[jomson13]

DIY Sunday - Fitting of Marsh preload adjusters

Big shout out to bhpian sukiwa; Not only did he order the preload adjusters (way back in October 2022) but also came down to my place, fully prepared with the necessary tools and installed them over the weekend.

Here's the man in his element!


I recently installed handlebar risers and that made the bike ready for the front fork preload adjuster upgrade.
After some planning and rescheduling, we decided to undertake the DIY on Sunday 4th Feb.

Step 1 - The handlebar was removed and flipped over to rest on the fly screen.

Here you can see the risers and the stock fork cap



The cleaning cloth proved to be a good packing material to keep the handlebar in place



Step 2 - Removing the stock fork covers.
This proved to be a bit difficult as the stock fork covers were a bit over tightened. I had the fork oil replaced during the last service and I'm guessing that my mechanic went overboard while tightening the fork covers.
We took turns but the nut would not budge.
Eventually some wd40 was sprayed at the right places, the steering was turned to the lock position in such a way that the steering stop would provide support while we tried to undo the fork cap.
It needed a fair bit of pushing and heaving but finally we managed to get it off.

Caution - We undid both fork covers one after the other. This caused the forks to compress fully under the weight of the front end. This can be avoided by working on one fork at time.

The fork has fully compressed under the weight of the front, notice the difference in position of the triple clamp


Clearer picture, you can see the spacer jutting out from the fork


Step 3 - Fitting the fork adjusters
Since the fork was fully compressed, we had to push down the back end of the bike to extend the fork. Owing to the front heavy weight distribution of the interceptor, this is not an easy task.Sukiwa managed to push and hold the back end down while I fitted the adjuster on the RHS fork. Its a fairly easy process - you need to push down against the spring and rotate the adjuster in the fork tube until it latches onto the internal threads. Once this was done sukiwa could let go of the rear end of the bike and I continued to tighten the adjuster by hand. The spring does not offer much resistance - I could tighten more than half of the travel by hand.

Stock vs Aftermarket





The LHS fork proved to be a menace!
I could screw on the adjuster onto the RHS fork very easily but on the LHS it would not turn more than a quarter turn. It behaved as it there was something jamming the threads.
After taking turns in trying to fix the adjuster, we decided to inspect the threading. The spacer was removed and kept aside and the threads were checked. I could see some metal shavings stuck in between the threads. On the adjuster, we found that the black paint on the threads was coming off. Both threads were cleaned - first by a toothbrush and then by a cloth and then we tried fitting it onto the fork tube again.
This time we were able to get it to latch on but it was not screwing on freely like the RHS.
Nevertheless, we tightened it with a socket (M21) and proceeded.

Step 4 - Rework!!
After tightening both adjusters we realized that the LHS spacer was not put back in! So we had to redo the left hand side and this meant another 10 minutes of fighting with the fork and the adjuster. Ultimately we managed to screw it in.

LHS spacer (on the right of the image) was removed and forgotten.



To tighten the adjusters fully we had to screw in the preload adjusting nut (M14) to make space for the M21 socket which was used to tighten the adjuster onto the fork tube.
In doing so we disturbed the stock setting of the adjusters and had to spend some time in bringing both adjusters back to somewhat nearer to their stock positions. There are 6 markings on the adjusters which can be used as reference to ensure that both sides are equally adjusted.

Step 5 - Setting the sag for my weight
I had no clue how this was to be done, Sukiwa took the lead on this one and explained the process.
3 measurements were taken (Fork height was measured between front axle nut and bottom clamp)


1. Bike on main stand, front wheel off the ground - 500mm
2. Bike off main stand, rider sitting on the seat with both legs on the footpegs, forks compressed and allowed to rebound - 460mm
3. Repeat 2 but instead of compressing forks pull the forks upwards - this was missed
4. Bike off main stand, no rider - 495mm.

Sag = 1 - Avg(2,3) (Formula sourced from the internet)

Since 3 was not done, we can approximate the sag to be 40 mm
This is too much sag for a road based bike (again, based on internet reading) and it definitely needed to be reduced. The adjusting nuts were tightened so as to have 5 lines visible. The stock setting has 6 lines and some space under the 6th line visible.

This increased reading # 2 from 460 to 465mm which meant the sag has reduced to 35mm.

