EXUP Worldwide

hey bros im new here.<br>pretty new to bikes like this rode strokers years ago.<br>the problem is my bike will run all day at 6/7000 but above that the engine dies.it chugs like @#%$,like racin on then dyin.<br>drop the clutch and the engine dies immediately.i had the problem before got it fixed ,bike was beautiful for a month.<br>the mech said it was some broken screws on the carbs, and now he reckons its the seals between the carbs and the cylinder head.its costing me a @#%$ fortune 300 euros and now another 300.anyone know what it is. <p></p><i></i>

I would start by emptying the fuel and checking the fuel filter. Then take the carbs apart and clean them. Could also be a fuel pump problem. May not be keeping up. <p></p><i></i>

check my thread on crank sensors and misfiring<!--EZCODE EMOTICON START :hat --><img src=http://www.ezboard.com/images/emoticons/pimp.gif ALT=":hat"><!--EZCODE EMOTICON END--> <p></p><i></i>

<!--EZCODE EMOTICON START :rolleyes --><img src=http://www.ezboard.com/images/emoticons/eyes.gif ALT=":rolleyes"><!--EZCODE EMOTICON END--> <!--EZCODE EMOTICON START :rolleyes --><img src=http://www.ezboard.com/images/emoticons/eyes.gif ALT=":rolleyes"><!--EZCODE EMOTICON END--> <br><br>Well, If the motor noses over on application of load, It's usually rich and you guys know what I have to say about carbs that run rich<br>Clean em...check those emulsion tubes (funny thing is I've seen other folks have worn tubes but I've never had any myself...ever...and I have upwards of 30 bikes)<br>do the carb test as perscribed by our own Flying Circus<br>(do a search) check the needle position on those jet kits, remove the freekin air correctors from those dynojet kitted carbs, and check the pilot air screws.<br><br>Did I miss anything?<br>Jim <p></p><i></i>

Yes Jim, you did. You said nothing about putting in a Big Bore Kit. <!--EZCODE EMOTICON START :rollin --><img src=http://www.ezboard.com/images/emoticons/roll.gif ALT=":rollin"><!--EZCODE EMOTICON END--> <br> <p>Tim<br><!--EZCODE IMAGE START--><img src="http://img69.photobucket.com/albums/v20 ... <!--EZCODE IMAGE END--><br><!--EZCODE ITALIC START--><em> Has anyone seen my keys?</em><!--EZCODE ITALIC END--><br><!--EZCODE ITALIC START--><em>Dir. of Entertainment<!--EZCODE LINK START--><a href="http://eddieandthecruisersmc.com" target="top"> Eddie & the Cruisers</a><!--EZCODE LINK END--></em><!--EZCODE ITALIC END--></p><i></i>

Could someone point out these air correctors to me please, or post a picture to save confusion. Thanks Steve <p></p><i></i>

The air correctors go in the air pilot air jets in the bell of the carb (mouth) they are a little brass plug with a smaller orifice than the air jet (thus ...restrictor) that has the function of making yur bike run even richer with a Dynojet kit in it!!!<br>it's the jet at the bottom of the bell mouth of the intake side of the carb on the left side...if there's a little plug in there. with no screwdriver slot....get rid of it!!!<br>Then Big Bore it!!<br>Jim <p></p><i></i>

Thanks for that dragracer, you have been a big help... Regards Steve p.s. Lots of talk about big bores on the forum but can you recommend a big bore kit. What size do they bore out to? <p></p><i>Edited by: <A HREF=http://p072.ezboard.com/bexupbrotherhoo ... 0muppet</A> at: 7/1/04 3:50 am<br></i>

Well let’s veer off the topic, the thou has a couple of options, but assuming you are talking about the 750 as your name implies, then it gets a bit complex. TTS in uk offered an 836 kit & APE used to offer a 856ish kit. <br><br>They withdrew it from sale as they had problems with it leaking. When I sent a spare barrel to an engine builder who has some experience Big boring stuff he said he could see why, there is very little meat & the bores sit like little islands. I want to pull off a 1000 block & see if I can get it to fit my cases & my 750 head. There would then be the question of whether the valves would hit the 1000 pistons & the final comp ratio.<br><br>Feel free to offer concise answers anyone?<br> <p></p><i></i>

