Guest gerrycormier Posted November 11, 2009 Share #1 Posted November 11, 2009 Does any one know the differences, if any, between the 26H(1983?) and 41R(1984-89?) models of the CDI/TDI. I put a used 26H in my 1986-1300 which had a broken 41R in it and it seems to work ok now but I think my gas mileage might have dropped?? Anyone got info? Gerry Link to comment Share on other sites More sharing options...
Snaggletooth Posted November 11, 2009 Share #2 Posted November 11, 2009 The 26H is for the '83 model only. The 41R is for the '84 and up until they went to the single coil pickup which was what guys? '90? The only real difference is the boost setting in the TCI. They will run but like you are seeing there are some side effects. I ran a 26 in my '84 until I found a good 41R. Ran fine. Carried it for a spare until I found someone who needed one for his '83. Link to comment Share on other sites More sharing options...
rhncue Posted November 11, 2009 Share #3 Posted November 11, 2009 Does any one know the differences, if any, between the 26H(1983?) and 41R(1984-89?) models of the CDI/TDI. I put a used 26H in my 1986-1300 which had a broken 41R in it and it seems to work ok now but I think my gas mileage might have dropped?? Anyone got info? Gerry By using the 83 on a later year bike your spark advance is now backward. When it is supposed to retard it will advance and vice versus. You are taking a chance of burning a hole in one of your pistons. Dick Link to comment Share on other sites More sharing options...
timgray Posted November 19, 2009 Share #4 Posted November 19, 2009 By using the 83 on a later year bike your spark advance is now backward. When it is supposed to retard it will advance and vice versus. You are taking a chance of burning a hole in one of your pistons. Dick Why? is it because of major engine differences that the 83 advances it to get better economy instead of retarding? is there a completely different cam on the non 83 bikes? I really need to know this info as I work on adding in the ingitech vac sensor to get the same behaivoir for the replacement TCI. Link to comment Share on other sites More sharing options...
rhncue Posted November 20, 2009 Share #5 Posted November 20, 2009 Why? is it because of major engine differences that the 83 advances it to get better economy instead of retarding? is there a completely different cam on the non 83 bikes? I really need to know this info as I work on adding in the ingitech vac sensor to get the same behaivoir for the replacement TCI. My memory is blurry now but the 83 gets its vacuum to operate the spark advance module at a different place on the carb. If I remember correctly the 83 draws it's vacuum before the butterfly and the rest of the years after the butterfly. Since one side of the butterfly has high vacuum at idle and low when the butterfly is open and if ported on the other side of the butterfly this scenario is reversed. They all use the same power module but the 83 TCI is designed to use the readings from the module to advance at certain vacuums and the later TCIs work just the opposite. This is one of the main differences between 83 and later bikes. the 83 #2 carb has a port for the power line hook up to the module and the rest of the years the port is on the manifold. Dick Link to comment Share on other sites More sharing options...
timgray Posted November 20, 2009 Share #6 Posted November 20, 2009 Ahh ok that Is what I already know, I was worried that they did a completely different cam in the early 1st gens and I was going the opposite direction in my tuning. Thanks! Link to comment Share on other sites More sharing options...
Dano Posted November 20, 2009 Share #7 Posted November 20, 2009 My memory is blurry now but the 83 gets its vacuum to operate the spark advance module at a different place on the carb. If I remember correctly the 83 draws it's vacuum before the butterfly and the rest of the years after the butterfly. Since one side of the butterfly has high vacuum at idle and low when the butterfly is open and if ported on the other side of the butterfly this scenario is reversed. They all use the same power module but the 83 TCI is designed to use the readings from the module to advance at certain vacuums and the later TCIs work just the opposite. This is one of the main differences between 83 and later bikes. the 83 #2 carb has a port for the power line hook up to the module and the rest of the years the port is on the manifold. Dick Link to comment Share on other sites More sharing options...
Guest gerrycormier Posted January 2, 2010 Share #8 Posted January 2, 2010 Just for info only: I changed the 1983 26H model to the correct 41R model for my 1986 VR and my gas mileage immediately increased by 20% from 40mpg to 50mpg. It also has major power increase from around 2000 rpm on up. Gerry:big-grin-emoticon: Link to comment Share on other sites More sharing options...
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