Ok, I have a 01 800 (non ves) going in a 98 xc chassis.

I have a set of HTG twins for an 01 and a SLP head (for twin pipes) with 49.5cc domes (3-6000 ft). I run at 700 ft elevation.

Is this setup going to be a bit much for 91 octaine? or should I get the 0-3000' domes ( 51.6 cc)??

I've run the 3-6000' domes on my 700 with a SLP single pipe with no issues.

I dont have any info on the HTG twins but I have heard they are similar to the SLP's? If I run the twins with the stock head do I need to retard the timing like the SLP twins?

Jetting specs are unknown as well. My plan was to gut the airbox and use stock jetting (460) as gutting the box is like running bigger jets. I was planning to try 10-66 as a start in the primary with an almond/blue spring. I run a cat roller secondary with a 60/48 cam with a yellow spring ( not sure on spring).

any info is appreciated

thanks

Gutting the air box is like running bigger jets? Don't you mean, when you gut the air box you need fatter jetting?

What I mean is when you gut the airbox the vacume signal to the carbs float bowl is reduced. This allows more fule to flow out of the jets. Even with the same jet size. The vacume created in the intake of the carb has to overcome less vacume (higher bowl pressure) in the bowl so the result is more fule is pulled out of the bowl. This is effectively like jetting up without changing jets.

If you pull your carb vents off the airbox and go for a spin your sled will run way rich and will run poorly.

The signal through the venturi is also reduced, but you're the cook on this one...

i have a 98 xc 700 with twin htgs and have to run 205 mains on the pto and 210s in th mag this seems to keep the egt temps the same.idont have a gutted air box maybee i should do that.any suggestions

You should be able to leave the timing. Run the 00 800 non-ves needles, the 01 are a bit lean in the midrange for twins. As far as the compression, I think it will be too much.