decided that with less than 30,000 miles on my engine, and everything operating really well, i didnt need to spend the money for a full rebuild right now.

so i went the "cheater" route. now i know everyone wont agree and im going to catch alot of flack for doing it this way, but its tried and true by many members here and often done in other engines. its similar to how i use to rebuild my dirt bikes. like i said i know people are going to loose their minds about not doing it completley "by the book" but in all reality i did it all exactly how the book says, just without disturbing all the bearings and possibly having to cut the engine out of the frame due to the front bolts very commonly seizing. ive got to give credit to tony.mon over on the VTR1000.org board for turning me onto this method. very knowledgeable guy on VTR engines. :p


Heres how it went basically:

1. strip the fairings, tank, airbox, carbs, rads, oil cooler, and anything else that would get in the way of the job.
2.get rear cylinder to TDC and remove valve cover, cam shafts, and then all the cylinder head bolts.
3.remove oil pan and you have easy access to the connecting rod bolts for the rear cylinder. (you will need an elbow socket joint)
4. pop the piston and rod out the top
5.get front cylinder to TDC and remove valve cover, cam shafts, and then all the cylinder head bolts
6.undo the con rod bolts for the front cylinder (note: one of the bolts is pretty difficult to get to but it can be done with the right tools, it would be alot easier to remove the clutch and oil pump but i chose not to go the route and i was able to get it done)
7.pull the piston and con rod out of the top
8.measure your bores and check tolerance, if all is well then lightly hone and wash really really REALLY well.
9.check the new piston ring gap in the newly honed bores and correct if need be.
10. put the front piston in and be sure to smear the gudgeon pin and its bore and small and big end bores of the con rod with 50/50 mix of moly grease and clean engine oil (note: it takes A LOT of patience to get one of the con rod bolts on and torqued if you dont remove the clutch and oil pump, i did it without removing them but i was very very carful not to strip and and get a good torque reading)
11.replace head gasket, and then front cylinder head and cams etc...
12. go back to rear cylinder TDC, and install rear piston making sure to measure ring gap as well as adding the moly oil.
13. replace rear head gasket and then the cylinder head, cams, etc...
14. replace the carbs, airbox, tank, rads, oil cooler, fairings, etc....

and your done!!

just took her out to "break her in" and she feels great. very smooth. much smoother than before. i was taking it easy and not getting above 6K RPM while making sure to load the engine both ways (accel and decel) to seat the rings properly. cant comment on HP yet as i was being just breaking it in but i will report more when i really get things going in 1-200 more miles after an oil and filter change. but so far im loving them!

i will say that the whole job was pretty pricey when you add in the pistons, gaskets, seals, bolts, special tools, etc...
i did it because im never going to sell the VTR and i knew i would want them eventually plus rumor has it that JE is going to stop producing VTR pistons pretty soon as they just arnt selling to many of them, so i wanted to get them before they are gone.


overall job was a good one! probably about 12-16 hours total of work. slow process but not one you can get sloppy with (although some will argue that my entire method was sloppy)

once its all broken in ill go have her dyno'd. ive read of people gainging about 7hp (cant remember the added torque they were getting) from only adding JE pistons. so we shall see once i get the bike to the dyno.

now i just need to balance the carbs.

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High Hindles.SP1frontend.SP2&900rrwheel.Ohlins.SAbrace&spools.AllBalls.jetkit.JE 11.5:1 Pistns.Stg 1 Cams. HPowerstacks.HRCthrtl.SSlines.RadMC.WveRtr.LtWtFlywhl.LEDtail.mosfet.MCCT.DePair.Tailtidy.DM rrsets.Lower.Carbonadis.hugger.sliders.
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gl_s_r
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Re: Finally got the JE High Compression pistons put in

Post by gl_s_r »

Hopefully you didn't follow Tony too closely and you got them in there the right way round! :oops:
Why ask... sometime you just go to do it and find out?
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bigtwinthing
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Re: Finally got the JE High Compression pistons put in

Post by bigtwinthing »

They look great. I hope it all works out ok.

We do 4 rebuilds a year on our engines (V20,s) and they look great all new before the heads and turbo,s go on. Our last rebuild cost 289K complete and took a week longer than first thought as we had to get the liner lands machined. Great job though. I still shite myself when we first press the start button.
missing the noise, not the vibes. However never say never!
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kenmoore
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Re: Finally got the JE High Compression pistons put in

Post by kenmoore »

Great work Scobey, wait until you nail it the first time and it will all be worth it.

Based on your comments about the pistons I think I will secure another pair for the future..

Well done and keep living the dream, also no matter what you think about the way that you did it, I can assure you that the next time I do it I will go your way.

By the book takes too long and the cost is horrendous!

Let us know what you think as I have never dynoed my bike with these pistons.

It costs an arm and a leg over here and I would rather spend the money on more mods.

I ride with a variety of people on all sorts of bikes and have never been disappointed when the pace is upped.

Now ride and enjoy,!
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10robbo
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Re: Finally got the JE High Compression pistons put in

Post by 10robbo »

great article you have written.
really enjoyed reading it,just hope it doesn't tempt me to do the same sounds expensive
tony.mon
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Re: Finally got the JE High Compression pistons put in

Post by tony.mon »

Good write-up, good result, well done.
Looks like you got them the right way round- I may try that myself this time......

Glad it's feeling good; I'll be doing exactly the same very shortly. I'm just playing a little airbox game first.

I may also skim 30 thou off the heads as well, to add a little spice to the standard heads before swapping to a set I've gas flowed and will then fit oversize inlet valves. But all changes done one at a time and a dyno run in between, so that we can all see what changes get what results.....keen to see your dyno numbers, though.