Current position - 5 rings visible (5th is flush with the bottom surface)




We decided to leave it at that and for me to make further adjustments after trying out the bike over varying road conditions.
I use the bike for my daily commute to office and find the following changes:
1. The front feels tighter, the very persistant khat khat sound from the front end has reduced quite a bit
2. I feel that the front wheel is staying in contact with the road surface much better now. Extremely sharp speed bumps taken at moderate speed do not feel as scary as earlier.

Further adjustments would be made over the weekend (sunday morning ride) Will update this thread from time to time.
Suggestions if any are welcome.

[Aditya]

DIY : Fitting of Marsh preload adjust on a Royal Enfield Interceptor 650 - Post moved to a new thread.

[neil.jericho]

Originally Posted by jomson13

We decided to leave it at that and for me to make further adjustments after trying out the bike over varying road conditions.
I use the bike for my daily commute to office and find the following changes:
1. The front feels tighter, the very persistant khat khat sound from the front end has reduced quite a bit
2. I feel that the front wheel is staying in contact with the road surface much better now. Extremely sharp speed bumps taken at moderate speed do not feel as scary as earlier.

Further adjustments would be made over the weekend (sunday morning ride) Will update this thread from time to time.
Suggestions if any are welcome.

jomson13, its nice to see another happy customer of the Marsh preload adjusters. I have installed them on my Royal Enfield Continental GT 535 (Royal Enfield Continental GT 535 : Ownership Review (32,000 km and 9 years)) and certainly appreciate the difference that they made to the overall riding experience. As you keep experimenting with the settings on the front, do remember to check and adjust the preload on the rear suspension as well (if necessary), to balance out the overall feel.

While the reference sag numbers are great starting points, there is nothing quite like finding the sweet spot for our individual riding preferences, based on the roads that we ride on, and the type of riding that we enjoy doing. What works for one person, may not always work equally well for the next.

Happy experimenting and looking forward to your posts on the different suspension settings.

[jomson13]

Originally Posted by neil.jericho

As you keep experimenting with the settings on the front, do remember to check and adjust the preload on the rear suspension as well (if necessary), to balance out the overall feel.

While the reference sag numbers are great starting points, there is nothing quite like finding the sweet spot for our individual riding preferences, based on the roads that we ride on, and the type of riding that we enjoy doing. What works for one person, may not always work equally well for the next.

Happy experimenting and looking forward to your posts on the different suspension settings.

Thanks Neil, the rear sag was supposed to be adjusted over the last weekend ride but that did not happen. For some reason my bike's tool kit did not have the c spanner needed to adjust the rear suspension else I would have played around with the settings already.
Will keep this thread upto date with the adjustments.

[rajeevsulu]

Congratulations on the DIY. I will be actively following this thread for the front is a little iffy on the Interceptor. It thuds, bottoms out, is sort of draggy and basically lacks proper feel.
A taut setting for the front would make the bike much more "tight".
Eagerly following this thread
Cheers

[jomson13]

The next round of adjustments were carried out over the weekend.
As always, sukiwa was available to help with his expertise and nifty tools to make the whole process enjoyable as well as quick.

Activities done:
1. Front - Take measurements again (with a proper measuring tape)
2. Rear - Measure and adjust

Measured values for the front suspension:

These were our previous measurements (no preload, bad quality tape)

1. Bike on main stand, front wheel off the ground - 500mm
2. Bike off main stand, rider sitting on the seat with both legs on the footpegs, forks compressed and allowed to rebound - 460mm
3. Repeat 2 but instead of compressing forks pull the forks upwards - this was missed
4. Bike off main stand, no rider - 495mm.

Sag = 500 - 460 = 40mm

New measurements (Preload at setting # 5, good quality tape and forks were pumped 2-3 times)
Measurements were taken between lower clamp and front axle bolt

1. Bike on side stand, front wheel off the ground - 490mm
2. Bike with rider, forks compressed and allowed to settle - 455
3. Bike with rider, forks extended and allowed to settle - 450
4. Bike on side stand, no rider - 485mm

Sag = 490 - 452.5 = 37.5mm - This is roughly 1/3rd of total travel (110mm)

No changes were made to the position of the front fork adjusters. They are at level 5.

