Head gasket question

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nr
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Head gasket question

Post by nr » Thu Dec 26, 2019 10:26 pm

'ello all,

I know there's a search function here, and I tried to search for this info, but when the search function returned 723 matches, I thought it'd be easier to just ask the question! I'll be taking the top off the TRX in the coming days, to just check that all is well, and replace the valve stem oil seals as there's a definite smoky thing going on when I open the throttle, or on startup. And besides, last time I rebuilt the top end, I just refitted what was there, so it's probably about time anyway. While I'm in there, I'm thinking about fitting a thinner head gasket (or modifying what's there) to raise the compression ratio a touch. I'm using 97 octane fuel, and an Ignitech unit, so I should be able to use that extra compression, I hope. I'll also give the valves a good once over and clean up the ports, as after a few years the exhaust ports for sure are looking a bit crusty.

So on the head gasket front, any advice? Is it as simple as stripping the middle layer from the stock gasket, and maybe using some Yamabond or Hylomar?

Finally, while I'm here - the old Renegade pipes have finally been worn through on the right hand side [1], so I'll be fitting something better. Was thinking about the Projection Components 2 into 1 system, mainly because it's just about all I can find for sale in the UK right now, other than shonky old stock headers on eBay that are in a pretty advanced state of decomposition. Again, anyone have any thoughts on the Projection Components system?

As well as the Ignitech I'm running a set of FCR41s, so once all this is done, I'll be heading back to the dyno to get the fuelling and advance setup properly - it's not a million miles off at the moment, although I suspect it's a bit rich given the colour of the plugs that have just come out and the build up in the exhaust ports. But I've got a friendly place nearby that lets me use their dyno, so why not?

[1] This is a fantastic example of just how good modern road tyres are. The bike was built as a race bike with those pipes, and 20 years ago, the tyres were the limiting factor, not the pipes. These days, I can ground the pipes out either side on road tyres.

Thanks all,

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dicky
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Re: Head gasket question

Post by dicky » Thu Dec 26, 2019 11:41 pm

You can use the advanced search function to narrow down the results if you get too many hits.
So on the head gasket front, any advice? Is it as simple as stripping the middle layer from the stock gasket, and maybe using some Yamabond or Hylomar?
Short answer, yes. Long answer, search Cobba's posts for Hylomar. He has detailed how to do this and has also used thinner gaskets to up the compression.
Again, anyone have any thoughts on the Projection Components system?
They are known by everyone who uses them to be very good, and made by someone who loves TRX's, so it's a match made in heaven.
But I've got a friendly place nearby that lets me use their dyno, so why not?
FCR's can be a right royal pain in the arse to set up correctly, so you should take as much advantage of your friend as possible.
dicky
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cobbadiggabuddyblooo
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Re: Head gasket question

Post by cobbadiggabuddyblooo » Mon Dec 30, 2019 12:13 pm

Yep. That’s it Dicky,
Remove the 2 brass rivets and seperate the MLS sheets.
Next take the 2 outer spring sheets and clean off all the old viton seal and barrels/head.
Then coat with Hylomar blue On the 2 spring sheets ( only needs 1 inner side coated tho) and slip into place and bolt the head back on.
Removing the 0.2mm inner spacer may not sound like much but bumps up your compression close to 11:1 and reduces your Squish/quench for a better burn.
No need to re rivet the 2 spring sheets either as the 2 metal dowels that insert into the head/barrels aligns the gasket.
Don’t be suprised if you need to drop the std 150 main jet on the FCR’s to a 145 even with bellmouths and drop the needle deeper into the main( 2nd clip position from top ) even with a larger bore system.
Dial in a steeper advance curve up to the 37* around 5000rpm
laughter is the best medicine

nr
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Re: Head gasket question

Post by nr » Tue Dec 31, 2019 8:13 pm

Brilliant, thanks chaps! Sorry for not answering sooner, I've been away for a few days hols. Hopefully should get back out to the garage tomorrow to get on with things. Always nice to get back to normality after some time with the in-laws. Shivering in a cold garage with a cuppa sounds just the ticket to kick off the new year :)

Nobbynumbnuts
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Re: Head gasket question

Post by Nobbynumbnuts » Tue Dec 31, 2019 9:28 pm

I have RC set of pipes going if you're looking. With a Delkevic carbon can , though this has a bit of damage on the inside where it was rubbing on the brake hose bracket.

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