[man_of_steel]

Have been stealing some time in between my work for the Interceptor. As I mentioned before the bike seriously has some weight issues which is very much visible with the stock setup in handling and braking sides. My KTM MC upgrade was a huge success and took care of the braking side of things. Now the brake provides good initial bite and is progressive as well. So the weight is now felt way less while braking. Now, in my previous post, I have mentioned that I upgraded the fork oil and installed preload adjusters as well. I left it as it is and went looking for a solution for the death wobble. Mistake, as I didn't unlock the potential of the setup I now had.

I decided to spent some time and adjust the front and rear rider sag (suspension sag with the rider) in pursuit of a sporty and planted feel. I measured the Sag with the preload adjuster wound out all the way out (This should be pretty close to the OE measurement) and the bike was having a 39mm rider sag! That is a lot of sag even for a road setup. This along with soft springs and 2w fork oil explains why the stock bike handled like a pig. So I set out and dialed in the preload step by step and reduced it to around 28mm of rider sag. I went from 6 rings visible to only 1 ring visible during the journey from 39 to 28mm rider sag. The rear too was set up similarly below 30mm sag and I am now at the 4th step from the softest. This did make a huge impact on the handling of the bike. The bike was now stable in the corners, turned in much willingly into the corners and held the lean and line beautifully. This did make the bike stiff but is not bone jarring and everyday usability is not compromised. Infact a friend who was looking to buy an interceptor took my bike for a testride and found the front end a bit too stiff for his liking initially. He rode a stock INT650 the next day as a part of his bike hunt and just couldn't comprehend the overall feel of the stock bike in corners and then was all praises for the setup of my bike [/end of brag]. Even after all this the horrible death wobble above 80kmph persisted.

Now to the next money-well-spent mod I have done so far.. I always liked my road bikes to have 17" rims just because of the pain involved to source the tyres of my liking for any other sizes. I did expect some handling advantages too due to the smaller rims and upsized and rounded tyres. My plan was to use 110/70-17 and 150/60-17 Apollo Alpha H1s on the 650. And I was particular that I didn't want to spend too much time to try and center another bike's alloys to the INT650's forks. And IMO, aligning the disc of another bike's alloy to the stock caliper of interceptor will not center the tyre to the fork. So the only option was to use the stock hub and go for a different 17" rim and spokes. Ultimately I want excel aluminum rims on the bike, but I decided to run a trial with locally available cheap rims. So I procured 2 17" Himalayan rims and made some custom spokes to match the stock hub and new rims. After a bit of struggling voila! 17" conversion was done. Bought a set of Alpha H1s and plonked it on the new rims and she was ready to go.


Stock


After Conversion





The front end dips a bit because of the lower profile tyre so I slid down the fork by around 15mm to compensate for this a bit.



The front mudguard was having a gap after the conversion. It looked okay but I removed the front fork brace and mudguard and bolted it from below the stock mount. Worked like a charm!







I will note down my feedback in bullet points.

- The dreaded death wobble is 100% cured. The bike is now rock solid(in CAPS AND BOLD) even at triple digit speeds
- Stability at highway speeds has increased. Earlier the bike felt nervous at speeds above 80
- Flickability has increased many fold. Much eager to turn into corners now
- Holds the line beautifully once leaned in
- At slow speeds, earlier the bike had a tendency to not turn in and then suddenly used to fall into the corner. Now it handles slow speeds in a controlled and neutral manner
- ABS is working perfectly
- Ground Clearance is acceptable haven't grounded out even once in city speed bumps even with pillion

In short. Feels like an entirely different and lighter bike!

Cons
- Acceleration has taken a hit. Expected due to the increased contact patch and probably higher weight of the steel Himalayan rims. The stock excel Aluminum rims of the 650 is just top class and weighs very less
- Speedo error at almost 14% or so from the phone GPS reading
- Need wider rim for rear. Atleast 4.00 or 4.25 inch wide, the 150 section Apollo is rounded off too much. Might go for excel aluminum rims


Why I need wider rims

[RiderZone]

Originally Posted by man_of_steel

- The dreaded death wobble is 100% cured. The bike is now rock solid(in CAPS AND BOLD) even at triple digit speeds

Fantastic work! The fact that the new rims come with a free exhaust upgrade is a bonus Why the hide and seek with the rear and front mudgards though?

About the wobble issue, I wonder if the fix is down to the tire change, or if it's the combination of the rim and the tire. From what you described, the suspension upgrade alone did not get it sorted. Was there any coneset tightening involved in there too?

[man_of_steel]

Originally Posted by RiderZone

Fantastic work! The fact that the new rims come with a free exhaust upgrade is a bonus Why the hide and seek with the rear and front mudgards though?

Hehe. The mudguard goes on and off frequently based on rains. And yes, free exhaust was a good deal!

About the wobble issue, I wonder if the fix is down to the tire change, or if it's the combination of the rim and the tire. From what you described, the suspension upgrade alone did not get it sorted. Was there any coneset tightening involved in there too?

Coneset and all the bearings were the first ones to be checked thoroughly and ruled out. IMO, the increased proper contact patch did the trick.
[EDIT] Still sticking on to the recommended tyre pressure.

[sandeepmohan]

Originally Posted by man_of_steel

Even after all this the horrible death wobble above 80kmph persisted.

Can you explain what this is? Not that I have not experienced this but calling it a "death wobble" seems a bit much and my bike is bone stock, so the problem should be pronounced. I face a wobble on certain kinds of road surfaces, where there is no tar to seal the stones. Its only under this condition where the bike isn't happy. Otherwise, 100 and above feels absolutely stable.

I see you've made suspension, tire and rim modification changes to help with this problem.

[man_of_steel]

Quoting an earlier post of mine.

