Decided on the Kraken KV5TT

[Bandit2013]

A few upgrade parts arrived before the KV5TT. Interesting design. I am pleased with the purchase. Waiting on some parts to come in to finish what I wanted to swap out. I have read through many of the build logs here on the Vekta, and want to say thank you who contributed with your build logs, comments and efforts, I found it all very helpful.

 

[PortCityRC]

Love the beast rc arms they are some chunky aluminum
Sad no more Kraken KV5TT builder kits, I wanted another.
This is my build thread, I've literally bought everything you can buy for this so if you have any questions, feel free
https://www.largescaleforums.com/threads/kraken-kv5tt-build.26015/post-316825

 

[Bandit2013]

Love the beast rc arms they are some chunky aluminum
Sad no more Kraken KV5TT builder kits, I wanted another.
This is my build thread, I've literally bought everything you can buy for this so if you have any questions, feel free
https://www.largescaleforums.com/threads/kraken-kv5tt-build.26015/post-316825

I read through your build log, that is one sic beast. Well done sir. I will not be going that far but is tempting. First time you pick one of these vehicles up, first thoughts are " I need a bigger engine". The Taylor 35CC just seems tiny on the chassis. Will see how it works out once broken in. Could always change the engine later on.

I should have the RCMAX billet front diff housing in a day or so. Found that at Detroit Performance RC. I do not mind ordering from Taylor RC UK as that was the only resource that had the front lower control arms. Too bad they do not have bronze bushing inserts like the one's for the Vekta.5 I did not see those before. May have to get a Vekta.5 LSE kit now.

https://www.taylorrc.co.uk/product-page/vekta-7075-billet-front-suspension-arm-set-4pcs

 

[Bandit2013]

Front differential housing arrived yesterday. Nice part and well made.
Just a few more components to get to complete the front end.
Time to figure out what gearing to order with the Vertigo transmission assembly.

 

[PortCityRC]

Front differential housing arrived yesterday. Nice part and well made.
Just a few more components to get to complete the front end.
Time to figure out what gearing to order with the Vertigo transmission assembly. View attachment 81319

When installing make sure your diffs are installed in the same direction or your wheels will spin opposite of eachother. Also what were you installing the Taylor 35? And do you know if you plan on upgrading the wheels, because tire size will make a difference when making a gearing selection

 

[Bandit2013]

The Taylor 35 is installed on the KV5TT chassis. Waiting on performance pipe. I did run the Tlr35 with the stock exhaust off of the 29cc engine that came with the KV5TT. Not ideal, not planning on running much until I get the better exhaust pipe and correct the clutch bell wobble (new transmission assembly).

I will most likely stick with the stock Vekta tire size. May change to DDM spoke wheels. Still thinking on that.
About the diff going in backwards, I am aware but thanks for the advice.

With the Vertigo Transmission assembly, the pinion that comes with it is a 19T. Not much information on DDM or Detroit performance website on what gears to choose. There are two that require a different pinion gear. I will settle on the 19/22 gear set to keep it stock at the moment. I can always change the gear later on.

 

[Bandit2013]

A few more parts came in this week. Expecting more to arrive.
What arrived first was ordered last. Steering components from the UK (Taylor RC shop). I would have expected to pay more due to taxes and such. The cost was actually $11 less than getting the parts separately from DDM.



DDM order was next to arrive. CVD drive shaft, Front sway bar kit, Turtle racing steering link, Vertigo bell crank and chassis support brace. Vekta alloy spindle and spindle carrier set. Could not find the upper control arms though. Out of stock in places I have searched. Front end parts for now.



Part defect on the one spindle carrier. It appears the tool jumped on the part and did not finish the mill. May have to level it by hand so the screw head can sit flush. Will determine if it is needed during assembly. The right side is a bit thicker than the left in the questionable area. Since the king pin or screw will be rotating with the spindle, may have to grind it down flat. May add a thrust bearing on the top and bottom if I do not like the fitment. Assembly is similar in some respects to the Exceed Barca such that the spindle is threaded and did not extend over the carrier. King pin screw would easily back out due to movement of the assembly.

