Been reading to change the small jet to a 45 and the big one too a 180 with the high flow air filter, well i got the high flow put on (SE) and a Dyno jet kit. It looks like he just put in the 175 main jet and took out the stock 180. The bike is running great but should it be running better ?? Why didn't he change the small jet and will this take away from the bike??? Also why did he size the main jet down do the dyno jets have different properties then the stock ones??? The bike idles at 1000 rpms know where before it was .8

 

I think for most it's a hit or miss situation... they go by what has worked for them in the past.

Though it's been awhile since I've done anything like that and with the computers they have these days things may have changed a lot.

We use to use pyrometers in the exhaust to determine the exhaust temps... and select the proper jets from those readings... a piston will fry around 1325 degrees or so you jet to stay under that by a comfortable margin... like I said though they may do it defferent these days to figure out the exhaust temps...

There are no plugged holes in my exhaust so I know they didn't use a pyrometer in mine...

My bike runs on the rich side, though not too rich... I would say they got it fairly close... on the safer side...

Charlie D.

 

Mine had a stock 42 and 170. I put in a 45 and 175. The idle speed is a seperate adjustment. 1000 rpm is better than 800 as far as getting more oil moving in the engine but you could turn it down. The most important part of your description is that you say the bike runs great. It was probably set to a dyno. Otherwise it's trial and error. The only way to know if it could be better would be to experiment.

 

no dyno he siad he could tell from the sound that is was good. Looks like he followed the instrutions in the jet kit to a T. With the dyno jet kit i got a free dyno run which im going to use this weekend to get the skinny. From what i see from the search the dyno jet kit can be used withought switching the small jet. The bike is not poppong through the pies anymore and pick up after first gear is noticably better

 

I would see if you can find someone with an exhaust gas analyzer to see if it is close. Tim

 

Easy 1200 rejet. 45 slow 180 main, stock needle with one shim, fuel adjust out 2-3/4+-.