The $400 1999 Monster 750 Dark Thread

[EEL]

I'll preface first with I have not worked with carbs that much but.......

Are you sure a vaccum gauge works for a carb sync? I've always thought those bounce around too much to give you a good measurement?

Dont you need something like a manometer?

[IamnotJim]

Good call. I just called a rental/repair shop right next to my shop, and they have a few they pulled off of bikes. He's giving me one for $20. SCORE!!

[SpikeC]

I always thought that a manometer was a vacuum gauge....

[MotoPsycho]

Nope. Manometer are long, usually u-tubes. Gauges are round with a needle.

I don't get why it's so detrimental to not have that sensor operational. The only time I ever saw the light come on on my OE dash was when it died. I've seen pics from a long time ago somebody put a pressure gauge or a thermometer on there. Or was that in the fill hole ?

[brad black]

a manometer uses a U (of some sort) shaped column of liquid to measure a pressure differential.   a gauge has a coiled tube that expands and contracts with pressure inside it, moving a needle.  the manometer is more responsive in this instance and generally seems to work better.

you don't really need an oil pressure switch.  if it loses pressure it's rooted and you can't do anything about it unless you stop straight away, which no one ever does.  and generally by the time you see the light it's over anyway.

[Howie]

Matched and damped vacuum gauges will work, but not the ideal set up.  I would suggest googling cylinder balancing tools.  Maybe something like this 
http://www.ascycles.com/detail.aspx?ID=2146
or
http://stuccu.com/s/Motion+Pro+Syncpro?tr=related_search
or
http://www.650ccnd.com/mano.htm

[the_Journeyman]

I synched my 750 with a vacuum gauge.  It's not the best, but it will tell if something is way off.  They do bounce around, but if you watch them for a minute, you'll should see them bounce between the same readings if they are in synch.

JM

[oldndumb]

Manometers are quite simple to fab using cheap materials, as explained in howie's last link. Comparative readings, not precision, is the objective.

The ones I have built used ATF fluid. I have used MIG welding head wire nozzles, if  that is what they are called, as snubbers for the fluid. Maybe they could also be used on a vacuum gauge setup to tame the needle?

[IamnotJim]

I went and picked up the oil pressure sensor yesterday.

It was a local place and the guy had a spare 750 engine in the back, so he pulled it off and sold it to me for $20.



He was a really cool guy. The shop's name is Irish Mike's. I would HIGHLY recommend his shop to anyone who lives in Las Vegas, Nevada. PM me if you need more details on his shop.

Here is the old defective sensor next to the new one. He threw in an aluminum crush washer ilo the copper one, but it ended up being too big so I used the copper washer.



I put it on and started her up. She is running dryer than an 90 year old granny's P#^$!! I think I might name her Mildred.

I adjusted the idle screw on the carb and she is running sooooo sweet!

[IamnotJim]

I still have a few minor issues.

First: The blinkers are working, but they don't blink.

When I click them on, they stay a solid yellow color. Anyone have a fix for this?

Second: The shifter is binding up on the spring for the kickstand.

When I downshift, it will get stuck on the spring and I'll have to kick it up with my toe.

Here are some pics.

Does anyone have any pics of what it is supposed to look like?

[Howie]

No blink is probably the flasher, one of the relays under the seat, either 2 prong or 3.  Can be purchased at any parts store.  Shit lever looks bent to me.  If you remove it and bend back carefully you might get lucky.

[bond0087]

First of all, I'm very jealous that you found an M750 for $400. Looks like a fun project. Shift lever also looks bent to me. Your kickstand/spring also doesn't look OEM to me. I just walked outside and snapped a picture of my shift lever from above with the kickstand up for reference (2000 M750).


Also, regarding the carb sync, a home made manometer with ATF, as described by others works great. Higher sensitivity than a mercury manometer, not to mention much cheaper. I took quick videos of mine before/after a carb sync with that method. You can hopefully hear how the bike runs more smoothly with the better sync, although it wasn't terrible to start with.   

[memper]

When I had the stock carbs I used a set of dial pressure gauges for the carbs. The trick is to use the little valve that usually comes with them and you just crack them a bit. This reduces the bouncing and you can get a better look at the needles.
I would just replace the whole side stand. Probably a few on eBay.

[brad black]

gear levers catch on the round style side stands when they've been bent in.  common issue.  bend the lever out gently, otherwise it'll crack and then break.