lean or not lean, that is the question

[fonzerellie]

i've been building my 89 gsxr750 streetfighter for the last few months and am not sure if i've come across a problem or not. i've got some K&N air filters and have a new exhaust (the only engine mods). When i rev up the engine it hits a flat spot after about 5grand and struggles to rev up but when i pull out the choke i can rev it up easier.

What do you guys think, is it leaning out, what can i do to fix it?
thanks

[Iceman]

Welcome aboard fonz, have you tried banging it on the tank and saying "Eeeyyyy!"

Just kid'n.

I haven't done it myself but I know that alot of guys have there bikes re-tuned after changing exhausts and filters.

[Slingblade]

You need to increase the jetting, as you correctly diagnosed the filters and pipe will have leaned it out. Take it and get it dynotuned or alternatively look for a dynojet or factory jet kit to suit your bike. That hole it falls into and never comes out of is the bike starving of fuel. You dont want to run it this way for long as an engine running lean is bad news in the long run.

[Gix11]

Welcome Fonzie. When you say K&N filters, you mean pods yea? After fitting pods and a pipe a stage 3 dynojet kit is always a good move. As Nath says, don't run it lean as you'll fuck it pretty badly in the long run! Just confirm the following : Carb size (they're 36mm yea? or was '89 the bigger ones - lads?) - air filter type (sinlge/ dual pods or K&N in airbox) - Pipe (just for the record).

[Tone]

36's on the 89 K model.38,s after that.
And hello Fonz.Nice choice of bike.

[fonzerellie]

http://www.streetfighters.com.au/forum/upload/54421127440684.JPG

I'm not sure on the size of the carbs i've got. I can tell you that the bike is a 12th month 89 and I have dual pod K&N filters. The exhaust is new but not off the shelf, i've custom built all the pipes to come out under the swingarm. The previous owner told me that the bike has had some power kit put in the carbs but after running it i'm not too sure.

[fonzerellie]

http://www.streetfighters.com.au/forum/upload/54421127442553.JPG
Here is another photo, have not got around to building a seat yet

[latheboy]

cool pipes fonz ... and welcome ... buddy if you've got strong legs done worry about a seat!! :D

[Gix11]

That looks trick mate! Supercharger Mark will like to see this one.
Yep, there's your problem straight up mate. Get yourself a dynojet kit pronto:

http://www.dynojet.com/jetkits/index.aspx

[fonzerellie]

Thanks heaps for the web site Gix11. I've got the day off today so i've already sourced out the kit and picked it up. Will be spending the weekend install it i think.

If anyone has some handy tips for fine tuning with this kit that would be great.

[Rocket]

quote:Originally posted by Iceman

Welcome aboard fonz, have you tried banging it on the tank and saying "Eeeyyyy!"



hahahaha, that's GOLD iceman.

Nice pipes Fonzie, more pics please.

[ozkat]

fonzarellie works at the same place as i do, and i saw his near finished fighter today... WOW it looks bloody great. The seat unit... well the seat unit could have come straight from germany, but he made it himself. Im most impressed. Mate get some pics up on here ASAP.

[Nate]

hey fonz have you got a side pic of pipes looks great so far

[Gix11]

Yea Fonz, Shayne rang me from the car park. You need to get that bike to the Bearded Dragon on the 27th mate (http://www.streetfighters.com.au/forum/topic.asp?TOPIC_ID=3770) no ifs or buts! It's just out the back of Tamborine mate and then we are riding down to Tallebudgera Valley for a BBQ night at a members place. I can meet you and ride there with you if you want as I Shayne told me you don't know where it is and there should be some good bikes for you to check out. Where do you live mate? Get in touch.........