Come on guys, get off the fence, I really need your advice

Post here if you are doing anything different
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Manfriday

Come on guys, get off the fence, I really need your advice

Post by Manfriday »

Come on fellas, (other than Teazer) I really need your help.

I cannot find any advice on what size jets to put in my 1976 GT750 carbs, or whether to leave them as they are!

Teazer has made a suggestion, which I am grateful for, but I was hoping to get a few suggestions to see if there were similarities and agreement.

If I'm on my own, trial and error style, with no dyno and no experience, what is this forum for?

If you've got kids that are going off the rails or you want an opinion on rock music; I'll give it. I'd give you my opinion, the benefit of my experience. Please give me yours.

I am running Allspeeds and open carbs (with either those K&N style pods which offer no resistance or bellmouths).

We all know that running the wrong jets could mean disaster, which is why there is reluctance to offer advice, I get that, but together, we have a much greater chance of getting it right, or at least nearer. :(

Thanks in advance.
Roger Ackery
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Re: Come on guys, get off the fence, I really need your advice

Post by Roger Ackery »

Hi sorry mate,I can't help you..no experience with jetting....& chambers...I've always had Kettles with stock pipes & air boxes ;) I'm sure someone will answer you post shortly.....don't forget it's Summer in Europe & lots of people away on holidays, IOM TT etc enjoying themselves :P
Cheers,
Cheers.
Roger
GT750A.
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mark.read3
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Re: Come on guys, get off the fence, I really need your advice

Post by mark.read3 »

I'd worry about that at a later date.
The bikes been standing for a very long time so get the rest of it sorted first, are the electrics ok ?
Get it running on std carbs for the moment. Until you're happy the engines going to be ok.
No water or oil leaks, crank seals ok , charging system ok etc etc then ride it around for a bit as long as you don't thrash it , it'll be fine.
Then fine tune the carbs with the bigger jets , then thrash it until the crank seals fail.
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Gary66
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Re: Come on guys, get off the fence, I really need your advice

Post by Gary66 »

Can't help as only run a gt380 but if I could I would help you, sorry. What about contacting Mick Abbey, he may have some info :-/
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JOHNJENKS66
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Location: Cork City Ireland

Re: Come on guys, get off the fence, I really need your advice

Post by JOHNJENKS66 »

Hi,what type of Allspeeds, Gibsons or Microns.

I have had both,but only ran with a standard airbox. The manufacturer's advice,which came with the pipes,when bought new,advised a 2 size increase, ie. 110 to 115's.if using the airbx. A 3 size increase when using pod style filters.
Have had no issues on any bike that I used this setup,and have used them for many years,on both long and short trips,covering between 2000 to 1000,miles in a week long run.
Of course your milder climate may dictate a slightly higher increase,but as a starting point would suggest a 2 size increase. Ideally you would have the bike put on a Dyno,if possible,but as already suggested by Mark,make sure all other aspects of the bike are in good order first.

Hope this helps,good luck with the bike.

PS. Forgot to ask,did you get the bike fitted with the Allspeeds,or standard pipes ??? If it had the spannies,all ready fitted,the jetting would have already been upped.??
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PaulD738
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Re: Come on guys, get off the fence, I really need your advice

Post by PaulD738 »

As Mark says if you don't want to spend a fortune on it until your sure it will run ok I would stick with what you've got. Clean the carbs (properly) clean & set points and ignition then just try and start it. Running for a short while won't do any long term damage, notice I said running not riding? as long as the motor isn't under load you will be ok. Alan H's trick of filling the crankcase with diesel for a week before you attempt to start it is a good idea if you suspect the crank seals may be suspect. Once your sure it's a runner then you can worry about jetting.
They're rubbish them Jap bikes lad they won't last five minutes! you want to get yourself a nice Royal Enfield!
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astrax
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Re: Come on guys, get off the fence, I really need your advice

Post by astrax »

I had Higgspeeds and and K&N filters on, tried #122.5 mains that was still a bit lean at the top end when they checked the gasses on a dyno, ended up with #125 in all 3 carbs.

But that was on mine, can not say yours would be the same.


Ian
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bobd

Re: Come on guys, get off the fence, I really need your advice

Post by bobd »

I have allspeeds and k&n filters and i have 120 mains, its not been near a dyno but plugs are a good colour after a plug chop
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raysunners
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Re: Come on guys, get off the fence, I really need your advice

Post by raysunners »

I have run mine on 120 mains for 30 years with allspeeds and k&n filters no problems with this set up
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Manfriday

Re: Come on guys, get off the fence, I really need your advice

Post by Manfriday »

Thanks so much. This is exactly what I'd hoped for.
Looking through, it seems 120 mains are popular for others running similar setups, so I've ordered a kit from Baz with 120s specified.
Also located a Dyno not too far away and joined my local vintage bike club.

Can't wait.
Thanks again to everyone who replied.

Lozz
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