Poor Running issue??

So I thought I had it licked but back to the drawing board I guess. My 85 is kinda new to me. I bought it awhile ago but until the summer I just sat and waited for my attention. PO needed money and it was to good a deal. I have done alot of work thus far, from draining the gas tank to replacing the fuel lines and filter and ran a can of sea foam thru. After the filter was changed it seemed to run better but today I went for a good 200km ride and its not fixed. I have not opened the carbs yet. I was hoping to avoid that, seafoam has worked on other bikes I have owned in the past.....I believe the bike sat for 2 years ish before I got it. On the road it pulls ok up to 4000rpm then dies....like its running on pilot jets. Check the plugs and they are black? To much fuel? New air filter. The bike starts and idles perfect. Just won't pull on the road, I mean these bike were known to pull.....hell its a vmax motor....ideas as to why it would run aok up to 4000rpm and then die's out....hard to stay at 100kms/hr in 5th?? My Buell would go 100 in 1st/2nd!! HELP! Any, even bad imput is ok with me:) Does someone in Ontario excell at carbs? My budget is kinda tight and it seems to be a big job if the carbs need to come out according to my searches on the site.

Thanks a bunch!!

Have you looked at your carb diaphragms yet? The carbs do not need to be removed to do this. If they are full of holes they will not open causing a rich condition and severely poor performance. These bikes don't run to well without the air-box completely installed, but will run nevertheless. Take the top off the air-box and watch down the carbs with it running. It will buck and backfire a bit but look to see if all the carbs bounce and open somewhat the same. Don't stick you face right over the top while doing this.

Yep, let us know on the diaphragms, and if the sliders move. If they are working then there are more options without taking those carbs apart, but if it needs doing, we'll get 'er done.

It does sound like your'e still dealing with fuel starvation. With sitting that long the Sea Foam may not fix everything. Keep after the treatment letting the SF sit in the carbs for a time and see what clears up. Mine sat 9 years before I bought it and SF bought it around... almost. Still had to pop the carbs to get it done right.

The plugs should be burning a nice tan color when running right. The black shows rich fuel mix. BUT !!! With the heavy SF treatments it does foul the plugs badly. Everything the SF remove ends up where? Burning onto the plugs.

I see mraf just mentioned the diaphragms. Be a good thing to check out. The bike will run worse with the air box cover and and like he said.... face out of the way!! It will pop back though the carbs.

I would check the fuel level settings on the carbs to and find out if that is low on any or all of them. Low fuel level will do the same thing you are talking about. Checking fuel bowl level is an easy trick with a short piece of clear air line and a male/male adaptor to plug into the carb drain line. No need to pull them off for that. But it will tell you where you are at with that issue.

Mike

You can do a lot with the carbs still on the bike.

Remove the diaphrams and sliders and the drain plugs.

Carb cleaner and compressed air in every opening and orifice you can find.

50/50 sea foam/gas treatment is another idea.

There are threads on how.

Ok so I took the side covers off the carbs and wow I should have started there. The back 2 were seperated by and inch and not pinching the diaphram. The front 2 were in peices and completely apart. On a good note all 4 diaphrams look in new condition. My question is can I just re-assemble and put back togeather? Should the slide assemble come apart like that? To me the rings that pinch the inside of the diaphram should be tight and not just gome apart?? Maybe the PO took it apart and changed the diaphrams? No damage or pry marks on the slides at all and the diaphrams look perfect.

Ideas? When I reassemble how do I make sure the rings don't seperate again?

Thanks, Very Cool, I love fixing things!!

The diaphragms move the slides to allow more air and fuel into the engine. This is a self-adjusting method for correcting for changing load conditions and altitude.

If the slides do not open, the engine will not run above 4 - 5k rpm. You have likely found most of the problem. Your picture 4 & 5 show that the diaphragm has separated from the slide. My guess is someone incorrectly installed new diaphragms. Be sure to hold each of the diaphragms up to a light source and check for tears or holes.

If a 4k rpm limit still occurs after the slides are working properly, it is likely there are blocked jets.

Thanks for the info. When reassembling, should the 2 outside and inside rings that pinch the diaphragm be locked together with the black sleeve somehow? Currently, all pieces are completely separated. Do they need to be glued? or pressed together? Thanks again.

Sure looks like you found it.

As mentioned, when you check the diaphragms, hold them up to a bright light, even extremely tiny pin holes will make a difference. If the diaphragms look new the PO likely replaced them and did not do it right. The 2 edges that hold the diaphragm onto the slider are not supposed to come apart. I am not sure if they should be pressed or glued in place.

That is what i mean. I put it all togeather and it seems to fit tight but with a little back and forth with my fingers and the whole assemble will come apart. Any ideas on how to hold it all togeather? This must have happened to someone before. I was thinking of glue. It would hold everything togeather. Not sure what would standup in a gas rich envroment though??

I'm open to ideas. It would seem reasonalble that the PO did this seeing as the diaphrams look new!!

Make sure that the rings are put in the way, you can tell by the grooves. Then press them together and they should stay put. Make sure that they slide into the carbs nice and easy, if they bind, then they most likely are split and need to be replaced, it should be a perfect fit. If they still come apart, then you can use a bit of Seal All, found at Home Hardware, or CTC. Gas doesn't bother Seal ALL and it takes only about 30 sec to set up. While you have it apart, it's a good time to blow all the ports out with a carb cleaner,,, CRC works good, get the ports from the top while you are at it was well. Then when you have it all back together let the gas tank run down and add a can of carb cleaner to the tank. Use the spray stuff, it works better. Once you have the cleaner in the tank, let it run for 30 minutes or so at idle, running the choke on once in a while, then take it out for a ride and run the rpm up to 6000 for a few minutes, you can do that while keeping it in 2nd, you don't have to go 160kph. After that refill the tank, and tell me it don't run right.

Well I put it all back togeather as it should be. The rings around the small metal shaft pinching the diaphram with the rear one right way around and it seemed to snap into the black sleave and stay tight. Sprayed everything including the dog with carb cleaner and put it all back togeather.

WOW!!!

Now I remember why I bought this bike.....pulls hard all the way around. I will run it for a while and then take it apart and see if the slides are coming apart again. If so I will lock it togeather with sealent as mentioned above....It may be ok....not sure you can ride a bike harder than I just did for 30 mins.....good thing there was no OPP around:)

Thank you everyone, again this site is a great place to get info!!