Originally Posted by man_of_steel

...Right from the moment I took a test ride of this particular bike before buying, something felt very very wrong with the front end of the bike along with a prominent wobble from the front end which translated to a tankslapper when you take the hands off the bar even for a second!

Earlier the wobble was there when hands were taken off the bars at even city speeds. After wheel truing the wobble reduced a bit and then was present only after 80kmph. This happens when you take the hands off the bars for even a second and the whole front end slaps from side to side violently. The wobble was also felt slightly while engine braking.

Originally Posted by sandeepmohan

I see you've made suspension, tire and rim modification changes to help with this problem.

Nope. Suspension mods didn't even make a difference in the wobble. It was the tyre change and rim conversion that fixed it for me.

[Aditya]

17" wheels conversion on my Royal Enfield Interceptor 650 - posts moved to a new thread.

[shaikhmimran]

Those are great purposeful mods & sharing them here in detail for fellow owners & certain fence sitters is a very kind gesture. Also saw that you penned down the post mod feedback in "bullet" points !!
With your knowledge & expert resources at MotoNerdz, I am sure you will keep leveraging the 650 twin platform thoroughly.

[CarManMotorcycl]

Originally Posted by man_of_steel

- Need wider rim for rear. Atleast 4.00 or 4.25 inch wide, the 150 section Apollo is rounded off too much. Might go for excel aluminum rims

Hi, now that you are using the Himalayan rims, the unsprung mass has gained a lot compared to our stock alluminium rims. What size tubes did you use when you changed to 17s? I used 120/80 for both front and rear, but the front was giving us a tough time.

I have also changed my stock rims to some local Mild Steel 17 inch rims but they started to rust in under 6 months, so I bought alluminium rims from Dismotech because I couldn't find anybody who sells 4.00 17s Excel rims.

[man_of_steel]

Originally Posted by shaikhmimran

T.. Also saw that you penned down the post mod feedback in "bullet" points !!

You caught that, didn't you!

Originally Posted by CarManMotorcycl

What size tubes did you use when you changed to 17s? I used 120/80 for both front and rear, but the front was giving us a tough time.

Yes, the unsprung mass has gone up quite a bit. I got 110-17 and 140-17 tubes.

[r_nairtvm]

Originally Posted by man_of_steel

The front mudguard was having a gap after the conversion. It looked okay but I removed the front fork brace and mudguard and bolted it from below the stock mount. Worked like a charm!

Nice innovative thinking.

Nicely done without affecting stock looks

Best Regards & Happy Miles ahead

[man_of_steel]

Originally Posted by r_nairtvm

Nice innovative thinking.

Nicely done without affecting stock looks

Best Regards & Happy Miles ahead

Thank you sir! That was indeed a suggestion from one of my guys.

[DH82 Tiger Moth]

Awesome work and post, man_of_steel.

I've been following your posts on the mods to your interceptor and learning so much! On a side note, the Royal Enfield twins and the Himalayan may have their fair share of niggles but they have brought so much value to the community of bikers that like tinkering with and modding their bikes, that it actually has spurned so much of a learning and exchange of knowledge in the process. There's nothing like finding solutions to mechanical problems and getting a vehicle (2,3 and 4+ wheels) dialled in the way you like it to suit your needs.

Really cool work and thanks for sharing with the rest of use out here. Happy and safe riding and look forward to reading more on your work on the bike as you go along.

Stay well and safe!

[ambarkhan]

Originally Posted by man_of_steel

- The dreaded death wobble is 100% cured. The bike is now rocking solid(in CAPS AND BOLD) even at triple-digit speeds

I have experienced Tank Slappers a few times but only during the fast straight sections in rally stages, and basically, they were zeroed down to going too fast for the suspension capability (Himalayan with stock suspension).

During my research I have found; Tank Slappers have probably one accepted mainstream solution Steering Dampers.

Originally Posted by man_of_steel

removed the front fork brace and mudguard and bolted it from below

Changing your fork brace location might have helped. People often added them on offroad bikes for additional stability in front.

Were you running different sizes of tyres in the back or front instead of OEM Pirellis?
If not what I suspect is there was some bad component in your stock setup
My guesses were uneven worn tyres, bent rims or loose spoke. It's not uncommon for dealerships to ignore them on PDI.
Also when you remove your forks next time check if they both react similarly when compressed if not please change springs inside them.

[Mr.Perera]

This is Fantastic. I really like the new 650s from RE. Have ridden the Interceptor quite a lot and I found the front end to be very vague. I guess this should fix the problems, really appreciate the effort you took !

[man_of_steel]

Originally Posted by ambarkhan

I have experienced Tank Slappers a few times but only during the fast straight sections in rally stages, and basically, they were zeroed down to going too fast for the suspension capability (Himalayan with stock suspension).

This is nowhere close to that! The wobbling issue used to occur at city and low highway speeds. This video 01:30 minute shows the exact issue I was facing (All credits to the creator of the video).

https://www.youtube.com/watch?v=UW5ij9VCxdU

During my research I have found; Tank Slappers have probably one accepted mainstream solution Steering Dampers.
Changing your fork brace location might have helped. People often added them on offroad bikes for additional stability in front.

Yes, But I wanted to try and eliminate the problem without a damper. And I tested the bike after conversion with the brace at stock position and then the relocated position. Felt exactly the same in both scenarios.

Were you running different sizes of tyres in the back or front instead of OEM Pirellis?
If not what I suspect is there was some bad component in your stock setup
My guesses were uneven worn tyres, bent rims or loose spoke. It's not uncommon for dealerships to ignore them on PDI.
Also when you remove your forks next time check if they both react similarly when compressed if not please change springs inside them.

They were stock Pirellis. All other components were checked including bearings, cone set, swingarm bushes and also did wheel truing.