The frame? Ah the original aim was to get the bike up and running so I could ride it, cosmetics a secondary concern
Next job here was to put in a new cam-chain. I suppose I could have got a split-link but prefer to do it the proper (hard) way, and an opportunity to check over some of the other internal parts at the same time.
Clutch has to come off:
Primary drive:
Cam cover, and cam sprocket:
New chain, 50-quid!
TDC timing mark on the flywheel:
And the cam:
Cam cover back on (top engine mount connects to this so that had to come off as well)
Clutch cover, kick-start, clutch cable…
Brake pedal:
Footpegs, header pipe, etc, etc….
Clean the screen filter in the down-tube:
New filter:
And then spin the motor to check the oil’s circulating:
Well it was, but would it start? That is the next part!
The Big DR350 Project. *Updated*
- BIG BILL
- Posts: 894
- Joined: Tue Apr 12, 2011 6:45 am
- Location: Northumberland
- Has thanked: 29 times
- Been thanked: 6 times
Re: The Big DR350 Project. Updated- Part 4 Cam Chain
OOOoooooooooohhh keep em coming keep em coming.............
I need to go to bed early me thinks...
Frame what about the frame....
And all the Oily bit's tell us more...
Seriously great thread keep em coming :woohoo:
BB
I need to go to bed early me thinks...
Frame what about the frame....
And all the Oily bit's tell us more...
Seriously great thread keep em coming :woohoo:
BB
Don't wait for your ship to come in, swim out and meet the Bl**dy thing ( Barry Sheene )
Your along time dead..
Your along time dead..
-
- Posts: 1138
- Joined: Wed Oct 17, 2012 1:44 pm
- Has thanked: 165 times
- Been thanked: 159 times
Re: The Big DR350 Project. Updated- Part 5 Getting it RUNNING
Well it took little effort to fire up the beast, or at least after it had leaked fuel all over the patio out the carb. The float valve had already been cleaned so took a gamble and it stopped of its own accord, once the valve had remembered how to “valve” and the float had remembered how to, er, float.
The engine ran very smoothly, and revved up crisply with no smoke or mis-firing, good-good! Time for a test-ride then eh? Well will come back to that in a bit, but this bike has no battery so I had no idea if the lights would work. But with the engine running they did, and the indicators!!
Wow. But no sign of brake lights, and subsequent investigations found both switches badly corroded and in need of some help. The rear:
And the front:
Which was a right pain as the little toggle switch (middle-top) had to come apart to clean the contacts. Held together with a tiny but strong spring it was VERY fiddly to reassemble and I cursed like a good-un. Could have bought some new ones and saved an hour or two…. But…..
No speedo either, another thing rusted up and broke:
So what does it go like, come on get on with it!!
OK OK need to find some private ground first (obviously) then fire her up and settle into that mouldy old seat which sure is soft and comfy. The clutch is (now) smooth, as is the engine, pulling from low revs without complaint, and pretty much vibe-free.
But what does it REALLY go like?? !! Come on man!
OK, all right! Just need to find some more space and then wind the loud-handle to full.
WOAH!! - I wasn’t expecting that! The lower gears disappear very quickly and even in 6th its still pulling hard at 70 - it really has got some go for an old air-cooled 350!
Certainly feels a lot different to my old DR back in ’98, the engine having a much gruffer tone and a significant step-up in power, while still retaining the DR350’s trademark smoothness and flexibility.
The lower gears can be used from idle, the engine then pulling hard right through the rev range and well into the red, with no hesitation, flat-spots or anything. Even at 30mph in 6th it picks up strongly, and will, allegedly, indicate 90+ quite easily!
It would seem that a pumper-carb, Vortex airbox, over-sized header, and Kientech-modified silencer are very worthwhile modifications…
20 years old an’ all - very impressive.
With the lights now working, the brakes fixed, the suspension play sorted, spokes tightened, carb fixed, cables replaced, knackered tyres removed, and all sorts of other stuff repaired the bike went in for an MoT and passed with flying colours – yeay!
Now, with that the bike was put to good use, from March onwards last year, and a load of photos to come, but first quite a major mod to be done, perhaps called a “farkle” as likes to be said here, and that is for chapter 6.
The engine ran very smoothly, and revved up crisply with no smoke or mis-firing, good-good! Time for a test-ride then eh? Well will come back to that in a bit, but this bike has no battery so I had no idea if the lights would work. But with the engine running they did, and the indicators!!
Wow. But no sign of brake lights, and subsequent investigations found both switches badly corroded and in need of some help. The rear:
And the front:
Which was a right pain as the little toggle switch (middle-top) had to come apart to clean the contacts. Held together with a tiny but strong spring it was VERY fiddly to reassemble and I cursed like a good-un. Could have bought some new ones and saved an hour or two…. But…..
No speedo either, another thing rusted up and broke:
So what does it go like, come on get on with it!!
