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re-jetting needed with cherry bombs?

651 Views 5 Replies 4 Participants Last post by  ScottRNelson
Hi all, I want to put cherry bombs (ala Speeddog style) on my "99 M750. Going to use the 1.75" ID x18" body ones.
Will i need to re-jet? Should I maybe restrict the outlet to 1.250 "or 1.5" for some backpressure, and maybe eliminate jet changes? Im' not looking for more power, just more sound.

Also, any ideas what he used for the mounting bracket and how it is attached to the muffler?
Thanks, Wayne
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wzuccarello said:
Hi all, I want to put cherry bombs (ala Speeddog style) on my "99 M750. Going to use the 1.75" ID x18" body ones.
Will i need to re-jet? Should I maybe restrict the outlet to 1.250 "or 1.5" for some backpressure, and maybe eliminate jet changes? Im' not looking for more power, just more sound.

Also, any ideas what he used for the mounting bracket and how it is attached to the muffler?
Thanks, Wayne
PM him. I'm pretty sure he'll share info with you. or you can wait for him to post.
2
I'm not sure if you'll need to re-jet, our engines aren't very similar, so my results don't mean a whole lot for your bike.

Anyone that has put aftermarket cans on their carbie 750 should be able to get you close as far as the jetting goes, the cherrybombs aren't really much different internally from the more common aftermarket cans.

Here's a couple pics of the mounting bracket and header end of 'em.



The bracket is 1/8" x 2" steel strap.

Mine are 2" diameter, so I had to pie-slice the spigot to shrink the diameter.
You shouldn't need to do that with the 1 3/4" size.

You can see the small length of bend with a short straight section that was necessary to match up with the header.

The end that slips inside the header was a bit of an issue, I *happened* to have a piece (barely long enough) from an old Honda exhaust that was the right size, it's a metric diameter.

A good muffler shop should be able to shrink or expand a piece of inch sized tubing to fit inside the header.

I recommend making a crude jig to hold the rear ends centered and at the same height, I didn't do that, and they're a bit askew.
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Hey Speeddog, Thanks for the reply and pics. I fighued out that i need a short 1 5/8''od tube with a 22 deg bend, slightly
expanded on the header end to fit inside, and expanded on the muffler end too. I may try a no-weld system, making the bracket T-shaped and using two SS 3" muffler clamps or maybe hose clamps on each bomb to attach them.
Thanks, Wayne Z
I think that the T-bolt style band clamps are the only ones that will have enough muscle to do the job, other than the muffler clamps.

these can be had from McMaster-Carr for reasonable money, page 232 at mcmaster.com:

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Unless your bike was already lean before switching to open pipes, you shouldn't need to rejet. Monsters don't seem to be affected a great deal by differences in back pressure. Changes to the airbox make a BIG difference, though.
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