1999 monster 750 not as snappy at my friends carbed 620. What should I do.
I'm comparing it to my girlfriends monster dark 620. I know the 620 is supposed to be fuel injected, but this one definitely has a choke. Did they make the 620 in 2002 in dark with carbs? I can't find it online anywhere.
The reason I ask i could understand a fuel injected 620 feeling more powerful then my 750, but not a carbed one. She swears it says 620 on the tank. I need to go home and check for sure.
What should I do first. This 1999 750 has 8k for miles and the valves, carbs and belts were not done at 6k.
I wanted to check the compression but i don't have a fitting for the smaller plugs. What compression range should I be seeing.
In 2002 all monsters were injected. The "choke" you refer to is an idle control to warm the bike up.
As far as the 99' feeling less snappy, clean the carbs, full tuneup, make sure belts are changed. Check ignition for good spark etc...
Get a 620? [evil]
Snappy?
I would make sure the bike is performing correctly. When was the last service on it?
Check out some kind of EFI tuning like a PCIII or similar and have it dynoed.
Also, the 750 can be fun but it's not a race bike. 60hp. Shed weight, to get more out of it, but it will never be comparable to a 700cc I4
620 is snappier than a carb 750.
And different gearing, 43 rear f e.
Yep, that's how it is. The 620 makes about the same power, but revs quicker, is more responsive due to the FI and they are typically geared lower. FCRs and lower gearing would make your 750 very snappy.
FWIW most FI bikes of the 90s had fast idle levers (ducati was about 5-6yrs behind in adopting FI). A lever on the bar does not equal a choke.
Quote from: bikepilot on October 18, 2011, 08:33:36 AM
Yep, that's how it is. The 620 makes about the same power, but revs quicker, is more responsive due to the FI and they are typically geared lower. FCRs and lower gearing would make your 750 very snappy.
FWIW most FI bikes of the 90s had fast idle levers (ducati was about 5-6yrs behind in adopting FI). A lever on the bar does not equal a choke.
i read that he had an efi 750... duh
We'll that clears a lot up. Thanks guys. I went home and checked and hers is in fact a 2002 618cc and that idle lever explains a lot. Damn.
So even if I get all my service done and clean the carbs, does that mean the bike still is not going to feel as quick as her 620?
That is a bummer.
I thought the 750 was gonna be nastier.
If I wrap the throttle and pull the bars I can get my front wheel to flutter off the ground on the 750, I can't do that on her 620. But other then that her 620 is way more fun right now.
change the gearing, put FCRs on it.
you will notice a difference, but it won't be a rocket. it will beat the 620.
Quote from: Cloner on October 18, 2011, 06:36:29 AM
Get a 620? [evil]
Ooooo Ooooo Ooooo...go for the Capirex and you can do 140!!!
Correct, your 750 all tuned up and running as it should probably won't be as snappy as a 620 running as it should. Also, your wheelie technique might be off. My wife's 620 will loft the front without much trouble [cheeky] - just goes to show that wheeling isn't a good measure of performance. Gearing is cheap and can make a big difference on how snappy a bike feels. Play around with it first and maybe it'll do all you need. FCRs make a huge improvement in throttle response, but are $$$ - might make more sense to sell and get a DS1000-powered monster or even a 4-valver if you are after power/$$ in a monster.
Don't sweat compression, your bike isn't worn out at 8k miles. Do keep on top of the maintenance, especially belts, if you don't want very expensive engine damage.
Go +2 in the rear - sure you have to shift a little sooner and it'll only do 120 if dropped off a cliff, but it goes ZZZOOOMMM!!! off the line. Assuming you've got open-ish pipes, stage 2 jets, and K&N. If not, get that stuff too [evil]
Thanks for the input so far guys.
I've ran it about 50 miles with seafoam in the gas, sprayed seafoam into the top of the carb with it idling and also reving while spraying. It seems to have helped a fair amount or maybe I'm just getting used to the power delivery. I've read about disconnecting a vacuum line on the carb and sucking seafoam directly in that way. When I search for vacuum lines under the carb I cann't seem to find any. Do you have to remove the air box in order to get to this?
