Guest Bigin Posted December 11, 2006 Share #26 Posted December 11, 2006 Marcarl, thanks for that save, I thought it did not appear to be from rust or damage, looks like it was posssibly drilled or punched. Any tips on where to look for the cause of backfiring on let off around 4-5000? No other obvious leaks. Thanks Link to comment Share on other sites More sharing options...
Guest Bigin Posted December 11, 2006 Share #27 Posted December 11, 2006 Gearhead, the carbony water does not appear after the bike has been ridden and left idling which I did today after a ride. It appears just cold starting then left idling to warm up, which I now think is normal after extended idling from cold start. Mileage was only 17 when I recieved the bike, but have replaced parts and tuned a great deal, now looks like its approaching 35 this last tank with the Sea Foam, Ring free, shocking, continued Sea foam in the tank, and running it hard. I have owned many lumpy, rumbling sounding bikes, Harleys, Boxers, many British, Guzzis, Many vintage Jap- inline 4's, vertical twin, and ridden the original Vmax years ago, and this year a pretty run out Venture 1200, this is more of a thump amongst the lumps that is very steady and pronounced as rpm rise, fading until around 3000 when it seems to still be there but just blends in at higher rpm. You know how a lumpy engine at idle is a thing to behold, but one of the lumps is permanent, always there, not part of the cadence or the engine, throughout the range, very steady dull thumping unlike the other 3 cylinders. I may have to find a dealer with an EGA to check it. It has clutch basket rattle but Im used to that, common with high mileage Jap bikes with 4 cylinders. Its not that but thanks for the input. I will figure this out. Link to comment Share on other sites More sharing options...
CrazyHorse Posted December 12, 2006 Share #28 Posted December 12, 2006 My 90 does similar smoothes out above 4000 rpm and starts to take off. My Harley Evo is quicker off the line to about 3000 rpm but after that it dies out to the Venture. Used to riding Harleys where all their power is down low below 3000 rpms. Took some getting used to. Mileage starts to suffer though if your cranking that throttle and reving it to 8000 rpms. Link to comment Share on other sites More sharing options...
Venturous Randy Posted December 12, 2006 Share #29 Posted December 12, 2006 bigin, are you familiar with the Jason mod? It is where the front cylinders are connected to the back cylinders with small vacuum hoses. If your bike is set up like that, you are going to have a lumpy idle. It comes with the mod. randya Link to comment Share on other sites More sharing options...
oldandcrotchety Posted December 12, 2006 Share #30 Posted December 12, 2006 Is what you are saying is that you have a dead miss, or a "almost dead" miss until you get up in the rpms? If so, what you might try is to let it warm up and then disconnect one plug wire at a time and see if it makes a differance. If you pull one of the wires and it makes no difference to the idle then you have isolated the problem to that one cylinder. Then it could be addressed individually for the problem. You could then replace the plug and see if it fixes it, then the wire, the cap etc., one piece at a time. I know you said you have already replaced most things, but it never hurts to try rechecking. I have, on rare occassions, gotten a bad plug or wire brand new right out of the box and ran me nuts cause I assumed everything had to be good. Link to comment Share on other sites More sharing options...
oldandcrotchety Posted December 12, 2006 Share #31 Posted December 12, 2006 And, by the way, I'm no motorcycle mechanic at all, but I was an auto mechanic for years, and if this was on a car I would say that it sounds like a classic description of a plug wire that is weak. Miss at low rpm and then finally starts carrying the juice at higher rpms. Sumpin to check anyway........... Link to comment Share on other sites More sharing options...
Gearhead Posted December 12, 2006 Share #32 Posted December 12, 2006 "And, by the way, I'm no motorcycle mechanic at all, but I was an auto mechanic for years" Hey, and engine is an engine, and your auto experience is of the utmost value in troubleshooting any engine! ...Well...maybe not a jet engine... I guess the water coming out when the engine is hot is unusual. Is it very cold and humid where you are? Thinking about your gas mileage and progression of fixes, I think more about the carbs. Did you say you've removed and cleaned them out? Sometimes Seafoam doesn't do it. The other thing that isn't too hard to check is the TCI connection. Remove the battery and batt box, and you can reach the TCI connectors. Remove them, have a look, use some terminal cleaner and reassemble with grease. Have you checked your pressure sensor (vacuum advance) operation? Mine had corrosion on the connector for that, also located under the battery, which completely stopped it from working. Jeremy Link to comment Share on other sites More sharing options...
