85 GPz750 Refresh Project

Hope it turns out better in the future Steve, very best wishes for you and keep the rubber side down

Brett

Don't get me wrong. It is better this way. I don't have anymore selfish people in my life. That leaves way for the good ones. My granddaughter's birthday is tomorrow. Gonna watch her ride and her mother bought her a tent to camp out with her friends in.
It's all good. Riding Bossie to get there is half the fun.
Steve

swest wrote: Don't get me wrong. It is better this way. I don't have anymore selfish people in my life. That leaves way for the good ones. My granddaughter's birthday is tomorrow. Gonna watch her ride and her mother bought her a tent to camp out with her friends in.
It's all good. Riding Bossie to get there is half the fun.
Steve

Outstanding! Have a great one, happy early b-day to the kiddo and be safe and have a blast, these are the times that memories are made from

Brett

And good clips too. :woohoo:
Steve

Well got it scheduled to ride Saya over to Pops place and meet at his shop at 10am tomorrow morning. Will then be spending some time reinstalling the K&N filter and then trying to see if we can fatten up the carbs enough to get past the lean spots and make it run right with the high-flo filter. If not then will have to order some larger jets to accommodate it.

On a side note, while it was colder than an ex's heart at cruising speed on the state highway, I was able to get a ride in yesterday for about 40 minutes during my lunch break. I had swapped the stock filter back in and she was riding well again. That being said, when she was warmed up the idle was so low that about 50% of the time at idea she would die. Also above 8K rpms it would lean out and would hit a flat spot where she wouldn't accelerate very hard, at least nothing compared to how she was before. I suspect that is due to how cold the air was, the colder the air the denser the air charge which means it is getting more air than it normally does riding at 70 degrees or above and leaned out. Seems like it is already even with the stock filter so close to being too lean that ANY extra air over normal would put it into a lean condition and badly affect the performance. Just another indicator of how lean these are jetted from Ma' Kawi especially at Mile High Elevation here in Colorado.

Should also get a chance to get the tank done and just have the dents pulled and new tank should be on in the next 7-10 days tops.

Brett

Ok bit of an update, got a decent amount of stuff accomplished yesterday but the tank was not in the cards to dig into so no tank.

That being said here is the story, so when I pulled into the shop Pops and I got to gabbing a bit and talking about the fueling issues and adding in the filter to the mix. I had swapped back to the stock filter to ride it as is for a while and noticed that even with the stock airbox and filter above 8k rpms I was still finding some flat spots where it was leaning out and having a bit of idle trouble. Started digging around low and behold the fuel feed going to the carb bank was slightly kinked where it makes the turn to go down and connect to the carb feed. So pulled all of that crap off, ran to Ace Hardware and found a few 3/8" brass 90* elbows. Went back and fabbed up a little line and filter combo again and stabbed it all back together. Came out pretty well I think....

Put it all back together and went for a 5 min shakedown to see if that fixed it. Two lane backroad, no side traffic and no one on the road but me for over a mile in all directions, lit her up from stop and ran up to 9000 rpms in every gear to see how she acted through the whole thing, do the ton baby

Lean condition fixed and she rides like a friggin' banshee! So now that we proved that we got it back to 100% in stock trim, time to add in the new element and see how she behaves with the new filter. Swapped it over and did another short shakedown ride same test, and it hesitates and stumbles from idle to 4000rpms sadly and especially off idle trying to engage the clutch and pulling away it has a lot of trouble and nearly dies. Above 4000rpms she rides pretty darned well. Could be that I am so focused on trying to notice or see an issue that I am imagining things, but it seems that it is either right about spot on above 4500 rpms or just a touch lean. Feels like there should be a bit more pull in the seat of the pants but I could be imagining it because I am so focused on trying to see it. You know how it goes, if you go out looking for a fight you WILL find one lol, wondering if the same thing is happening here in my mind. Ether way its on the hairy edge of being lean at the top end too.

So came back and put the pilot screws to 3.5 turns out on each carb to max it out for what I can do with current jetting, Back for one more shakedown run. The pilots being turned out all the way did help noticeably but there is still a significant hesitation and stumble below 4500 rpms. Twist the throttle and there is almost like a delay before it surges forward, reminds me a lot of old fashioned turbo lag honestly, best way I can describe it and still has issues off idle pulling away.

So here is where I think I am at, I think I need to go up one size on the main jet to be safe in case I really am that close to being too lean on the top end, plus it will help for future mods down the road. Then I think I need to go up 1-2 jet sizes for the pilots as well. What do you guys think and what jet sizing should I go to for Main and Pilot? My carbs are BS34 Mikuni's fyi, haven't looked up what stock jetting is so can't say for sure, but looking into it today. Last thing, remember I am at elevation and live at nearly 1 mile high so lot thinner air up here than most of y'all are at.