Its also possible that since the 620 I ride has a beautiful sounding remus dual exhaust that I think I'm accelerating more then I am. The remus exhuast sound is very progressive as in the more you rev it the more and more deep and loud it gets. Fools you into thinking you're making a ton more power. Kind of like driving a miata.
On the other hand my 750 with the two into one arrow exhaust is loud, but not as deep and loudness does not seem as progressive as you crank the throttle.
Ultimately I really feel like I should take the carbs out just to blast them out with carb cleaner and an air compresser and see what the jet needle looks like.
Should my jetting be modified if I have an arrow two into one exhaust? I don't think its a full exhaust.
I've only ever done carbs on a snowmobile polaris 600 xc, so I think I can do these too. It made a huge difference on the snowmobile.
I million questions I know. Thanks for any advice.
Unless the intake on the 750 has been modified - freer flowing filter, open air box etc you shouldn't need a different needle/jetting. It's only when you mess with the air that you really need to mess with the fueling - just an exhaust won't (shouldn't) do it.
But you're probably due for a solid carb service at this point. I bet a new set of needles and a good cleaning will help
As all the folks have noted so far - I bet a lot of it comes down to the final drive gearing. Stock gearing for the 750 is 15/38 and stock for the 620 is 15/46
http://www.ca-cycleworks.com/shop/catalog/ducati/chain.html (http://www.ca-cycleworks.com/shop/catalog/ducati/chain.html)
- That's a good bit of difference and if the 620 is running 14/46, even more so. Even if you both had 620s and were running 15/38 on one and 15/46 on the other you'd notice the one with the bigger rear sprocket would get off a line faster.
If you pop the tank up & see a plastic thing covering the airbox with 2 snorkles coming out of it, chances are you've got a stock filter & jets. Taking the carbs out is the one pain I hate to do on that thing, and I've avoided it for years now since I did the jets like 5 years ago. But it's not complicated. And I don't think the carbs have vacuum lines - there's two air intake tubes I think on the top - they've got little permanent filters attached to them.
I'd like to see a 2-1 Arrow on this bike, haven't seen that before.
For an economical solution, follow the gearing advice, fit a jet kit with K&N filter and open air box.
A more pricey solution is to buy the FCR 39 carbs as well.
Another solution if you prefer the air cooled Monsters is to sell the bike and get a 900 injected or carbed model and you might pick up a carbed 900 with FCR 41 carbs, etc.
For the extra price of the FCRs you might pick up a 900 in your part of the world.
Cool. I have a drz400sm with the airbox side cut open and jetted. Do you just cut open a hole on the top of the aibox on this one as well? Are their any guides online.
Yea I suppose new jet needles would be the way to go since the stock ones have 8000 miles on them and are 12 years old.
Yes the air box is stock, has a paper filter and does have two snorkles coming out of it.
I'll try and get a picture of the bike posted up here. I like the look of the two into one exhaust but it'd be cooler if it was a high mount. It also does not sound nearly as sweet as the remus on the 620.
Also, is the remus stock on my friends 620. It says remus on the back of the pipes and ducati performance on the sides of the pipes.
Another question. When i did have the airbox open and was spraying seafoam into the carb I noticed the left carb slide door opened a tiny bit when I'd rev it up, but the right one never moved.
Is that normal? Does that mean my carbs are out of sync.
What controlls how those slides open. I guess on idle in the driveway they don't open much, but riding down the road they open quite a bit?
Quote from: koko64 on October 20, 2011, 12:06:49 AM
For an economical solution, follow the gearing advice, fit a jet kit with K&N filter and open air box.
A more pricey solution is to buy the FCR 39 carbs as well.
Another solution if you prefer the air cooled Monsters is to sell the bike and get a 900 injected or carbed model and you might pick up a carbed 900 with FCR 41 carbs, etc.
For the extra price of the FCRs you might pick up a 900 in your part of the world.
