DR750 & DR800 owners thread

Thanks guys for your advise. really helpful :)

seeing the Mikuni are so expensive, the FCR are so hard to tune ...
I might just buy a Microsquirt ECU (http://www.microsquirt.info/), that would be a little less money than the Mikuni (but not much) ... and it might prove easier for me than jetting the FCR (I'm doing programming for smartphones) ... and quite challenging

or I can take care of the Fork and rear shock before tampering with the engine ... yeah, that's what I gonna do :)
one thing after another ...

cheers
I'll post pics when the bike looks nice

I think there is no cheap or easy solution if you want to tune the intake.
For fuel injected Big check these links:
http://www.youtube.com/watch?v=BlyDYvoajPs
http://www.advrider.com/forums/showthread.php?t=417178

You needn't wait. We're all used to seeing "used" bikes here and enjoy watching them being reborn.

I'm a bit confused about the EFI controller. Wouldn't you still have to sort all the hardware problems involved with converting to an injector system, intake air sensor, exhaust sensors etc. Personally, I'd rather spend my time jetting carbs. But then I do not own even one injected bike so the whole thing is just MAGIC to me...Black Magic at that.

Depending on the type of riding you do, spending money for a good quality rear shock and improving the front forks will certainly give you more overall performance per dollar/euro/pound than any other modification you can make to the bike. The standard engine makes good power IMHO and there doesn't seem to be any really easy solution to making it produce significantly more.

Good suspension will let you at least get most of the power to the ground particularly if you're riding off-road.

seem to be any really easy solution to making it produce significantly more.
Yes there is, pumper carbs, large air cleaner, larger header , open can, and a reground cam .
whats so hard this is a easy solution ,
But it is true what you said earlier about tyre wear, Ray 500klm out of a Dunlop 606 :eek1. when there down to the last 1/3 of tread depth I chuckem but you can still have a lot of fun with that last bit .

After much thought i am going to buy a complete ss system for the DR i bought this GSXR can as i was going to fit it .It is as new not a mark on it ,so before i ebay it it"s for sale on here ,like i said it is as new .£40 plus postage

Any idea what it would cost to ship it to California?

Those things are very difficult to find over here.

Seems like rates should be dropping soon as even the N. Koreans have figured out how to send us air-mail.

Rob,

I guess I should have written that there is no easy and CHEAP way to make the Big make more power.

With the SR43 engine in my SR41, I've gotten just about 1500 km out of a T63 Michelin. But that's with a few easy street miles. I generally change mine about like you do as a knobblie is useless without ...well...knobs

I guess at the end of the day, HP is just expensive, no matter how you look at it.......sure it FUN though

Some of my thoughts. Based on experience or attempts at.
Reducing DR weight and replacing suspension and brakes with good ones will allow SR43 with stock motor to be ridden faster than perfectly clean DR with 60 bhp motor in stock weight. Adding second set of wheels (for paved road) will allow it to be ridden at crazy angles in corners like giant supermoto and it will easily take on much faster bikes in real twisty road.
54 bhp is fully sufficient for what it must do.
Carbs won't add power but will quicken response. Which can be both cool (if you experienced) and bad (if you are novice or intermediate offroader - I consider myself still novice).
Converting to FI will cost twice the price of Mikuni TM36.
FCRs are not best choice for bike like DR, because they are a bit more about precision and controls. TMs are stone reliable carbs with enough but not over the top adjustments with shedloads of parts available.
Header-exhaust combo on top size singles are VERY sensitive area and it is easy to make engine curve worse by simply putting too big header and too open can or too tight header and open can or ...any combination can end better or worse.
Same goes for airfilter. It must be sufficient to provide pulsing supply of air and one "gulp" but also open enough to compensate and isolated enough to avoid turbulence etc. etc. etc.
Here is example for you. ANY modifications to VTR1000F airbox will make it worse for engine. ANY. There are 1 person, who knows how to change air intake path but he only does it on already tuned motors with lots of different parts.
DR very much same sensitive. Advantage of FI - it will make DR much less sensitive to bad exhaust-header combos. Second advantage - easy tuning. BUT this is true for factory or factory + aftermarket addons solutions and never ever easy for DYI FI.

E.g. best way to make DR go faster - by combo of good exhaust and header, tested airbox mods, dropping of unnecessary weight and replacing suspensio and brakes. Cheap? No way. I had done all this and I did spend some money, despite I was really careful on budget.

Where does the idea that carbs won't add power come from?

Regards,

Derek

Spen, can you figure out the postage to germany, please?

Cheers,
Lars

Don,t tell me Blue forgot to take his medication again , .

Ok Derick unleash your wisdom .
round one ding ding. .

From actual experience with actual bikes which I worked on, from at least 50 of my friends I worked with.
Getting fueling right can add power. Improving flow can add power. Changing carbs type by itself - not.
You can achieve same peak power with stock carbs or TMs on DR in my opinion.


