Triumphrat

HiVel · 07-31-2007

What can I expect to gain performance wise by enlarging the hole in the slide to 3mm? Very vague benefits described in JenksBolts Tuning Manual.
Increased or quicker throttle response?? Is this a consensus among those who have done this mod? Just looking for some real world experiences before I do the unrevokable deed. Thanks.

bonnevillebilly · 07-31-2007

It did help the throttle response a little.
Still not as quick as the old Bonnie's with the amal carbs.
I think it's just the nature of the beast with the vacuum
actuated carbs.
Bill

TCL · 07-31-2007

I notice a smoother shift due to the increase in throttle response. I ran really wrench on the throttle and shift with a flick of the wrist. No increase in horse power or anything, but I would definitely recommend it if you have time to kill and want to do an easy mod that you can notice.

amanger · 07-31-2007

I did it and didn t notice any difference.I m with jenks on this one.I can understand the theory behind it allowing the slide to lift faster but am sure the design engineers that made the carbs know what they are doing.I had pod filters,open exhuast and rejetted.

Colonel_Dorkus · 07-31-2007

I'm on the fence about doing this as well. Any more care to comment on benefits of drilling those suckers???

-Aaron

ttbonnie · 07-31-2007

I recently did it, after i swaped out my counter for a 19t,
and it realy made a diference, after i put the 19t on it opened up the top end, but 1 +2 were a lil slow getting up, after i drilled it out It made
( not a replacable difference) but definitly more responsive
I sugest using a drill press , or a press you can fit on a corded drill- It makes for a very clean job ( and a new 7/64 bit)

HiVel · 07-31-2007

Looks like I will crank up the drill press tomorrow !!Will report my adventures.

ttbonnie · 07-31-2007

1 more thing,
i used a drill bit the same size as the stock hole for setting up the press this way you dont drill a ob-longed/ off set hole-also
set the press on its slowest setting, the metal is very soft and from what I read on RAT it will mess up real easy and is unfixable
good luck!
tt..

BlueJ · 08-01-2007

I used a handheld cordless drill, hang on tight to the slide so it doesn't spin. Takes about 1.5 seconds per hole to drill, slightly more to gain access to the slides in the first place. I coupled this mod with rejetting and the new air filter, snorkle removal, and TORs, because I only wanted to take those carbs off once if I could help it. Can't say how much of the difference is due to the new holes, but I now understand why folks want that 19t sprocket! In the tuning process Jenks mentions making sure the bike "pulls" well at all RPM ranges. While trying to determine whethere it was "pulling" I kept finding myself north of 6000 and shifting, wrapping it on trying to feel the "pull", north of 6000, etc.

I guess it pulls.

English_Spanner · 08-01-2007

Quote:

Originally Posted by ttbonnie

I sugest using a drill press , or a press you can fit on a corded drill- It makes for a very clean job ( and a new 7/64 bit)

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7/64 ain't 3mm