Measured values for the rear suspension:

Measurements were taken between the suspension mounting nut (lower) and the bike frame. The suspension was at level 3. Stock setting is level 1

1. Bike on main stand, rear wheel off the ground - 360mm
2. Bike with rider, adjustment at level 3 - 325mm

Sag (before) = 360 - 325 = 35mm

Using the c spanner (courtesy surjaonwheelz), preload on the rear suspension was increased to level 4.

Measurement after adjustment:
Bike with rider, adjustment at level 4 - 330mm

Sag (after) = 360 - 330 = 30mm - This is roughly 1/3rd of total travel (88mm)

Observations:
I've ridden around 200 kms on the initial adjustment (only front) up until now.
The feedback from the road is definitely on the higher side but at the same time it feels stable and not like its going to fly off after hitting a speed bump.
The khat khat sound from the front has reduced quite a bit.

After the added preload on the rear, the bike does not bog down once its off the main stand. I couldn't notice any other difference during my morning ride to office today.

Plan for next adjustment:
Increasing preload on front by one level. Currently its at level 5, will increaese it to level 4.
This will be done sometime next week or during the weekend ride.

[jomson13]

Update / Feedback:

I ran with the first setting (Front at 5, rear at 4) for a week.
The set up does feel quite stiff and is not very comfortable but at the same time I feel that the bike is a lot more predictable and stable on the road.

New setting made last weekend (Front at 4, rear unchanged at 4, tire pressure dropped to 30/34)
I wanted to see how the front behaves if I further increased the preload hence I tightened the adjusters further so that 4 rings are visible. To make the ride a little less jarring I dropped the tire pressures by 2 psi both on the front and the rear.
I can feel the effect of the reduction in tire pressure on the performance - the bike is definitely a bit sluggish.
Ride quality is marginally better.

A noticeable difference was felt when riding with the pillion. The ride quality was much more comfortable.

I am yet to test the bike on the highway, the daily office commute and the increasing temperatures have reduced motivation for weekend rides

[Kirthy]

1. Do you have stock fork oil or have you switched to thicker grade?

2. From among these other options - Ohlins FSK 145, YSS and Way2speed, any reason why you chose Marsh? Other than the price.

3. I'd like to perfect my Interceptor front suspension as well - looking for expert advice on:

a) Spring constant - progressive vs linear (what stiffness values in N/m are preferable)
b) Damping oil - which viscosity (cSt) or which SAE grade
c) Preload adjustment - how to set correctly for rider weight and riding conditions.

Can someone with expertise or experience offer their thoughts on this? Thanks in advance.

[jomson13]

Originally Posted by Kirthy

Can someone with expertise or experience offer their thoughts on this? Thanks in advance.

1. Do you have stock fork oil or have you switched to thicker grade?
- I switched to 5W during the last change. The stock one is 2.5W. I know people who have tried 7.5 and even 10W oils

2. From among these other options - Ohlins FSK 145, YSS and Way2speed, any reason why you chose Marsh? Other than the price.
- Didn't consider any of the other makes

3. I'd like to perfect my Interceptor front suspension as well - looking for expert advice on:

a) Spring constant - progressive vs linear (what stiffness values in N/m are preferable)
b) Damping oil - which viscosity (cSt) or which SAE grade
c) Preload adjustment - how to set correctly for rider weight and riding conditions.
- No clue about A & B but for C you can find many videos on how to do this online. These serve as a good starting point, but you need to keep making minor adjustments to find what suits you best.

[dinu2506]

Query, does the Interceptor have 41mm forks? Wanted to check if these can be used for my aircooled Bonnie.

[jomson13]

Originally Posted by dinu2506

Query, does the Interceptor have 41mm forks? Wanted to check if these can be used for my aircooled Bonnie.

Yes it does, Haven't heard of anyone making such a swap - what is the reason behind you making such a consideration?

Originally Posted by Kirthy

1. Do you have stock fork oil or have you switched to thicker grade?

The fork seals started leaking a couple of weeks back and this time I have switched to a heavier oil. Will get more details today but I think its a 10W oil

[dinu2506]

Originally Posted by jomson13

Yes it does, Haven't heard of anyone making such a swap - what is the reason behind you making such a consideration?

Simple, I have been running basic preload adjusters since 2019 and over time, the main nut sort of rounded off a bit (mainly my carelessness) due to steel spanners used on the aluminium nuts. Wanted to replace with some better quality ones. Marsh looks good and if the fork size is 41mm, it should match (I'm certain the thread pitch should be pretty much standard).

