I'm thinking about upgrading my 30+ year old Mikuni VM-34 round slides to new TM-36 flat slides but I was hoping to get a few questions answered.
1. Do the TM flat slides use the same throttle cables as the round slides?
2. What clearance issues might I encounter with the bottom of the right hand float bowl and the hump in the case for the clutch? The round slide Mikuni's hit there now.
3. I've been looking at reinforced silicone hose to maybe be able to bend enough to provide a slight angle for the carb mounting to cylinder to solve clearance issues. I can fab up a supporting bracket to maintain stability and support. Has anyone tried this and achieved good results or have any suggestions on how to get more angle for the carb mounting without cutting and welding??
I've looked at Honda CB750 rubber intake boots that have some angle built into them but I can't find any dimension information i.e. inside diameters and angles. That would be an easy way to provide a good mounting solution.
Any help would be appreciated and thank you in advance
VM36 is pretty big unless the motor is in a really high state of tune. MOTA suggests zero extra HP on a 115HP configuration from 36mm carbs but loses almost 1hp lower down. It doesn't adjust for flat slide versus round slide, so there may be something there. I'd speculate that with fat pipes and much larger transfers or boost ports, bigger carbs would probably help.
I don't have a TM36 but the 38s I have are taller than a VM so need angled inlets. Try a GS1150 inlet rubber.
Rubbing on the motor causes cavitation in the float bowl that can lead to high RPM lean mixtures and meltdowns.
Thanks TZ! I'm using Ocelot ported cylinders with a 3mm rise and Ocelot expansion chambers that are fat. The spigot size of the TM34 flat slides is 40mm and the VM34 round slides are the same so I reckon I'll stay with 34's. The TM36 spigot size is 43mm and I'm sure they will still fit in the intake boots. I was curious if 36mm would be too large and kill all the bottom end. This bike is gonna be for fun and annoying all my HD buddy's when I pass them. I got a little nervous after reading Pearljam's post about the cruiseimage boots cause I bought a set to use on my engine. I can purchase carbs pretty cheap. VM's for $89 and TM's for $125 so for the money I want to buy what's gonna work best. If I could just verify the throttle cables are the same between VM and TM, I can work through clearance issues I hope.
VM 34 carbs are 137mm in height and TM 34 is 160mm in height. This info was from the Mikuni catalog. I believe the major difference in height is the area above the float bowl??
I've never tried the UFO's. I read some reviews and the technology seems to make complete sense plus the price is right. I don't need bling just functionality. Thanks for the suggestion ja-moo
Has anyone used these and have dyno or performance #'s. Just curious
You might want to look at KOSO flatside carbs. I've bought 36mm and they were half the cost of the Kehins and performed fine. They are Chinese knockoffs of the PWK but that doesn't mean they aren't any good. The cart boys rave about them and it doesn't hurt to check them out.
Here's a 28mm but it came with good pics so you can see it better!
Jeff, are those OK copies of a Keihin PWK or cheap knock off copies of OKO? The slides and carb body look really rough in their photos and they are much cheaper than "genuine" OKO I have seen before.
I just posted a quick link, I honestly didn't even read the ad.
There are a bunch of knockoffs out there, some are only trash while others seem to be gaining in reputation. I would check out the cart forums and see what the guys using them are saying. Another way to find "issues" is to google "KOSO(or OKO) carb problems" and read the comments of guys who have bought them. Some of the knockoffs seem to work fairly well but are a little more difficult to setup initially. That was my own experience as well. A friend asked for help completing his bike and had already bought a set of three for just over 120 bucks! The difference of a 1/16th turn made all the difference in the world....who da thunk? Once setup, they performed well and it's been several months since we installed them and he rides nearly every day.
Thanks all! I believe I'll start tuning with what I have and then try the UFO's. They do sound interesting if the claims are accurate.
Jeff, what experience do you have the UFO's? They state using a much smaller slow jet when tuning and much crisper throttle response. I was considering a power jet or dial a jet too but the problem arises again with clearance. Can the fuel feed nipple be put into the side of the bowl rather than the bottom?? I'm a little reserved about drilling into the bowls for something that isn't going to perform.
pull the wire wrote:Thanks all! I believe I'll start tuning with what I have and then try the UFO's. They do sound interesting if the claims are accurate.
Jeff, what experience do you have the UFO's? They state using a much smaller slow jet when tuning and much crisper throttle response. I was considering a power jet or dial a jet too but the problem arises again with clearance. Can the fuel feed nipple be put into the side of the bowl rather than the bottom?? I'm a little reserved about drilling into the bowls for something that isn't going to perform.
Sorry that I didn't see the question till now but with UFO's, your pilot or the secondary (small) jet will be about half of the stock configuration and WILL gain power all other things being equal and most flat sides have the fuel port on the side of the carb body so no drilling required. One thing, if you are planning on using 36 flatsides, use 34 flats or 34mm rounds with UFO's instead. The large carbs pull less because of the larger opening & 99% of guys will tend to over-carb their engines so unless you are doing endurance racing where it's going to be in the power band all the time, go a little smaller and you'll thank me later because the response will nice and crisp!! <LOL>
The bottom line is that you will gain nearly all with UFO's on rounds as you will with equivalent flats and you'll save money.
Very cool. Thanks Jeff. The 34 round slides I have are really old and the bowls look different than the newer VM's. All the pictures I look at don't really show how or where an additional fuel port is added for a power jet or thunder jet installation. Using a larger main jet/bowl drain nut is out obviously. However I did find the auxiliary fuel bowl from Thunder Jet interesting.
