Finally got the JE High Compression pistons put in

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tony.mon
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Joined: Wed Jul 25, 2007 10:46 pm
Location: Norf Kent

Re: Finally got the JE High Compression pistons put in

Post by tony.mon »

Sir-knob-head wrote:Who did yours tony.mon?
Newman Cams.
Not really recommended though, as I had to chase a lot to get them done.
Luckily they're local to me, I pass them on my way to work each day, so was able to make a nuisance of myself and get them done, but it still took weeks longer than promised.

It's all in my thread about getting these done- I know there's a lot of stuff on here, just use search to find it.

In my experience, high comps on their own work well, it's not cheap but gives good results, especially with a free flowing air filter and cans or a full system.
It's not falling off, it's an upgrade opportunity.
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darkember
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Location: South Wales Abergavenny

Re: Finally got the JE High Compression pistons put in

Post by darkember »

8541Hawk wrote:I guess I need to add more qualifiers to my posts for you guys......

Yes of course you will get gains in the top end when you up the compression ratio.

You should have power gains everywhere, though if you want the engine to breath at the top of the rev range with higher compression, you need to change the cams.

If you are not going for top end, then the stock cams should work pretty good for you though you might need to play with the timing a bit for max power.
Or just go for exhaust cams all round :thumbup:
tony.mon
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Joined: Wed Jul 25, 2007 10:46 pm
Location: Norf Kent

Re: Finally got the JE High Compression pistons put in

Post by tony.mon »

darkember wrote:
8541Hawk wrote:I guess I need to add more qualifiers to my posts for you guys......

Yes of course you will get gains in the top end when you up the compression ratio.

You should have power gains everywhere, though if you want the engine to breath at the top of the rev range with higher compression, you need to change the cams.

If you are not going for top end, then the stock cams should work pretty good for you though you might need to play with the timing a bit for max power.
Or just go for exhaust cams all round :thumbup:
Sadly that makes no noticeable or measurable difference.
The lobe height difference is point something of a mm, which helps a little, perhaps, but as I said, isn't measurable. I think that its more of a psychological boost, a placebo effect.
Sorry, but done many swaps, no boost.

But I will have a pair of 2nd hand std bore JE high comps for sale in the very near future....
It's not falling off, it's an upgrade opportunity.
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darkember
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Location: South Wales Abergavenny

Re: Finally got the JE High Compression pistons put in

Post by darkember »

tony.mon wrote:
darkember wrote:
8541Hawk wrote:I guess I need to add more qualifiers to my posts for you guys......

Yes of course you will get gains in the top end when you up the compression ratio.

You should have power gains everywhere, though if you want the engine to breath at the top of the rev range with higher compression, you need to change the cams.

If you are not going for top end, then the stock cams should work pretty good for you though you might need to play with the timing a bit for max power.
Or just go for exhaust cams all round :thumbup:
Sadly that makes no noticeable or measurable difference.
The lobe height difference is point something of a mm, which helps a little, perhaps, but as I said, isn't measurable. I think that its more of a psychological boost, a placebo effect.
Sorry, but done many swaps, no boost.

But I will have a pair of 2nd hand std bore JE high comps for sale in the very near future....
Ton are those the ones with holes in :lol: :lol:
tony.mon
Posts: 15938
Joined: Wed Jul 25, 2007 10:46 pm
Location: Norf Kent

Re: Finally got the JE High Compression pistons put in

Post by tony.mon »

Very droll!
These are the ones I bought as a replacement for the ones with holes in.
It's not falling off, it's an upgrade opportunity.
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Stephan
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Location: Prague, Czech

Re: Finally got the JE High Compression pistons put in

Post by Stephan »

tony.mon wrote:
darkember wrote:
8541Hawk wrote:I guess I need to add more qualifiers to my posts for you guys......

Yes of course you will get gains in the top end when you up the compression ratio.

You should have power gains everywhere, though if you want the engine to breath at the top of the rev range with higher compression, you need to change the cams.