By the way I'm not considering the Interceptor forks, in case you misunderstood. Wanted to see if the Marsh Preload adjusters for the Interceptor would suit the Bonnie, thats all. Bonnie also has 41mm forks, hence the ask.

My install in 2018 is there in post #1084 in the link below
https://www.team-bhp.com/forum/super...t-sold-73.html (My Triumph Bonneville. EDIT: Sold!)

[dinu2506]

The Marsh preload adjusters for the RE Interceptor got delivered couple of days back and as expected it was a straight fir for my Bonneville. Since I already had experience installing similar adjusters few years back the the same bike, I knew exactly what to do. Planned to do it today, so got everything ready by yesterday. First things first - The build quality of the March adjusters are really good, far better than what I have been running on my bike. They are heavier, built very well and the design is far superior. The Marsh adjusters are made for the Interceptor which means the existing spacer tubes can be used and it provides a 4mm additional preload than stock at stock setting. The spacer tubes of the Bonnie cannot be used in the same way as the Inty, so I calculated the length of the tube needed so that I get a 3mm softer than stock preload at softest setting and 15mm harder than stock at tightest setting. As I had done earlier, I used a 1.25inch CPVC pipe for the spacer. I have been using a similar setup last 5 years and it has held up well. When I opened the fork tops today, I could see that the earlier CPVC tubes were as good as new.
The following preparations were done beforehand
- 2 spacer tubes in CPVC of the desired length\
- 2 washers with center hole to be placed on top of the spacer tubers before the adjuster is screwed in
- The required tools
- 32mm ring spanner to tighten the Marsh adjuster
- 19mm box spanner to remove the old adjuster
- Stanley socket and allen set
- Scissor jack to push up the bike so that front wheel is off the ground and the forks are fully extended
- Rags and clothes
- White petroleum jelly to lubricate the threads before installing
- Masking of the marsh adjuster mounting nut and adjustment nut with teflon tape to prevent damage

Went about the job in the morning and could finish it in 45 minutes since everything was planned and things were in place. Really happy with the outcome especially the looks - the black adjuster with the golden stem really looks good on my black bike. Performance as expected was good and similar to what I already had. Happy to have the same performance from a made in India product of much better quality and good looks.

The process is not being explained as it is similar to the ones explained earlier in this thread.

Some pictures of the install

[nidhinpr]

Originally Posted by dinu2506

The Marsh preload adjusters for the RE Interceptor got delivered couple of days back and as expected it was a straight fir for my Bonneville. Since I already had experience installing similar adjusters few years back the the same bike, I knew exactly what to do.

The process is not being explained as it is similar to the ones explained earlier in this thread.

Some pictures of the install

I've been trying to reach out to Marsh about their preload adjusters for my ST900, but haven't received any response yet. I’m only interested in the preload adjusters and not the handlebar risers, but I can only find them selling both together as a combo. I'm unsure how to proceed and just get the adjusters. Am I missing something? Also, I plan to add progressive springs later on. Based on your experience, do you think these adjusters will fit properly once I install the springs?

[dinu2506]

Originally Posted by nidhinpr

I've been trying to reach out to Marsh about their preload adjusters for my ST900, but haven't received any response yet. I’m only interested in the preload adjusters and not the handlebar risers, but I can only find them selling both together as a combo. I'm unsure how to proceed and just get the adjusters. Am I missing something? Also, I plan to add progressive springs later on. Based on your experience, do you think these adjusters will fit properly once I install the springs?

If you do not want the risers, just get the preload adjusters for Royal Enfield. It is listed at a price of 2899. This is what I bought and installed on my Bonnie. It’ll be the same for the Street Twin as well as it has also got 41mm forks. Just check if there is space for the adjusters under your handlebar. In case there is no space you might anyway need the risers. In the Bonnie the bottom of the handlebar was slightly offset and so I did not need the risers. See the attached photo. Ideally you might also need a shorter length spacers inside else the spring might be compressed more than stock when you use the adjusters, so at the softest setting the preload will be more than stock if you use the same spacers.
This will also work well when you change the springs, just make sure you use the correct length of the spacers depending on the difference in length of the springs. In fact, I'm using progressive springs from Tec Bikeparts since the last many years