GT550A top end woes

[Alan H]

Ok, it'll be 'some time' though.

[vulcanman]

Time not a problem as i cant ride at mo due to my hopefully temp double vision.got nxteye scan this Sat ,hoping for some better news.in meantime im slowly working on 650 Honda single ive aquired.all up n running but needs fork seals ,tyres & some cosmetic tlc.ima long way from you but happy to make the drive up.im in East Sussex & only 7miles from coast.just let me know and i be up.thank you Alan

[Vintageman]

I see people recently discussing GT550 Pipes. Always great topic

I believe Jemco 's 3 into 1 is where Omar asked them to copy Strader's 3 into 1 design ->
http://www.loudfastugly.com/exhausts/stradergt550.htm

I have Strader on mine now. Strong mid and still can over rev into redline, where it is I who choses to back off vs it running out of breath. I think the chamber section makes a difference vs straight like Higgs 3 into 1. Also, the Strader's tuned length is on shorter side vs even some 3 into 3s, So maybe why it doesn't ruin top end and I'd say it is equal to stock at least (Haven't tried my stock exhaust for a while though, so honesty don't recall what I was getting, but don't remember being disappointed that it would not get touch redline)

I also have 3 into 3 Bassani's (so I have be told), Well made, can keep center stand, and have a longer tune length. Very strong low end and good midrange boost, better low end than Strader. It did take away from top end a bit as getting into redline was not a natural affair.

I have 3 into 3 Ocelots with short tuned length, not as much bottom/mid as the the others above. Strong mid is fun street riding for sure.

My GT550 is 1973. The last mod I did was to stock rubber intake boot. I took out the inner straight rubber tubes. They extend intake tuned length in theory and appeared to also limit my top end. They also extend very near to the back of boot, possibly so close limiting air flow. The 74-77 boot also has straight tubes, but not as long as 72-73 and/or at least not as close to back wall of boot. I did this mod while running Strader and that allowed me to get into redline notably further I am now curious to see how Ocelots work with this mod.

I just order studs vs exhaust bolts. The idea is that I can now switch between my Strader or Ocelots more easily and not worry about stripping aluminum exhaust threads in the barrels.

Other mods

My Ex ports are a 2-3 mm wider, and+1 mm raised vs stock, <1.5 mm off Piston skirt and running 0.020" head gaskets. Originally, the Bassanis' and intake boot may have been what was holding back top end as those mods. not radical by any means, did not give me the change I expected. Soon to find out.

Oh, with the pipes that give boost lower RPMs, where the GT550 tune from factory is already strong, would cause pinging when I backed off throttle. I had to back all the way off throttle, after a pull into upper RPMs for no pings to occur. Very annoying. I finally cured this by larger needle jet. Changing Pilot or raising needles was not the right spot to squelch the ping properly and caused to rich idle or poor cruising MPGs respectively.

Great bike! 3 into 1 and 3 into 3 each give unique sound and character.

[vulcanman]

1st day back on road.14 weeks.felt like forever waiting for vision to improve.finally back to 100% and signed off by doc as fit to ride albeit with glasses.550a ran well.nxt stop Manx Grand Prix !

[Alan H]

By the way, after a 'rearrangement', I now have 3 x GT550S. A rebuilt J which is as near standard as I could get, but with later linked exhausts with retaining springs underneath, the Earwig (B) with 3-3 Abbeyspannies, and B on standard pipes. The B needs some tweaks, but runs well up to 70mph when the front wheel is very much out of balance, but otherwise runs clean now the fog has cleared.....

[vulcanman]

3 and counting ! Well done Alan.i was out at our bike night at 6 Bells last eve .500+ bikes.mostly older stuff.lots of strokers.mostly kettles ,H1 H2 a few RD400 etc.didnt see any other 380/550 though

[Alan H]

https://www.kettleclinic.co.uk/kcforum/ ... hp?t=13779 for pics etc.

[vulcanman]

Smashing photos Alan

[vulcanman]

Hi Alan ,any further thoughts on selling your Piper ? I know you said be a while.Manx only 6 weeks away now.

[Alan H]

Still trying to convince the guy who I sold it to a couple of years ago, that he doesn't really need it.

[vulcanman]

Ok Alan.understood.hope we manage to meet up at MGP ?

[vulcanman]

I dont really like the style of the new Higgs 3 into 1 but if i have to thats the route i will have to go.my std pipes are still very good but fear one day sommit will happen for the worst.

[Alan H]

Ok Alan.understood.hope we manage to meet up at MGP ?

Hopefully. Booked today. Check your email.

[Evans Ward]

Congrats Vulcanman on being able to get back to riding!

[vulcanman]

Thank you Evans.just being able to ride again is the best tonic .the 550 running lovely and my 650 Honda single is back in one piece having refreshed the front end.new tyre/tube/pads/seals/bearings/forks/hub painted .Manx GP only a few weeks away.