Following a trial in the Oakland County Circuit Court, the jury determined that both defendants were liable on negligence and breach of implied warranty theories. Damages were assessed at $40,000, and plaintiff Stephen Klanseck* 1 was found to be 60% negligent, resulting in a reduction of his recovery to $16,000. Plaintiffs now appeal as of right.
On May 27, 1976, plaintiff purchased a Honda G. L. 1000 motorcycle from Anderson Sales & Service. At the time of this purchase, plaintiff had only three hours experience with a motorcycle of this size and some ten hours of experience on a dirt bike which plaintiff described as "just a little toy”.
Approximately three to four hours after plaintiff took delivery of the motorcycle, he was involved in an accident while travelling north on Telegraph Road toward his home in Flint. At this time, plaintiff was travelling at 55 miles per hour, which *79was in excess of the speed limit. Moreover, plaintiff did not possess a motorcycle operator’s endorsement on his driver’s license.
The accident occurred shortly after plaintiff noticed the motorcycle "sort of fishtailing”, whereupon he removed his hand from the throttle and applied the front brake. The motorcycle started to slide; plaintiff hit the pavement and rolled across three lanes of traffic.
Plaintiff’s wife, who was driving ahead of him in a car, stopped and transported plaintiff to St. Joseph’s Hospital in Pontiac. Plaintiff received sutures in his left arm, was x-rayed, and released. Approximately two weeks later, a fracture of plaintiff’s right wrist was diagnosed. Plaintiff also sought additional treatment to alleviate pain in his left arm and hand.
At the trial, plaintiff offered the expert testimony of O. Edward Kurt to establish his case. Mr. Kurt testified that he had discovered a short slit in the front tire tube of the motorcycle. He testified that the slit could well have been caused when the tube came into contact with the metal heads of the spokes on the front wheel rim of the motorcycle. According to Mr. Kurt, a protective rubber strip that would have prevented the slit from developing was not properly placed on the wheel rim.
The expert for defendant American Honda, Mr. Jameson, testified that he doubted that the spoke heads could create the slit found in the front tire tube. He further stated that he found no chafing in the area of the slit, which would be expected if, in fact, the tube was making contact with the spoke heads.
Other evidence will be set forth as is necessary to resolve the several issues raised by plaintiff on appeal.
*80Plaintiff first contends that the trial court erred in charging the jury that it could infer negligence on his part because he was driving the motorcycle without the proper licensing endorsement, MCL 257.312a; MSA 9.2012(1), and MCL 257.312b; MSA 9.2012(2), and since he was travelling in excess of the speed limit, MCL 257.627; MSA 9.2327. Plaintiff asserts that the claimed statutory violations do not permit an inference of negligence in this case under the Michigan Supreme Court’s holding in Zeni v Anderson, 397 Mich 117, 138, fn 2; 243 NW2d 270 (1976). There the Court said that, for a statutory violation to give rise to an inference of negligence, three conditions must be met: (1) the statute must be intended to protect against the injury involved; (2) plaintiff must be within the class intended to be protected by the statute; and (3) the evidence must be sufficient to support the conclusion that the statutory violation was a proximate cause of the occurrence.
This Court’s decision in Turri v Bozek, 79 Mich App 212; 261 NW2d 264 (1977), rev’d on other grounds 406 Mich 900; 276 NW2d 457 (1979),2 is cited by both defendants as supporting the propriety of the court’s instruction that the jury could infer negligence from the fact that plaintiff did not possess a motorcycle endorsement. In Turri, the plaintiff’s motorcycle was involved in an accident with the defendant’s camper. The court instructed the jury that plaintiff’s violation of the motorcycle license statute by plaintiff constituted negligence per se, and the jury returned a verdict of no cause of action. On appeal, plaintiff asserted that the circuit court had erred reversibly in instructing *81the jury that a violation of the motorcycle license statute would constitute negligence per se.3 This Court disagreed, noting:
"1. The motorcycle license statute is intended to protect against accidents involving motorcycles driven by persons who have not been legally recognized as competent in their operation.
