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The curve does look good but the loss of 8HP is unacceptable. What was the AF Dave?
That is frustrating Dave, Maybe I need to get some 31's, lol. Once I get a few more miles in on my build I will try to get it on a dyno for some results. Thanks for all the work you have put in on the 34's... I am kind of glad I don't have the easy access to the dyno you have, this has been troublesome for you to say the least. Not knowing what I have as far as numbers might be a good thing.It will still get a dyno run sometime soon.
Quote from: tweakin on April 15, 2012, 11:08:45 AMThat is frustrating Dave, Maybe I need to get some 31's, lol. Once I get a few more miles in on my build I will try to get it on a dyno for some results. Thanks for all the work you have put in on the 34's... I am kind of glad I don't have the easy access to the dyno you have, this has been troublesome for you to say the least. Not knowing what I have as far as numbers might be a good thing.It will still get a dyno run sometime soon.Forget CR31's, CR33's are what you need. Anyway, from my runs we know you're in the ballpark for jetting. That alone makes me feel a bit better.
Here are some photos of the Mikunis that arrived yesterday.I wasn't sure what I was going to use for the rubber manifolds on these as the spigots are 40mm.I had a new set of Honda K rubbers which were tight to get on, but they have snapped on perfectly with a small amount of lube and some even downwards pressure.Mick
Buca, I dont think jets are going to be your problem 36mm are going to be very much on the LARGE side of big..... think about it, people here fit 34's to highly modified 250cc cylinders (i.e. 1000 cc kit) you want to fit 36mm to a 225cc cylinder in an almost stock motor, dont think they will be easy to setup, would go with 34's or even 32's. BTW, 36 dellortos is what i have in my 850 le-mans, just to give you an idea....TGI thought might be to much..I have 38 on my BMW 998cc. But I was asked what I thing about this, and I ask you, just to be sure. Thank U
It wasn't until I got to the idle fuel orifice, a tiny hole on the bottom of the engine side of the carb body, that I noticed an issue. The guitar string only went through one of the ports.Seems someone, odds are it was me, over tightened the pilot fuel screws on 3 of 4 carbs causing the delicate tapered tips to jam in the idle port and shear off. In my defense, the springs and o-rings on the screws create some resistance, making it hard to know exactly when the screw has bottomed out.Never having had all the screws off at the same time, I didn't notice that the tips of the screws looked different. Pretty obvious once they're on the table together though.It's not an unusual problem, so I'm not beating myself up too badly. However, getting the broken off tips out of the carb bodies isn't the most fun I've ever had. In any case, this explains some of the problems I was having, and new screws are on the way.The other issue was one of the accelerator pump sticking. This was solved by using a felt polishing bob on a Dremel, and some Mother's to clean out the pump piston bore. Much nicer now and it returns fully every time.As for jetting, the needles that come with the carbs might be fine for a stock GS750, but on a modified 836 they're too lean. 9DZH03's are much better, curing the huge lean-out that was occurring right after the end of the accelerator pump stroke finished. 127.5 mains were too lean with my open 4 into 4's and 50mm velocity stacks, but with balky pilots and a lean needle it's not an accurate measure. As soon as the new screws are in hand, we'll get back on the dyno and try again.
Does anyone know how to remove the broken tips from the carb??? I have the exact same issue...not good.Quote from: Doctor_D on March 31, 2012, 10:12:25 AMIt wasn't until I got to the idle fuel orifice, a tiny hole on the bottom of the engine side of the carb body, that I noticed an issue. The guitar string only went through one of the ports.Seems someone, odds are it was me, over tightened the pilot fuel screws on 3 of 4 carbs causing the delicate tapered tips to jam in the idle port and shear off. In my defense, the springs and o-rings on the screws create some resistance, making it hard to know exactly when the screw has bottomed out.Never having had all the screws off at the same time, I didn't notice that the tips of the screws looked different. Pretty obvious once they're on the table together though.It's not an unusual problem, so I'm not beating myself up too badly. However, getting the broken off tips out of the carb bodies isn't the most fun I've ever had. In any case, this explains some of the problems I was having, and new screws are on the way.The other issue was one of the accelerator pump sticking. This was solved by using a felt polishing bob on a Dremel, and some Mother's to clean out the pump piston bore. Much nicer now and it returns fully every time.As for jetting, the needles that come with the carbs might be fine for a stock GS750, but on a modified 836 they're too lean. 9DZH03's are much better, curing the huge lean-out that was occurring right after the end of the accelerator pump stroke finished. 127.5 mains were too lean with my open 4 into 4's and 50mm velocity stacks, but with balky pilots and a lean needle it's not an accurate measure. As soon as the new screws are in hand, we'll get back on the dyno and try again.
For any carbs with larger spigots, like webers , mikuni 32 flat slides etc I have purchased 3 sets of rubbers from Japanese ebay over the last couple of years from the the same guy. Everything that is bad about them for a stock carb is good for the modified carbs, ID is 32 mm so dont have to grind out, very soft so they flex over the larger spigots , and Cheap at $35 per set of 4 with clamps. johno
Try googling " Cruizin Image " he has a ebay store happening, if not I'll have a look for the link tonight.cheers johno
Quote from: johno on April 21, 2014, 08:21:41 PMTry googling " Cruizin Image " he has a ebay store happening, if not I'll have a look for the link tonight.cheers johno-These that have 32mm ID?http://www.ebay.com/itm/Honda-CB750K-K1-K2-K3-K4-K5-Carb-Intake-Set-4-Intake-8-Clamps-CI-CB750KINBT-1-/131120059802?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item1e875d559a
