[Sutripta]

Originally Posted by ringoism

I suppose carbide burrs don't really "grind"... but whatever they DO they do it well!!!

Burrs/ cutters would be ideal. For aluminium, even HSS would do fine.

Lighten the piston as much as possible, and see if you can reliably add weight to the counterweights. (Keep in mind clearance issues, and centrifugal forces. You don't want flying pieces of metal near your leg.)

Regards
Sutripta

[ringoism]

Originally Posted by Sutripta

Burrs/ cutters would be ideal. For aluminium, even HSS would do fine. Lighten the piston as much as possible, and see if you can reliably add weight to the counterweights. (Keep in mind clearance issues, and centrifugal forces. You don't want flying pieces of metal near your leg.) Regards
Sutripta

Hey Sutripta, how about adding weight to the balance shaft instead? That might be removable through the side-cover without having the whole cases split.

The new X-Pulse is distinctly more vibey, I wonder whether it has a balance shaft at all, and if so why it doesn't seem to be taming it as well, at only 200cc...

I've got plenty o' burrs of all shapes / sizes, have done this sort of thing on occasion...

-Eric

[Sutripta]

Originally Posted by ringoism

Hey Sutripta, how about adding weight to the balance shaft instead?

You will have to split the weights between the crank and the balance shaft.
Must add a word about adding weights.
The piston, the crank, and the balance shaft work together as a system trying to compensate for unbalanced forces. Each of these, by themselves, is quite unbalanced. Putting a tremendous strain on the bearings. Adding weights is only going to add to this. Maybe the rev limit will have to be decreased a bit.

The new X-Pulse is distinctly more vibey, I wonder whether it has a balance shaft at all, and if so why it doesn't seem to be taming it as well, at only 200cc...

The Dukes have balance shafts. And are vibey. I think it is deliberate - a projection of a high strung high power no nonsense primal engine.

Regards
Sutripta

[petrolhead_neel]

Eric Sir,

Thanks a lot for this thread. Have been a silent admirer for a very long time. Guilty as charged!

Have always had a sort of soft corner for the Impulse. I had high hopes for the XPulse, and I love it for what it is. But somewhere, I still kind of prefer the Impulse over it, owing to the fact that I have always dreamt of having one right since when it was launched.

Now, something has come up. The owner of the workshop that we take our bikes to has an Impulse. He's a biker who's known quite widely in the motorcycle community in this side of the country, and he's very trustworthy. My father and I were talking to him about getting a used Impulse. One thing led to the other and my father asked if he was willing to sell his bike to us, since he had mentioned that he wasn't getting time to ride it.

Now, coming to the bike, it appears to be in immaculate shape. I know that he keeps his bikes well maintained. But the (sort of) caveat is that this particular bike, with the odo having stopped a few times during trips, doesn't read all the mileage that the bike has covered and according to his calculations, it's a shade over 100,000 kms. However, the bike went through a sort of restoration some time ago and got an engine rebuild. Again, I trust his engine rebuilds since my Twister has been running like a dream after he worked on the engine last year. However, with our limited experience, we still don't know if we should take the plunge.

As for the usage of the bike, the Impulse probably won't see a lot of running for now. Normal city commutes with my Dad and a few weekend expeditions here and there will be the norm. Being 17, most of my riding happens on off road trails. When I get my license next year, the Impulse will be used more often, and the bigger idea is to make it into a project bike.

What do you think about this? Thanks!

Neel

[Sutripta]

^^^
As your first (working) bike would strongly suggest you stick with something more mainstream and in current production. Preowned is not the issue.

However if you think it will become a classic, and you want to start building your collection now ...

Regards
Sutripta

[petrolhead_neel]

Originally Posted by Sutripta

^^^
As your first (working) bike would strongly suggest you stick with something more mainstream and in current production. Preowned is not the issue.

However if you think it will become a classic, and you want to start building your collection now ...

Regards
Sutripta

Thanks a lot for helping me out!