If you are not going for top end, then the stock cams should work pretty good for you though you might need to play with the timing a bit for max power.
Or just go for exhaust cams all round :thumbup:
Sadly that makes no noticeable or measurable difference.
The lobe height difference is point something of a mm, which helps a little, perhaps, but as I said, isn't measurable. I think that its more of a psychological boost, a placebo effect.
Sorry, but done many swaps, no boost.

But I will have a pair of 2nd hand std bore JE high comps for sale in the very near future....
IN valve lift 10.3, EX 10.15

Ex cam swap doesn't help at all.
NZSpokes
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Location: Auckland, New Zealand

Re: Finally got the JE High Compression pistons put in

Post by NZSpokes »

General question. Is there any use in skimming the heads to lift compression? Keeping the stock bottom end?

Ive not had one of these apart so not sure of the head area etc.
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lloydie
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Location: In the garage somewhere in Coventry

Re: Finally got the JE High Compression pistons put in

Post by lloydie »

NZSpokes wrote:General question. Is there any use in skimming the heads to lift compression? Keeping the stock bottom end?

Ive not had one of these apart so not sure of the head area etc.
From what I've read you can skim the heads ,
Unless it's done with other mods ,like Pistons ,cams , porting, and full exhaust it's not worth it .
You'd be better off $$ selling up and getting a busa !!

I didn't skim my heads when I build my engine tho I might on the next one .
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Stephan
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Re: Finally got the JE High Compression pistons put in

Post by Stephan »

NZSpokes wrote:General question. Is there any use in skimming the heads to lift compression? Keeping the stock bottom end?

Ive not had one of these apart so not sure of the head area etc.
I would do it if I don´t have hc pistons, have some calculations for it (how much .x mm is for CR ...), but keep in mind you have to readjust timing of cams (on cam sprockets), and you will be able to go somewhere to 10.5 max.
NZSpokes
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Re: Finally got the JE High Compression pistons put in

Post by NZSpokes »

lloydie wrote:
NZSpokes wrote:General question. Is there any use in skimming the heads to lift compression? Keeping the stock bottom end?

Ive not had one of these apart so not sure of the head area etc.
From what I've read you can skim the heads ,
Unless it's done with other mods ,like Pistons ,cams , porting, and full exhaust it's not worth it .
You'd be better off $$ selling up and getting a busa !!

I didn't skim my heads when I build my engine tho I might on the next one .
Was more wondering out loud. Would only bother if i needed to have the heads off.

Busa's are to common. And nowhere here you can really open one up.
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lloydie
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Re: Finally got the JE High Compression pistons put in

Post by lloydie »

There common here to tbh but like the bird you don't need to rev the crap out of them to make silly fast progress .

Really looking forward to getting the track bike finished just so I can ride a twin again .
Sir-knob-head
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Re: Finally got the JE High Compression pistons put in

Post by Sir-knob-head »

lloydie wrote:There common here to tbh but like the bird you don't need to rev the crap out of them to make silly fast progress .

Really looking forward to getting the track bike finished just so I can ride a twin again .
What's your track bike lloydie? Don't tell me. Stormer?...
Idiots exist everywhere
Doesn't mean you have to argue with them

Live to ride. Ride to live
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lloydie
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Re: Finally got the JE High Compression pistons put in

Post by lloydie »

Sir-knob-head wrote:
lloydie wrote:There common here to tbh but like the bird you don't need to rev the crap out of them to make silly fast progress .

Really looking forward to getting the track bike finished just so I can ride a twin again .
What's your track bike lloydie? Don't tell me. Stormer?...
Yep a storm
Image
If I ever finish it
Sir-knob-head
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Joined: Sun Nov 15, 2015 10:58 am

Re: Finally got the JE High Compression pistons put in

Post by Sir-knob-head »

Good stuff.

You're almost there right?
Idiots exist everywhere
Doesn't mean you have to argue with them

Live to ride. Ride to live
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lloydie
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Re: Finally got the JE High Compression pistons put in

Post by lloydie »

No lol months off tbh .
Lots to do ,just can't be arsed
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