"2. Plaintiff is within the class of persons intended to be protected by the statute. Under the statute plaintiff should have passed an examination which included a driving test designed to assess his competency to drive a motorcycle.
"3. Plaintiff did not submit to such an examination and this violation could properly have been considered by the jury to be a proximate cause of the accident.” Id., pp 215-216.
The Turri decision adopts the minority rule in respect to whether negligence may or must be inferred where the operator of a motor vehicle or motorcycle is not licensed. The vast majority of courts have held that a party’s lack of an operator’s license is immaterial to the issue of negligence. See, Anno: Lack of a proper automobile registration or operator’s license as evidence of operator’s negligence, 29 ALR2d 963, § 5, p 970. If Turri were the only reported Michigan decision on this question, we might be persuaded to adopt the majority rule. However, the decision in Parks v Pere Marquette R Co, 315 Mich 38, 48-49; 23 NW2d 196 (1946), is clearly at odds with the *82majority view. There, the plaintiff brought suit to recover damages for the death of his son in an automobile accident. The decedent owned the vehicle involved in the mishap. However, the vehicle was actually being driven at the time of the accident by an unlicensed minor with the decedent’s permission. The Supreme Court determined that the jury had the right to consider that the driver of the decedent’s vehicle was unlicensed, stating that it bore on the issue of the contributory negligence of the driver, which negligence, on the facts of the case, was to be imputed to the decedent. The Court specifically based its decision on the fact that an unlicensed driver who operates a motor vehicle does so in violation of statute requiring licensing. Given Parks, we believe the court’s charge to the jurors properly informed them that they could infer negligence from plaintiff’s failure to obtain a motorcycle endorsement.4
We also conclude that the trial court correctly *83instructed the jury that plaintiffs violation of the basic speed law, MCL 257.627; MSA 9.2327, would permit the jury to infer that plaintiff was negligent. In Resolute Ins Co v Marshall, 350 Mich 218, 222; 86 NW2d 313 (1957), the Supreme Court flatly stated: "It is the rule that speed in excess of the statutory speed limit is negligence per se.”5
Plaintiff next contends that the trial court erred in instructing the jury that comparative negligence would be a defense to plaintiffs breach of implied warranty theories. The Michigan Supreme Court recently held contrary to plaintiff’s position. Karl v Bryant Air Conditioning Co, 416 Mich 558, 568-569; 331 NW2d 456 (1982).
Plaintiff next asserts that this case must be reversed because the trial court’s supplemental instructions to the jury deprived him of his right to a jury of six members. During the course of deliberations, the jurors sent a note to the judge which indicated that five of them agreed on responsibility and asking whether the sixth juror should be allowed to participate in assessing damages. The trial court then proceeded to instruct the jury that the same five jurors who agreed on liability also had to agree on damages. The court did not indicate, however, that the juror who did not agree on responsibility could not participate in the deliberations on the issue of damages.
We first note that the transcript fails to reflect that the verdict was not unanimous. Following the completion of the reading of the verdict, the court asked the jurors as a group whether this was their verdict. The transcript fails to show that any juror answered in the negative. All counsel declined the *84opportunity to individually poll the jurors. Under these circumstances, we believe that this claim has not been properly preserved for appellate review. Nonetheless, we choose to use our discretionary powers to address this claim on the merits.