I think that the best bet for a 750 is to transplant a 1000 engine in the frame. It would be cheaper and perform a hell of a lot better than some conglomeration of parts from both engines. It might be possible to use a 1000 jug on a 750 motor because most of the major parts are physically similar. But, there are a lot of details which are different. It would be futile to use a 750 head since it would just choke the additional displacement. The valves are smaller and the ports have a smaller volume. You would have to make custom pistons, which would be expensive and offer very little in return. You would essentially have the worst of both versions. Low flow from the 750 and a poor combustion chamber from the 1000. <!--EZCODE EMOTICON START :x --><img src=http://www.ezboard.com/images/emoticons/sick.gif ALT=":x"><!--EZCODE EMOTICON END--> <p></p><i></i>

Ports on the 750 are still too big, Yam 5v ports are improved by adding material not removing it. I have heard of someone using 1000 pistons in an OWO1.<br><br>I don't want to transplant engine as here it would lead to legality issues. A bigbore they couldn't detect so easily. Besides I can get some barrels cheaper than an engine (from an engine with duff crank). Pistons are an issue though as they would prob be too old to run. <p></p><i></i>

So we need to get hold of some 1000 barrels and do the measuring exercise don't we.... <p></p><i>Edited by: <A HREF=http://p072.ezboard.com/bexupbrotherhoo ... 0muppet</A> at: 7/1/04 11:50 pm<br></i>

Yes, I agree that the flow in a 5v head would be improved by filling in rather than removing material. It's due to the difference between the center to center spacing of the cylinders versus the carbs. The amount of misalignment that the carbs have to contend with is obvious when you look down the throat of the carb into the intake port. Cylinders 1 and 2 have the left part of the ports masked off from flow and likewise 3 and 4 are masked off on the right. This leaves a stagnent area that creates turbulence. Filling some of this in judiciously would enhance flow. This is obvious on the exhaust ports on aftermarket heads for small block chevys (such as Brodix) where the exhaust ports went from round to a D shape. Even though this is the case, a 750 with smaller ports and valves will not give you a boost. The ports are smaller, but they also have this mis-alignment problem. The valves are much smaller in diameter and you have to remember that they are open fully a small fraction of the time. most of the time they are in transition and open only slightly. When this is the case, flow area past the valves is measured as (valve circumference X valve to seat gap). If you look at the changes taken by the Japanese since the mid 80s in to produce bikes with ever higher horsepower/displacement levels you will notice 3 trends:<br><br>1. Bore/Stroke ratios have become increasingly over-square. An over-square bore allows you to stuff bigger valves into an engine of a given displacement.<br><br>2. included angles between the intake and exhaust valves have been tightened up. Tighter included angles increase the compression ratio and allow straighter flow paths. <br><br>3. Carbs, airboxes and mufflers have grown.<br><br> <p></p><i></i>

Just had to throw it in but over square also gives you more top end. <p></p><i></i>

When you add the air correctors you're supposed to drill the slides. So theorectically if you ditch the air correctors and the slides were drilled, woiuldn't you run lean?? <p></p><i></i>

Yea....It will run lean...just lean enough to over come the PIG RICH condition<br>and the air correctors don't have to do with drilling the slides...that's to correct the vacuume signal for the lighter springs...<br>Jim <p></p><i></i>

F5 or 750M, 1000 cc cyl block (quick) specs - <br> outside cyl. spacing 85mm Center to Center<br> 2 - 3 cyl. C/C spacing - 120mm<br> Block deck height 81mm<br> lower barrel protrusion O.D. 80mm. Barrel depth below block -16mm<br> If you need cyl. stud location measurements also, let me know, it will take a little longer to measure out. Bob. <p></p><i></i>

Hey thanks a chunk, I’ll go measure my (borrowed) 750 head & see if that lines up. Don’t suppose anyone has a 750 with the barrels off & can tell me if the cases are a tight fit on the sleeves? ie: will I need to split the cases & core them. <p></p><i></i>