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**devils doom** · 05-29-2019, 07:22 PM

Re: Hero Impulse ownership experience

Originally posted by Ankitvile View Post

Good to see you again Bala. Thanks for the insiders, a real help to my vague comprehension of motorcycle dynamics.

Didn't you have the XR's linkage rear monoshock? And hows the Zedling performing. Its a tad costly though. Any other alternatives you suggest? Xpulse's?

I'm on the Karizma's mill now too. Need a new carb. Solely because the stock Keihin is prone to malfunctioning. What would BS29 get me in comparison to Keihin26 as in ZMA? The 33mm fron 200NS seems a lil overkill to me. Mid and low end is what I need and a decent fuel economy too. Given I'll be mostly on tours around Himalayas.

CV Carb's are good for mileage and perform decent with with less headache but have you tried D slide 28mm PWK carb or Flat slide VM 28mm carb.

----consecutive posts auto-merged-----

Originally posted by alinel View Post

I also happen to study these things in details when i build my impulse with the following mods, and learnt a bit or 2 about how chassis mechanics work.

1. Engine swap
2. Fork upgrade to 43mm Showa Cartridge from 1989 Honda CR125R
3. 21'' DID Al rim w/ Ceat 90x90 21 Himalayan tyre
4. Speedo wont work with the 21 inch wheel, so used a wheel sensor magnet with a generic computer for Speedo, ODO
5. Pro Taper CR high SE bars, MSR handguards
6. Tank painted white and shrouds removed
7. Taper roller 32005 Bearings replacing the cup and cone ball bearings
8. Swingarm swapped from a 1986 Honda XR250R - increases wheel base by 40mm and reduced flex
9. Zedling Suspension (Pune) custome made rear shock for the XR250R swingarm
10. BBR big bore kit and CAMs, BS33 CV carb 118 Main jet, 20 Idle jet
11. Same old mega phone exhaust, the DB killer fell off in the event !
12. 1988 XR200 rear wheel and hubs along with Drum Brake backing plate with cam.

Can i please know more about the fork upgrade ? and from where did you sourced BBR bigbore kit and cams ?

**Ankitvile** · 05-30-2019, 06:04 AM

Re: Hero Impulse ownership experience

Originally posted by devils doom View Post

CV Carb's are good for mileage and perform decent with with less headache but have you tried D slide 28mm PWK carb or Flat slide VM 28mm carb.

Also the CVs are rather linear across the rpms. Flatslides like PWK or TM are a little more track based, performance oriented. Used to be fun on Yamaha 135 5speed but being more of a tourer, on Impulse, I stick to the CVs for obvious reasons.

**alinel** · 06-12-2019, 10:46 AM

Re: Hero Impulse ownership experience

Originally posted by devils doom View Post

CV Carb's are good for mileage and perform decent with with less headache but have you tried D slide 28mm PWK carb or Flat slide VM 28mm carb.

----consecutive posts auto-merged-----

Q: Can i please know more about the fork upgrade ? and from where did you sourced BBR bigbore kit and cams ?

A: This is the BBR kit - https://bbrmotorsports.com/Products/...d=411-HCF-2301 , You can buy it from BBR directly or chose to order from Ebay.com which might be cheaper.Please note that You will need a professional to hone the cylinder in a proper lethe/machineshop/turning works ..

Forks: Forks like mentioned are from a 1989 Honda CR125 Mx bike (open cartridge showa 43mm fully adjustable for rebound and compression dampening) with about 10.5 inches of travel (265 mm). This specific model uses the same steering stem bearings to work on the impulse without any mods. 26 x 47 x 15 - 32005/26 if i recall the bearing size. (https://www.allballsracing.com/forkconversion - refer here for any such info)

Work involved :