If all goes according to plan, we should have another (hopefully, new) motorcycle in the garage sometime next year.

I do think that the Impulse will become a future classic, and as I said, the dream inside is still very much alive.

I wouldn't mind waiting for parts, since the Impulse will probably never me the daily ride anyways. I also don't have a problem with the fact that it's pre-owned, what is worrying me is the more-than-average mileage of the bike. I know that Hondas last a lifetime, and my experience with the Honda CB Twister w.r.t reliability has been mind-blowing, so far. But I just want to make sure that riding this across trails and off-roads won't be a problem. I don't know how an Impulse ages, and if the high mileage would affect how the bike performs.

Neel

[Sikkimese4x4]

Hi Ringoism
I'm also planning to do a 21 inch front set up on my impulse but I wanted to know how ur 19 inch impulse spokes on a 21 inch rim is holding up. Any risks of HUB damage under load. Also by any chance do u still have some left over spoke nuts which u got for ur wheel setup. If so I'm keen to buy any 40 pcs.... Thanks a lot

[FloatingCanvas]

Originally Posted by ringoism

A long history (that try as I might, I can't seem to make shorter),
...

So what was I to do? (To be continued...)

Chanced upon your thread now, in 2020, and man, what a fantastic piece of writing!

You should definitely start an epic travelogue with all your adventures on 2 wheels with as many photos as you can find!

Your writing is very engaging and takes the reader along with you on the journey. Please do write a travelogue covering all your favourite rides, with tons of pics and the adventures - riding and otherwise that you encountered.

[ringoism]

Originally Posted by petrolhead_neel

I wouldn't mind waiting for parts, since the Impulse will probably never me the daily ride anyways. I also don't have a problem with the fact that it's pre-owned, what is worrying me is the more-than-average mileage of the bike. I don't know how an Impulse ages, and if the high mileage would affect how the bike performs.

Mine seems to be holding up well. Probably ready for a set of piston rings but not bad enough to be smoking, still starts and runs well even being minimally maintained. Speedo/Odo wire has broken internally a couple times, so not sure of true mileage but would guess 35-40,000-ish.

Past year it has been on loan to a young graduate friend in exchange for some IT/media work on our behalf... he's really warmed up to it and wants to buy it next Spring... I'm not quite sure I want to let it go, still dream of doing a big-bore kit and better pipe, but finding it hard to justify holding onto, eh, five bikes (four of them registered/insured)... Roads in general getting better up here, and after riding the modded Machismo, find it hard to bear with the low power of the stock Impulse/X-pulse... which means another project... The plush ride, silky smoothness of that balance-shaft 150, generous GC, high riding stance / wide bars and basic simplicity of design are superb, the whine from the primary drive (from new), its anemic nature and the continual water/mud splashing on the pantlegs are the only real downers IMO (maybe the lack of center-stand). At least three of these would be correctable.

Originally Posted by Sikkimese4x4

Hi Ringoism
I'm also planning to do a 21 inch front set up on my impulse but I wanted to know how ur 19 inch impulse spokes on a 21 inch rim is holding up. Any risks of HUB damage under load. Also by any chance do u still have some left over spoke nuts which u got for ur wheel setup. If so I'm keen to buy any 40 pcs.... Thanks a lot

No extra spoke-nuts, sorry, but should be common with other bikes and even buying a whole set of desi/China spokes to glean them should prove a reasonable option.

Durability-wise all's well so far. (Pulsar) hub holding up fine. I think I broke one a spoke at some point, but then I broke a couple front/rear ones with the stock setup, too. I beat it quite mercilessly in truth. I wouldn't guarantee it, but don't personally fear it coming apart at speed or potholes or whatever. It's proved itself in my case.

Originally Posted by FloatingCanvas

Chanced upon your thread now, in 2020, and man, what a fantastic piece of writing!

You should definitely start an epic travelogue with all your adventures on 2 wheels with as many photos as you can find!

