DMC 916 Jetting Question.

[J. Allen]

First, let me say that I know very little about carburetion. I've read the pinned topics and lots of other's questions regarding their changes and troubleshooting. I've also purchased a Clymer's manual.

 

I plan to go slowly, and attempt to accomplish this myself.

 

I do, however, have a few questions regarding the necessary jetting changes required to install the DMC 916 exhaust, a K&N filter, and a K&N powerlid.

 

Aside from these proposed changes the bike is completely stock.

 

I live in Western NY where the elevation ranges between 800 and 900 feet above sea level. Temperatures this time of year ranges between 70-90 degrees.

 

I've been running VP 108 with a fully synthetic two stroke oil in a 24:1 mix ratio (I know most of you run 32:1 or higher, but I just figured I'd be safe, hence I used the higher octane to offset more oil in the mixture).

 

The DMC instructions call for a 280 main while using the airbox lid with a hole cut in it, or a 320 main or higher when using an open airbox. With the power lid I figured I'd split the difference and go with a 300 main. Does this sound reasonable?

 

I was going to buy a jet kit, but after reading some posts on here, some feel that they're a waste. I've gathered that the best plan of attack is to buy only what jets I need (well maybe a couple sizes of mains).

 

Also, for those who have installed this combination, did you need to change the pilot jet or could you tune the pilot circuit well enough with the air screw?

 

Lastly, in preparation for this install, I started tearing the bike down. I cannot for the life of me loosen either of the carburator caps. I don't think the person who owned the bike before me had ever taken them off. The manual states loosen but do not remove the caps while the front (engine) and rear (intake) clamps are in place, then remove clamps and carburetor. I tried this for an hour before I took the whole assembly out to try and get a better grip. Even tried some pliers with a shop rag wrapped around the cap, but I don't want to fuck it all up. I used some penetrating fluid, letting it soak in for a while, but, no dice as of late last night.

 

Any insight you guys have for me would be greatly appreciated.

 

Thanks.

[J. Allen]

MarineNYC was kind enough to talk at length about his experiences jetting the 916's. With his advice I think I have a solid starting point. Thanks Sean.