Part is fine everywhere else. Bummer. May not be an issue. There are also two small shims. Have no clue where they need to be used. I will figure it out during the assembly process.


Also have some different wt shock oil on order. The stock suspension is too soft and seems to promote easy roll-overs. The front sway bar may help reducing that. May also look for some alternate springs for the rear. Sure, the wheelbase is on the narrow side when compared to the Vekta.5 unlimited 1500 series truck. Not looking to widen the stance any but may need to for stability improvement. Will see how change in shock oil will work out.

Debating on trimming the servo mounts from the battery box and go dual servo on the steering. Have a new 78KG AGFRC servo coming in with the other parts. I can also pull one from one of the Bajas for the second servo if needed as that is what I am using with two of them. I am sure the Kraken Servo will do fine on the Baja. Note: Seems that the Flysky Noble receivers work with the Kraken servos. At least in the short term usage so far. Dual servo should do the trick to counter the torque steer issue. I can do that mod anytime. Will try it with just the one for now.

 

[PortCityRC]

You've got some sweet upgrades there. The hub carriers I wouldn't grind them, I'd send them back to exchange though if you have the patience. These alloy bits become scarce and take months to restock. The little factory bushings must fit the hub carriers and it's a very tight finish when assembling. The ddm chrome springs listed for the KV5 are stiffer than the kv5tt springs and will stop the rear from sagging. The truck is meant to run the spares on the back, or it'll buck on rough ground or jumps. Heavier shock oil is a must, I'm running a bigbore so I'm running 70wt. We've looked around for custom springs because with all alloy upgrades, it made the truck 56lbs, unfortunately there is no aftermarket options for springs like the losi and baja. We have a couple ideas floating around the forum though for a dual rate setup
@Haric makes a super sweet upgraded alloy battery box, once you add your kill switch reciever and lipo there's not much room left in the factory plastic box, if your thinking dual servos, you'll also need the dark soul servo kit. If your looking for a one and done servo I recommend the Hitec 1005sgt or 1100wp and will need a killer rc voltage regulator and a 4s lipo. It will actually be about the same cost as dual servos. Amain hobbies is selling the servos right now and are offering a coupon code for a $25 off $250+ MAR2522

 

[Bandit2013]

Thank you for the suggestions.

I may check some other resources for springs. Die springs would be way too much but there may be some others available with different spring rates. Will have to look into the V.5 springs you recommended. Will see how change in shock oil works first.

Thought about running a smaller diameter spring over the shock shaft. Would be a pain to install though. A secondary set of shocks was another thought. Need to get the final weight before I begin making suspension changes.

 

[Bandit2013]

More goodies came in this week.

These parts should help the Taylor 35cc engine breath better.


Thought about returning the Kraken spindle carriers due to the defect on the right side. Wanted to try something out with the set I have. I found a surplus of precision ball bearings that would almost fit. They are the flanged type with a 3/8 inch outer diameter and 1/4 inch inner diameter. Good fit for the M6 cap screw. I did confirm the dimensions of the parts including the offset of the flange and extended race would not be an issue before modified the parts. After drilling, I corrected the defect on the right spindle carrier.





If this is an epic fail, I will get new spindle carriers and use the bushings from the original parts. However, I may opt for some high load lubricated flanged bushings if the ball bearings fail. I also ordered some thrust bearings earlier so I can use those to keep the screw from backing out. Had done this to another 4WD vehicle that worked out quite well. Here is an image for reference. Thrust bearings on the upper and lower bolts. I have beat the crap out of this vehicle and the thrust bearings are still in good shape, the screws have not moved yet. It was an experiment that worked out.



To improve the handling characteristics of the front assembly, here are the parts. Still waiting on the upper control arms to be stocked.