Actually, US carbed Monsters came out of the factory leaner than what most of the rest of the world got. There was (is) a stage 1 Dynojet kit designed for a closed air box and stock exhaust or slip ons. As I remember, different main, needle and spring. This would relieve the cold blooded running and low speed throttle issues.
Quote from: drewbabich on October 20, 2011, 04:39:10 AM
Another question. When i did have the airbox open and was spraying seafoam into the carb I noticed the left carb slide door opened a tiny bit when I'd rev it up, but the right one never moved.
Is that normal? Does that mean my carbs are out of sync.
What controlls how those slides open. I guess on idle in the driveway they don't open much, but riding down the road they open quite a bit?
Not normal. The slides are open by vacuum. They will open more (assuming they are working) under load. This could be a synch issue or a bad diaphragm. Check synch first. The diaphragms are expensive.
Did you check your sync via the vacuum gauge method that chris talks about on his website:
http://www.ducatisuite.com/carbsynch.html (http://www.ducatisuite.com/carbsynch.html)
I looked for the brass nipples on the pipe between the carbs and the engine. My fitting is silver metal not brass and it looks like a allen head fits in it.
Do I just thread this out to check the vacuum?
The air box lid is cut open leaving a square frame that clips down. Don't do this until you have the appropriate jet kit from Factory Pro or Dynojet, or the bike will run like crap. Their websites will reference the kits for your model and mods.
You need a K&N filter too. Paper one doesnt like wet conditions.
Carbs should open the same for the reasons mentioned. I would also change the needle jets with Factory Pro ones. The stockers wear out quickly. All this stuff is available from Cal Cycleworks.
The manometer will sort the synch. You done it before?
Quote from: koko64 on October 20, 2011, 02:04:39 PM
You need a K&N filter too. Paper one doesnt like wet conditions.
FWIW you don't need a K&N branded one - you just need something that isn't paper media if you open that box top. K&N and BCM are oiled (important to oil them!) cotton supported by wire mesh. There's also foam filters from Piper Cross
http://www.pipercross.net/motorcycle/applications.asp?m1=6&m2=119 (http://www.pipercross.net/motorcycle/applications.asp?m1=6&m2=119)
I got a fancy aluminum "rig" with my k&n, that uses the stock clips and looks like it won't stay on, but it always has. In retrospect I should've dremmeled the stock lid, it just sits around. I can't bear to throw away Ducati parts.
Quote from: drewbabich on October 20, 2011, 06:51:37 AM
Did you check your sync via the vacuum gauge method that chris talks about on his website:
http://www.ducatisuite.com/carbsynch.html (http://www.ducatisuite.com/carbsynch.html)
That will work, I prefer something like carb sticks (mercury manometers), Twin Max (what I use) or you can build these
http://www.powerchutes.com/manometer.asp (http://www.powerchutes.com/manometer.asp)
I looked for the brass nipples on the pipe between the carbs and the engine. My fitting is silver metal not brass and it looks like a allen head fits in it.
do I just thread this out to check the vacuum?
The nipples have been replaced with those screws. If you stop by a dealer they probably have a bunch they took off other bikes. They might throw you a couple. If not, whatever tool you buy should come with adapters.
Quote from: bikepilot on October 18, 2011, 02:48:59 PM
FCRs make a huge improvement in throttle response, but are $$$ - might make more sense to sell and get a DS1000-powered monster or even a 4-valver if you are after power/$$ in a monster.
+1 on that. I have a 2001 M750 and had thought about putting on FCRs, big bore kit, M800 heads, 6-speed tranny, etc, etc. In the end I just got a Factory Pro jet kit from ca-cycleworks.com and enjoy the bike for what it is: a simple bike you can have loads of fun with.
See above post. I would spend the $100 on the factory pro kit and cut the stock airbox. Maybe change the front sprocket. The jet kit and open air box will make the throttle response much better and it's not too difficult to install. I While I really like the FCR's, at that point ($$$) you are better off looking for a used 900 or something.
I've had both the 750 & 620. The 620 feels and runs better IMO. Move to a 900 and you will smile again