Post by bdalameda on Dec 4, 2011 17:11:24 GMT -5
I have just ut about 200 miles on my recently restore RE5 - as many have experienced i had the severe hesitation when accelerating away from a stop as the carb transitions from the primary to secondary fuel circuits. I did all the port valve adjustments, check the accelerator pump cleaned the carb very well and tried the larger primary main jets without eliminating the problem completely.
What bothered me about this was that I have had a lot of experience with the RE5 's, back when they were new, and I did not remember having this kind of problem back then. The hesitation was usually just a port valve adjustment being out, as simple as that. I have owned three Re5's and this is the only one that I experience difficulty with getting rid of the hesitation.
I began to think of what was different about the older Re5's having the problem vs. the then new machines and what could have changed. I looked at anything I could think of that may have changed with age. I noticed a couple of things. One thing that has degraded with age is the vacuum hose fitting that is pressed into the top of the fuel enrichening circuit diaphragm cover on top of the float bowl. I started researching how this circuit worked and discovered that the circuit this enrichener is responsible to keep the mixture from suddenly going lean when he secondary throttle butterfly just begins to open. I took the diaphragm valve assemble off the carb and gave it a very close look. I found that the white plastic vacuum fitting had shrunk from age and it could be moved around. I took some epoxy and sealed it to the cover using a toothpick to run a bead of epoxy around the edge of the fitting base. I also looked at the spring the pushes against the diaphragm. I checked the specs on this and noted that it should be 14mm long - mine measured about 11mm so a gently expanded it so that it stayed at about 15mm. I looked closely at the valve that the diaphragm is connected to. I had just replaced the diaphragm but I did notice that the valve just barely moved up and down and it just did not feel right. I took the valve apart and noticed that the inner side of the valve under the diaphram had a fiber sealing washer that seated against th opening. This fiber seal seemed to have flared a bit and was no longer flat. The valve also just barely had enough clearance to move and did not seem to open and close very well. I found another small fiber washer in my parts junk box and also found a very small steel washer that fit on the should bolt of the valve. I used the washer as a shim to basically make the shoulder of the screw a little longer and this allowed the valve a little more clearance to open and close cleanly. I carefully re-assembled everything and held the assembly together with my fingers and worked the valve. The valve worked much better and had a solid opening and closing click to it - much better than before. When re-assembling the parts on the carb I also noticed that the small vacuum hoses to the enrichener and secondary diaphragm seemed a little hard from age. Still pliable but not quite right. I replaced these hoses as well to insure a good seal.
After re-assembly I went out for a ride. - What an incredible difference! It was like a totally different bike. No hesitation at all.
Anyone having this hesitation problem should check this out. I am not sure if any one single thing I did fixed the problem or perhaps it was a combination of the loose fitting. spring tension and valve seating that made the difference. A leaking vacuum hose could also cause such a problem.
Dan
What bothered me about this was that I have had a lot of experience with the RE5 's, back when they were new, and I did not remember having this kind of problem back then. The hesitation was usually just a port valve adjustment being out, as simple as that. I have owned three Re5's and this is the only one that I experience difficulty with getting rid of the hesitation.
I began to think of what was different about the older Re5's having the problem vs. the then new machines and what could have changed. I looked at anything I could think of that may have changed with age. I noticed a couple of things. One thing that has degraded with age is the vacuum hose fitting that is pressed into the top of the fuel enrichening circuit diaphragm cover on top of the float bowl. I started researching how this circuit worked and discovered that the circuit this enrichener is responsible to keep the mixture from suddenly going lean when he secondary throttle butterfly just begins to open. I took the diaphragm valve assemble off the carb and gave it a very close look. I found that the white plastic vacuum fitting had shrunk from age and it could be moved around. I took some epoxy and sealed it to the cover using a toothpick to run a bead of epoxy around the edge of the fitting base. I also looked at the spring the pushes against the diaphragm. I checked the specs on this and noted that it should be 14mm long - mine measured about 11mm so a gently expanded it so that it stayed at about 15mm. I looked closely at the valve that the diaphragm is connected to. I had just replaced the diaphragm but I did notice that the valve just barely moved up and down and it just did not feel right. I took the valve apart and noticed that the inner side of the valve under the diaphram had a fiber sealing washer that seated against th opening. This fiber seal seemed to have flared a bit and was no longer flat. The valve also just barely had enough clearance to move and did not seem to open and close very well. I found another small fiber washer in my parts junk box and also found a very small steel washer that fit on the should bolt of the valve. I used the washer as a shim to basically make the shoulder of the screw a little longer and this allowed the valve a little more clearance to open and close cleanly. I carefully re-assembled everything and held the assembly together with my fingers and worked the valve. The valve worked much better and had a solid opening and closing click to it - much better than before. When re-assembling the parts on the carb I also noticed that the small vacuum hoses to the enrichener and secondary diaphragm seemed a little hard from age. Still pliable but not quite right. I replaced these hoses as well to insure a good seal.
After re-assembly I went out for a ride. - What an incredible difference! It was like a totally different bike. No hesitation at all.
Anyone having this hesitation problem should check this out. I am not sure if any one single thing I did fixed the problem or perhaps it was a combination of the loose fitting. spring tension and valve seating that made the difference. A leaking vacuum hose could also cause such a problem.
Dan
but I was introduced to the Micapeak site when I got my first RE5 years ago and learned so much, yes it's an old site from the early days and it's showed it's age but there is so much information there.