Your writing is very engaging and takes the reader along with you on the journey. Please do write a travelogue covering all your favourite rides, with tons of pics and the adventures - riding and otherwise that you encountered.

Many Thanks, bro... we're all in this together, I guess, and happy to offer my 2cents/paise... good to know that some don't mind my lengthiness.

Travelogue? I dunno...Serious travels much further and fewer between these days... Lots of great memories, and a few dreams still... Been thinking for about four years whether to finally post my Mizoram write-up...

[ringoism]

Originally Posted by ashwinprakas

Do make sure there's sufficient liner left before going ahead with the mod cause I doubt there would be considering the near 6mm shave, as even a wafer thin liner would most likely end up biting you in the arse when you least expect it to.

Knew some one from another community who went for P220 OS piston in ZMA by reboring it and using 17mm to 15mm adapters, the adapters even had minute oil channels to prevent overheating.

Everything went well until a spirited hill run and that was the end of it.

Since your daily runs are hill-run's to begin with I doubt an adapter is the right way to go, though I'd still be curious to know the specifics if you go ahead with the project anyhow.

Despite my original skepticiam, this is sounding increasingly like solid advice...

As it turns out the stock.200cc block won't fit into the hole in the 150cc case without a custom "naked" sleeve and some modding of the oil supply passage. Lots of work and potential for error.

Plus 2V X-Pulses are turning out to have quite a lot of engine problems (their oil-coolers notwithstanding) according to staff at our local ASC, and being that it was pretty much a big-bore kit on a 150, I might have been repeating the mistake that Hero themselves may have.

Plus those 200's were in no way as smooth as the Impulse's silky balance-shafted 150 had been...

I have two good used 200cc cylinders but am going to cancel that plan.

Yet a bit more power is definitely called for.

Could advance the cam timing (for increased low-end), put a free-flow pipe, bore to max size and mill the head for some compression bump... That would probably get me near to where I want to be without too much work, and as such is probably the most sensible option.

Less cheap/ sensible would be the (commonplace) ZMA/CRF230 223cc engine swap... which adds weight and gives me an invalid engine serial number...

OR... Go in for a Hero/Honda 160cc crank/ cylinder. This would give me more stroke for the torque I want, is still very smooth (same 150 bore-size featherweight piston), and probably would bump the compression without needing any milling.

Unfortunately since the cylinder is taller, would require the new block, as well as a new crank/rod and longer timing chain. Secondhand would work for the block at least. With the added stroke and an overbore on the 160 cyl, I should be able to easily manage 175cc and at least 10:1 CR. Good pipe installed and it should fly.

Need to find parts, and so far haven't. New ror everything is going to take me into considerable money I'd rather avoid spending.

Hopefully this will be a Spring project and not get delayed too long. Eager to ride this bike again.

Rode it down the stairs of our new place to its current resting place - what a great suspension... But it's not going to get back out till it can do so on its own power!



If I can get it up and running will consider taking it to Mizoram this winter and keeping it out there (some great trails that side) for use during annual visits till (God willing) we transition from these to those hills...

Engine's apart sitting in two boxes, valves are shot - been like this since last autumn, and there's no going back now.

Whatever, it deserves better than this...

-Eric

[ringoism]

Originally Posted by ringoism

...Engine's apart sitting in two boxes, valves are shot - been like this since last autumn, and there's no going back now... it deserves better than this...

On the way back from Mizoram in the Getaway, went up to the border at Nepalganj to attend the wedding of a good friend's son.

Noticed an inordinate number of Nepalese-numbered CB Hornet 160's up there on the Indian side, which is where a long string of two-wheeler mechanical and spares shops cater to 90% Nepali customers.

So the morning of our departure, asked around at a few shops till I found one that had an old standard-bore 160 cylinder block, they gave it for ₹600. I then put a little less than that into a top-quality Goetz-TP modest 1.0mm (58.3 diameter) overbore piston, and a couple hundred on a fresh (& longer) 160 timing chain. Couldn't find a used (rebuildable) 160cc crankshaft up there or anywhere unfortunately, so will probably have to spend ₹4k on a new one from Honda - that proved hard to find even in Karol Bagh (DL) as I was to discover last week. I will take this as confirmation of the claims that these cranks hardly ever wear out, much less fail. So reliability of bottom-end isbasically unquestionable.