Guest Bigin Posted December 13, 2006 Share #33 Posted December 13, 2006 Randya, I will check that, is there any more info about where and why this was done? Thats interesting thanks old and crotchety, I have done that every cylinder appears to be firing, all 4 wires cause rougher operation when pulled. Getting a bad plug is maddening, I agree, changed plugs also no change. Gearhead, The water issue has resolve itself for some reason, no problem today even afte cold start and idleing for 10 min or so, tells me the carbs may need attention. dealer had them off and inspected, cleaned, but found nothing needing attention except diaphrams, intake boots, drilled the mixture screws, had never been done, synced them, adjusted valves. I live in the Ozarks of Arkansas not too cold or humid now.I will check the connections at the TCI was in there today, did quick visual is all, vacuum advance seems ok as the engine is responsive. The shake is hard to describe, I am new to the v4 but an engine IS an engine. This feels and sounds just like a dead cylinder to me but they are all firing, making good power, like maybe someone bored one out and oversized the piston, but the top has never been off it. Im riding the hell out of it again today, hoping the pilot jet is an issue, just did a quick 60 miles loaded with Sea Foam again riding in the rpm range for that jet. The last tank was 39 mpg. That was a lot of roll ons and heavy throttle use. I think it is making the power it should expecially above 3k when it smooths out and sound like a Ferrari. It is smoother except for 5th gear which I can live with. Starting to wonder if the Sea Foam is working on my mind or the jet. Feeling oh so slightly better or its wearing me down, just had a great ride down HWY 7 to Jasper, man it was nice, the world was perfect, what a sweet bike this is, have always wanted to try one since they first came out. Thanks for all the help, you guys are great. Im riding it for now. When I catch up with one of you on the road, then I can compare lumps! Link to comment Share on other sites More sharing options...
sarges46 Posted December 13, 2006 Share #34 Posted December 13, 2006 Not carb related....could you have a broken engine mount? Would that do the bad vibration thing? I'm half asleep so if I need a slap let me have it! Link to comment Share on other sites More sharing options...
BradT Posted December 13, 2006 Share #35 Posted December 13, 2006 Not carb related....could you have a broken engine mount? Would that do the bad vibration thing? I'm half asleep so if I need a slap let me have it! Possible the rubber is worn out, but broken I am not sure. Brad Link to comment Share on other sites More sharing options...
Guest Bigin Posted December 13, 2006 Share #36 Posted December 13, 2006 you know what, engine mount is a possibility I havent considered. Thanks guys! Link to comment Share on other sites More sharing options...
Denden Posted December 13, 2006 Share #37 Posted December 13, 2006 I've read the whole 4 pages of this...it sure sounds to me that the carbs aren't synced. You said you drilled the mixture screw plugs and synced them.(???) You really need to get a carb sync tool, either the Motion Pro mercury sticks ot the Carbtune. This V4 really needs to be synced to run smooth. I would never trust a dealer to get it right. You say that it feels like one cylinder thumping harder than the rest...that sure sounds like it is out of sync. It will also affect your gas mileage. Close isn't good, that's what a dealer will do, just get it close. It's got to be right on. Link to comment Share on other sites More sharing options...
Guest Bigin Posted December 13, 2006 Share #38 Posted December 13, 2006 Denden, the folks at my dealer here are pretty thorough, and are fans of the 1st gen. One of the mechanics was there when they first came out and is very knowledgable, has some of the service bulletins in his head from the 80's. He rode it and agrees it shakes, but is certain it is in tune, at least what I had them do-carbs, valves. Says it runs strong especially on the top end. I have been thinking about the Carb tune and have been checking around for a deal on one, as the budget is stretched on this ebay special, but a good thing to have. Im going to check a few possible issues the members have suggested, if no luck, ride it until the weather turns, if the Sea Foam doesnt continue to make progress with it, or I get to compare to another that shakes, or I learn to live with it, I'll be taking things apart myself after holidays. Thank you for your thoughts. Link to comment Share on other sites More sharing options...
Rick Butler Posted December 13, 2006 Share #39 Posted December 13, 2006 Bigin, If this happens at 2,500 rpm in 5th then you are below the ideal rpm limit (3,200) for the Venture and yes it will shake a bit. But if I understand you, when you get it over 3,200 rpm then it smooths out? In other words, the shift points are anything above 3,200 rpm, where it really likes 4,000 to run in it's sweet point. Now if it's a hesitation from 800 to 1,000 rpm you have a transition issue from the low speed circuit (the air mixture screws) to the mid range circuit when the slides start coming out and putting you on the main jets. But if it's the first problem, then you really don't have a problem and just need to ride it like your ex-wife's lawyer is after you. But if it's the 2nd issue let me know. Rick Link to comment Share on other sites More sharing options...