As you can see. There is a fair bit of work involved. Now, the fork swap is something pretty straight forward if you have the entire kit like I did (Wheels, brakes, T clamps, Spacers, etc) however, what is critical with the impulse is to make sure that the geometry is set correct with the same or close to same as the OE specs. Castor, trail, wheel base etc. Also, another key metric is to ensure that the front and rear suspension have identical travel (6.8 inches F, 5.9 inches R for Impulse) to ensure that they compress and rebound at "Comparable rates". This meant that I had to have atleast 4 more inches of travel at the rear without increasing the seat height by the same which will end up making the bike really tall. So this is where the 1986 xr250r comes in. It has a different motion ratio (15mm closer than the OE swingarm at the pivot fulcrum, more about motion ratio https://www.quora.com/How-do-I-calcu...arm-suspension) by enhancing the stroke of the rear shock, as well as losing some unspring weight and gaining rigidity as its a aluminium unit. More unsprung weight has been lost using 1986 xr250r wheels (DID aliminium 1.65 & 1.85 vs Mild steel 1.85 & 2.15 for the original) and Hubs, which are made from magnesium ! The original rear shock in an impulse has a stroke of 48 mm. The shock we made has 62mm and with the change in ratio, it has a 9 inches travel at the back.

Hope this helps !

**curse** · 06-12-2019, 01:34 PM

Re: Hero Impulse ownership experience

Forks: Forks like mentioned are from a 1989 Honda CR125 Mx bike (open cartridge showa 43mm fully adjustable for rebound and compression dampening) with about 10.5 inches of travel (265 mm). This specific model uses the same steering stem bearings to work on the impulse without any mods. 26 x 47 x 15 - 32005/26 if i recall the bearing size. (https://www.allballsracing.com/forkconversion - refer here for any such info)

[MENTION=75258]alinel[/MENTION]

I need your help.

I am in planning to swap Karizma Suspension with impulse.(Both front and rear)
Front and Rear rims will be 18 inch.

I am not clear with the geometry.

Both Karizma and Impulse have 26 degree caster.(Stock)
Trail on Karizma is 94 mm and Impulse is 99 mm.

Once I swap the front forks all these numbers will go for toss.

The caster and trail will change to say x and y respectively.
The above will effect the ride dynamics.

I will not have provision to change wheel base,also I do not want to alter fork length by any means.

The only thing I will have control is over rear shock mounting angle/length and this will allow me to
set one of the parameter caster or trail to stock Karizma.

So my questions
Is my method of looking at the whole thing correct?
If not what geometry parameters i need to check/follow to do the swap?

If yes,what should I match Caster or Trail length?

**alinel** · 06-13-2019, 09:35 AM

Re: Hero Impulse ownership experience

Originally posted by curse View Post

Forks: Forks like mentioned are from a 1989 Honda CR125 Mx bike (open cartridge showa 43mm fully adjustable for rebound and compression dampening) with about 10.5 inches of travel (265 mm). This specific model uses the same steering stem bearings to work on the impulse without any mods. 26 x 47 x 15 - 32005/26 if i recall the bearing size. (https://www.allballsracing.com/forkconversion - refer here for any such info)

@alinel

I need your help.

I am in planning to swap Karizma Suspension with impulse.(Both front and rear)
Front and Rear rims will be 18 inch.

I am not clear with the geometry.

Both Karizma and Impulse have 26 degree caster.(Stock)
Trail on Karizma is 94 mm and Impulse is 99 mm.

Once I swap the front forks all these numbers will go for toss.

The caster and trail will change to say x and y respectively.
The above will effect the ride dynamics.

I will not have provision to change wheel base,also I do not want to alter fork length by any means.

The only thing I will have control is over rear shock mounting angle/length and this will allow me to
set one of the parameter caster or trail to stock Karizma.

So my questions
Is my method of looking at the whole thing correct?
If not what geometry parameters i need to check/follow to do the swap?

If yes,what should I match Caster or Trail length?

Ans:

The karizma axel to fork top length and difference when compared to impulse will give you how much rise you can expect from the swap. The rear geometry is going to be a lot more tricky as karizma uses twin shock setup vs a mono for the impulse. Not only this, the impulse frame has a offset for the shock mount. which means that using the impulse swingarm on a karizma might need some serious work too.

Why not just us the impulse ? whats the purpose of this swap ? infact the exact same thing has been done with the xpulse from here, where the frame of the xpulse is very very identical to a karizma.