. (160 cylinder on left, 200cc on right).

With the longer (63.1mm vs 57.8) stroke of the 160 crank I get both mechanical advantage in the form of more leverage/ torque - It also gets me higher compression since with that and the bigger bore I'll now have 168cc's (vs. 149) getting squeezed into that 16.5cc combustion chamber, so 10:1 compression vs. the Impulse's 9:1. Can gain even a bit more if I omit the cylinder base gasket in favor of RTV Silicone, as done on my Machismo build. Probably 10.2:1.

The Hornet itself is 10:1 compression, puts out 15hp/14.5nm stock vs. the Impulse's very tame 13/13.4. The extra 5cc's (the 160 is actually 163cc, 150 is 149cc) should get me near a half hp additional on its own, and with freer-flowing intake and exhaust & mild port cleaning-up, I figure I should end up easily at16hp or more (0.95hp/10cc, which is what the XPulse and plenty of other fairly tame bikes are able to achieve). That's a little less than the XPulse's ~19bhp, but being that the Impulse is considerably lighter and the long stroke in theory should improve the grunt considerably over the 150, I'd expect the net experience might be similar. Except that the much smaller, lighter piston than the 200's might vibe a little less.

Overbore is mild enough to not excessively thin the cylinder wall or stress the cooling capacity, so should be good there. And I think I'd be right to expect marginally better FE vs the 200cc also.

Also discovered that the 125cc Shine, which shares the same engine cases, has a lower-ratio 2nd gear set... which might help improve that too-large 1-2 gap. So will try and look for a pair and verify fit.

Anyway, good to be finally on the verge of doing something. If I end up not highly satisfied even after all this, I can bore another mm for a +1mm/59.5 HH Ambition piston (the flat-top design of which would give higher compression also) which would give 175cc's...

If all else fails will start looking for a cheap deal on a 2023-up Yezdi Adventure !

-Eric

[ringoism]

Well, I wish I could just delete that whole previous post...

Turns out the 160 cylinder, despite looking near-identical and having same provision for timing chain guides, etc, has mounting stud holes that have been moved inwards, and will not match the spacing on the cases!!! Odd that the Indian Honda has departed further from Honda's international models than Hero has! No feasible way to alter this, so am back to the beginning:

1. 200cc imported big-bore kit
2. all kinds of jugaad to the XPulse 200cc block /piston and probably a crank swap;
3. Karizma engine swap
4. modest 155cc overbore plus compression bump

Was down at the Hero svc center today looking at and measuring parts and weighing my options, head tech guy does a lot of mod work on the side and possesses much useful knowledge. Probably 80% of his official work is on XPulse now, as it has become the bike of choice for young local guys, who've made the place their hangout. Many bikes with rally kit etc, these guys race them competitively. One whom I talked with at length, whom also knows a lot. To him, even vs. the 4V, the ZMA conversion without question would give the best all-round performance. It's got the displacement and stroke, and can just fly. Especially on a bike 30kg lighter than what it was originally fitted to. Though from what I hear Hero hardly supplies spares now, and they are sensitive on preferring OE stuff.

Anyway... would need to find an engine and fully rebuild, which doesn't thrill me with so many other projects and work ongoing. And who knows if I wouldn't get snagged at the next passing five years from now over the swap and the engine numbers. Better to at least look legal.

I have a friend coming from abroad in May who's offered to carry the kit. Yes, it is likely of Chinese origin and no, doesn't likely have top quality stuff. But I figure if it runs only a few years even, it's worth it for ₹7600 equivalent. Other than the ZMA, nothing will give me significantly better performance that isn't going to take a lot of custom work and/ or preclude the possibility of returning the bike to stock at some point.