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When buying jets do not forget the pilot jets (also known as low speed jets). Sometimes lean mixture problems from using pod filters can be cured by getting bigger pilots. Also, contrary to popular belief, there are incidents in which one needs to go down a jet size or two when changing over to pod filters. Case in point: I have read many articles by BMW specialists which say pod filters on an airhead (boxer twin air cooled engine) can not be made to work. When going to pods on my R80 BMW I had to go down several jet sizes on both the main and pilot jets which made my bike run excellent. I think my result has something to do with increased speed of the air being sucked into the carb along with the reversion effect of the intake valve closing bouncing off the end of the pod filter and creating a secondary induction wave which would also draw more fuel. Or........ I may be full of shit and not really know why it happens.
 
:) ;) the factory servicve manual, download that
on the points spend the $35 or so for oem honda points the chinese stuff do not work well i couldnt get my 350 dialed in with them (the bike came with them in it and i bought more duh :( ) i wiggled em and they were so poorly fit the pivot post was loose as a goose and the contacts were crooked to each other as well, they came together with a knarley tapered gap
 
MotorbikeBruno said:
xb has the right idea on this one. "ignition tune up" kits are available with points and condensers. You'll learn a lot as you get this bike back up to running shape. Fire up a build thread or "help" thread in the right section and put a link so we can find you. Nothing crazy at all to get bigger jets. Those who drill jets are only doing so to get a rough idea as drilled holes in jets aren't round at all and aren't even close to being the same hole size if you drill several. Yours are "simple" buy new larger sized mains at various places (make sure they come with the o-rings if they are press-in jets) and you'll be all set. Start a thread and we'll help you out sir!
Click to expand...

Link to my new thread!
http://www.dotheton.com/forum/index.php?topic=68063.new#new
Thanks MotorBikeBruno! :)
 
dewjantim said:
When buying jets do not forget the pilot jets (also known as low speed jets). Sometimes lean mixture problems from using pod filters can be cured by getting bigger pilots. Also, contrary to popular belief, there are incidents in which one needs to go down a jet size or two when changing over to pod filters. Case in point: I have read many articles by BMW specialists which say pod filters on an airhead (boxer twin air cooled engine) can not be made to work. When going to pods on my R80 BMW I had to go down several jet sizes on both the main and pilot jets which made my bike run excellent. I think my result has something to do with increased speed of the air being sucked into the carb along with the reversion effect of the intake valve closing bouncing off the end of the pod filter and creating a secondary induction wave which would also draw more fuel. Or........ I may be full of shit and not really know why it happens.
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Derestricting air intake can in some cases result in the need to go to smaller jets. Most of our carbs operate on Bernoulli's principal. By derestricting can result in an increase velocity of the air traveling thru the carb venturi. This increases the efficiency and allows for more fuel to be pulled up into the venturi. In order to compensate for this increased efficiency/increased fuel flow thru the original jet, in some cases you will need to go to a smaller jet to achieve the same air/fuel ratio.

Its a velocity versus volume thing. Just like there are times when going to a smaller carb can actually increase overall performance by improving throttle response and improving low-midrange performance at perhaps a slight loss of top-end.

So if you have to go to leaner jets for pods, you haven't necessarily lost power. To many variables to make such a blanket statement.
 
A jet does not magically increase its capability to flow fuel just because there is more negative pressure (which there is not).

My statement is based on dyno results.
 
Barkingmadspeedshop said:
Not a new shiny part or tool but after a year of working at it I finally got papers for a bike
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Awesome, always a great day. That's actually saving a bike there. So many get trashed just because of some paperwork.
 
Dohc, according to my friend Thomas Blunk who is a mechanical engineer, it is entirely possible that the reversion wave created by the intake valve closing can cause a secondary intake wave which goes through the carb drawing another bit of gas from the jets in the carb. Also, according to Mike Brown , a certified BMW and Ducati mechanic, greater velocity will pull more gas from a jet than lesser velocity. Not only that...... to state that using smaller jets always creates less power is totally false. If the jets are to large they will create less power and decrease gas mileage. In the 70's the two stroke racers would jet their carbs so lean that they would oft times seize,but they would run like crazy until that happened. Besides all this...... Charlie T agrees with me ;D ;D ;D.
 
dewjantim said:
Dohc, according to my friend Thomas Blunk who is a mechanical engineer, it is entirely possible that the reversion wave created by the intake valve closing can cause a secondary intake wave which goes through the carb drawing another bit of gas from the jets in the carb. Also, according to Mike Brown , a certified BMW and Ducati mechanic, greater velocity will pull more gas from a jet than lesser velocity. Not only that...... to state that using smaller jets always creates less power is totally false. If the jets are to large they will create less power and decrease gas mileage. In the 70's the two stroke racers would jet their carbs so lean that they would oft times seize,but they would run like crazy until that happened. Besides all this...... Charlie T agrees with me ;D ;D ;D.
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If present in a given application, the reversion he speaks of would happen regardless of the filter system.

I didnt say that jetting leaner will always cause a power loss, this is taken out of context for the sake of your argument. I said that if changing to pods cause you to need leaner jetting, then have experienced a power loss.

DohcBikes said:
If you have to jet leaner for pods, you have lost power.
Click to expand...

My statement is a result of dyno testing.

In addition, some engineers are full of shit too. I'll continue to trust experience in practical application and real world results over an educated guess any day.
 
Unless you first ran jets that were big fat pigs so you could smell bacon while you ride... Hahaah ha

Chops man chops tells all regardless of education. Remember Einstein


Sent from my iPhone using Tapatalk
 
DohcBikes said:
. I'll continue to trust experience in practical application and real world results over an educated guess any day.
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Really?? Interesting. My opinion is on decades of tuning two-strokes, including some national championships.
 
Well..... since my engineer friend is full of shit, you have had my bike on the dyno, and Charlie (who makes his living at this) is wrong. I suppose I shall have to concede defeat. The better man (men) has won :'( :'( :'(.........
 
So this happened quite a while back, but I just got it at Barber. Another MR 175 elsinore to be an organ donor for my other one. This one is a '75. Piston and bore look good, but seems the previous owner had an aversion to using gaskets in gasket places. Oh well. Tank and seat are here too, just in a box.

 
Microscope for building/fixing stamping dies.

Screenshot_2015-11-02-17-39-18_zpsksnbwbzb.jpg
 
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