**curse** · 06-14-2019, 07:20 PM

Re: Hero Impulse ownership experience

Originally posted by alinel View Post

Ans:

The karizma axel to fork top length and difference when compared to impulse will give you how much rise you can expect from the swap. The rear geometry is going to be a lot more tricky as karizma uses twin shock setup vs a mono for the impulse. Not only this, the impulse frame has a offset for the shock mount. which means that using the impulse swingarm on a karizma might need some serious work too.

Why not just us the impulse ? whats the purpose of this swap ? infact the exact same thing has been done with the xpulse from here, where the frame of the xpulse is very very identical to a karizma.

[MENTION=75258]alinel[/MENTION] Thanks for the reply.

Looks like I have two options

1>Start studying about motorcycle geometry from basics.
or
2>Eyeball everything and pray it works

It is a project bike i want to build/modify.I will try to start a new thread for it.

**spartacus69** · 06-15-2019, 06:28 PM

Re: Hero Impulse ownership experience

Is anyone using Chest protectors for offroading? if so, which one?
I was thinking of getting the EVS F1 chest protector and later get the kidney belt and elbow pads.
Any suggestions?

Also my Impulse is out now and has evolved to Impulzma <3
I must say, it is bloody awesome.

----consecutive posts auto-merged-----

Originally posted by Ankitvile View Post

Though the NS carb seems an overkill for the ZMA to me I don't know what will that do to the 150 mill on Impulse. The thing is broader the throat more the power is located on the upper rpms giving you less pressure differentials at low rpms across the Venturi thus good for drags and high speeds which I doubt is a requirement on Impulse with a big carb. The stock 28mm is too large for it in the first place and the ZMA comes with a 26mm for that matter and Pulsar 150 with BS26 (26mm)

Please let me know how the mod turns out to be once you go with the RTR180 carb, BS29 or the NS one.

Hello, Ankit. Just got my Impulzma with ns carb out of the shop and my goodness it is on another level. I love it so much. It's torquey and easy to keep up with the domi and himalayan or even the Mojo. Need to spend more time on riding it, to see if any faults show up. Right now few more tweaks has to be done to get it complete. Speedo ain't working, need to find better brakes or change tyres, Swingarm bushes need to be changed and also need to add self motor to it. Once it is completed, will update more. Running shell 10w 40 oil.

**devils doom** · 06-17-2019, 11:01 AM

Re: Hero Impulse ownership experience

Originally posted by alinel View Post

A: This is the BBR kit - https://bbrmotorsports.com/Products/...d=411-HCF-2301 , You can buy it from BBR directly or chose to order from Ebay.com which might be cheaper.Please note that You will need a professional to hone the cylinder in a proper lethe/machineshop/turning works ..

Forks: Forks like mentioned are from a 1989 Honda CR125 Mx bike (open cartridge showa 43mm fully adjustable for rebound and compression dampening) with about 10.5 inches of travel (265 mm). This specific model uses the same steering stem bearings to work on the impulse without any mods. 26 x 47 x 15 - 32005/26 if i recall the bearing size. (https://www.allballsracing.com/forkconversion - refer here for any such info)

Work involved :

[ATTACH]250042[/ATTACH]

As you can see. There is a fair bit of work involved. Now, the fork swap is something pretty straight forward if you have the entire kit like I did (Wheels, brakes, T clamps, Spacers, etc) however, what is critical with the impulse is to make sure that the geometry is set correct with the same or close to same as the OE specs. Castor, trail, wheel base etc. Also, another key metric is to ensure that the front and rear suspension have identical travel (6.8 inches F, 5.9 inches R for Impulse) to ensure that they compress and rebound at "Comparable rates". This meant that I had to have atleast 4 more inches of travel at the rear without increasing the seat height by the same which will end up making the bike really tall. So this is where the 1986 xr250r comes in. It has a different motion ratio (15mm closer than the OE swingarm at the pivot fulcrum, more about motion ratio https://www.quora.com/How-do-I-calcu...arm-suspension) by enhancing the stroke of the rear shock, as well as losing some unspring weight and gaining rigidity as its a aluminium unit. More unsprung weight has been lost using 1986 xr250r wheels (DID aliminium 1.65 & 1.85 vs Mild steel 1.85 & 2.15 for the original) and Hubs, which are made from magnesium ! The original rear shock in an impulse has a stroke of 48 mm. The shock we made has 62mm and with the change in ratio, it has a 9 inches travel at the back.

