Topic: Dyno Jet kit

[d9canada]

I'm trying to help a friend with his 1981 Honda 900C with four Keihn CVs. He recently picked up a Dyno Jet kit and drilled slides for it. He has not installed it yet, but is anticipating issues he may run into.

The bike is running a K&N air filter and 985 Wiseco kit with high compression pistons, so it's about 10.3:1. He had to richen the original carb setup with main jets one size larger and 2 shims under the stock needles along with the richening the idle to get it to run acceptably.  So as it is, it runs OK and he's hoping the Dyno Jet kit will help.

The instructions for the kit are for a stock motor or one with a pipe but no internal mods. So the concern is, will he have to use richer settings with the kit such as raising the needles. Hopefully the main jets should be fine. Can anyone confirm this or provide some advice.

Thanks guys

[grcamna2]

Hi Brian ,
     I think you're friend should take the largest size main jets that come in the kit and use a special wire gauge to measure the hole of the largest mains provided..and then look around for a set of the next size up from that...just to be on the safe side.Those Dynojet kits have their own numbering system which are a way for them to try to convince you to buy Their jets.I have a few sets of main jets if you need some larger ones.I think you might be OK though because the Dynojet Kit needles flow much more fuel than stock..and you can raise them on their clips; DJ's biggest will probably be fine...unless he had the head ported...

[d9canada]

Hi Bill!

Thanks I will pass that along.  He actually did have some mild porting done as well.  He's a very good mechanic but like so many of us he is getting arthritis and he does not want to be yanking the rack three of four times to get it set up right. 

I was sort of surprised that the guys on the DOHC site couldn't help but they are real sticklers for stock airbox and original paper filter.  They argue that the air pressure in the carbs get's messed up by even using a K&N in the original airbox, and they go nuts on people running pods!

[Leino]

Most bikes I've installed a Dynojet Stage 3 kit in, are running very rich at WOT with the largest main jets in the kit but need a little playing around with the pilot screw settings and sometimes the needle as well.

[grcamna2]

d9canada,
    What Stage Dynojet kit is he running..? I assumed it was a stage 1 & not a stage 2 or 3.