OK OK need to find some private ground first (obviously) then fire her up and settle into that mouldy old seat which sure is soft and comfy. The clutch is (now) smooth, as is the engine, pulling from low revs without complaint, and pretty much vibe-free.
But what does it REALLY go like?? !! Come on man!
OK, all right! Just need to find some more space and then wind the loud-handle to full.
WOAH!! - I wasn’t expecting that! The lower gears disappear very quickly and even in 6th its still pulling hard at 70 - it really has got some go for an old air-cooled 350!
Certainly feels a lot different to my old DR back in ’98, the engine having a much gruffer tone and a significant step-up in power, while still retaining the DR350’s trademark smoothness and flexibility.
The lower gears can be used from idle, the engine then pulling hard right through the rev range and well into the red, with no hesitation, flat-spots or anything. Even at 30mph in 6th it picks up strongly, and will, allegedly, indicate 90+ quite easily!
It would seem that a pumper-carb, Vortex airbox, over-sized header, and Kientech-modified silencer are very worthwhile modifications…
20 years old an’ all - very impressive.
With the lights now working, the brakes fixed, the suspension play sorted, spokes tightened, carb fixed, cables replaced, knackered tyres removed, and all sorts of other stuff repaired the bike went in for an MoT and passed with flying colours – yeay!
Now, with that the bike was put to good use, from March onwards last year, and a load of photos to come, but first quite a major mod to be done, perhaps called a “farkle” as likes to be said here, and that is for chapter 6.
Last edited by Thedktor on Wed Jan 03, 2018 7:52 pm, edited 1 time in total.
- Steve
Southampton area
DR350, 349, DRZ, 701
Southampton area
DR350, 349, DRZ, 701
-
- Posts: 1138
- Joined: Wed Oct 17, 2012 1:44 pm
- Has thanked: 165 times
- Been thanked: 159 times
Re: The Big DR350 Project. Updated- Part 6 Keihin FCR Carb Conversion
Cheers stanbloke.
More test rides motivated me into further tinkering. Why you may ask. Well! I was quite surprised how well it handled and the fact that it actually feels pretty light.
Light? - yes, really! Relatively speaking of course – the wobbly old bathroom scales reveal a few more kilos than my old KTM-400, but the lower seat-height means the old DR can be chucked around with some enthusiasm and corners really well.
Of course the chassis is flexy and soft compared to a modern bike, but for road and trail riding that’s hardly a problem, and the ride is comfy as a comfy thing.
Anyway, the bike came fitted with a Mikuni pumper carb, which certainly gives it some go, and the jetting is spot-on. However, as I have found with other bikes, this carb suffers from slide stiction and does not give a very smooth throttle action – a real bug-bear of mine.
In particular, when decelerating and then re-applying the slide sticks and makes the engine jerk or snatch. The cause is engine vacuum during deceleration which pulls the slide hard against the carb body, creating a lot of friction, and you can feel it at the twist-grip.
This is why most modern off-road 4-strokes come with Keihin FCR carbs, the “R” standing for “roller”. The rollers are on the slide to prevent stiction, and hence give a much smoother throttle behaviour.
Now it just happens that there’s a 37mm FCR in the spares box, which is theoretically a little too big, but as the Yam and KTM 250’s use this size I figured it might actually work. Here’s the Mikuni on the bike (without airbox boot)
Take it off and lay the two carbs side by side:
The FCR is a chunky old unit but without the starter motor on this model there is plenty of room for it. However to get it to fit the inlet manifold required some grinding down of the engine-side of the carb as it was way bigger, and even now its quite a squeeze.
And squeeze on it does, but the Vortex airbox side took some effort to stretch out the pipe sufficiently.
The throttle cable just fits, so copied the Mikuni main jet size and went for a test-ride.
Did it work? Hell yeah does it work! The pull through the revs super- crisp, and the low-end seems pretty much the same despite the carb’s bigger bore. But more importantly the on-off throttle action is smooth as can be, especially coupled with the cush-drive. No snatch or jerk, bloody brilliant.
What a result, I almost couldn’t believe it! Mind you the fine-tuning of the jetting and pumper-jet took some time but got there in the end and its been running like a dream for nearly a year. Sweet.
So I went out for a proper ride and can report that it ran great!
The first of many photos, but next part is some more spannering as the DR had to come apart again for a "yearly" service!
More test rides motivated me into further tinkering. Why you may ask. Well! I was quite surprised how well it handled and the fact that it actually feels pretty light.
Light? - yes, really! Relatively speaking of course – the wobbly old bathroom scales reveal a few more kilos than my old KTM-400, but the lower seat-height means the old DR can be chucked around with some enthusiasm and corners really well.
Of course the chassis is flexy and soft compared to a modern bike, but for road and trail riding that’s hardly a problem, and the ride is comfy as a comfy thing.
Anyway, the bike came fitted with a Mikuni pumper carb, which certainly gives it some go, and the jetting is spot-on. However, as I have found with other bikes, this carb suffers from slide stiction and does not give a very smooth throttle action – a real bug-bear of mine.