Forgot to add.
There are actual attempts at "sport" cams on DRs. Changing to "sport" cam will make DR much less enjoyable - tested, ask Zappa from DR dutch club, he ditched sport cam and he is really good rider. It messes engine curve badly, requiring to run "Dakar style" offroad.
One more thing - to make clear what I am saying. I am not saying that combo of all things taken to extremes - pipe, airbox, ports, carbs etc. will make no difference. What I am saying is that pumper carbs, you can properly install on DR are TM36s and not bigger. Unless you cut frame etc.
TM36 carbs because of their size and venturi sizes etc. will not do much for power by simply replacing stock with those. They will liven bike up a lot because of response. This is for DR. But I had chance to inspect actual Dakar DRs and was surprise to see that even bored out 60 bhp + dakar Zetas use rather usual carbs. I also know from DR supermono racers that taking DR power beyond 60-65 will kill it rather quickly and do require totally new head, the one they used on UK and Dutch supermono racers with DR motor. I also saying that top reasonable header size etc. limited on DR by ports etc.

I am not stating that changing carbs on other bikes will have no effect - to talk about it I need to see ports, actual bike etc.
On some bikes I worked with attempts to use huge pumpers resulted in such loss of power on low rpm range (because of velocity) that bike became useless for real life riding and pure sport vehicle.

Not cool. You seem to take it tad too far, don't you think?

You got dyno run from your DR with pumpers and stock filter and exhaust vs. properly tuned? Please post. It will be rather useful for anyone.

You tried different carbs on 50 of your friends bikes? These were all DR750s and 800s, or are you making your statement universally?

Indeed.

Indeed.

If the carb you change to improves flow, the intake lobe duration is not too long, and there is no detonation from the improved cylinder filling, yes indeed.

Why do you think that is?

Regards,

Derek

No, I did not tried different carbs myself on 50 DRs. I have life beyond ADV rider, please note - I am from USSR and most of my DR owning friends are on ex-Soviet Union territory. We do not communicate on ADV rider.
Those were DR 750s and 800s, carbs attempted vary from PHBs Dellorto to FCRs (won't fit properly at least on SR43) and to TM40s. Results were...disappointing I must admit. I worked on bike with DYI TM carbs kit.

If carb improves flow - fully agree. But it does not. Purely practical application limit type of available carbs, you can put on DR without major mods to frame. TM36s fit. But they do not improve flow.
My statement not universal, I was referring to actual conversation.

As for why achieving bhp limited...well, I can speculate that it is limits of actual engine design. To make more on top it needs work on flow, e.g. head etc. I am no great fan of DR motor to be honest. I think it is incredibly tough and reliable, but attempts by supermono racers show, that head is limitation on power.

sorry - my bad, not PHB. PHB was on Aprilia bike I worked on recently (incredible piece of junk, that carb). I mean flat slide dellortos from Guzzi - can't recall specific type, it was while ago.

Sorry Lars I have been working just saw your post ,the can is sold , very sorry again

Blue you are too serious sometimes , hey do you think over the years all my mods I did and showed everyone on here was a waist of time .
I have bought 3 pairs of pumpers now these carbs are worth the money I wish you would have put some on your bike too to feel the difference it makes to your arms in the way that it pulls, one can tell just by feel that it would have a way better torque curve.
Speaking carbs did the Dakar bikes run 34 yes 34mm BST carbs I wonder why they did that , probably because they did not have access to HRT .

You caught me in properly bad mood...ignore it...long winter put me in depression mood and I just can't snap out if it. My apologies about harsh reaction.

I did not say pumpers were waste of time and money, I did not say they do not help to go faster. I myself was on verge of installing them on my bike. No. What I said - purely about not getting more max power, the BHPs. Ability to go faster and power is not same - I am sure you won't argue with that. At the end of the day "go faster" on bike is at least 50% in suspension-rolling chassis and not in +5 bhp on the graph. You yourself did not start your bike from pumper carbs, right? I remember you started from sorting rolling chassis and motor. E.g. sequence-wise I'd say those carbs are after rest is sorted. And BTW DR750 airbox still won't allow to utilize those carbs properly - even with cutout. It is important how much air you have at one volume of airbox.
Why they did not put pumpers on Dakar bike? I am 100% sure Gaston's garage guys knew very well what they were doing. And they had 60-65 bhp bike without pumper carbs. That tells me something. Perhaps that tells me, that too harsh reaction on throttle is no good for rally-raid riding.

It doesn't matter if you're building a race machine, just doing annual maintenance or prepping for a long ride - at some point TIME will affect the decisions you make in modifying anything. Particularly on a race bike when using other people for jobs and parts, things alway seem to come down to the last few days (or nights). So perhaps they just ran out of development time or maybe other carbs did not give the fuel range that is (or at least was) so crucial in the Dakar.

Anyways, I guess I started this discussion with my "NO EASY WAY" statement a few posts back.

I only hope that no one gets irritated and stops posting. I know all of us value the opinions of everyone on the thread and it would be a shame to loose someone.

Also, please allow for vast differences in culture and language remember this is a very international thread