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Carbs

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Re: Carbs
#16
JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
Dave & Chuck,
Let me know before you buy anything. There is a range of main jets, jet needles and needle jets you will probably need to get you dialed in.
I'm normally jetted for 5200' but I have notes from Road America that should get you within one or two jet & needle sizes.
jim

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Re: Carbs
#17
ceecpa Avatar
ceecpa Silver Member Charles Edwards
Richmond, Virginia, USA   USA
Jim,
Thank you very much for the images and the offer to help us get the correct jets and needles. I will surely contact you before I buy anything.

Thanks again,
Chuck

Re: Carbs
#18
cintitr4 Avatar
cintitr4 Dave Connitt
cincinnati, OH, USA   USA
Same here Jim.
Regards,
Dave

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Re: Carbs
#19
Triumph TR 250 Henning Ringsvold
Brumunddal, Østlandet, Norway   NOR
Hello Jim.
Would the Mikunis work for the TR 250 as well

Re: Carbs
#20
JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
They should work fine on the 250. Your original carbs are the 175 Strombergs right ? so were mine. The only difference being you would jet
richer for the extra displacement. I have a friend that's building a racing TR6 from ground up and he will be using three of them on Richard Goods
manifold.
jim

Re: Carbs
#21
JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
Some more pictures. This is how I attached the throttle cable. I'm sure there are better ways out there but at the time I had a pice of stainless plates and a tig welder right in front of me so this is what I came up with.
Like many things on the car I'll stare at it long enough and improve it someday.


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Re: Carbs
#22
Triumph TR 250 Henning Ringsvold
Brumunddal, Østlandet, Norway   NOR
Thanks.
I changed to SU when I rebuild my 250. I have never been a Stromberg fan.
Will the Mikunis give me any boost up.

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Re: Carbs
#23
JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
In reply to # 925406 by Triumph TR 250 Thanks.
I changed to SU when I rebuild my 250. I have never been a Stromberg fan.
Will the Mikunis give me any boost up.

Yes, they will improve power.
They don't leak or lean out during hard cornering.

Re: Carbs
#24
Triumph TR 250 Henning Ringsvold
Brumunddal, Østlandet, Norway   NOR
Can you send mean internet adress to get them and what I need of parts for the change.
You may send it on my mail hrings@broadpark.no.

thanks.
Henning

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Re: Carbs
#25
ceecpa Avatar
ceecpa Silver Member Charles Edwards
Richmond, Virginia, USA   USA
Jim, I'm preparing to purchase the Mikunis. You mentioned that you could offer recommendations with respect to jet choices and I wonder if you'd be kind enough to do that now.

My TR4 is currently stock. It's a low mileage engine that I recently started for it's first time in 25 years. I rebuilt the engine in 1974 and there's only 6,000 miles on the rebuild. Everything inside is stock. The cylinder liners and pistons are Mahler, the crank is the original diameter, the camshaft is original, the valves are original. Future upgrades would likely include a slightly warmer camshaft and hardened exhaust valve seats. It will be a street engine with occasional autocross events. I live 100 miles from the oceanfront at 400' above sea level and the mountain roads in Virginia are never higher than 2,000' above sea level.

Thanks for your help.

Re: Carbs
#26
JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
What altitude do you live at ?
jim

Re: Carbs
#27
ceecpa Avatar
ceecpa Silver Member Charles Edwards
Richmond, Virginia, USA   USA
In reply to # 930231 by JimG What altitude do you live at ?
jim

I live at 400' above sea level.

Re: Carbs
#28
JimG Avatar
JimG Jim G
Aurora, CO, USA   USA
Sorry Charles, I could see you are in Virginia.
I've been looking around for early notes on what jetting comes with the carbs but no luck.
For main jet I'd start with 195's, #97 jet needle's start on the middle groove and Y6 Needle jets.
No changes to the pump jet or the pilot jet. Pilot screw 2 turns out.
This should start you out rich.
One thing, when you change out a jet needle you need to unclip and back out part way the shaft that supports the slide. You may be tempted to drift the needle around the shaft but you will bend the needle if you do.
Moving the clip up and down the needle will have noticable differences. I use exhaust gas temps and air fuel ratio gauges to tune with. If you know someone with a gas anylizer that could help.
jim


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Re: Carbs
#29
ceecpa Avatar
ceecpa Silver Member Charles Edwards
Richmond, Virginia, USA   USA
Jim, thanks for the recommendations. I found the Mikuni site for setting up carburetors to use with Harley Davidson engines:
http://www.mikuni.com/fs-tuning_guide.html This will give me their knowledge base as well.

Thanks again.

Re: Carbs
#30
RickR Avatar
RickR Rick R
Fishing Point, NSW, Australia   AUS
Hi Charles
Have you fitted Mikuni carbs to your TR4 ???
If you have, are you happy with your install & can you tell me your jetting.
I live in Newcastle Australia, I fitted twin Mikunis to my stock TR4 about six months ago.
I have tried various jetting setups but have not got them quite right yet, main jets 190, 195, 200, needle jets Y6, Y8, ZP1, pilot jets 20, 22.5, 25.
Any suggestions appreciated.

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