Are "dynojet" jets numbers different then other brand jets?

[carlj75]

I'm trying to help out my friend who just bought a 400. He has a T4 slip on, k&N, with no lid. He didn't buy the jet kit....just one jet from the dealer. It is a 170 main, and it has the same markings on it as the stock 148. When I did mine, I put in a 170 main "dynojet". Well, his won't even start now. It's been so long since I jetted mine that I can't remember how to do it. I was thinking that his 170 is way too big......Any help is appreciated.

[BigThumper33]

yes they are

[K_Fulk]

Try a regular 155 and open up the airscrew a lil more (one on bottom of carb).

[trailburner]

If the bike does'nt start first put a knew plug in it, & yes the 170 main is alittle to big [thats prob why it fouled a plug?] mine is running fine with my mods in my sig below [allmost same as him K&N with lid off etc..] with a keihin 160 main or a 165 at the most. the rest of the carb I left pretty much in stock set up, hope this helps good luck!.......

[Sandragggen]

This is a Mikuni vs. dynojet conversion chart.

http://www.ds650.net/mikunivsdynojet.htm

[carlj75]

Ok, thanks for the replys everybody. It was just very flooded. We put the stock jet back in for now and put a new plug in. We got it started. I told my friend to buy the dynojet kit.

[cjames235]

what about the keihn(sp?) jets are they also different than the dynojets? cus the dynojet sheet is telling me to put in a 146 mj but im hesitant since the stock is a 148. but maybe the 146 dynojet is bigger than the stock 148.

[timewass]

Most jet sizes differ between companies. There is even the possibility of a difference within the same company. Jets are machined and machining is a pretty accurate process, but there is room for error.

[northeast400]

the dynojet numbers are very different so is the taper of the needle, I run a 146DJ main jet with my mods and the lid on.