Are you still running standard cams?
It's not falling off, it's an upgrade opportunity.
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Jscobey
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Re: Finally got the JE High Compression pistons put in

Post by Jscobey »

tony.mon wrote: Are you still running standard cams?
Yes. I've got my eye on a set of STG 1 moris but they aren't cheap. The only other option I know of is the hardwelds from web cams. But those are in between STG 1 and STG 2 and require new valve springs. A pretty top end oriented profile wich i like. Also they are about half the price of the moris ive found. I just don't want to sacrifice reliability for power and I know STG 1 components are pretty damn reliable.

I have heard the 11.5:1 JEs reffered to as STG 2 pistons opposed to the Mori pistons as STG 1 so I'm sure the web can profile would work nicely with the JEs. I'm going to email webcams and see if there is any other profile they can do. Maybe only intake cams or something.

Any other known source for cams?
High Hindles.SP1frontend.SP2&900rrwheel.Ohlins.SAbrace&spools.AllBalls.jetkit.JE 11.5:1 Pistns.Stg 1 Cams. HPowerstacks.HRCthrtl.SSlines.RadMC.WveRtr.LtWtFlywhl.LEDtail.mosfet.MCCT.DePair.Tailtidy.DM rrsets.Lower.Carbonadis.hugger.sliders.
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VTRDark
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Re: Finally got the JE High Compression pistons put in

Post by VTRDark »

Well done mate. I like that method of installation....why replace something that is not broke, it's only extra expense, bearings and everything are not cheap. What happened to guy that was supposed to be rebuilding the engine for you then, or did you get impatient.

(:-})
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Jscobey
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Re: Finally got the JE High Compression pistons put in

Post by Jscobey »

He was part of my decision. I can to him wondering about the method I ended up using. He said as long as you get the torque on the big ends then it should work great. He said at 30,000 miles unless there is reason for suspicion, why split the cases and disturb everything plus. He said to save that for the motor down the line if it ever needs OS pistons and a full build.

He gave me lots of tips and told me if I got stuck on anything he would come to my house and help me out. He's a great guy and a reallllllyyyyyyy good engine builder. Lots of insane engines coming out of his shop.

Plus on top of all that I had the satisfaction of doing it myself and learned a lot in the process. I'll tell you there is nothing more rewarding than that first tap of the starter button and your fresh motor that you just put together with your hands comes alive! :thumbup:
High Hindles.SP1frontend.SP2&900rrwheel.Ohlins.SAbrace&spools.AllBalls.jetkit.JE 11.5:1 Pistns.Stg 1 Cams. HPowerstacks.HRCthrtl.SSlines.RadMC.WveRtr.LtWtFlywhl.LEDtail.mosfet.MCCT.DePair.Tailtidy.DM rrsets.Lower.Carbonadis.hugger.sliders.
NZSpokes
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Re: Finally got the JE High Compression pistons put in

Post by NZSpokes »

I see you've updated your spec already :lol:

Nice one man.

Few questions

Whats all the black stuff on your old piston? Carbon?

Is that in your lounge? I see carpet...... I would not get away with that if it is.

What special tools did you need?
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sirch345
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Re: Finally got the JE High Compression pistons put in

Post by sirch345 »

Nice job and nice write-up, and with photo's too 8)

Chris.
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Jscobey
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Re: Finally got the JE High Compression pistons put in

Post by Jscobey »

NZSpokes wrote:I see you've updated your spec already :lol:

Nice one man.

Few questions

Whats all the black stuff on your old piston? Carbon?

Is that in your lounge? I see carpet...... I would not get away with that if it is.

What special tools did you need?

that is carbon build up on the piston. me thinks it has something to do with the product "seafoam" which is a pour in gas tank fuel system cleaner.ive used it a couple times but im thinking it was cleaning the sh!t out of the crud and my gas tank and then sucking all that crud into the rest of the fuel system.

it is weird but my garage has carpet. dont ask me why....

really the only special tools you "need" are a piston ring compressor (you dont NEEEEEED this but for $20 it helped A LOT!) and the honing tool. the rest is really standard tools. although you will need 12 point socket for the Big End bolts but those are pretty commmon. and if you choose to remove the clutch you "need" a clutch holder.
High Hindles.SP1frontend.SP2&900rrwheel.Ohlins.SAbrace&spools.AllBalls.jetkit.JE 11.5:1 Pistns.Stg 1 Cams. HPowerstacks.HRCthrtl.SSlines.RadMC.WveRtr.LtWtFlywhl.LEDtail.mosfet.MCCT.DePair.Tailtidy.DM rrsets.Lower.Carbonadis.hugger.sliders.
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lloydie
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Re: Finally got the JE High Compression pistons put in

Post by lloydie »

There isn't much carbon on the pistons . I've pulled apart engines with 1-2mm thick carbon build up on them before
NZSpokes
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Re: Finally got the JE High Compression pistons put in

Post by NZSpokes »

Was there much of a weight difference between the old and new pistons?
tony.mon
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Re: Finally got the JE High Compression pistons put in

Post by tony.mon »

NZSpokes wrote:Was there much of a weight difference between the old and new pistons?
JE's come with a spec sheet giving the machined weight and tolerance, and are paired up when bought as a pair. Target machined weight is 385 grams.
I've never bothered weighing the std ones, but there's no need to rebalance the crank- just plug n play!

The difference between the two pistons is more important that the weight compared to the std ones, as long as the weight compared to standard is about the same.
It's not falling off, it's an upgrade opportunity.
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