In particular, when decelerating and then re-applying the slide sticks and makes the engine jerk or snatch. The cause is engine vacuum during deceleration which pulls the slide hard against the carb body, creating a lot of friction, and you can feel it at the twist-grip.
This is why most modern off-road 4-strokes come with Keihin FCR carbs, the “R” standing for “roller”. The rollers are on the slide to prevent stiction, and hence give a much smoother throttle behaviour.
Now it just happens that there’s a 37mm FCR in the spares box, which is theoretically a little too big, but as the Yam and KTM 250’s use this size I figured it might actually work. Here’s the Mikuni on the bike (without airbox boot)
Take it off and lay the two carbs side by side:
The FCR is a chunky old unit but without the starter motor on this model there is plenty of room for it. However to get it to fit the inlet manifold required some grinding down of the engine-side of the carb as it was way bigger, and even now its quite a squeeze.
And squeeze on it does, but the Vortex airbox side took some effort to stretch out the pipe sufficiently.
The throttle cable just fits, so copied the Mikuni main jet size and went for a test-ride.
Did it work? Hell yeah does it work! The pull through the revs super- crisp, and the low-end seems pretty much the same despite the carb’s bigger bore. But more importantly the on-off throttle action is smooth as can be, especially coupled with the cush-drive. No snatch or jerk, bloody brilliant.
What a result, I almost couldn’t believe it! Mind you the fine-tuning of the jetting and pumper-jet took some time but got there in the end and its been running like a dream for nearly a year. Sweet.
So I went out for a proper ride and can report that it ran great!
The first of many photos, but next part is some more spannering as the DR had to come apart again for a "yearly" service!
Last edited by Thedktor on Thu Jan 04, 2018 7:49 pm, edited 3 times in total.
- Steve
Southampton area
DR350, 349, DRZ, 701
Southampton area
DR350, 349, DRZ, 701
-
- Posts: 4240
- Joined: Wed Mar 14, 2012 10:55 pm
Re: The Big DR350 Project. Updated- Part 6 Keihin FCR Carb Conversion
Thedktor wrote:-In particular, when decelerating and then re-applying the slide sticks and makes the engine jerk or snatch. The cause is engine vacuum during deceleration which pulls the slide hard against the carb body, creating a lot of friction, and you can feel it at the twist-grip.
Interesting STUFF this which was known about by Suzuki back in 1978.
This was when Suzuki introduced their first 4 stroke dirt bike the SP370.
Only manufactured for a couple of years this machine had a Slide carb with 2 cables to the twistgrip.
One to raise the slide & the other to pull/push the slide down.
This carb also had 2 pilot adjustments (AIR & MIXTURE) which could also clean up low RPM transitions.
When the SP370 became the DR370 in 1980 this nice, expensive, fiddly carb was dropped in favour of a CV carb which reverted to single cable opperating the butterfly & a vacuum controlled slide. One gained advantage here was the altitude compensation of the CV (Constant Velocity) carb.
Interesting STUFF this which was known about by Suzuki back in 1978.
This was when Suzuki introduced their first 4 stroke dirt bike the SP370.
Only manufactured for a couple of years this machine had a Slide carb with 2 cables to the twistgrip.
One to raise the slide & the other to pull/push the slide down.
This carb also had 2 pilot adjustments (AIR & MIXTURE) which could also clean up low RPM transitions.
When the SP370 became the DR370 in 1980 this nice, expensive, fiddly carb was dropped in favour of a CV carb which reverted to single cable opperating the butterfly & a vacuum controlled slide. One gained advantage here was the altitude compensation of the CV (Constant Velocity) carb.
Lightness is everything.
Lightness with Grunt is a Scratcher!
An Adventure is not a tank transfer.
Lightness with Grunt is a Scratcher!
An Adventure is not a tank transfer.
Re: The Big DR350 Project. Updated- Part 6 Keihin FCR Carb Conversion
Good job Steve, you should restore for a living.
Wish you were nearer, you could have sworn at the 640 for me :laugh:
Wish you were nearer, you could have sworn at the 640 for me :laugh:
"The trails of the world be countless, and most of the trails be tried.
You tread on the heels of many, till you come where the ways divide.
And one lies safe in the sunlight, and the other is dreary and wan, Yet you look aslant at the Lone Trail, and the Lone Trail lures you on....
....Bid good-bye to sweetheart, bid goodbye to friend, The Lone Trail, the Lone Trail, follow to the end.
Tarry not, and fear not, chosen of the true;
Lover of the Lone Trail, The Lone Trail waits for you"
You tread on the heels of many, till you come where the ways divide.
And one lies safe in the sunlight, and the other is dreary and wan, Yet you look aslant at the Lone Trail, and the Lone Trail lures you on....
....Bid good-bye to sweetheart, bid goodbye to friend, The Lone Trail, the Lone Trail, follow to the end.
Tarry not, and fear not, chosen of the true;
Lover of the Lone Trail, The Lone Trail waits for you"