Compression Loss..

[Ant132]

Has anyone used eBay gasket paper, the cheap £5 for 8 sheets or so. Is it any good for base gaskets on barrells?

Ya see, the problem is my bike was running perfect until the the typical foolish youth in me came racing to the surface and i decided to fit a big bore kit.

So i used new gaskets from what i cut out of this gasket paper, and when i fully re-assembles the top end it had compression of about 80-100 on the gauge so was no good and never started.

Spent the weekend fiddling with it and several top-end rebuilds later i was no further and decided to re-fit the original and see how it was.

Still using the gasket paper, i fitted up the old piston and cylinder and off i went. Started ok but cut out, started again and left to idle, heard a popping noise, and then it cut out.

Wouldnt start again so gave it a bump and it started, (suggesting compression, correct?)

So then it started pouring down and i had to pack up.. So back on here for some advice

So d'ya reckon them gaskets will be naff then or should i look else where, i also noticed the studs that the barrel and head go over, 2 of them where starting to tighten and then went loose again. So, i think theyll need replacing, (i have spare ones) but would these cause dramatic compression loss aswell?

When the bike cuts out, its like it goes to settle down at 1.5k revs and then slowly cuts out.

Cheers guys!
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1980 Suzuki TS50 ~ 1984 Honda CB400N ~ 1992 Triumph Trident ~ 1998 Suzuki Bandit 1200

[Timmeh]

you've got no chance of getting any compression if you can't torque the head bolts to the right pressure.
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GSXR400 x2 | '94 RVF400 | '93 TZR125 4DL (again)
20:22:30 BLUEX5: i would love to be forced to undergo a**l plugging with different sizes
20:48:18 Temeluchus: comp you hunk of smouldering homos3x you

[Ant132]

[Pete.]

You will have pulled the thread out of the casings. You'll be needing to fit a timesert or helicoil in order to re-fit the studs.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[superslick]

did the big bore kit not come with gaskets tucked right inside the box or in the pack with the instructions? i bought an 80cc polini kit for this supermotard i had a while back and that had all the gaskets shoved in the middle of the fitting manual.
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aprillia rs125 gp-1 2004

[Rockhopper]

Base gasket thickness is critical for getting the compression ratio right, to thick a gasket may be your problem. However if its too thin they you may even end up with the piston hitting the head.

[Ant132]

Thanks for replies..

I think im just going to stick with original now, Gasket set ordered and helicoils 6x1mm for studs.

Do you need that tool with it to compress or can you get around it somehow?

Ant.
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1980 Suzuki TS50 ~ 1984 Honda CB400N ~ 1992 Triumph Trident ~ 1998 Suzuki Bandit 1200

[Pete.]

You must use the tool, though they are quite cheap. Alternatively, there might be enough room to drill & tap for 8mm studs. You'd have to drill the head & barrell also of course.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good