Now for the best part, the transmission. The stock unit seems to have a flaw in the clutch bell design. Perhaps it is due to the welding process of the bell to the shaft. Damn thing wobbles too much. Defect by design or lack of process control?

The vertigo transmission seems to be a much better design. Double bearings for the clutch bell. Easy to change gears. Very nice assembly. Most important, no clutch bell wobble. It runs straight and true as it should. Got two sets of gears to start with. 20/21 and 19/22. The Vertigo trans setup complete with a single set of gears will run you $398.85 (excluding shipping and taxes) and the Kraken T90 list is $429. I see that Taylor RC has the 62mm clutch bell that will fit the Vertigo trans.



Since I have to do a tear down of the KV5TT, may as well experiment with some shock oil. The short springs I may experiment with as they should fit on the shock shaft. Doubt they are long enough for the rear shocks. I have longer one's at work with a higher spring rate than those in the picture. May not make use of them. At least the Taylor RC 35CC engine is not as heavy as the larger big bore engines. I guess Die springs would do the trick but doubt you would find any with a desired load rating.



Time to tear down the KV5TT and rebuild it. This should be fun.

 

[Bandit2013]

The springs I had at work would not fit the shaft. Found some at the local hardware store. 14.3mm x 76.2mm x 1.372mm (9/16"x3"x0.054"). They seemed to have the same spring rate to the larger coil springs. May be a bad idea as they may cause wear on the shock shaft. Limits the full travel of the large spring. Dual spring with slider coupling would be better option.


I did find springs the same length, but the inner diameter was too narrow: 1 3/8" (1.375"). The minimum inner diameter of the spring needs to be 1.42" (36mm). I can find some online but have a much higher load rating (112lbs max, with a rate of 50lbs/in.)
I will have to look up the mechanics of springs, shock angle, leverage and such to determine what would work better.

 

[Bandit2013]

Sorry for lack of pictures for this post.

Started the rebuild process this weekend. Two issues I encountered with the teardown. One was with the drive shaft removal. Took a while with a heat gun to separate the uni yoke joints from the pinion shaft and the slipper shaft.

The other issue was removal of the stock bearings from the slipper shaft. They were pressed on. Not what I expected. Required complete disassembly of the slipper and use of a hammer to remove.

Test fit of the slipper shaft into the Vertigo bearings revealed the shaft diameter was oversized. I did not want to try to pry out the bearings from the Vertigo transmission plates to press fit onto the shaft. The rear shaft bearing surface measured 0.003" oversized and the front measured 0.002" oversized. Was able to grind the shaft ends down to 0.001" under for a snug fit onto the Vertigo bearings. Easy to do with a drill and sandpaper. Did a fine polish on the shaft ends with 8000 grit once I got to the desired diameter.

 

[Bandit2013]

I started on the front end rebuild. Did not take many pictures when I corrected the binding issue with the right side which was the worse of the two. I did manage to get pictures of what I did when I worked on the left side.

I had reason to run the KV5TT first before rebuilding it. The clutch bell wobble was something that needed attention. However, there were other issues with the frontend assembly that needed some attention as well. the CVD joints were binding on both left and right sides. I had to adjust servo travel to prevent the issue to the point where it had too wide of a turning radius. The CVD joint would not always bind, just under some circumstances. After running for a short period, you will see the areas making contact due to wear of the oxide coating.



I tried to get a good image of the scoring on the inside of the axle cup.



Tried to see if this issue could be fixed. The axle cup was easy. Chuck it into a drill and spin it. I did run a diamond file on the inside to remove the burs from the drilled holes and used sandpaper wadded up around a small screwdriver handle to apply pressure to the cup surface when it was spinning in the drill.





Next up was reshaping the ball end with a soft emery sanding pad on the air grinder. I did also run a small flat file in the pin slot since it was not very smooth to start with.





