Does size matter?

[Kev L]

OK now I hopefully have your attention, has anyone got any advice, either for or against, the varying of the induction bellmouths. I know there has been some discussion around bonuses in low down grunt when two long trumpets are used and higher revving power when two short are used. So is there really any difference or is this an urban myth?
Whilst I have the tank and airbox off at the moment, trying to fit the front vacuum take off (By the way how the F**K do you get the blanking bolt out. You need the manual dexterity of a gyneacologist!) I am thinking of putting the longer trumpet on.

[darkember]

Ok about the vaccum adapter to the front cylinder. For ease of carb balancing in the future you should fit the adapter & extra length of vac pipe at the same time. The best way is to remove the carbs as well. I did not do this but fitted the vac pipe to the adapter then screwed the adapter in using the vac pipe as a flesible long screwdriver. I also liberaly coated the adapter thread with threadlock then managed to just get a set of longnosed thin pliers onto 2 of the flats to give it a nip.

About the trumpets have have no idea

[tattoo]

i used a long reach allen key to get the little bugger out without taking the carbs off(i have small hands ) and the adapters from carbtune has a slot in the top so you can use a long thin blade screwdriver to screw it in...don't forget to take the rubber washer off and put some loctite on the threads before you fit it too..

[Kev L]

Thanks for the comments. I bought some of the morgan carbtune adapters, which have a slot in the end to allow tightening by a screwdriver. The allen headed blanking bolt is very tight and very inaccessable. Lost the light (don't it get dark quickly now? and why is it a surprise each year when that happens?) early so I will have another go tomorrow.

[Wicky]

Like tattoo there's no need to remove carbs - I used a long socket extender with an allen socket to get the blanking bolt out, just enough room past carbs to get access. Same as him to install takeoff adapter.

[tony.mon]

Have a search in Workshop, I dyno'd two long vs short and long a few years back.
Made a bit of difference, but felt right with two long, the extra torque for me, at least, was worth sacrificing a couple of bhp.
Why not just try it and see, they're cheap enough.

[Kev L]

Cheers Tony, I took the plunge and bought the bits a while back but only just got round to doing a bit of maintenance. I had heard talk of gains but just wanted to see whether anyone had hard evidence of advantages.
I will have a pop at two long un's. OOOOhh errr missus.

[benny hedges]

trumpty things.... on a standard engine you will notice a midrange boost with 2 long, moreso with a 15t sprocket!
2 short tend to make the engine more rev hungry and its noticeably more powerfull at the top end - mine is anyway with different cams & light flywheel.
makes the bike feel very different but you have to get used to the power delivery to appreciate it.
at peak rpm the engine is making more power than in the mid range so it does feel faster to ride.
tbh there isnt much difference in fuel economy whether you ride at mid rpm or up at the redline all the time.

[budd]

Like tattoo there's no need to remove carbs - I used a long socket extender with an allen socket to get the blanking bolt out, just enough room past carbs to get access. Same as him to install takeoff adapter.

what size is the allen / socket is the blanking plate?

[Wicky]

IIRC 4mm or 5mm. 1/4" or 3/8" will do depending on what long extender wobble bar/s you can get your mitts on.

Like tattoo there's no need to remove carbs - I used a long socket extender bar with an allen socket to get the blanking bolt out, just enough room past carbs to get access. Same as him to install takeoff adapter.

what size is the allen / socket is the blanking plate?

[sirch345]

Don't over tighten the brass adaptor

(A) it's only a small thread with a hollow center.

(B) it's made from soft metal, brass.

It doesn't need to be over tight as it's not going to move with thread lock on the threads, but do allow (as instructions) the specified time before using the bike, for the thread lock to go off.

Chris.

[Kev L]

Thanks for your comments chaps, I managed to get the adapter fitted along with the take off pipe. Fitted the two long induction trumpets and changed the clutch line to a Goodridge ss one. I will test ride it tomorrow and expect great things or Mr Mon gets it!!!

[sirch345]

or Mr Mon gets it!!!

what Tony gets your bike for keeps

Chris.

[Kev L]

Mr Mon, you will be pleased to know your safety is assured. I had my first decent ride on the bike today following the fitting of the two long inlet trumpets and it feels a lot livlier through the mid range, it had the front wheel lifting when rolling on the throttle overtaking.
Great fun and for the £9 I paid for the two inlets a bit of a bargain. If you haven't tried it yet I would recommend having a go.
Thanks very much to those who put me onto this,

[tony.mon]

My experience as well.
After all, how often do you wring its neck for that last HP/mph?
But at every lights or overtake you can use torque.
If it's either/or, I know which one I prefer.