thoughts & opinions wanted

[SIR REAL ED]

I've been collecting the components for a while for a putting together a light weight street bike based on a Suzuki DR650.  I've got most of what I need, now just need to decide on a direction.

Since the DR650 is a bike with good bones, it seems like an easy enough project, with the hardest part being improving the looks of the DR650.  Different gas tank, sub-frame, seat, etc.  Looks of course, are subjective.

The internet is loaded with lots of custom DR650 based street bikes.  Quite a few are good looking bikes IMO. 

I recently bought a DR650 that has been rode hard and put away wet and does not have a title.  It is good sacrificial Ox material.

If I can get a title for this bike, I will probably put a V-Strom 650 front end on it and proceed with some mods, different wheels, etc.

The other thought is putting the DR650 engine in an MZ660 chasis.  Advantages would be the simplification of air cooling, single carb, and elimination of the MZ oil tank.  I likes the looks of the MZ Skorpion bikes.

I have lots of options such as CBR250 wheels, SV650 wheels, Ninja400 wheels, and possibly swapping the swingarm for an aluminum swingarm from a DR650, SV650, or Ninja400.

Still in the noodling phase.  I should get started in a couple months.

As a favorite teacher used to say after presenting material:  "comments, questions, criticisms, doubts, wise ass comments?"

I welcome one and all.  Thanks in advance.

[faffi]

I like simplicity, and getting rid of both a dry sump and a redundant carb and a radiator in one go is a Kinder Surprise in itself.

An alloy swingarm sounds like a good idea. A single sided swingarm would look cool and make tire changes simpler, but also add weight. I would also consider a cartridge style fork, preferably from a bike of a similar weight and purpose and known to work well, to reduce the hassle of re-valving. Personally, I would want a single front disc brake; less unsprung weight, easier to check air pressure, and fill air.

However, it is not what I want, but what you want, Sir 

[SIR REAL ED]

I like simplicity, and getting rid of both a dry sump and a redundant carb and a radiator in one go is a Kinder Surprise in itself.

An alloy swingarm sounds like a good idea. A single sided swingarm would look cool and make tire changes simpler, but also add weight. I would also consider a cartridge style fork, preferably from a bike of a similar weight and purpose and known to work well, to reduce the hassle of re-valving. Personally, I would want a single front disc brake; less unsprung weight, easier to check air pressure, and fill air.

However, it is not what I want, but what you want, Sir 

All those opinions make sense to me.  How about a picture of your 1990 XT600Z.

Several people have mated the air cooled XT600 top end to the MZ 660 engine cases.  I looks very clean.  If you want, I can send you some pictures.

The cam chain is the same and the only series mod needed is running an oil line from the oil filter cavity to the end of the camshaft.  The electric start version of the XT600 has a much more robust bottom end than the previous SRX/XT engine.

Still got the dry sump and the oil tank however.

[faffi]

This is a press photo, but when new it looked like this


It still does, only scruffier. Engine is electric start.

[Perazzimx14]

The DR650 is a great bike, I've had 4 of them. But the DR650 is heavy. The 1996+ DR650 also has no subframe. If you want to chop the tail, you have to involve a welder. I'd also forgo the DL650 (V-strom) forks as they are the same 90 year old damper rod tech and only lightly larger diameter. In either case fork brace, new springs as the OEM are made for 110lb riders and some sort of fork valve like a Ricor will make the front end tolerable and not dive 12 inches every time you apply the front brake. The rear wheel on the DR650 has a cush drive that is made out of bricks and lead.

I too like simplicity and recently bought my first DRZ400s and its just as simple as the DR with and bolted aluminum sub frame, cartridge forks (not great but 1000X better than the DR/DL) and is already about 40 lbs lighter than the DR650.

Swapping wheels will not be easy either unless you have access to a machine shop that can machine the wheels and/or make custom spacers. Swingarms will be an even bigger challenge but will include cutting, welding and more machining. 

I loved my DR650's but the DRZ is quickly making me rethink ever getting another.

FWIW if the DR650 is a pre 1996 (one of my 4 was a pre 1996) I probably would not even fool with it. There were known for timing chains not being adjusted because you had to remove the side case. Then they would get lose and the chain slap would wear away at the surrounding case internals and putting aluminum shaving all through the engine and in some instance enough to plug internal passages and oil starve engine components. If it's a pre-06 drain the oil and see how much metal is in it. If it nice and slivery bolt it back together and find another project.

The 1996+ were a huge leap forward. The other advantage is 1996 - 2023 are all essentially the same so there is no shortage of inexpensive part both used OEM and aftermarket.
 