GCR 1963, 512.1, provides that "in civil cases, tried by six jurors, a verdict shall be received when five jurors agree”. Although it is an issue of first impression in this state as to whether this rule requires the same five jurors who agreed on liability to agree on damages, this problem has been addressed in other states. The weight of authority requires that, where less than a unanimous jury is permitted, the same jurors who agreed on liability also agree on damages. The effect of GCR 1963, 512.1 in this situation is discussed in 2 Honigman & Hawkins, Michigan Court Rules Annotated (1983 Supp), p 167, as follows:
"Where a single cause of action is submitted for general verdict, five jurors must agree upon everything that is encompassed within the verdict — i.e., both liability and damages — or there is no verdict. This conclusion is supported by decisions from several other jurisdictions having similar provisions for less than unanimous verdicts. See Bernard v Seyopp Corp, 11 AD2d 140; 202 NYS2d 707 (1960), aff’d 9 NYS2d 676; 212 NYS2d 412; 173 NE2d 235 (1961); Clark v Strain, 212 Or 357; 319 P2d 940 (1958); Hupf v State Farm Mutual Ins Co, 12 Wis 2d 176; 107 NW2d 185 (1961); contra, Ward v Weekes, 107 NJ Super 351; 258 A2d 379 (1969).”6
We adopt the majority view and decline to reverse on this basis.
Plaintiff next asserts that the trial court erred *85in instructing the jury that, if it found that plaintiff had failed to use ordinary care to minimize his damages, any portion of the damages which resulted from this failure should not be charged to defendants. Plaintiff asserts that this instruction misled the jury as there was no evidence from which the jurors could conclude that he had failed to mitigate his damages.
The duty to minimize damages includes the duty to seek and follow medical treatment which does not involve danger to life or extraordinary suffering, and which stands a high probability of being successful. See, Inter alia: Kolbas v American Boston Mining Co, 275 Mich 616, 621-622; 267 NW 751 (1936); Poikanen v Thomas Furnace Co, 226 Mich 614, 619-621; 198 NW 252 (1924); Earls v Herrick, 107 Mich App 657, 667-668; 309 NW2d 694 (1981).
In this case, the deposition testimony of Dr. Roat, who had treated plaintiff for his injuries, was presented to the jury. Dr. Roat indicated that plaintiff had refused to undergo certain diagnostic tests which he had recommended and which might well have enabled him to isolate the cause of back problems which plaintiff alleged resulted from the accident. Dr. Roat also stated that plaintiff had failed to inform him of all the symptoms he experienced as a consequence of the mishap until approximately a year after the occurrence. In our opinion, plaintiff’s refusal to undergo diagnostic tests and his failure to fully divulge his symptoms to Dr. Roat justified the trial court’s instruction on mitigation of damages.
Plaintiff next asserts that the trial court erred in dismissing his claim of breach of express warranty. We initially note that both defendants were found to be liable to plaintiff on, among others, his *86breach of implied warranty claim. Thus, allowing the express warranty claim to be submitted to the jury would not have changed the outcome in this case. Had defendants also been found liable to plaintiff for breaching an express warranty, in light of Karl v Bryant Air Conditioning, 416 Mich 558; 331 NW2d 456 (1982), they would not have been more liable than had already been found. Although the Court in Karl was concerned with whether comparative negligence was a defense, in a products liability action, to a claim based upon an alleged breach of an implied warranty, the Court’s opinion makes it clear that comparative negligence may be asserted as a defense in all products liability actions based on any theory of recovery. Karl, supra, pp 567-569. Thus, even if plaintiff was entitled to have this claim submitted to the jury, the failure to do so was clearly harmless. GCR 1963, 529.1.
In any event, we find that plaintiff unduly relies on two exhibits which he contends show that an express warranty existed. The first of these exhibits is a delivery checklist which makes no representations concerning the motorcycle’s tires and wheels with the exception of indicating that the air pressure of the tires had been checked. This hardly constituted an express warranty that the tires and wheels of the motorcycle were defect free. Plaintiff also introduced into evidence a photocopy of a sales brochure pertaining to the type of Honda motorcycle which he purchased. However, this brochure had been obtained by plaintiff from a friend, not from defendants. Thus, even if this sales material could be said to include an express warranty that the tires and wheels of the motorcycle were defect free, this warranty ran to plaintiff’s friend and not plaintiff. In any case, we are *87convinced that neither exhibit amounted to an express warranty of defect-free tires and wheels under MCL 440.2313; MSA 19.2313.