Hope this helps !

So you ordered the CRF 230 big bore kit (piston,cam and springs) and bored the stock cylinder to 67mm ? what compression have got ? cause i read somewhere that CRF 150 F 06 onwards big bore kit which includes cylinder,piston,cam and springs making it to 196 cc and 9.8:1 compression is direct fit onto the impulse bottom end.

how you sourced the CR125's front (forks,both T,wheels and brakes ?) btw have you calculated the spring rate of rear shocks ? stock and xr's ?

**trnaren** · 06-18-2019, 12:26 AM

Re: Hero Impulse ownership experience

Originally posted by spartacus69 View Post

Is anyone using Chest protectors for offroading? if so, which one?
I was thinking of getting the EVS F1 chest protector and later get the kidney belt and elbow pads.
Any suggestions?

Also my Impulse is out now and has evolved to Impulzma <3
I must say, it is bloody awesome.

----consecutive posts auto-merged-----

Hello, Ankit. Just got my Impulzma with ns carb out of the shop and my goodness it is on another level. I love it so much. It's torquey and easy to keep up with the domi and himalayan or even the Mojo. Need to spend more time on riding it, to see if any faults show up. Right now few more tweaks has to be done to get it complete. Speedo ain't working, need to find better brakes or change tyres, Swingarm bushes need to be changed and also need to add self motor to it. Once it is completed, will update more. Running shell 10w 40 oil.

Nice!
Which carb did you upgrade to? The bs3 or bs4 of ns200... Pls share more details in the jetting, cdi, etc

**alinel** · 06-18-2019, 09:11 AM

Re: Hero Impulse ownership experience

Originally posted by devils doom View Post

So you ordered the CRF 230 big bore kit (piston,cam and springs) and bored the stock cylinder to 67mm ? what compression have got ? cause i read somewhere that CRF 150 F 06 onwards big bore kit which includes cylinder,piston,cam and springs making it to 196 cc and 9.8:1 compression is direct fit onto the impulse bottom end.

Ans: Impulse bottom end and karizma bottom end are totally diff. CRF150F (read as CBZ for bore and stroke) and CRF230F (read as karizma for bore and stroke) are the same. so any cylinder parts compatible with both generally will work on the karizma engine. The BBR kit has a compression ratio of 11.5:1 with a significantly larger crown on the piston top.

how you sourced the CR125's front (forks,both T,wheels and brakes ?) btw have you calculated the spring rate of rear shocks ? stock and xr's ?

Ans: Combination of hand carry parts when visiting abroad and ordering via Ebay. I am not using the stock rear shock. to match the front fork (spring rate .38 kg/mm) travel of 285mm, new rear was made from scratch with a stroke of about 62mm vs OE (48mm) to give additional travel. Its a twin piston chamber shock which has separate valving for compression and rebound dampening and has been set up for my weight for desert racing. The new shock as you can see also has a preload adjuster which is missing in the original unit for adjusting SAG which was not possible before. Hope this helps. cheers.

----consecutive posts auto-merged-----

Originally posted by devils doom View Post

So you ordered the CRF 230 big bore kit (piston,cam and springs) and bored the stock cylinder to 67mm ? what compression have got ? cause i read somewhere that CRF 150 F 06 onwards big bore kit which includes cylinder,piston,cam and springs making it to 196 cc and 9.8:1 compression is direct fit onto the impulse bottom end.

how you sourced the CR125's front (forks,both T,wheels and brakes ?) btw have you calculated the spring rate of rear shocks ? stock and xr's ?

Impulse bottom end and crf (150/230) are totally diff. they dont share any engine parts whatsoever. my bike has a compression ratio of 11.5:1 using the BBR kit.

**devils doom** · 06-18-2019, 12:02 PM

Re: Hero Impulse ownership experience

Originally posted by alinel View Post

Ans: Combination of hand carry parts when visiting abroad and ordering via Ebay. I am not using the stock rear shock. to match the front fork (spring rate .38 kg/mm) travel of 285mm, new rear was made from scratch with a stroke of about 62mm vs OE (48mm) to give additional travel. Its a twin piston chamber shock which has separate valving for compression and rebound dampening and has been set up for my weight for desert racing. The new shock as you can see also has a preload adjuster which is missing in the original unit for adjusting SAG which was not possible before. Hope this helps. cheers.