Guest Bigin Posted December 13, 2006 Share #40 Posted December 13, 2006 It has no transition issue that I can detect, It responds to throttle with no problem, just shakes hard below 3000 or so especially in 5th gear below 55, and idle has a single steady chuff sound. This may be inherent with the design, but I would be surprised if this isnt excessive. Getting underway 2 up, between the chuffing and the shaking is more of a dance on the clutch and throttle than any large bore bike I have ridden or owned. It pulls reasonably for the tall gearing it has, but the shuddering sure detracts from the overall enjoyment of the ride. Might be the way it is though. That 3200 is a magic number with it. Thanks for your help. Link to comment Share on other sites More sharing options...
Rick Butler Posted December 13, 2006 Share #41 Posted December 13, 2006 Bigin, Just shift gears around 3,500 and above and you should be just fine, especially in 5th. If you get below 3,200 you are lugging the engine. Rick Link to comment Share on other sites More sharing options...
Guest Bigin Posted December 13, 2006 Share #42 Posted December 13, 2006 Rick, still have couple things to look into to be certain its 100%. If it still shakes, so be it, fighting the nature of the beast is always futile. Beautiful here today, gonna ride like you said, like the ex wifes lawyer is chasing me! Appreciate the assistance, and thanks again to all the members that took the time to respond. The membership here makes this a truly great site! Link to comment Share on other sites More sharing options...
Gearhead Posted December 13, 2006 Share #43 Posted December 13, 2006 "Getting underway 2 up, between the chuffing and the shaking is more of a dance on the clutch and throttle than any large bore bike I have ridden or owned. " The way you describe this is not normal. That is a fast bike which pulls smoothly (albeit with a little lump) almost from idle. The performance specs on it (not 2-up, of course :-) are 0-60 in 3.7 sec or so, and 1/4 mile in about 12.7 sec. The power required to do that to an 800 lb bike should not and in my case does not require any theatrics with throttle / clutch. Even when my carbs were way out of sync, it was easy to do a standing start with my wife aboard. Not that this helps you any - I'm just moving more in the direction of "what you describe can't be normal". Jeremy Link to comment Share on other sites More sharing options...
Guest Bigin Posted December 13, 2006 Share #44 Posted December 13, 2006 Hey Gearhead, its getting better, just back from 110 miles through the Ozarks and It is cleaning up somewhat. Still there though. Im not getting those 1/4 mile stats yet, and still 39 mpg for the last 2 tanks but it is pulling harder down low today. Still sound the same at idle though.. Making progress with the Sea Foam appears. Making enough power now the clutch is showing its age slipping occasionally above 5000, on some of those twisty and steep hills. I know this is the warning to get clutch parts together, but at least we are making power! This has the Vmax diaphram type clutch. Ive seen the detailed tech info on this site to do that job, looks straight forward though I should go in and inspect for what is actually needed before ordering parts. Great ride today, on a sweet machine, getting sweeter everyday. Thanks Link to comment Share on other sites More sharing options...
BradT Posted December 13, 2006 Share #45 Posted December 13, 2006 Well Bigin sounds like it is cleaning out for you glad to hear. Hate to say this but sure wished I had a problem like that, where I can keep going for a 100 mile ride to see if gets any better. My bike has not been running for about three weeks now, packed away for winter I guess. Brad Link to comment Share on other sites More sharing options...
Guest Bigin Posted December 14, 2006 Share #46 Posted December 14, 2006 Yeah, I guess I am blessed. My only problem now is deciding when to park the bike to work on it without missing any winter riding days. I guess I was born to whine about something! Link to comment Share on other sites More sharing options...
BradT Posted December 14, 2006 Share #47 Posted December 14, 2006 I guess I was born to whine about something! You have a lot of Twins here, not to mention any one in particular, maybe that is why we are such a close family. Brad Link to comment Share on other sites More sharing options...
Denden Posted December 14, 2006 Share #48 Posted December 14, 2006 Once you get it cleaned out enough that feels like it's running right, you should sync the carbs again. They were synced when the pilot jets were clogged, so now that Seafoam is working it's magic, it will change the vacuum readings, and needs to be synced again. Link to comment Share on other sites More sharing options...
Guest Bigin Posted December 14, 2006 Share #49 Posted December 14, 2006 Denden, I have been thinking the same thing. Should be able to get over 40 mpg with it from all that I have seen, so it still needs tuning. Will try to ride today again in the interest of tuning. LOL. Any leads on a carb tune out there? Link to comment Share on other sites More sharing options...
Condor Posted December 14, 2006 Share #50 Posted December 14, 2006 Any leads on a carb tune out there? I kept searching Ebay for one, but everytime one popped up it went for about what you could pick one up for from Carbtune. So, i finally said to myself... screw it and bought one direct from the UK. Took about 7-8 days to get here. Good luck on finding a used one at a good price ..... Link to comment Share on other sites More sharing options...
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