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-   -   De-restricting an 89 Dommie (https://www.horizonsunlimited.com/hubb/tech/de-restricting-an-89-dommie-74991)

sheffsteve 6 Mar 2014 22:26

De-restricting an 89 Dommie
 
Evening all.

Any ideas on how to gain extra power from a 1989 Dommie? I cant seem to find a dyno kit for this year. Has anyone fitted jets from another bike or know if a jetting kit is available?
Will fitting a K&N make a noticeable difference?

Thanks in anticipation

Steve

sheffsteve 7 Mar 2014 18:12

Quote:

Originally Posted by Steiner (Post 457268)
is it the same carburettor as other years
also stock exhaust can be a limiting factor

Not sure if the carbs are the same throughout the model changes, although I'd be grateful if anyone has this information.

My Dommie has a replacement can at the moment

*Touring Ted* 7 Mar 2014 21:06

Same engine mostly..... Same carbs too.

If you plan on doing it yourself, I would do a lot of reading up on jetting and how the carb works at different throttle openings.

sheffsteve 9 Mar 2014 14:26

Thanks Ted

I'll do some more research!

*Touring Ted* 9 Mar 2014 14:57

Quote:

Originally Posted by sheffsteve (Post 457436)
Thanks Ted

I'll do some more research!

If you were more local, I'd happily of given you a hand.

I've tuned all mine up so if you need any help, just let PM me bier

sheffsteve 9 Mar 2014 20:40

The Wirral is a stones throw away mate. Thanks for the offer, I appreciate it. Think I can fit the Dyno kit from an XR650 so maybe taking your offer up when it arrives, although the first job is to get the tank fitted. Spoke to Acerbis last week and thet have said they'll sort it as soon as possible.

Jethro 9 Mar 2014 20:54

XR650 kit will be different as the XR650 has a totally different water cooled motor. The XR650L has the same motor and carb but different exhaust and airbox. The biggest things that effect tuning on a big single are the airbox and pipe so the 650L dynojet kit may not be any good either.

I have a straight through laser single "silencer" on my dommie and it's been on the dyno. No major jetting changes required and no major increase in power over the stock twin exhausts but throttle response feels a bit snappier. Biggest restriction seems to be the airbox. Removing or hacking down the snorkel seems to be the way to go to get a bit more power. It's certainly not the best airbox design in the world.

cheers

Stewart

*Touring Ted* 10 Mar 2014 12:25

The Dynojet is just a few jets, a lighter CV spring and a different profile needle.

The one for the XR650L would be a much better match in my mind as it's the same Carb and the same engine. You might just need some smaller main jets as the airbox is more restrictive on the Dommie.

You could get away with just putting in a bigger main jet and drilling the slider hole (research 'DAVES MOD')...

The jets are all available separately from many places. inc Ebay.

I'd cut off most of the snorkle off and put a free flowing filter in too.

Tuning carbed bikes is just a case of changing this and that until you get it right. Trial and error really.


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