[SIR REAL ED]

The DR650 is a great bike, I've had 4 of them. But the DR650 is heavy. The 1996+ DR650 also has no subframe. If you want to chop the tail, you have to involve a welder. I'd also forgo the DL650 (V-strom) forks as they are the same 90 year old damper rod tech and only lightly larger diameter. In either case fork brace, new springs as the OEM are made for 110lb riders and some sort of fork valve like a Ricor will make the front end tolerable and not dive 12 inches every time you apply the front brake. The rear wheel on the DR650 has a cush drive that is made out of bricks and lead.

I too like simplicity and recently bought my first DRZ400s and its just as simple as the DR with and bolted aluminum sub frame, cartridge forks (not great but 1000X better than the DR/DL) and is already about 40 lbs lighter than the DR650.

Swapping wheels will not be easy either unless you have access to a machine shop that can machine the wheels and/or make custom spacers. Swingarms will be an even bigger challenge but will include cutting, welding and more machining. 

I loved my DR650's but the DRZ is quickly making me rethink ever getting another.

FWIW if the DR650 is a pre 1996 (one of my 4 was a pre 1996) I probably would not even fool with it. There were known for timing chains not being adjusted because you had to remove the side case. Then they would get lose and the chain slap would wear away at the surrounding case internals and putting aluminum shaving all through the engine and in some instance enough to plug internal passages and oil starve engine components. If it's a pre-06 drain the oil and see how much metal is in it. If it nice and slivery bolt it back together and find another project.

The 1996+ were a huge leap forward. The other advantage is 1996 - 2023 are all essentially the same so there is no shortage of inexpensive part both used OEM and aftermarket.

Good information Perazzimix14.  I can agree with pretty much all of it.

In riding the DRZ400 and the DR650 back to back, I noticed the DRZ400 lack of torque relative to the DR650 more than I noticed the extra weight of the DR.  But there is no doubt about the lighter weight of the DRZ.  The dRZ is heads and shoulders above the DR in terms of ANY off road situation you will encounter.

Oddly enough, the MZ is about 40 lbs heavier than the DR, but maybe due to lower seat height and lower CofG, it is not very noticeable.  Luckily, since the MZ are famously heavy, they are two great places to save weight.

I agree that staying away from pre-1996 DR650's is a good idea.  The only one I ever rode was riducously easy to kick start!  I was stunned.

I've already got Suzuki SV650 wheels that are machined to fit the DR, and the Ninja 400 front end will slide right into the MZ triple clamps.  Lots of options!!

 

[fotoguzzi]

[Perazzimx14]

Good information Perazzimix14.  I can agree with pretty much all of it.

In riding the DRZ400 and the DR650 back to back, I noticed the DRZ400 lack of torque relative to the DR650 more than I noticed the extra weight of the DR.  But there is no doubt about the lighter weight of the DRZ.  The dRZ is heads and shoulders above the DR in terms of ANY off road situation you will encounter.

Oddly enough, the MZ is about 40 lbs heavier than the DR, but maybe due to lower seat height and lower CofG, it is not very noticeable.  Luckily, since the MZ are famously heavy, they are two great places to save weight.

I agree that staying away from pre-1996 DR650's is a good idea.  The only one I ever rode was riducously easy to kick start!  I was stunned.

I've already got Suzuki SV650 wheels that are machined to fit the DR, and the Ninja 400 front end will slide right into the MZ triple clamps.  Lots of options!!

 

Torque specs between the two are 26ish verses 39ish (depending on where you look) FT/LBS of torque. That extra 250cc makes a big difference. I got lucky when I had my second DR650 and found a guy selling an FCR39 that was already modified and jetted for a DR650 for $125. That made a pretty big difference in performance and also aided in chewing up rear tires much faster.

The BST series carbs on the DR/DRZ are okay but never as good as a pumper. I've been reading up on the FCR clones on eBay and Amazon for the DRZ that are $121 vs the $650+ for originals and people are having good results with them. I might have to give one a try as what's the worst that can happen and I've certainly pissesd away far more money on far less things in the past. 

[SIR REAL ED]

Torque specs between the two are 26ish verses 39ish (depending on where you look) FT/LBS of torque. That extra 250cc makes a big difference. I got lucky when I had my second DR650 and found a guy selling an FCR39 that was already modified and jetted for a DR650 for $125. That made a pretty big difference in performance and also aided in chewing up rear tires much faster.

The BST series carbs on the DR/DRZ are okay but never as good as a pumper. I've been reading up on the FCR clones on eBay and Amazon for the DRZ that are $121 vs the $650+ for originals and people are having good results with them. I might have to give one a try as what's the worst that can happen and I've certainly pissesd away far more money on far less things in the past.

IIRC, the dyno from my 790cc showed 40 ft-lbs at 3000 rpm vs 27 ft-lbs for the 650 at the same rpm.  One of the best parts of single cylinder bike ownership & modification, is that foolishness & experimentation are much cheaper.

At that cost, might as well try out the FCR clone.  Amazon has a no questions asked return policy.  Worst case is you end up with a cool paperweight!!