Punsun Dnepr build with questions

[sno-bro]

Greetings all!

It is -24c outside here in northern Finland, so a good day to be on the internet!

I've started a diesel bike build this winter and I'm making slow and steady progress, and thought I'd share some pictures for your entertainment, and also have some questions.

The bike is originally a K-750, made by KMZ which later became to be known as Dnepr. I've restored to original condition two similar bikes, so the technology is familiar to me, hence the selection. As an engine I've got a Winsun 22hp purchased directly from the factory in 2008. Below some pictures of my progress. I'm using the original 4speed tranny, still not sure if I'll use the 9% faster or 30% faster 4th gear and what final drive ratio, I've got all the parts.

Two questions (for now )
1) -I've read some worrying threads on cranks braking on the Punsun 22hp engines. Has anyone made any final conclusions on that? Eg certain years were worse etc. I'm also hopeful the problem is not with Winsun, as to my best knowledge Punsun and Winsun are made by a different company. I'm not sure but it seems both factories are in Nantong but have different addresses, contact persons and telephone numbers. Could be the parts come from the same place though. . Are there people happily driving around their Punsun/Winsun bikes or are they all going to brake and I'm doomed and crazy to continue?

2)-has anyone tried to change the injection lines on these engines so that instead of the line coming up from the pump to sideways? It would require an L adapter and either some bending of the original tube or new tubes. The pipes currently interefere with the top frame tube when removing the engine requiring the removal of the subframe.

Anyway, some details of the build below. Overall it has been fun to build but surely is taking a LOT more time then I anticipated.

-Frame bottom tubes are widened, bent forward and the whole frame is lengthened about 7cm.



To strengthen the bottom tubes and drop the engine in the frame (for looks and gas tank clearance) I welded some 40*4mm bars on the tubes and have made them into box. This picture is missing the final piece welded completing the rectangular structre



The engine is bolted to a subframe with rubber bushings



here is a picture of an earlier stage of engine fitting. In it you can see how the injection lines will intefere with the fuel tank and are the critical dimension in removing the engine (eg for crank replacement )




I have more pictures and I can also update moving foward if there is interest.

Happy dieseling!
sno-bro

[nanno]

Now that is very interesting. Talking of another bend in the Diesel-lines, I would say, it shouldn't matter really.

I would be extremely interested to see how the engine bolts into the adapter and how you fix all this to the frame as the gearbox is mounted solid, I am not sure, whether this is clever or not, as it could put some extra stress onto whereever the gearbox is bolted to the frame or if that is not the case... well, sooner or later you will have to bolt something to the frame rigidly.

Looking very good though.

Greg

[sno-bro]

An update on today's progress. I got the engine where I want it and next will start worrying about footpegs, battery tray, air cleaner, fuel filter etc.

These pictures should also clarify a bit my engine mounting method.

Here is a picture of the subframe with rubber bushings in the bike without the engine.



in this picture the engine is attached. The subframe is bolted to the bottom engine attachment point by the eight bolts, and at the rear with additional two.



In the above you can again see how the injection lines interfere with the fuel tank forcing it up by a few centimeters. If the hardware from the pump had an L piece first it would clear the tank. Any comments/suggestions?

I cranked the engine with the starter just to see what happens, didn't want to start it without the mufflers, but I probably eventually will. Even when I make the exhausts I won't be able to test them until they come from the chroming house, they won't chrome used pipes.

sno-bro

[zarquon]

I give you my thumbs up for this build!

[Henk]

Very good project.
I to have used (partly) a Dnepr-frame , the rear. But building a total fifferent bike.
I see you have cut the backside of a Dneprengine to fit the gearbox on the Punsun. That's a clever idea.

The Punsung engine max rpm is about 3600, so take the highest gearing you can find.

I am using also a Dnepr gearbox, at the moment the 4the gear is 1:1 the final drive from a solo .If I got the licences for driving on the highway I will build the gearing to maximum for more speed.

I to have difficulties with the original fueltank, so I build it by myself . That's more work I could imaging but the tank is finally ready.

[coachgeo]

Locomotivebreath went a differnt route with tank. He left it off. Well the stock tank he did. Put box tank on side rear.

He also found the higher speed gears much better. His build is pictured in here as well though not a "build thread". Search by his name maybe?

[sno-bro]

Thanks for your comments!

Henk, any pictures of your bike? Would be nice to see!

I found pictures of Locomotivebreaths bike, very nice! However my idea has all the time been to keep the bike looking as much a K-750 as possible, so I'll be keeping the original tank. I'll take the injector lines tomorrow to a diesel shop to see if they can make new ones with a smaller bend that clears the tank better.

sno-bro

[coachgeo]

... I'll take the injector lines tomorrow to a diesel shop to see if they can make new ones with a smaller bend that clears the tank better.

sno-bro

Will be interesting their responce. Quick search findings are. Injector lines have to be same length so reaction time is equal per cylinder, the ends are special- not just a simple flare. Far as I've found no "L" like fittings exist. Again though that was a very quick search

[XLerate]

There are many small hand held tubing benders available, used both in automotive & also A/C Refrigeration. These make it real easy to bend fuel lines, brake lines etc.

