kev34 Posted November 24, 2015 Share Posted November 24, 2015 Hi, Just a brief introduction first, i was a member of the old forum and have joined this one too, but more of a serial reader that poster and plus the fact that any questions that i do know the answer to are usually answered by someone else first as my knowledge is limited, that's why im on here to ask some questions as im in the middle of resurrecting my gsxr 1100 turbo that was buried in the back of the shed for a few years.Basically i was out on the bike about 4 years ago and the turbo started smoking very heavily, so i sent off the turbo to be reconditioned, bolted back on the turbo and it was still smoking heavily, there were a few other issues at the time, misfiring, cutting out, and i was pissed off with the whole thing so buried it into the back of the shed.Ive now decided to put it back on the road for next year, stuck a battery on it wound it over with the starter a few times then noticed a petrol pissing out of the carbs.So i decided to strip the carbs which are fcr 39, to give them a clean.I only removed no. 1,2,3 float bowls as no.4 has something attached to it (Lift pump?) but looks complicated to disassemble, so thought i would just clean out the first 3 float bows which were not very dirty.Rebuilt the float bows and floats etc, turned the carbs upside down and blew into the feed pipes with my mouth and there seemed to be no leaks through the floats.Installed the carbs and petrol feed pipes switched on the fuel pump and the three carbs that i stripped are leaking petrol from which looks like through the bolts and float bowls.Question 1, If the floats/needles were leaking would the petrol come out the 2 top pipes at the top of the carbs?Question 2, Does the float bowls have to be sealed with sealant as the pressure of petrol is greater than normal?I will have some more questions but i will start with these first.Thanks in advance,Kev. Quote Link to comment
Captain Chaos Posted November 24, 2015 Share Posted November 24, 2015 Question 2, Does the float bowls have to be sealed with sealant as the pressure of petrol is greater than normal? NOOOOOOO!!!!11! Don't use sealant anywhere near petrol. I have no experience with FCR's so I'll let someone else answer your other questions.Welcome back on OSS by the way. Quote Link to comment
Gpz1100_Convert Posted November 24, 2015 Share Posted November 24, 2015 flatslides with turbo......possible but a likely headache.Given it smokes I am assuming you have a scavenge system fitted in some form? Has that failed?Mark Quote Link to comment
kev34 Posted November 25, 2015 Author Share Posted November 25, 2015 Welcome back on OSS by the way.Thanks.flatslides with turbo......possible but a likely headache.Given it smokes I am assuming you have a scavenge system fitted in some form? Has that failed?Mark I'm thinking this must be a sealing issue, as if the needles were passing the fuel would come out the two ( i assume overflow pipes at the top of carbs, maybe i'm wrong and this is clouding my judgement)I have since bought a new facet return pump which i think should solve my smoky turbo, once i get the engine running i will see if it works. Kev. Quote Link to comment
Phill106 Posted November 26, 2015 Share Posted November 26, 2015 (edited) Don't use sealant... But there should be a rubber gasket between the float housing and carb body, but im sure you know that. The first thing that comes to mind is fuel pressure is too high, the pressure builds up in the float housing and needs to escape, obviously I don't know your setup so unsure if you have an adjustable fuel regulator or pump but I'd check that first just to make sure it's not been played with or knocked over the years <.2bar I know is safe so if you can't remember the pressure from before that might be a good starting point to at least try to get it idling. Edited November 27, 2015 by Phill106 Quote Link to comment
Gixer1460 Posted November 26, 2015 Share Posted November 26, 2015 <2bar I know is safe I hope you meant to type 0.2 bar or about 2.5 - 3.0psi? Obviously a boost sensitive regulator is a requirement to add boost pressure to that setting. Certainly the FCR's are an unusual choice but they are about as good as possible using roller slides to prevent boost induced slide jamming. Smoking could have a few causes not necessarily turbo - fubar'd rings / bores through over fuelling is a possibility? Quote Link to comment
kev34 Posted November 26, 2015 Author Share Posted November 26, 2015 (edited) Don't use sealant... But there should be a rubber gasket between the float housing and carb body, but im sure you know that. The first thing that comes to mind is fuel pressure is too high, the pressure builds up in the float housing and needs to escape, obviously I don't know your setup so unsure if you have an adjustable fuel regulator or pump but I'd check that first just to make sure it's not been played with or knocked over the years. <2bar I know is safe so if you can't remember the pressure from before that might be a good starting point to at least try to get it idling. Iam working away from home and trying to gather as much info as i can to try when i get home again.I think the regulator is a malpassi? it probably has about 5 different fuel connections on it. Maybe something has happened to it with lying for so long, can these be stripped and cleaned? That could be an explanation that the carbs are overflowing as its getting to much fuel pressure.First thing that i could do is fit a gauge going to the carbs to check the fuel pressure.I hope you meant to type 0.2 bar or about 2.5 - 3.0psi? Obviously a boost sensitive regulator is a requirement to add boost pressure to that setting. Certainly the FCR's are an unusual choice but they are about as good as possible using roller slides to prevent boost induced slide jamming. Smoking could have a few causes not necessarily turbo - fubar'd rings / bores through over fuelling is a possibility? Is 2.5 3.0 psi a good starting point for the fuel pressure?Is there a way to check the rings before i start up again, can this be done with a compression tester?Edit, i recon ive just answered my own question here, i should have asked what would be the reading for a good compression test, bearing in mind i would have to purchase or borrow a tester. Thanks again for your help,Kev. Edited November 26, 2015 by kev34 Quote Link to comment
Phill106 Posted November 27, 2015 Share Posted November 27, 2015 I hope you meant to type 0.2 bar or about 2.5 - 3.0psi? Obviously a boost sensitive regulator is a requirement to add boost pressure to that setting. Certainly the FCR's are an unusual choice but they are about as good as possible using roller slides to prevent boost induced slide jamming. Smoking could have a few causes not necessarily turbo - fubar'd rings / bores through over fuelling is a possibility? ty for correction, auto correct must have changed it Quote Link to comment
Captain Chaos Posted November 27, 2015 Share Posted November 27, 2015 ty for correction, auto correct must have changed it it's easy to blame autocorrect for everything nowadays. Must remember it when talking to the wife. 1 Quote Link to comment
Gixer1460 Posted November 27, 2015 Share Posted November 27, 2015 Most carb float needles won't withstand much above 2.5 - 3.0psi fuel pressure (usually lower) before leaking - remember most are only designed for gravity flow ie. virtually zero psi (relative to atmospheric). A compression tester is a start - a std say what now!? is about 160 - 200psi with no cylinder more than 10% drift against the others. This will indicate general cylinder state but there could be valve leakage and / or ring leakage - only definitive test is a leak down - not many workshops will have these but they are pretty foolproof as they'll show what is leaking, by how much and in each cylinder.....irrespective of any compression ratio Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.