Thanks,
Brett

One size up on the main won't hurt. I'd focus on figuring out how to lift the needle first. I'm not familiar with Kawasaki's version of the BS34's but lifting the needle should be possible. On the Suzuki version BS34 the needle height is controlled by the washer stack on TOP of the needle clip but again, Kawasaki's version may be different. At any rate, lifting the needle will richen the mixture in the low and mid range so I'd give it a try and see what happens.

Nessism wrote: One size up on the main won't hurt. I'd focus on figuring out how to lift the needle first. I'm not familiar with Kawasaki's version of the BS34's but lifting the needle should be possible. On the Suzuki version BS34 the needle height is controlled by the washer stack on TOP of the needle clip but again, Kawasaki's version may be different. At any rate, lifting the needle will richen the mixture in the low and mid range so I'd give it a try and see what happens.

So Ed you would suggest lifting the needle over getting new Pilot jets? Hadnt even considered that, will have to try to look into that and see what I can find. Im not much of a fan of pulling off and apart carbs multiple times so my thought was I really only want to do it once, if I am already in there going to replace the main jet and should do the pilots too since I am already there and don't want to do it again. Is it not necessary to change the pilots and more important to just lift the needle?

Thanks,
Brett

On most bikes you can pull the carb top off and then remove the slides with the carbs bolted to the engine. I'd most definitely work the needle before anything else. With the Dynojet kit they don't even change the stock pilot jet and those kits are primarily for pods and a header.

Nessism wrote: On most bikes you can pull the carb top off and then remove the slides with the carbs bolted to the engine. I'd most definitely work the needle before anything else. With the Dynojet kit they don't even change the stock pilot jet and those kits are primarily for pods and a header.

Thanks Ed, that makes a lot more sense and will check into that. Helps a lot knowing that even the higher stage Dynojet Kits don't up the pilot jet. Will check into this more now.

Thank you,
Brett

Well figured out a few things I think, got the stock jetting information which is shown below. According to this the jet needle clip position is not adjustable which worries me as I am not sure how to correctly shim the needle valves up to get more fuel there. As for the main jet it looks like I am currently running #110's, so to go up on those to help the current situation and make sure future mods don't lean it out what Jet # should I be purchasing, any brands or company that are better that I should buy from? Im sure this sounds so stupid and noonish, but this is the first time I have ever dealt with carbs, before this bike everything I have done short of just getting an older car to run was on fuel injection so I am clueless on this stuff.

Lastly, to confirm the direction I need to be going here is to buy larger main jets but leave the pilots alone and just raise the needle up to let more fuel in for the low and mid range, right??? Just confused at why I wouldn't replace the pilot jets at the same time with larger ones since I am already in there. Its a major PITA to pull these carbs off and on with such a cramped and tight space on my bike. The backbone of the frame right above the carbs is much lower than many of the other years and makes it a true hoe-bag to try to connect all the cables and lines and everything. Really don't want to try shimming just to find out it didn't work and need to up the pilots and pull it out again. I am the noob here for carbs so I will listen and take the advice of those that are smart and have come before me but want to make sure this is the right direction????

Wrap up:
1. What size main jet to increase to, current have #110's
2. How to shim the needle valves since according to FSM these are not adjustable??????
3. Do or do not change the Pilot Jets, and if change then to what size since stock is #37.5


Thanks all this is really confusing to me and still very much in the infancy stages of my understanding and knowledge with carbs!

Brett

Well on a completely unrelated note, while I am still grinding away on this frustrating carb tuning issue with the filter I have been making progress elsewhere :evil:

My C10 petcock manual conversion kit/rebuild was ordered and will be arriving Thursday so that I can finally fix this damned petcock fuel leak once and for all!!! Secondly, working with a friend who is strongly considering having us team up to create our own fork brace for these bikes since the only once I am aware of is that ugly as sin Tarozzi monstrosity that neither of us like, he has the skills and tools to start producing them and I am acting as a guinea pig for it. Got all of the measurements and design input done and sent to him and should see some info and maybe even a design soon!

Moving on, also have nearly finished off my final design and mock up of my fender eliminator kit, and thanks to a friend from another forum and input and assistance from him I think we've got a real winner here. I am going to do the final test fit and mock up with my completed template this evening and do any tweaking that is necessary and then it should begin the fabrication phase slowly. This is going to take a bit of time but I am in no hurry so not a big deal at all. Here are some pics of the completed template and mock up, all in all I have probably around 5-6 hrs into this template and mock up and really like how it came out... :woohoo:

More to come as time progresses!

Brett