Plaintiffs final claim on appeal is that the trial court erred in denying his request for an instruction on aggravation of a pre-existing mental condition. Plaintiff contends that evidence was introduced which showed that he suffered from a latent neurological brain disorder which resulted in an organic schizophrenia as a result of the accident. Plaintiff’s expert psychiatrist, Dr. Joel Dreyer, did indeed testify that the accident may have aggravated a pre-existing mental condition. However, this testimony was based upon the assumption that plaintiff had experienced a serious blow to the head when the helmet he was wearing cracked after he fell from his motorcycle. Dr. Dreyer further testified that, if plaintiff had not suffered a head injury, the subsequent manifestation of schizophrenic symptoms would be unrelated to the accident. In fact, the testimony adduced at trial was uniform in showing that plaintiff had suffered no head trauma and that his helmet had not cracked. Since there was no evidence presented which connected the accident to plaintiffs mental condition apart from Dr. Dreyer’s testimony, which was based on an assumption not supported by the evidence produced at trial, the court properly refused to give plaintiffs requested instruction on aggravation of a pre-existing condition. See, e.g., Goggin v Peoples Transport Corp, 327 Mich 404, 409; 41 NW2d 908 (1950).
Affirmed. Defendants may tax costs.
D. F. Walsh, J., concurred.Plaintiff Steven Klanseck sustained physical injuries arising out of the incident forming the basis of this appeal, and plaintiff Karen Klanseck brought a claim for loss of consortium. For purposes of this opinion, references to "plaintiff” refer to Steven Klanseck.
Turri was reversed in light of the Michigan Supreme Court’s adoption of comparative negligence in Placek v City of Sterling Heights, 405 Mich 638; 275 NW2d 511 (1979). Thus, plaintiffs negligence would not necessarily constitute a complete defense.
Following the trial in Turri, Zeni v Anderson, 397 Mich 117; 243 NW2d 270 (1976), was decided in which the Michigan Supreme Court abandoned the view that violation of a statute constitutes negligence per se in favor of the rebuttable presumption of negligence rule now in effect. However, this change in Michigan law does not undercut the continuing vitality of the Turri holding that negligence may be inferred from the failure of a party to comply with the motorcycle license statute.
In Vogan, Torts: 1978 Annual Survey of Michigan Law, 25 Wayne L Rev 673, 684 (1979), Turri is criticized as follows:
"The logical problem with [Turri] is that the licensing statute involved does not pass the threshold requirement for applicability; it says nothing about what the plaintiff should have done under the circumstances of the accident. The licensing law only prescribes procedures and prerequisites for obtaining a license. It simply has no bearing on the operation of motorcycles. The mistake in the court’s analysis is that it ignored this preliminary issue and proceeded to analyze the statutory purpose and proximate cause aspects of the problem.” (Footnote omitted.)
Mr. Vogan distinguishes Parks from Turri on the basis that Parks was arguably a case of negligent entrustment so that the decedent’s knowlege of the operator’s incompetence was relevant in assessing the decedent’s fault. Mr. Vogan would limit Parks to its facts. However, to the extent that Mr. Vogan is correct in his assertion that the licensing law has no bearing on the operation of vehicles, neither does it have any bearing, in and of itself, as to whether one negligently entrusted a vehicle to an incompetent person. To the extent that Turri could result in the imposition of liability without fault (as Mr. Vogan fears), Parks allows this same possibility. Thus, we are not convinced that Parks can be persuasively distinguished from Turri as suggested by Mr. Vogan.
In light of Zeni, supra, violation of the statutory speed limit would raise a rebuttable presumption of negligence and would not constitute negligence per se. See fn 3, supra.
While the Honigman & Hawkins treatise is not binding on the courts, it is persuasive authority and has been cited frequently by the appellate courts. See, e.g., Cleveland-Cliffs Iron Co v First State Ins Co, 105 Mich App 487, 494, fn 2; 307 NW2d 78 (1981).