175 Carb Start Point

Good Morning,

Does anyone have any advice on what size amal mk2 and jets and needle settings is a good starting point.


Regards



Eddie

Ed,

I started with a 34mm MK2 Amal I will look up the settings I used when I get chance, moved to Mikuni which I have found more predictable.

I think Steve Frayne is using a 36mm Mk2 at the moment on his 175 he may have some suggestions

Are you going for a standard or or a powerjet carb ?

James

Hi james,


Thanks for that and the info would be great if possible, have a 36 and a 38 aswell if need to go up sizes. Was going for standard as i thought power jets werent allowed.



Many Thanks



Eddie

I know where you are coming from Ed... Rules say that:-

Power Valves are prohibited on a 175. A power valve is a blade or cylindrical valve which alters the exhaust port timing with greater engine speed. 125's can have them though!

Power jets on carbs are allowed on 175's as long as carb max size 38mm diameter and cirular bore...

Can't help with Amal info as I run 'Lectrons'

Mike

Hi Mike,

Thanks for the information, hopefully a few people will be able to give me some ideas so i have a base to start with.



Eddie

Edward

My 175 uses a 32mm Mikuni TMX (Steve Panter at Allens Performance supplies) and runs on 160 or 170 main jets with 80 power jet.

Chris

Hi Chris,



Many thanks for the information and settings, i wil look into that.



Eddie

Good Morning all,

now excuse my ignorance as i am getting confused. You can use any type of slide ie tmx is a flat throttle slide compared to say an amal mk2 which has a circular slide.


Eddie

Ed,

I think the rules state a circular bore not a circular slide, if the Mikuni (rather than Amal) is an option for you like Chris I am currently using a 35mm TMX with 180 main 85 power.

I have found them to be very predictable and stable which as a relative newcomer helpd tremendously with understanding the effects of changes

James

Hi James,


Thanks for that, i think that is where i was getting confused, well i have a few sizes of amal mk2 and i have a tmx but i think its a 38 so is probably too big for a start off point i would imagine.


Eddie

FAO - Derek,



Do you have any ideas or settings i could put together for 34mm to 38mm amal mkw amals and whats your opinion on usuing a mukuni tmx 38mm on a 175


Eddie

Hi Edward just spotted while doing this" why we are all losing our / the text/ posts - we post then have to re write it ?, so frustrating - the secret is don't touch the eascape button, if you touch the escape button, which is almost a natural finger touch, it deletes everything your have just typed, done as a reason why I'm re-typing this. in most case.

anyway moving on : edward

34mm amal
320 to 360 main jet
107 sometimes 108 needle jet
2D1 NEEDLE - MIDDLE GROOVE
1.5 to 2.5 turns out on pilot screw

38MM (NONE POWER JET)
380 /400 MAIN JET
108 /110 NEEDLE JET
NOT SURE ON NEEDLE ? SORRY.

BIGGER THE CARB THE MORE DIFFicult IT IS THE CARBURATE ?

blimy my speeling is getting worse ? mind you I have been indulging in three glasses of (none alcoholic ? ) red wine ?, a stressfull day" whileIve been typing this.!

keep going - "we are all looking forwards to meeting you" and the bike and SOON.

Tell - your dad Macolm, my dad said its about time he got his finger out and finished the thing, ??????????.

best reagards Derek

Hi Derek,

Many thanks for the carb details, will build the amal and see whats in the tmx already, i know all too well about the wine and stressful days plus a divorced accountant and an av technician dont make engineers/bike builders but we are giving it a go.

Dad has seen the post so and is currently writing a list.


Eddie

Good Evening all,



I would like a genuine opinion from 175 riders, is the purchase of a mikuni tmx the way to go rather than playing about with amal mk2's



Eddie

On my 175 I replaced a 34mm Amal Mk II with the Mikuni TMX and found it to be significantly better all round. Whether this was due to the Mikuni being new and the Amal being slightly worm is open to debate...

Chris is correct in saying that you should not go for a large carb size, stay small and it will go better and be easy to set up, 38mm is no good at all.
Alan

Hi Guys,


Thanks for the info, may give dad a list of questions to ask on friday providing people arent too busy.


Eddie

I will be wandering the paddock aimlessly for at least part of the day on Friday! So feel free to seek me out. I will be doing the Scrutineering seminar for part of the day, but the rest I will be helping out Nick Bramley and Derek Betts where I can...
You are welcome to talk me out!
Cheers
Alan

Hi Alan,

Many Thanks for that, i wont be there but my dad so i will get him to find you to have a chat.


Eddie

Hi Ed glad its of use to you, Yes I spoke to your dad at length, he should be out this year and soon by the sound of things, sounds like he is nearly there, you just need to push him along, as the sooner he starts you can ?.

The Amal technical info, I always found usefull when you finished coppying just bring it with you to mallory do not post it or we will never see it again, I'm not saying the royal mail is crap but the parcal service is"!, so far this year they have managed to lose a new set of gears, a set of crankcases, and a barrel, so please bring the paperwork, I can wait for it.

we should swop numbers PM my number next time I'm down in that there yocal locality, will call you and meet for a beer with my dad.

regards Derek

Hi Derek,

Yeah he did mention that and thanks to robbie and alan and anyone else that took the time to chat to him.

i thought it would be safer to give it to you in person, well yeah he is hoping to and picked up a few little bits today and never say never.


Numbers sounds like a plan as we stopped for a pint on our way back today to talk things over, would be good to meet up with your dad too.


Eddie