As long as you start out with all tubes of equal length, then bend them up to fit, you don't need to worry about lengths, they're all the same. They're most likely double flare fittings if they're flared, but you'd have to inspect them to know. Double flare requires a special tool designed to make automotive brake lines, most auto parts stores sell them. Also available online. I doubt they are a flared type fitting. Most are a compression type fitting.

Build looks great, keep up the good work!

[Sibbo]

st it would clear the tank. Any comments/suggestions?

I cranked the engine with the starter just to see what happens, didn't want to start it without the mufflers, but I probably eventually will. Even when I make the exhausts I won't be able to test them until they come from the chroming house, they won't chrome used pipes.

sno-bro

Wow ! That is slack ! I've had no trouble at all .

and an excellent build ..I'll keep watching .

[coachgeo]

There are many small hand held tubing benders available, used both in automotive & also A/C Refrigeration. These make it real easy to bend fuel lines, brake lines etc.

As long as you start out with all tubes of equal length, then bend them up to fit, you don't need to worry about lengths, they're all the same. They're most likely double flare fittings if they're flared, but you'd have to inspect them to know. Double flare requires a special tool designed to make automotive brake lines, most auto parts stores sell them. Also available online. I doubt they are a flared type fitting. Most are a compression type fitting.

Sorta thought the same thing as many others did but quick research seemed to dispell these thoughts for myself and others who asked similar questions on various boards I reveiwed. Seem's the tube is NOT fuel or brake line but much more specific, harder etc. cause they endure dramatically higher pressures. Material I read was more automotive/truck diesel Inector line discussions so not sure relavency to the smaller industrial diesels like we often use for our bike projects. What I read also said that due to the high pressures they were NOT flared ends normally but instead often had special welded fittings, again though that was larger diesel engines soooo relavency??

[Henk]

Thanks for your comments!

Henk, any pictures of your bike? Would be nice to see!

I found pictures of Locomotivebreaths bike, very nice! However my idea has all the time been to keep the bike looking as much a K-750 as possible, so I'll be keeping the original tank. I'll take the injector lines tomorrow to a diesel shop to see if they can make new ones with a smaller bend that clears the tank better.

sno-bro

I am posting pict. on this site. Look to "Building a dieselbike with a Daihatsu 950TD" or something like that.

I reformed the frame rigorously because the dieselengines are somewhat bulky and heavy when you want a few Hp extra.
I used the backpart of the frame and made the front by myself. I bought a 10 ton;s hydr.handset for bending tube's for the frame. Welded together, all weldings are full penetration .

[XLerate]

There are many small hand held tubing benders available, used both in automotive & also A/C Refrigeration. These make it real easy to bend fuel lines, brake lines etc.

As long as you start out with all tubes of equal length, then bend them up to fit, you don't need to worry about lengths, they're all the same. They're most likely double flare fittings if they're flared, but you'd have to inspect them to know. Double flare requires a special tool designed to make automotive brake lines, most auto parts stores sell them. Also available online. I doubt they are a flared type fitting. Most are a compression type fitting.

Sorta thought the same thing as many others did but quick research seemed to dispell these thoughts for myself and others who asked similar questions on various boards I reveiwed. Seem's the tube is NOT fuel or brake line but much more specific, harder etc. cause they endure dramatically higher pressures. Material I read was more automotive/truck diesel Inector line discussions so not sure relavency to the smaller industrial diesels like we often use for our bike projects. What I read also said that due to the high pressures they were NOT flared ends normally but instead often had special welded fittings, again though that was larger diesel engines soooo relavency??

Not sure here, Coach. I'm only directly familiar with Cummins engines with Bosch VE type pumps. The fittings are a flare type & part of the sealing is a type of rubber o-ring. They also use a soft copper or brass/bronze type sealing ring on some. There's no tremendous pressures involved, but I understand that an inline pump runs higher pressures. Many fuel injection designs use o-rings of one sort or another.

Not sure what type of pump is used on Punsuns, but thinking it's similar to a VE, not an inline pump high pressure pump?

Overall, if it was me, I'd look at picking up a hand held tubing bender suitable for the specific diameter of fuel line tubes, use it to re-bend the stock fuel lines as needed to clear obstacles.

[sno-bro]

The injection line is NOT ordinary fuel line or brake line. The pressures even in these small diesels are in the hundreds of atmospheres, and in this is a pulsating pressure putting a lot of stress on the metal. In addition there is constant vibration.

