28/08/2022
Following the success of the release of our TM40 pumper and VM single carb conversion kits for Yamaha XV Virago’s, we have now received stocks of our specially made 2 and 2 1/2” wide pancake filters allowing us to now also offer Mikuni’s apex Carburetor in these kits, the TM42 Pumper also know as the HSR42 Harley carb.
This Mikuni TM42 pumper type carburetor, like the VM roundslide or TM40 pumper options, will fix all your old stock carb issues and look great whilst also giving you the maximum performance improvement over all others when fitted to larger XV Virago engines over 750cc.
The kit includes: A pre-jetted TM42 Mikuni Carburetor fitted with a side pull k**b choke. A Mikunioz designed cast two into one manifold with an enlarged mid manifold plenum area to better facilitate the fuel mixture between the cylinders. To allow for a wider manifold with better holding grip whilst still isolating the cylinder head heat from the fuel delivery system, the OEM carb rubber mounting fl**ges are replaced with 2x shorter Mikuni heavy duty fl**ges designed and made for the Harley market. A 3rd heavy duty rubber fl**ge is supplied for the manifold to Carb connection. A purpose designed USA made 2 1/2″ wide Pancake Filter being 1/2″ wider than the others is to accommodate the extra 17CFM demand of the TM42. Hardware includes all bolts and washers. Plus also A side pull throttle and push/pull cable combo with an option of lower profile left or standard righthand carb side connection.
Throttle cable to carb connection options- As show in the picture you can see how close and low a stock 1100 tanks sits in relation to the top of the OEM cable bracket, where on some bikes minor adjustments may be required to set clearances. When using some custom tanks this OEM bracket may prove to be to tall. As a solution we offer two options here being the cheaper standard TM42 RH throttle attachment (cable 980mm) or a custom made and fitted low profile LH option (cable either 960mm or otherwise supplied (1050mm) for std bars. The RH cable 980mm option as being a shorter travel distance is shorter than the 1050mm LH, whereboth match stock bars, sorry no shorter option available for the RH. If using 1″ handle bars there’s a separate TM42 product file with options available.
No Air-filter support system is provided or should be needed, where if installing another heavier custom filter, the fabrication of a bracket or brackets will be required.
The jets to make this carb operate on Yamaha XV models have been fitted and there are spares for fine tuning the main jet circuit doing WOT tests. Climate, altitude and fuel density from different octane fuels all have varying effects on final fine tuning as does cam, exhaust and cylinder head porting etc. For this reason, we have included what we have found to be a range of fuels.
FUEL PUMP MODELS: With an 1100 or others if you still use the fuel pump , sometimes you may encounter leaking out the overflow at idle. The float height is factory set and will be correct. This is caused by the pressure from your pump which is popping off the needle and seat. Adjusting float height 2mm may work but usually not. Otherwise there are two options:
1) install an extra “T” on the carb supply line so as to then run a return line to the tank. This line needs to be plugged with a restrictor so as to work as a pressure relief whilst to not take flow preference away from the carbs. Usually a 1mm hole in a restriction plug fitted inside the new line is good.
2) replace the 4.2 needle and seats with the 2.3mm options from the 786-27001 option drop list found in the main menu needle & Seats page. There is a video in our “How to Videos” main menu option “leaking needle and seat causes and removal”, watch the removal process for your carb type if changing seats.
Our technicians can guide you through any after sales carb related inquiry.