[ATTACH]250102[/ATTACH]

----consecutive posts auto-merged-----

Impulse bottom end and crf (150/230) are totally diff. they dont share any engine parts whatsoever. my bike has a compression ratio of 11.5:1 using the BBR kit.

I am asking about the rear shock spring rate, Front i calculated its comes between .38kg/mm to .40kg/mm cause i dont have a big vise hence i am not able to do the rear calculation.

These are Zedling suspension pune, i am from pune only only bro have visited there place i am gonna get front fork internals from there only but rear i need dampening adjustments and that zedling doesnt have.

You didn't tell what exactly you did on your impulse, you bored the stock impulse cylinder to 67 mm ?

And i confirmed with the guy who did job onto his impulse for the CRF 150 F BBR kit of 2006 till present, he replaced the cyclinder, piston,cam and springs.

BBR Motorsports, Inc - Products

https://bbrmotorsports.com/Products/Products.aspx?Prod=411-HCF-1901

BBR Motorsports is the industry's premier adult four-stroke playbike performance technology company. Engineering from the minds of racers, coupled with the latest in CAD and CNC technology, allows BBR to house one of the largest selections of innovative four-stroke MX performance parts in the world. Names from McGrath and Stanton to Costella and Abrigo dominate the nation's premier adult mini cycle races riding BBR product. BBR specializes in the Honda CRF50, Honda CRF110F, Honda CRF150F/CRF230F, Honda CRF150R, Kawasaki KLX110, and Yamaha TT-R125.

**alinel** · 06-18-2019, 08:17 PM

Re: Hero Impulse ownership experience

Originally posted by devils doom View Post

I am asking about the rear shock spring rate, Front i calculated its comes between .38kg/mm to .40kg/mm cause i dont have a big vise hence i am not able to do the rear calculation.

These are Zedling suspension pune, i am from pune only only bro have visited there place i am gonna get front fork internals from there only but rear i need dampening adjustments and that zedling doesnt have.

- Zedling has dampeneing adjustments at the piston valve for the rear shock but not externally adjustable, Valving can also can be changed by changing the shim stack.ALSO, YOU CANNOT CALCULATE SPRING RATE USING JUST A VICE FOR A COIL OVER SPRING.

You didn't tell what exactly you did on your impulse, you bored the stock impulse cylinder to 67 mm ?

And i confirmed with the guy who did job onto his impulse for the CRF 150 F BBR kit of 2006 till present, he replaced the cyclinder, piston,cam and springs.

https://bbrmotorsports.com/Products/...d=411-HCF-1901

YOU CANNOT INSTALL THE CRF150F KIT ON THE IMPULSE, WITHOUT THE KARZIMA ENGINE. the engines are totally different. You cannt replace just cyl, piston and cam. as you claim.

**devils doom** · 06-19-2019, 03:05 PM

Re: Hero Impulse ownership experience

Originally posted by alinel View Post

YOU CANNOT INSTALL THE CRF150F KIT ON THE IMPULSE, WITHOUT THE KARZIMA ENGINE. the engines are totally different. You cannt replace just cyl, piston and cam. as you claim.

Okay then you tell me what did you do, are you saying that you bought the BBR piston, cam and springs for CRF 230 which makes it 240. so have you bored the stock impulse cylinder ?

**spartacus69** · 06-25-2019, 03:46 PM

Re: Hero Impulse ownership experience

Is anyone using Timsuns? Which size is better for offroading? Was planning to invest in the 819's 90/90-19 & 110/90-17. Has anyone tried the 830's 110/80-17?

**Raakhesh Varshan** · 06-25-2019, 06:56 PM

Re: Hero Impulse ownership experience

Originally posted by spartacus69 View Post

Is anyone using Timsuns? Which size is better for offroading? Was planning to invest in the 819's 90/90-19 & 110/90-17. Has anyone tried the 830's 110/80-17?

819 is a better option and one of my friend was using it.

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