Tight fit (real tight!) Pulse by Kettler comfort bike-Sick Shifter Kit

i-paint

New Member
May 24, 2008
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I ordered this bike online because I liked it (a lot)! I thought I could get an engine in there maybe. If not I would send the bike back. When it arrived I opened the box and became sick. I got my engine and held it up to the bike and it would not go in the frame at any angle. I called the bike store I had bought it from and told them I wanted to return it. Long story short they needed around $100.00 to take it back. I then put it on eBay and tried to sell it. After five days and no bids I decided to try the engine in the frame again. I stripped the mounts, studs, sparkplug, manifold and carburetor. With the front mount shaped to fit the down tube and the rear mount gone I was able to fit it in at one angle with very little up and down clearance. You need some to adjust the chain on the shifter kit. I rough shaped the front mount with a wood rasp which worked really well. I formed a piece of tin to fit the tube perfectly and embedded this in the engine with cold weld. I cut the rear mount down to about 1/8" and reinstalled it on the engine. While the cold weld was still soft I put the engine in the frame so the angle on the front mount would be correct. After this dried I filled in the voids on the front mount with more cold weld. It seems to be a very solid mount. There is less vibration on this bike than any of the others I have built. I can't say for sure it is the mounts but I think they help. On my other bikes the front mount sits on a plate u-bolted to the tube.

The rest of the bike went together with no major problems. I wanted to run 2.125" or more on the tires but was limited by the sprocket on the shifter kit to 1.85". I have a set of the 2.125" tires and they are wider and taller. There is maybe 3/16" clearance between the tire and the sprocket now. I rode the bike for a while and decided I needed black rims. After I changed the rims and tires the bike rides even smoother. I think it is because the rims are truer with better bearings. They spin forever. A lot longer than the originals. I think the tires are truer ( if that is the correct terminology) as well.

I added the pipe last. The engine only had about 150 miles on it, but the pipe still made a significant difference. It will continue to improve I hope. I made the head pipe 12". I don't know if this is the best length but that is what it was from the factory. Others on the forum have suggested this length as well. With a little over 200 miles on it the bike tops out at 36mph.
It has six gears. My other bikes improved with mileage hopefully this one will also.
One last note. After I finished taking these pictures I dropped my camera and now it doesn't work so these are the best I have.
 

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Jul 22, 2008
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Northglenn,Colorado
Simply WOW. Proof that these kits can fit ANYTHING with some thinking.
I would never think it would work.
I do see a weak point.
Your front motor mount bolts. Keep an eye on them.
But because your mount hugs the frame on the ends maybe it would be okay.
No room for washers,huh. Washers run across the bolt would strengthen it.
Are the bolts at least a grade 5?

(edit) Woah! I just saw the pull starter! NICE!!
 

UncleKudzu

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May 26, 2008
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Deep in the American South
you know, the tight fit makes it look like it was made to fit. that's a good looking ride! don't you love the different frame geometries the bike manufacturers are coming out with these days?
 

i-paint

New Member
May 24, 2008
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Thanks Large Filipino, Those are all thread studs used in the front mount. They go through a plate that fits the bottom of the down tube. It is actually one side of a chain idler so it is pretty heavy before I put the self-locking nuts on is a small tube spacer cut at the angle of the plate on one end and square on the other. This keeps the stud from trying to bend to the angle of the plate across the tube. It is probably 45 degrees or more.
 
Jul 22, 2008
656
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Northglenn,Colorado
I think I see it now. VERY NICE! Nice job indeed!

I hope you don't mind my input. :D I just love how you did all that particularly how you tackled the carburetor.

Just an insight that's all :D but if you flipped the intake manifold over so the carburetor is on the left then you can finagle with the choke while your right hand is on the throttle!

I originally wanted a China engine on my schwinn (cronus). If you look at my frame is pretty much the same geometry. I never tried to do it when I got my engine and instead bought another bike. The Titan is on it now.
 
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i-paint

New Member
May 24, 2008
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Thanks Large Filipino. I welcome any and all insight. I didn't know how the long manifold would affect the engine but it seems to run fine.
 

i-paint

New Member
May 24, 2008
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Pablo, There wasn't room for the SBP engine mount. The engine is almost to the seat tube. I cut the original mount down to 1/8" probably. The front mount must hold more than its share to keep the engine from twisting. It hasn't moved. I also think the chain tensioner helps. It sure makes it easier to adjust the chain. There is only about 1/16" clearance between the head pipe and the frame. It has never touched.
 

i-paint

New Member
May 24, 2008
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jerseykat, I made the plate that fits to the engine from 1"X 1/4" steel. I bored the holes with a drill press. The tube is copper. It is refrigeration tubing not plumbing. They are different iszes. I'm not sure what they call the size but it is 5/8" od or close to it. You can buy at a heat and air supplier. I soldered the tube in the steel plate. I also soldered the brace to the tube. I bent a long piece of tubing by hand then cut it off.
 
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Clotho

Member
May 25, 2008
304
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Beautiful bike! Nice job overcoming the various challenges. Congrats on reaping the rewards! :)
 

jerseykat1

New Member
i am thinking about getting a shifter kit. does it make the bike ride smoother? better acceleration? is it worth the money and time to install it? i am not having any problems with the stock chain drive now but i cant help but to foresee problems in the future and god forbid there is a problem while i am 10-15 miles from home.
 

i-paint

New Member
May 24, 2008
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jersetkat1
Absolutely yes to all your questions. I wouldn't build a single speed bike for myself any more. This is my second shifter kit. It is a blast shifting gears!

Larry (i-paint)