Had to assemble and check for binding. grind down some more and repeat. Not removing much metal from the part, just enough to improve its rotation in the cup when pinned together. After sanding and reshaping the ball end, the two front axle assemblies rotate freely with full articulation and no binding. Too bad you cannot fit a boot over the assembly to keep dirt out.



So here is the partial assembly completed. The parts fit rather well. No slop on the hinged parts, tight fit but loose enough for free movement. No shims required.



Next task is to remove the remainder of the front parts from the chassis. My thoughts on the front differential: It seems rather stiff /tight compared to the rear. Wonder if they packed it with grease or mixed-up what fluids to use in the differentials. The rear one moves effortlessly in opposing direction. I would assume you would want a higher viscosity oil in the rear to stiffen it up to behave more like a locked diff, and lower viscosity oil in the front to improve rotational speed offset when turning. Once I get the front differential freed from its plastic prison, I will have more of an idea if it is the fluid or something else that is preventing free movement. the assembly rotates well so I doubt there is any loose screws. It is when trying to rotate the outdrives in opposite direction is difficult. Will have the KV5TT back together with new parts soon enough. At least I am giving the front yard a chance to regrow. Planted grass seed three weeks ago and it is finally sprouting. The front yard became a dust pit with all of the Baja activity. Hopefully the KV5TT will be a beast after I am done with rebuilding it.

 

[Bandit2013]

I wanted to loosen up the front differential in hopes to improve steering response. Figured a lighter weight oil would help to promote different wheel speeds when turning. The stock fluid was like thick snot. It was about the same viscosity as the grease that was inside the front housing. Allowed for most of the fluid to release itself from the parts for 24 hours before reassembly. Was not concerned if some remained. Had some fresh diff oil that seemed as thick. I thinned it with a small amount of 40wt shock oil. After all that, I was able to rotate the drive cups in opposite directions. Still took some effort but not as tight as it was before.


Did not take long to get the front half of the KV5TT assembled. A few minor things to address but will get the rear assembly installed first. Then radio/battery box (going with the stock unit for now). Need to figure out how the exhaust will mount. Sort of hard to visualize it when the rear assembly is missing.

The only issue I had discovered was the brake cam. Tight fit in the Vertigo transmission. Had to remove the brake assembly to see what I can do to remedy the problem. Easy fix. Chuck the brake cam into the cordless drill and do some light grinding with sanding pad on the air tool while spinning the cam at a high speed. Followed up with some polishing and fit like a charm. Easy to move now. Before It would just get stuck or jammed.

 

[Bandit2013]

I have yet to take pictures of the final assembly. Sorry for that.

I did get some new springs as suggested by others. DDM Racing Vetka.5 chrome plated springs. Stock rate as the Vekta.5. Not the same spring rate as the KV5TT. When the new springs arrived, first thing I did was get a crude measurement of the spring rate. Easy thing to do, suspend a weight of known value and measure the compression of the spring. The rear chrome springs have a 10.5lb/in rate. Once I got the KV5TT springs off of the shocks, I measured them the same way: 7lbs/in rate. I also removed the smaller spring off of the shock shaft as I felt it did nothing to improve performance. I did not measure the front springs but there is a notable difference in spring rate from the KV5TT and Vekta.5. I also added load straps on the rear axle to keep the rear suspension from extending when turning and stopping. Much more control with the KV5TT and less rollover issue. Truck did not squat down as much under acceleration. A lower cost option than alternate springs from sources like Mcmaster-Carr or MWComponents (they sell springs, mostly closed end flat ground types with much higher spring rates). 1.42inch inner diameter and 6-to-7-inch free length as search criteria will land you several choices from 15lb/in to 51lb/in rates. If you opt for higher spring rates, expect to replace the spring retainer cups and shock ends. I doubt the plastic will hold up to higher spring rates. They will cost more than the Vekta.5 springs from DDM or other resources. At least I am no longer in the dark as to the spring rates used on the Vetka. Would have been nice if they listed that in the part descriptions.