Triumphrat

webonnielad

Hi Guys

I've just ordered an Air Box Elimination Kit from Mike at BellaCorse. Wanting to make a proper job of it I also ordered the billet Intake Manifolds from New Bonneville at the same time. ( see Link ) So that my carbs are 100% bullet proof and sturdy on the bike.

http://www.newbonneville.com/html/bi...manifolds.html


My bike is a 790 T100 Bonneville so does'nt come standard with the intake isolator blocks fitted on the later 865 models.

My questions are:

As the rubber mounts are single ended and smaller than the standard mounts.

1. Is there any likely hood of Thermal Conduction from the cylinder head to the carbs via the manifolds pre warming the carbs giving me problems with the mixture?

2. Should I buy and fit isolator blocks as per the 865 model?

I'm gonna forward this to sweat as he's the man but any other contributions gratefully accepted.

Jon UK

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790cc 2003 T100 Bonneville. 18T Front Sprocket, AI Removed, 125 Mains, 40 Pilots, Thruxton Needles, 1 Shim,3mm Air Hole, Mixture screws 3 1/4 turns out left carb, 3 turns out right carb, Unifilter, NH Belmouth, NH Classic Togas with no mutes inserted, Stock Ignitor Unit. Hagon 320mm rear shocks & progressive fork springs. Last measured. 61.60 hp, , Max torque 48.40 in 5th gear at the rear wheel at 7200 rpm, 105 mph in 5th at 6500 rpm.

Brooksie

I have the intake manifolds on my 790/904. I did it the same time I did the air box removal. I did it when the bike was a 790. You do not need any isolators, at least I didn't, even with the big bore kit. I stuck with stock carbs as they are more forgiving for street use.

Retro-Racer

A: No.

A: Yes.

/Mike

SHILOH

It really doesn't matter, but since you asked, FYI, unless the mainfolds are modified, you cannot get the required 30 mm bolt lenght in place. Max length is just 20 + mm which will not allow the spacer to be installed and adaquate connection to the cylinder head.

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Tusitala - Mt Vaea

22856

Hey guys.....what are these isolator blocks?....do you have a link on
where to buy em?

Thanks.

sweatmachine

can you esplain more? I'm interested.

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"If you will it Dude, it is no dream"

904cc Custom Bonnie Cafe Fighter!

mikeinva

I can not see why you would need the isolator 790s dont have them and they work fine.The billet manifolds are shorter then stock but i cant say they helped or hurt when i had them on a stock 790 .They do hold the carbs good.

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Why do I feel young on my bike

grayghost

My new Intake Manifolds just arrived from New Bonneville. I'm looking at them (they are beautifully machined) and wondering;

1. Do I need to apply a thin coat of any type of high temp sealant between the head/plastic block or
2. Install everything clean and dry and torque the bolts to the specified torque.

Any thoughts from those that have installed them?

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" My bike pulls to the left......or the right....depending on what side of the road the Tim Hortons is on"

SHILOH

Just clean, everything is o-ring sealed. You might want to use allen bolts/Hex bolts as the two inside bolts are a real pain to get to. Sizes are M6x1x20 without spacer block, M6x1x30 with spacer block (I think this values are correct)

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Tusitala - Mt Vaea

Retro-Racer

The spacer blocks are black phenolic plates that are between the cylinder head and the intake manifolds on 865cc engines. The older 790cc engines had longer manifolds and no spacers.

When the America & Speedmaster were introduced, they came equipped with shorter intake manifolds (compared to their 360° counterparts) and no spacers. With the introduction of the 865cc Thruxton, the factory started using the shorter manifolds from the 270° engines and a 6mm thick spacer. I assume this was done to reduce the need for 2 versions of manifolds, replacing the longer one with a cheaper spacer.

If you have eliminated the airbox, one can add the spacers to the longer 790cc manifolds to create a longer intake trac for increased HP. The SouthBritishTriumphBayCustomUSAwhatever manifolds are not only short like the 865cc OE parts, but they also lack the 5° angle built into the stock rubber couplers. Adding the spacers will help with petcock clearance and air filter-to-side cover alignment.

To get around the inability to add longer bolts to the billet manifolds, use studs screwed into the head with hex nuts and lock washers. I needed M6x35 bolts with OE manifolds & spacers, but didn't have any, so I cheated with M6x40 bolts and some stacked washers. Crude but effective.

/Mike