I visited the local authorized Bosch diesel service center yesterday and explained the situation, I had the original injection lines with me. They measured the old lines and sold me a pair of straight factory made diesel injection lines of the exact same length. They were available in 5cm increments.

Picture below.

The person in the shop said straight out that they are not as robust as the originals, but are widely used for three purposes: Antique equipment where original lines are no longer available, applications where original lines are hugely expensive or as field repair lines in commercial equipment. They felt that for my application the lines should hold up very well.

Mind you this shop is not your ordinary cheap garage, they service almost solely industrial diesel machinery and only with reputable brand parts. I guess that's why they cost 20€ a piece

The lines are very heavy gauge with factory made tapered ends. They warned me that the line will take bending quite well but only once. If you then try to straighten them again they will not last.

This looks to be the solution I was looking for!

sno-bro

[XLerate]

That sounds like the solution. I'm sure it's all partially dependent on what injection pump system is used & what kind of pressures are involved. DOM-ERW certainly won't work, seamless only. What sort of injection pressures are found in the Punsun injection system? Direct injection or multi-point?

[sno-bro]

A short update on my build for possible comments:

I have all the modifications made and did a final assembly of all the parts to verify they fit without interference, the battery is big enough to start the engine etc. Everything looks good and now I'll disassemble it and start sandblasting, painting, chrome/zinc plating etc. A Picture below.



sno-bro

[sno-bro]

and adding a video....

http://www.youtube.com/watch?v=Lpf_8CTH6jc

[old clunker]

Nice build! and I'm glad that you're keeping the original look with the fuel tank. Keep posting the progress and photos, we're all interested!!
Looks to be a good bike, and I'm sure that it will be fun to ride.

[coachgeo]

excited for you. Looks and sounds GREAT!

[henneberg]

Well done great work. Looking forward to see the bike running

rgds, Erik

[Stuart]

Great stuff, looking good

[XLerate]

Most excellent buid there, Sno-Bro! I share your [and most everybody here] love for classic machines. That bike has some great lines and somehow the diesel almost looks factory installed at the time! Can't wait to see it with pretty new paint and plating. Great job!!

[Sphere]

Very nice. If the wheelbase stretch can be limited to 6cm it would be a good choice for Dutch builders. Thanks for posting eye candy

[sno-bro]

Thanks for your support guys! Right now the boring part is ongoing: sandblasting. It seems my hair has a small beach worth of sand every time I finish the evening .

About the 6cm more wheelbase: My bike came out at 7cm increase. In addition the forward down tubes are bent forward to allow for more room. I think 6cm would be possible with my setup provided that you get an engine where the crank is uniform thickness all the way to the block. Mine has a "step" about 1.5cm before the block that limits how far back the clutch can be. The engine-gearbox came out to be then 1.5cm unnecessarily long. Of course the step is not in the crank drawings by Punsun nor Winsun so I don't know where it came from. Maybe to make the crank stronger? (I hope ) See picture below about what I mean:


Another pointer for anyone thinking about following a similar path: There are two types of blocks in these engines, like the one I have (see above) and a newer one where the engine attachment is part of the block casting. The NEW block below. Notice the attachment bolt direction is VERTICAL, and in my engine it is HORIZONTAL. It helps if you get the right one. (The picture is large and will show the left side only unless your browser window is wide enough. So please make it as wide as possible to see what I mean)



The build continues! I WILL ride this summer!

sno-bro

[Sphere]

Actually I wonder if your engine won't be better. My Hatz also has separate steel brackets, but the bolts go in horizontally. With the new design you have to rely on the cast quality of the Chinese builder. I don't really feel comfortable to give up this security for easier mounting.

[Sibbo]

Sno Bro, have you calculated your road speed at 3000 rpm?

A great looking build mate !

[punsunV2engine]

Hi Everyone ,

I am Jason from Punsun engine , I am so glad to join in this big family !

When i put the key word (punsun engine ) into google , i find this dieselbike website . So i click the link and find a big surprise . There are so many people are discussing the punsun engine ! Cool motorbike with our punsun engine .

Also i find some problems with our engines, so i decide to be a member in this family , if anyone who need my support , i can discuss with them online . Hope that i can supply more good service for everyone who like our punsun engine .

best regards,

Jason

PUNSUN TEAM

2012-5-21

[Sibbo]

Hi Jason ,
I'm sure your input and expertise will be very welcome. May I suggest you post up in Member Introductions and General Chat as your message may be seen by more readers.

[coachgeo]

..Jason, .... May I suggest you post up in Member Introductions and General Chat as your message may be seen by more readers.

Sibbo your a day late and dollar short lol. Jason posted in both two days ago.

[punsunV2engine]

Hi Sibbo,

Thanks !

Yes, i did

best regards.

Jason

Hi Jason ,
I'm sure your input and expertise will be very welcome. May I suggest you post up in Member Introductions and General Chat as your message may be seen by more readers.